Willis Hames: Well we're at 7:59am and you are in D3 session one southern appalachian and analysis terrains part one, we have 11 presentations today a full morning and then an afternoon.
Willis Hames: To a company that will be that will be quite full i'd like to remind everyone that this is arise events, we wish to encourage the respect and protocol for proper professional meeting into include.
Willis Hames: Of be inclusive, we speak up and act responsibility if there are any things that we might wish to report there are mechanisms to do that, but for the most part we're very grateful to.
Willis Hames: Be here just have the chance to speak to share science and and talk about technology to get us rolling with that this morning, I have a presentation by Dr Thomas that i'm going to share on my screen.
Willis Hames: Dr Thomas really needs no introduction for our for.
Willis Hames: The.
Willis Hames: He.
Willis Hames: Is an emeritus Professor from the University University of Kentucky and is with the geological survey of Alabama presently.
Willis Hames: his introductory remarks, the whole of the origin from the crystal an intern Ides to the cemetery for Ireland, the presentation will take a little bit over 20 minutes and we're on schedule and move again this now it's a pre recorded presentation.
Willis Hames: decision to do consider the whole the origin Crystal and, in turn, is sentiment for land, while we work on specific areas and by a specialized research techniques it's important to keep in mind the context of the whole of the origin, as well as the integration all the types of.
Willis Hames: How began with the Assembly any credible origin which we.
Willis Hames: recognize and click multiple episodes.
Willis Hames: The island plastic cited leverage and Asian external management safes here.
Willis Hames: rebel basement marks on the basis of your ministry in here delegate have an interest in with the interior rigid.
Willis Hames: And suggested that these vertical rocks are Amazonian you're applying a Center which may be the New York Alabama like Nick layman.
Willis Hames: In England is so strongly expressed in a paramedic Maya.
Willis Hames: Using.
Willis Hames: Paleo polar wonder data.
Willis Hames: Amazonia between about 1200 and 1159 very good sentence don't strike slip past the margin per region, perhaps really knocks and parts of the census and leverage and generating the suture between Amazonia.
Willis Hames: Turning next to the history of the breakup of everything and opening the evidence ocean Center igneous rocks at radiation about the numbers and read their, ranging from 765 to 30 am a.
Willis Hames: Senior settlement accumulated on long words and greater thicknesses in the areas as isolated here in blue.
Willis Hames: Similar settlement also accumulated in the nervous.
Willis Hames: system.
Willis Hames: That similar sentiment and sources potentially from all of the interior orange included various broken promises.
Willis Hames: That being attended across I can see here the unconformity at the top of the.
Willis Hames: precambrian basement with various parameters from superior to wrangle.
Willis Hames: which were available to supply sediment to the Center of garbage along with that margin knowledge we're also reject the best in ref dignitas rocks the transgressing passing warranted sandstone.
Willis Hames: rework the predators from across the.
Willis Hames: unconformity and subsequently sand in inner layers within the carbon a Shell faces.
Willis Hames: We have been derived from the same sources said, certainly reaching out to the.
Willis Hames: supermarket shelf edge was transported down the slope and her eyes.
Willis Hames: And all of the systems that were available to be incorporated in the organic milk when collisions occurred.
Willis Hames: Well, this model on design with ages of the comic shows that collisions between either art director drains or.
Willis Hames: Created continental arrangements content margin arcs generated and accretionary prison or retro Arc first will depending on the polarity of seduction and these in turn graded a tectonic load that produced.
Willis Hames: fletcher subsides, for I basin, which was filmed the settlement it routed from the organic uplift.
Willis Hames: alone with angels for the allegheny suggested allocation.
Willis Hames: So much in the plastic word is in the fall and basing were derived from basement rocks as well as the Center of sedimentary marks and piracy market sentiment.
Willis Hames: And for the economy pathak medicine, a metric Marxism those acadian ones and the synthetic classic legends associated with the College competed.
Willis Hames: In the allegation for land and any sin we're doing settlement is not well represented.
Willis Hames: Nor is.
Willis Hames: Creating terrains boss testing.
Willis Hames: In praying into that we reduced it somewhere in this part of the word into the tournament was restricted to these ideas going out into the game classic which.
Willis Hames: know if we look at the.
Willis Hames: Information here, including the appalachian trust mountain the appalachian nation.
Willis Hames: Always recognized within that.
Willis Hames: Two major classic wedges about jump pottsville classic which centered on the Pennsylvania say lead program did Southwest work during the mississippian.
Willis Hames: And to the Northwest and they are pennsylvanian the paint the plastic words in Tennessee salient began modesty in a Mississippi and probe narrated for the North during Pennsylvania in the permian basin.
Willis Hames: During the early pennsylvanian wanted to monitor any system formula this department that logic like basic terms like settlement toward the southwest.
Willis Hames: Now, if we look at the composition of the classic were just.
Willis Hames: 29 samples 30 764 to try to check on Greens are only seven of those range that represent the elegant in numerous green to represent acadian mechanic.
Willis Hames: relatively little sentiment comes from God wanting to rains very apprehensive trucks and later contribution no problem lots of bramble age.
Willis Hames: older than granville a smattering of ages scattered through various provinces intervention and this window, either from older enclaves within the.
Willis Hames: range or problem recycling Center have said that these this distribution to suggest we can call them appalachian sitting the girl for identifying avalanche and detritus further out onto the krypton.
Willis Hames: Thinking more detailed look at the.
Willis Hames: appalachian signature.
Willis Hames: This is a multi dimensional scaling plot, in which the samples that have wishing with Colonel click on distribution spot or puts it together.
Willis Hames: And as you could see using colors came for cream for the other parts of the classic which.
Willis Hames: song plot in this area over the accepted one outlier here.
Willis Hames: Similarly, in change it reoccur there are more parts of the macho pottsville classic which other mostly concentrated in this area within a couple of outliers here.
Willis Hames: And then I use a great home for the longitudinal very generic pennsylvanian.
Willis Hames: know.
Willis Hames: The samples plot generally with the launch of pottsville signing books gaining as much as possible classic, which was the source for.
Willis Hames: The longitudinal drainage, and this suggests that we need to and thinking about so we currently pour it out on to the CRATE on we may need to look separately, we are the macho culture classic which.
Willis Hames: You know, turning into the coastal plain on.
Willis Hames: Alabama where.
Willis Hames: They disappear from view.
Willis Hames: We can recognize a crystal Internet chair a MOD and the settlement for land in the appalachian mountains like where bison when I first moved to Alabama 1963 started to work on mississippians cryptography here.
Willis Hames: In my intent was to.
Willis Hames: find a distribution of plastic settlement from.
Willis Hames: Ruby from the people and the approximate.
Willis Hames: Distribution and therefore land.
Willis Hames: On three or four sections in the Atlantic.
Willis Hames: ocean wills snowbird which is.
Willis Hames: The boundary between close to contaminate tracy's strike roughly perpendicular to appalachian stroke, to strike with plastic box number Southwest in carbonate marks to the Northeast.
Willis Hames: The session today will consider the whole of the origin Crystal and Internet instead of metric for land.
Willis Hames: While we work on specific areas and by a specialized research techniques it's important to keep in mind the context of the whole of the origin, as well as the integration all the types of data.
Willis Hames: began with the assembly or any other group of origin which we.
Willis Hames: recognize include multiple episodes.
Willis Hames: The island plastic side of the blue Ridge and Jason external safes here.
Willis Hames: revelation marks on the basis of the Ministry.
Willis Hames: have been contrasted with the removal of Interior Richard.
Ryan McAleer: A bell that the talk restarted.
Willis Hames: of each vertical rocks or Amazonian implying a Center which may be to New York, no, no, like magic Lehman.
Willis Hames: In England is so strongly expressed in a.
Willis Hames: lab.
Willis Hames: easy.
Willis Hames: Paleo polar wonder data.
Willis Hames: Amazonia between about.
Willis Hames: Strikes it past the margin per region.
Willis Hames: Really knocks invert the sentence and leverage in generating the Center between Amazonia and.
Willis Hames: turn.
Willis Hames: up, let me pause for a moment to talk restart.
Arthur Merschat: Yes.
Willis Hames: i'm not sure fine.
Willis Hames: If anybody has a suggestion as to fly.
Willis Hames: I believe we were.
mark carter: right back back just move that deal.
Willis Hames: Thank you suck my apologies let's.
mark carter: back up here.
Willis Hames: This is an alien geologic man premise is.
Willis Hames: based on real data.
Willis Hames: credentials are used to construct this now the avalanche interest to retrace blissed out from the outcrops into Mississippi soon really watch it on Western countries in your crops in Arkansas.
Willis Hames: Around to eastern Mississippi where the wash it answers from is predicated by the number appalachian trust falls.
Willis Hames: it's also important to note that the tracer the ramayana on Washington terrace trend is such a parallel with his face each founder described earlier.
Willis Hames: Review feeling for the beta the wounded us reconstruction of.
Willis Hames: The light code black lines, here are some reflection profiles for us primarily tracing out the structure.
Willis Hames: Also, numerous wheels, as you can see, increasing the threshold this cluster of small black dots here represents the wells that we introduced and putting together graphics to the east of the Mississippi and that's when it drops in my water basin.
Willis Hames: Now, looking at the top of every Christian basement rocks.
Willis Hames: At South by Southwest.
Willis Hames: Washington restaurant not too much toward the southeastern on the southeast Asia Southeast Asian falls underneath the appalachian trail so it's quite clear, the debasement production wash it off for us from here.
Willis Hames: And now, Australia, at the Cross section on this line, which is perpendicular to the Washington was parallel and you have watch.
Willis Hames: The shows primarily progressive thinking into the southwest into mason my.
Willis Hames: Church, which.
Willis Hames: which threatens marching sandstone which branches out into carbonate finishes to the Northeast class equations to this list.
Willis Hames: This is an isolated my up, based on those external exceptions out go to North Alabama and onto the appalachian first world it's very small wells in this area and on geologic maybe this merry.
Willis Hames: The point is to show a Southwestern pinch on the sandstone and northeast corridor limited set in stone, but also a South Eastern limit because it.
Willis Hames: Is not per se remote parts build structures.
Willis Hames: looking into the internal patients with an artichoke.
Willis Hames: course on the water no angle cross nominations are labeled here in the age, and these are difficult beach bases symptoms are wavering work.
Willis Hames: On We also found log log and stump fossils some trees are registering.
Willis Hames: In this area, here we interpret this to be part of a barrier flat low barrier island system is facing similar to the Northeast.
Willis Hames: across many directions here indicate wave break on to their own in here on the South in stand strong se recording tension coach but it's in beta launch or drift along very around the southeast and.
Willis Hames: So.
Willis Hames: On reconstruction very around southeast shelburne bars and carbonates to northeast.
Willis Hames: and move up to the upper Mississippi Bangor limestone children would show faces.
Willis Hames: Southwest nip in the bud carbonate re open open.
Willis Hames: Back at the total.
Willis Hames: This is a cross section moonstone will loans children spontaneous potential resisted occur for worlds, the dark shading these whales chose rails, for which we describe the girl cuttings to give details to the theology this isn't an analytic range don't.
Willis Hames: The kosher Green Card annotations are here my.
Willis Hames: son, as well as thin and read into money face installing the southwest in the thing into black shield the to.
Willis Hames: This is overlay man for what jail and then by the partner information which is a succession of course Albert pair sequences for him stem major interpreted to be available for faces and, as you can see the progress toward the ne ne.
Willis Hames: ne tracy's there's one very extension on carbonate punctuates system.
Willis Hames: or more.
Willis Hames: pair sequence listen to these in the ballpark.
Willis Hames: In terms of map distribution, which could be mountainous area.
Willis Hames: counters show the thinning of the coordinate ramp to the southwest and then the area like shale.
Willis Hames: Importantly, we can also recognize these faces in the appalachian first wheelchair.
Willis Hames: spastic with a patient carbonate tracy's northeast of replacement showing faces on the southwest indicating that the faces that we see more information extends into pilot faster pre location, they trust me.
Willis Hames: And i'll refer to all this, as the creator black nation, which included the legend terrestrial.
Willis Hames: So geographically instruction sheet she don't take sandstone.
Willis Hames: front deposits Atlantic onto the show the show preseason action.
Willis Hames: Now, moving into the upper part of the section we're punching my new.
Willis Hames: House very your holidays is more things too much stone and belt extension to kind of prepare sequences now for a.
Willis Hames: Little.
Willis Hames: bit.
Willis Hames: On the electrical entrepreneur on a red dash mind at the baseline so to continue to function and spontaneous potential career indicating these masks and stones.
Willis Hames: These are the fiction and stuff that we see on the caption.
Willis Hames: For the rest, milestones connection here notice that the spontaneous potential burgers does not hundred away from me.
Willis Hames: Jay baseline.
Willis Hames: through several hundred feet of section in the film for the Western Mississippi.
Willis Hames: fanning upward pair sequences there's no short basis, these are sandstorms some this court variables, as indicated alone.
Willis Hames: and
Willis Hames: The succession of these.
Willis Hames: The distributor proceed so plot location to answer it takes them to a.
Willis Hames: Separate location.
Willis Hames: and spacing much don't preseason and very talented and stones and the appalachian trust world are mostly barrier islands and stones, but when the oil here in the columns inclined impaled festive occasion the same face as an intern very relman sands.
Willis Hames: Indicating the same pattern that much interest, as in the microwave.
Willis Hames: And so, in pain your your graphic restoration.
Willis Hames: i'll take finishes.
Willis Hames: You bear on complex and.
Willis Hames: The upper bus does not have distinctive period massive very.
Willis Hames: Relatively thinner they'll take deposits at some smaller barrier island finishes was a very extensive trump's amaze these deposition sides of the commercial code that also predicts cope with nothing and Mike were racing when very interesting well here.
Willis Hames: build a volcanic ash, but in no difference and stones on the upper pottsville this engine or not hard on a single man May.
Willis Hames: indicate our organism contemporaneous with this bird podge still.
Willis Hames: looking into sandstone photography in the sense barrier islands and stones in the hearts open pottsville.
Willis Hames: Our quarter grenades nearly 100% porch but the bill take sense don't department in particular litigator and I.
Willis Hames: Think cranes include better Pilates fully, of course, Michael box.
Willis Hames: sure.
Willis Hames: texture the Church in.
Willis Hames: order to.
Willis Hames: Change.
Willis Hames: which indicate.
Willis Hames: authentic source.
Willis Hames: And it's important to notice, too, that the mechanic ran into him the church range proportionally increase upward inflection tripper wouldn't approach.
Willis Hames: So we.
Willis Hames: Would all of.
Willis Hames: That letter.
Willis Hames: For the flood water basin Alabama promontory.
Willis Hames: Before the initiation of technology, moving forward and basin carbonite Shell from before that it was removed margin, so we have here the space for accumulation of.
Willis Hames: reverted merging.
Willis Hames: deposits off the shelf derived from Lee continental crust of North America, as I described earlier for the appalachians than the emotional carbonite children's your parent in at some point.
Willis Hames: That position of the chronic plastic settlement may have made its way out to the carbonite shelf and and off into the deep water, and this is also decided, because of the quarter Church, which is the archives on the vacuum that.
Willis Hames: In the plastic surgery population and so as a.
Willis Hames: accretionary prism Arc approach to cognitive chills and the collision.
Willis Hames: ballooning North American continent crushed.
Willis Hames: The Arc accretionary prison planet around driving the wash it off first build and providing settlement to the foreign nation in the classic which.
Willis Hames: indicated here chillers for preparation of the park when they'll take system.
Willis Hames: At the.
Willis Hames: Virtual goods last year one presentation presented comparing the current ver conch populations from a jack forks and stone and wash it off with the popsicles and stones in Alabama indicated that these are so similar.
Willis Hames: indication to.
Willis Hames: Come settlement source which was interpreted in the southern appalachian Tina suggestion was so concerned it.
Willis Hames: Was transport, it was for the cost of like order basin.
Willis Hames: In contrast to the data supply that mothers.
Willis Hames: and enter of the wash it off.
Willis Hames: Now.
Willis Hames: commendation all data can be used here.
Willis Hames: This interesting a sedimentary metamorphic and volcanic province provenance on the southwest moving rice's pronunciation plastic settlement northeast put into blackboard basin.
Willis Hames: And at the same time.
Willis Hames: The spiritual urbanites into the deep water of the.
Willis Hames: system consistent with your current asked does.
Willis Hames: This accommodates the other than your current data and pay the graphic reconstruction to the whiteboard animation as well as the symmetric cryptography.
Willis Hames: So oh without sort of representation of the coordination of home the raw data i'd like to say forward to an exciting program during the day today.
Arthur Merschat: amazing introduction by by Bill Thomas to really help set the set the whole day for everything so.
Arthur Merschat: Really really helped me trying to get again looking at both the hinterland for land and not just for that parts of the appalachians to the watchtowers an excellent start to this morning, and so I guess with that we're we're pretty close on a little bit behind on time.
Arthur Merschat: Well i'll try we'll try to keep time so I may do this five minutes for when you have 15 we have 15 minutes.
Arthur Merschat: I got three minutes 17 Minutes should be hopefully time we're all finishing up at 77 there'll be at 17 minutes and then after that.
Arthur Merschat: You know we'll have to hit 20 minutes let's try to stop the just to keep on time, but you know try, we see three minutes really be wrapping up so they can be time for questions or anything else, and just chat.
Arthur Merschat: The again chat like everything put a question in the chat we're just also say.
Arthur Merschat: I have a question on and then we'll try to also let you unmute and ask your question, if you feel comfortable good good, well, I just have us all interact with it.
Arthur Merschat: And so, with that we'll go ahead and move to our our next talks which is uranium alleged chronology and lead isotopic.
Arthur Merschat: evidence in support of the exotic Mars hill train transfer hypothesis compelling links between southeastern lorenza in the Paraguay katana Southwestern Amazonia presented by David mocha.
Dave Moecher Univ. Kentucky: hi good morning everyone good to see everybody i'm going to mute my video just because I had my signal is unstable every so often and that will reduce the possibility of things screen up and i'm.
Todd LaMaskin: going to.
Dave Moecher Univ. Kentucky: share my screen here.
Dave Moecher Univ. Kentucky: All right, everything we got that.
Dave Moecher Univ. Kentucky: Are there and see that.
Dave Moecher Univ. Kentucky: Hello Arthur we see that.
Ryan McAleer: yeah we see it.
Dave Moecher Univ. Kentucky: Okay yeah so i'm going to pick up actually where bill started and go back in.
Dave Moecher Univ. Kentucky: Time to the even.
Dave Moecher Univ. Kentucky: Earlier evolution of the southeastern wrench in margin before granville collision between laurentian Amazonia and the what i'm presenting today is presented published recently and American Journal of science.
Dave Moecher Univ. Kentucky: So you can take a look at that for.
Dave Moecher Univ. Kentucky: Further details, so the.
Dave Moecher Univ. Kentucky: The exotic Mars hill terrain hypothesis relates to the ultimate origin of southeastern lynch including South central appalachian basement.
Dave Moecher Univ. Kentucky: And it's been referred to as either an exotic or an orphan block that ultimately was derived from Amazonia so the This concludes the basement rock shown in blue here and that's what we're going to focus on a little bit later in the talk, but the basis for this hypothesis is that.
Dave Moecher Univ. Kentucky: Based on lead isotopes there's a clear distinction between the lead isotope composition of rocks that comprise the Amazonian cray Tom shown and yellows and Greens.
Dave Moecher Univ. Kentucky: And those from lauren she has shown and reds and whites and the differences, primarily in the amount of that ratio of lead 207 and the.
Dave Moecher Univ. Kentucky: Did this difference had to have been a very, very early.
Dave Moecher Univ. Kentucky: difference that arose between the two creighton's in there with a spirit sources earlier in earth history, because those differences are so distinct and they're Long live.
Dave Moecher Univ. Kentucky: Okay, so this has been known for quite a while the data sources are there in the lower left and this led to the idea that the basement of southeastern Virginia has a.
Dave Moecher Univ. Kentucky: southeastern lunch yet is either Amazonian or laurentian and that there's a boundary in here, that is a lead geochemical boundary, but it must be a.
Dave Moecher Univ. Kentucky: Also, a terrain boundary that was established pretty early on.
Dave Moecher Univ. Kentucky: There are the oldest rocks in northeastern Eldoret excuse me in the northeast in the US and we're unsure about 1.35 billion years old, those aren't present both in Vermont and New Jersey.
Dave Moecher Univ. Kentucky: And we're going to show you today that those old rocks and even even older crystal component is present in the southeastern appalachians.
Dave Moecher Univ. Kentucky: So the original idea for this old basement component in the southeastern in the southern appalachians was the work of Calvin Miller and his group and Bob hatcher.
Dave Moecher Univ. Kentucky: published by chuck kerrigan here and they were they found it micro prob ages that were really pretty old and some of the rocks from the road mountain area in western North Carolina.
Dave Moecher Univ. Kentucky: And what they found were ages of uranium lead ages that tend to spread along Concordia.
Dave Moecher Univ. Kentucky: And the carver's gab granular Nice was interpreted as a Meta Platonic rock and so these nice upper intercept for this spread of ages was interpreted as the age.
Dave Moecher Univ. Kentucky: Of the oldest igneous rocks it turns out that well the additional evidence for the ancient heritage of these rocks is there neodymium isotope compositions that are all.
Dave Moecher Univ. Kentucky: evolved and not juvenile so there's this crystal component thing could be as old as 1.8 billion years old subsequently line a cough and others.
Dave Moecher Univ. Kentucky: went back and dated more of these are cons and the carver's graph carver's gap granular Nice.
Dave Moecher Univ. Kentucky: And they did decided, based on the morphology of the zircons and the age distribution that you see here that this has to be another sedimentary rock not many igneous rock and the important aspects are there's these old age.
Dave Moecher Univ. Kentucky: old age components that are 16 to 1800 million years old there's also this 1320 age component and then they also found that there are a lot of metamorphic agents, so these rocks were older than.
Dave Moecher Univ. Kentucky: neoproterozoic and that they were metamorphose probably during the auto and or rigoletto phase of grenville or a genesis.
Dave Moecher Univ. Kentucky: So what we've been doing over the last couple decades is looking at the rocks in the Dell what area of the southwest French broad massif.
Dave Moecher Univ. Kentucky: Here shown in the white box, the Dell what area was mapped by handling Goldsmith and we map by southworth at all, and the geology is shown here.
Dave Moecher Univ. Kentucky: The important components are the oldest components, and this was recognized by handling Goldsmith early on that the oldest components include to mythologies the.
Dave Moecher Univ. Kentucky: Horn blend nice shown in pink and the bio tight Nice is shown in grey the Oregon Nice and gratitude Nice, these are your typical grenville age showing again in Ottawa and Meta.
Dave Moecher Univ. Kentucky: metamorphosed igneous rocks that also have auto in and read the Latin metamorphosis in there, those rocks were in the neoproterozoic recovered by the yoko a supergroup and then.
Dave Moecher Univ. Kentucky: underwent to conduct regional and civilized face she's metamorphic ISM this entire area has been an upper and civilized face she's and the.
Dave Moecher Univ. Kentucky: Meta Meta sedimentary rocks are.
Dave Moecher Univ. Kentucky: magnetites and then the final phase of defamation and these rocks was in the Neil kayden delegation and that's mostly responsible for the folds that you see here, so this is an incredibly complex geologic history that has to be sorted out very carefully.
Dave Moecher Univ. Kentucky: And the key with the logic discoveries that we made over the years, where the was the presence of this.
Dave Moecher Univ. Kentucky: What will call 1.33 billion year old or a nice and it's seamless that it contains, most of the rocks in the Dell would quarter highly deformed.
Dave Moecher Univ. Kentucky: And some of their deformed equivalence are shown on the right.
Dave Moecher Univ. Kentucky: And so, if we hadn't seen this outcrop this was sort of the rosetta stone outcrop for us, you wouldn't have been able to interpret some of the other mythologies now these analysts are present.
Dave Moecher Univ. Kentucky: In undefined and under form versions and so those same rocks are also deformed here Okay, and this is typically what the organizers look like and the Dell would quad and so.
Dave Moecher Univ. Kentucky: From this we were able to focus then on the geo chronology of these least deformed basement rocks and the Dell would quadrangle.
Dave Moecher Univ. Kentucky: The biotech nice's our magnetic metal, plastic rocks and we included them in our analysis and they were all mapped as one unit, but as we'll see they turn out to be two different Meta classic pathology.
Dave Moecher Univ. Kentucky: here's some of the geo chronology for these basement rocks the discordant arrays just like you saw at Rome mountain tend to have upper intercepts and clusters that are around 1325 and are 1335 or so.
Dave Moecher Univ. Kentucky: The there is an old age component in them as well, you can see some inherited zircons and here's a deformed.
Dave Moecher Univ. Kentucky: ortho Nice that was metamorphose during the auto one has big thick auto and overgrowth on the 1.3 billion year old metamorphic course.
Dave Moecher Univ. Kentucky: And then the xena lists are roughly the same age to slightly older so here's this, this is the the old age component, then that corresponds in age to the oldest age component that we see on the left hand side of that lead isotope line.
Dave Moecher Univ. Kentucky: Looking at so we've got the Horn blend nice's then that are 1.352 1.3 billion years old, and the next thing to look at, then, is these politik paradises so excuse me.
Dave Moecher Univ. Kentucky: we're going to look at these bio titan ISIS and take those apart.
Dave Moecher Univ. Kentucky: So here's a magnetic rock on the left, you would you would look at that and go well i'm not quite sure what the protocol, it was, but we.
Dave Moecher Univ. Kentucky: took the approach that these are Meta classic rocks and even though there are really high metamorphic grade we're going to treat them as a large and the titles are con sample and in which we're going to.
Dave Moecher Univ. Kentucky: interrogate as many of the zircons as possible for their zoning and age history so on top there you see one of the samples.
Dave Moecher Univ. Kentucky: And the different ages successively younger ages of detritus zircons, all of which have these very thick overgrowth so here's a core and a thick metamorphic overgrowth.
Dave Moecher Univ. Kentucky: And so we, in some cases we dated the metamorphic morphic overgrowth and come some cases we did the course and on the left, then, is the title certain age histogram.
Dave Moecher Univ. Kentucky: For this particular sample and the really important thing to focus on is the abundance of these really old agents.
Dave Moecher Univ. Kentucky: Okay, and those old ages and then also a major age component, that is, about 1340 and age and then some of these older age components that we would assigned to the elza variant.
Dave Moecher Univ. Kentucky: phase of early grenville or a genesis the ages of all those metamorphic grains well here's the other sample shown on the bottom two samples, and here again we've got this major.
Dave Moecher Univ. Kentucky: 16 to 19 1.6 1.9 billion year old plastic component with metamorphic overgrowth is major 1310 or so age component very little of the granville age component and in this particular sample a lot of peconic overgrowth.
Dave Moecher Univ. Kentucky: So these are the ages this very distinct age mode is the age of metamorphic ISM during the auto and riddle lead, and you can see, it really clean break here between at about 1.1 billion.
Dave Moecher Univ. Kentucky: billion years ago between those overgrowth and the cores that they're, on the other, sample down here doesn't have quite as much in the way of metamorphic over girls.
Dave Moecher Univ. Kentucky: But these are really, really not the wrench in and type of classic rocks and they're also older than they must be older than about 1.1 billion years old.
Dave Moecher Univ. Kentucky: So it when I say that they're not Lorenzo and I want to quickly go through the the the evidence for what we consider laurentian.
Dave Moecher Univ. Kentucky: basement rocks, and this is a compilation of shrimp ages from a variety of sources there on the lower left that define both the two main periods of.
Dave Moecher Univ. Kentucky: greenville magnetism and the ashwin again in Ottawa and and then from the MID Eastern a common area, the southern Granite realize Eastern Granite Granite right like basement components there's also an age component down here that corresponds to the.
Dave Moecher Univ. Kentucky: Mozart salt or rajini towards Eastern Central the ratio.
Dave Moecher Univ. Kentucky: If we look at the aco a supergroup, in particular the bass and bass solo co a supergroup and the upper most of the supergroup we see.
Dave Moecher Univ. Kentucky: That the Detroit zircons in the neoproterozoic sentiments are dominated by these grenville age modes and include.
Dave Moecher Univ. Kentucky: Both the ashwin again an odd one, and this 1.3 billion year old age mode as well, these rocks are deposited in the late neoproterozoic so they're sampling, the entire eastern lunch in margin and basement at that time.
Dave Moecher Univ. Kentucky: If we go into the cambrian then that grenville dominance continues and we've got the granville doublet as I call it the auto insurance again.
Dave Moecher Univ. Kentucky: agent so so this defines for me the eastern laryngeal basement provenance source.
Dave Moecher Univ. Kentucky: So the other group of paradises that are in the Dell would quadrangle van look more like granville derived.
Dave Moecher Univ. Kentucky: organize the apparent axis and the Gambia interrogated as many of Missouri Kansas was possible.
Dave Moecher Univ. Kentucky: And what we see in these late neoproterozoic sediments is something that looks like yoko a supergroup okay so we've got these.
Dave Moecher Univ. Kentucky: Dominant granville peaks here and our what i'm going to call the prequels of during peak and there's even a little Eastern Granite right like stuff.
Dave Moecher Univ. Kentucky: thrown in so these rocks over here, these old are what we would call post auto and paradises or post granville paradise it so those Gray nice's in the Dell would quadrangle clearly are two different crystal.
Dave Moecher Univ. Kentucky: types of rocks alright, so the old age component, then, are these 1.32 1.9 billion year old zircons.
Dave Moecher Univ. Kentucky: The additional evidence and these rocks for their antiquity, is the neodymium isotopes again we see.
Dave Moecher Univ. Kentucky: all ages from 1.5 to 1.9 billion years So these are evolved these sediments were involved, excuse me were derived from evolve crystal rocks just like we saw in the Marcel terrain in western North Carolina.
Dave Moecher Univ. Kentucky: So finally getting to the lead isotope results for these samples.
Dave Moecher Univ. Kentucky: These are whole rock lead isotope analyses and shown here are the compositions for the great smoky mountain basement complex and, in particular, you can see.
Dave Moecher Univ. Kentucky: These are clearly in the Amazonian field there is some overlap down here between the two fields of the less radiogenic compositions.
Dave Moecher Univ. Kentucky: But these rocks fall clearly in the Amazonian field and in particular I want to highlight these samples that are the same age from Southwestern Amazonia.
Dave Moecher Univ. Kentucky: And that's what I want to do next, is to then go to Southwest Amazonia to explore, specifically where the marciel terrain might have been derived from so.
Dave Moecher Univ. Kentucky: This is a basement map of northern South America, the particular area we're interested in is the is this area here okay in the red box that represents the.
Dave Moecher Univ. Kentucky: paraquat krypton that includes the some sauce belt in the.
Dave Moecher Univ. Kentucky: rondonia in San Ignacio province, the geologic map for that area is shown here from bowser at all, and in particular we're interested in this area that includes the.
Dave Moecher Univ. Kentucky: Little mouse my nature basement complex, this is the old basement complex that's the same age as the oldest detritus zircons we see in the basement and southern appalachians.
Dave Moecher Univ. Kentucky: there's also this San Ignacio granted sweet that is contemporaneous an age with the oldest ortho and ice ages, that we see in the southern appalachians and then the sunsets belt, which is the correlative grenville belt that was involved that form during the collision of Amazonian laryngeal.
Dave Moecher Univ. Kentucky: So this is in fact that since I spelt is a really small area it's really it's hardly a match for the granville origin, but it has the rocks of appropriate age, for the time of granville collision.
Dave Moecher Univ. Kentucky: here's a comparison of the basement relationships, then, and the two areas Okay, most of the there are some subtle differences in terms of presence or absence of showing and granites in terms of when these.
Dave Moecher Univ. Kentucky: settlements were deposited on top of the basement and you can see some age differences here, but the important thing is we've got these old.
Dave Moecher Univ. Kentucky: Grenada rocks that have inheritance, just like the San Ignacio granted sweet has the problem is, is that.
Dave Moecher Univ. Kentucky: The San Ignacio rocks are clearly intruded into that moment when he his basement.
Dave Moecher Univ. Kentucky: But it doesn't appear that that's the case for these rocks because in the granville for in the southern appalachians we've got 1.352 trials are cons in there, so this might be more of a.
Dave Moecher Univ. Kentucky: little bit of a complex comparison, but most of the age components are present in both terrains so here's a tectonic model for the collision and origin of the MARS hill terrain, we start.
Dave Moecher Univ. Kentucky: Before grenville or genesis where we've got this pre Elsevier in ocean basin the southeast lower energy and margin was reworked.
Dave Moecher Univ. Kentucky: That this time and here's the paraquat cray time that it contains be once eventually going to be the MARS hill terrain transferred to rancho.
Dave Moecher Univ. Kentucky: We have this pre sales of European continent alarm that's represented by the rocks in Vermont and New Jersey and the adirondacks.
Dave Moecher Univ. Kentucky: Then we've got the San Ignacio rajini at this time, the convergence begins with the sinister a bleak convergence that was worked out by tovar and others.
Dave Moecher Univ. Kentucky: The screens covering up this part for me, so I can't see it exactly, but this is the pre Elsevier into rajini we which we don't see evidence for in southeastern Southwestern Amazonian.
Dave Moecher Univ. Kentucky: Elsevier Finally, you get the grenville the initial grenville collision and you start to form these.
Dave Moecher Univ. Kentucky: shenanigans granites and the schwinn again rajini starts to add more granites to the MARS hill side.
Dave Moecher Univ. Kentucky: There are no shenanigans granites in the San Ignacio para blah blah, but then we'd get the sun saucer rajini in Ottawa and rodney and that's where the two.
Dave Moecher Univ. Kentucky: histories really start to converge and then finally down here, we see the interesting of Amazonian laryngeal that leaves Mars hill terrain on the ranching side.
Dave Moecher Univ. Kentucky: So.
Dave Moecher Univ. Kentucky: In spite of this very complex history we.
Dave Moecher Univ. Kentucky: Do have demonstrated that you can extract a lot of really good to chronology using the large in Detroit zircon approach and by looking at the individuals are congrats that takes extra time.
Dave Moecher Univ. Kentucky: But there's a lot of there's a wealth of information in desert con ages and textures so the oldest crystal components of southeastern dementia include.
Dave Moecher Univ. Kentucky: 1.9 1.6 billion year old detritus and 1.3 billion year old magnetic rocks.
Dave Moecher Univ. Kentucky: And although it's not a perfect match the query paragraph block of Southwestern Amazonian contains all the age components of the MARS hill terrain and the southern French broad massif.
Dave Moecher Univ. Kentucky: and cold, there was an early collision and could have involved the far traveled Paraguay block before it's it then collided with Amazonia and before the major phases of arranging Amazonian collision.
Dave Moecher Univ. Kentucky: And so future work should focus on the Amazonian side on the Amazonian classic sequences because it's the really it's the sedimentary rocks that contain the record of the Orange genesis and the.
Dave Moecher Univ. Kentucky: And we've got a really good record for southeastern ratio, but there's a much more scattered record for Southwest Amazonia and if someday we're allowed to travel that's where I will go Thank you.
Arthur Merschat: Thank you Dave that was excellent talk um, I guess, we have 20 seconds left.
Arthur Merschat: Those right questions as a rock may move on to the next talk.
Arthur Merschat: So.
Ryan McAleer: I think we'll keep going we're a few minutes behind so arthur's going to.
Ryan McAleer: Austin super fast in this next talk to catch up.
Ryan McAleer: So a couple things one is, if you guys have any questions, please post them in the chat to get some sweet discussion going, the other is, we now have 61 people in the session so that's most excellent.
Ryan McAleer: And yeah so Arthur take it away i'm timing you.
Arthur Merschat: Okay.
Frank Ettensohn: Good morning, everybody i'm gonna introduce arthur's talk is talk as entitled trump uranium lead source con GEO chronology from the globe massif and connections with the French broad massif the speaker is art mercian from the US geological survey art.
Arthur Merschat: Thank you.
Arthur Merschat: And so I guess we'll we'll go ahead and bring in with us a newsroom frame that led you to work on GEO chronology from the globe massey.
Arthur Merschat: So they give an excellent start here with with the overview of you know, the Grand rajini in the appalachians and also some of the very interesting connections with it so again I won't spend too much time here but, again, the master protozoa crocs his grandma rogen.
Arthur Merschat: they're exposed this nice linear belt of units going up the appalachians all the way in from Georgia and out Vermont and then even connects, on average, the adirondacks and into the granville province in Canada, where the grendel's define.
Arthur Merschat: So again, you know it's it's multiple phases of Roger that's actually in there there's Elsevier in shallow again in Ottawa and rigoletto phases again.
Ryan McAleer: A our third.
Arthur Merschat: Year in.
Ryan McAleer: turn your share your screen.
Oh no.
Ryan McAleer: you're doing great otherwise.
Arthur Merschat: Thank you RON you're always supportive if we see this now.
Arthur Merschat: All right, sorry everybody so anyways we'll we'll go ahead and get to hear so again the granville rajan he's grendel you know Messer protozoa crocs expose all the way up the appalachians again that the multiple phases of the grenville raji from Elsevier in shaolin gaining Ottawa and.
Arthur Merschat: You know they're recognizing several these different you know all the way up to the masses along the blue Ridge into Vermont and you know, mostly again there's these are granted mid crystal rocks and so we're going to focus at.
Arthur Merschat: You know this part in the southern southern central appalachians Virginia and North Carolina so again, so we kind of have these.
Arthur Merschat: grenville rocks are exposed a couple name massif the Shan toto massif which is up in in the Virginia blue Ridge it's mostly made up of grand at Monza Granite also.
Arthur Merschat: You know less you're trying to cut we're going to Iraq and Tony light ages from 1130 to 1028 ma.
Arthur Merschat: it's also affected by fifth light green light faces and more physical you know a lot of good summary of its there southworth and others.
Arthur Merschat: The next massif that really shows up as the French broad massif and it kind of goes from Southwest Virginia, all the way down into the great smoky mountains.
Arthur Merschat: Last talk by date mocha was really focusing a lot of the rocks right here and really you know, bringing in a really.
Arthur Merschat: You know, really starting to answer what are some of the older rocks in our message of predators oak rocks.
Arthur Merschat: And again with the sum of the 1.3 billion old rocks have been found in the northern part of the French rod massif and also in the southern part and we also see there's a big range from 1192 1140 ma Granite towards, and also the younger auto and phases from about 10 eight to 10.
Arthur Merschat: To 10:50am a.
Arthur Merschat: decade, also by a few black faces Metamorphoses and during the show again auto and as well.
Arthur Merschat: And we kind of see that both in both the northern and southern part and again, some of the interesting part is some of the MARS hill terrain rocks in the southern part of French broad, which has the.
Arthur Merschat: granular Nice, as it were, again kind of about a billion years old, now, not the old crusts we initially thought, and there are also some so protozoa crocs.
Arthur Merschat: focused out here in the eastern blues talks away and several down around who will falls down there are also kind of arranged by 1158 11 or three i'm a you can work for Caribbean and others hatcher and all.
Arthur Merschat: But the one we're going to talk about today is again the rocks within the globe massey, for these are the message protozoa crocs in the grandfather mountain window so just zooming in on just a little bit more.
Arthur Merschat: For northwestern North carolina's simplified electronic map, here again, this is a grandfather mountain window you'd have a grandfather mountain formation sitting right here, showed in Kansas.
Arthur Merschat: Round colored unit and it's neoproterozoic related feces and.
Arthur Merschat: they're sitting right up on top of part of again the rock Messer protozoa rocks and grandfather mountain went over the globe mass seat in the light light blue here or light bluish Green is the Wilson creek Nice, which is here.
Arthur Merschat: underneath the grandfather mount formation and then you also have been moving Western hired other threats to the blowing rock Nice and.
Arthur Merschat: Against more the Wilson created ISIS so we're going to look at the Wilson creek Nice in these places in.
Arthur Merschat: there's several different the most interesting ones wilkes and creek Nice, which has several different mythologies with it from Granite nice courts Monza night.
Arthur Merschat: diuretic Nice and layer Nice is and they've also been interviewed by different may fit and fell sick dikes and also the Cross recruiting across completing the brown mountain Granite.
Arthur Merschat: famous for its lights so we're going to start working here some samples and move to the east and kind of move structurally hired to look at some new GEO chronology ages in the messy messy.
Arthur Merschat: So the first one, we want to go to here is.
Arthur Merschat: Just long near along Wilson Wilson.
Arthur Merschat: Along Wilson creek here in it all corey.
Arthur Merschat: which this is what the strongly fully by ty granick nice it was originally.
Arthur Merschat: One of the early location after Brian read or during when Brian reed was mapping the grandfather mountain window area, this was an area sample for cheerio chronology back in 1962 and well it kind of gave a.
Arthur Merschat: Good answer that well the age of the rocks over over a billion years old, but the ranges are cons or 640 to you know 11.
Arthur Merschat: billion years old, so a lot of discourse with the data, and so our data on the shrimp we've kind of seen the same discordance here we have a kind of a.
Arthur Merschat: You know, most of the ages are about 1.1 billion years old, but we also see kind of tailing off down through here with discordant data lead loss pointing to like a lower paleozoic intercept down here, and if you kind of look at the thorium uranium.
Arthur Merschat: Florian uranium lead ages here are streaming authority uranium a ratios the blue show ones that are really low you know.
Arthur Merschat: And so, these are probably metamorphic ages so we're also probably have a 1050 metamorphic age here and again tailing off down towards here towards the lower paleozoic metamorphic age.
Arthur Merschat: So if we try to clean this up, we see we come up with an age five to 40 age of 1140 ma for this.
Arthur Merschat: grenache Nice and again about the same age here for also 1140 1138 plus or minus six ma will take the weighted average of the 22 analyses are that are you know, excluding the discord and ones.
Arthur Merschat: So that's the first sample, and this is now this part of you know, by type most intriguing nice interlaced grandfather mountain formation.
Arthur Merschat: So next let's move up to see what the blowing rock Nice and it's an exposure here long 321 your daily camp road.
Arthur Merschat: that many people went to it's a beautiful exposure that does Google earth image even shows you how impressive, it is.
Arthur Merschat: Large exposure, you can see era bikes even from this image of stuff coming through and several other units throughout the building off Nice.
Arthur Merschat: One thing showing you here is the layered Wilson creek nice everything else on both sides is blowing up nice so again was blowing rock nice look like it's generally good organize you can see us Nice.
Arthur Merschat: Day fails for for for Class here they're getting cheered up.
Arthur Merschat: Your bookshelf sliding it's also interested by again different fails to can pragmatic directions to this filter primitive types to.
Arthur Merschat: intrude into it and probably late in the lower knock nice age and then you also see here some of these may 5 dykes country through year, and these are part of the liberal Meta database to intrude.
Arthur Merschat: By new during the neoproterozoic just kind of put a little things on, and you can see again.
Arthur Merschat: The information, you know you know the affiliation here, probably paleozoic ready to allegheny and top Northwest sharing and also you have Northwest drifted folding and even this dykers probably a folded into someone's eyes carnal full.
Arthur Merschat: Of the basic tight, so we have a sample from here.
Arthur Merschat: And the data really was pretty well as well behaved golden age of about 1077 for Concordia age word again the weighted average is 1079.
Arthur Merschat: plus or minus nine or 10am a plus minus 9 million years and that matches very nice do we get and what hidden kerrigan and others pot also back in obtained through blowing recognized in 2003.
Arthur Merschat: So i'm just move on, down to the aircraft right here are the road cut where we have again the Wilson layered Wilson creek nice next part of the blowing rock Nice.
Arthur Merschat: So this is what kind of the contact looks like and you can see right along here, this is blowing rock nicest more lucrative in this zone.
Arthur Merschat: has less by a tight in it Mare less may fix in kind of see that some of it now, it looks to be in Soviet intruders along this layer Wilson creek Nice, and you can also see there's fully ation here.
Arthur Merschat: Okay, it along this so this rock definitely has to Blair Wilson creek Nice has to be older than the blowing nice so what's the results here again we have about the same age same age for the blowing recognize about 1080 plus or minus nine.
Arthur Merschat: 9 million years for his age we're looking at the Wilson creek Nice, the layered Wilson creek Nice we start to find some of these older rocks much like what day was talking about.
Arthur Merschat: Where it looks like we have some a bunch of ages up here around 1.3 billion years old, so maybe a little older, but again, that data is fairly discord important to our lower lower paleozoic.
Arthur Merschat: intercept form, so if we start to pull those off again so you can kind of see over here here's our ages again they're pulling down here.
Arthur Merschat: On can show see that the warm uranium ratios again the ones in blue are probably ones are probably more metamorphic are also different lead loss, although we didn't really have any good.
Arthur Merschat: rams to date on some of these, but when we do that we start to get back to about age with 1291 for Concordia for the rest of these.
Arthur Merschat: These 16 analyses here so that's probably close to what the age of the Wilson laird Wilson creek Nice is so again we're looking at this older positive 1.3 billion year old.
Arthur Merschat: age for the Wilson creek nice so more more of that 1.3 billion euros rocks so let's move on down keep on going down 321 down, you know off the blue scarf and one more outcrop.
Arthur Merschat: Again, a large rope cut here, right at the intersection us 321 and curvy mountain road again Google Earth.
Arthur Merschat: add some add some great views of it, you can see it again, most of what is the Wilson creek Nice is this, you know.
Arthur Merschat: You know Grenada rock here, you can see again everything's coming back to the southeast here about 30 degrees so again it's shared strongly to form, and so we collected, a couple of one.
Arthur Merschat: The the grenache brock's here that make up most of it, but then you also see some these dark color dykes summer Nice.
Arthur Merschat: May 5 dykes here, probably again again lindvall Meta database again they're getting transparent and shared out.
Arthur Merschat: However, with the interesting thing there's also a poor for riddick type so we'll look at some of the results results of jira chronology we got here.
Arthur Merschat: So first one Bo 18 dash five seemed pretty well behaved and we kind of age and older age of 1158 or 1160.
Arthur Merschat: million years for for weighted average and you're not you know still slightly discord and but it's pretty good age, so we have an older component here.
Arthur Merschat: We also sampled another nother genetic nice of the same outcrop.
Arthur Merschat: And you can see the ages were more discord is it kind of drag off down here towards the lower lower pillars open here began, you can see again Tory meridian.
Arthur Merschat: we're storing uranium ratios again are fairly low in the blue for again metamorphic.
Arthur Merschat: So we clean that up we're looking at again, possibly even a little bit younger age here about 1135 or 1137 for the weighted average here this frog so we're looking probably about an age 1144 part of the Wilson creek Nice.
Arthur Merschat: So my argument here was it based off the few relationships we had the Wilson creek Nice we had those poor for riddick unit here there's intruding it.
Arthur Merschat: We actually have part of blowing rock died blowing rock Nice, including his little dykes into the Wilson creek Nice, this is my argument again.
Arthur Merschat: Here, based in 2014 just looking at the textures in the rock.
Arthur Merschat: You know, it had also K felt scars and that's a little blue courts it looked very much like a really fine grain diet of what i'd imagine the blowing rock would be interesting, the Wilson creek Nice.
Arthur Merschat: However, get the geology back wrong the ages were dropped the IQ is 737 or 738 plus minus 10 million years, and so this is actually a referral a diet, because across more Platonic volcanic sweet.
Arthur Merschat: So trying to compare all the ages here from all the different massey's so again the globe massif with our new ages are right in here.
Arthur Merschat: Again, we have again we see some 1140 ages 1158 and then the ages of 10 at for the blowing rock Nice and new ones we have, and also the agent kerrigan and others the.
Arthur Merschat: Other minimum age of the layer Wilson creek nice around 1290 and we can kind of see the you know.
Arthur Merschat: We look to compare you know we don't see this older component up in the shadow and massey for hasn't been recognized, yet it is recognizing in part of the northern.
Arthur Merschat: Northern friend fraud massey and also as Dave you know dave's talk shows if the same age is recognized down in here in the southern French broad massey.
Arthur Merschat: We also have some of these 10 1140 ages to match up to the northern French broad as well.
Arthur Merschat: So we kind of all look again at northern French broad area, and so this is again around them out Rogers area law, the work here is done via.
Arthur Merschat: alone others in 2000 publishing American journal science 2017, these are the different ages of the different units again here again we're looking at Shaw again and auto and phase.
Arthur Merschat: And you can kind of see, we do have some of these 1148 granites and looks kind of you know, slightly less to form version of the.
Arthur Merschat: Wilson creek Nice, and then we also have an Alga nice up here, which is here date about 1066 very close to get into some of them organized with some bluish.
Arthur Merschat: bluish courts in it.
Arthur Merschat: I mean case bars didn't match up with the blowing rock Nice, so it seems even just on the on the basis of some of the mythologies that looks similar to what we have in the grandfather mountain Linda and then also looking at some of the new.
Arthur Merschat: Age of jira chronology from about the 10 at 1060 stuff and blue in the organizes down to.
Arthur Merschat: 1140 and even the 1.3 billion year old rock so we haven't.
Arthur Merschat: So, possibly even this this kind of fits with the pound stress pound, so we have a good reason for color palette spastic reconstruction of the globe being connected up to the northern part of the French broad massif.
Arthur Merschat: But then also maybe we start pulling things back apart in the cross section here, this is a big cross session goes, all I.
Arthur Merschat: had to draw across all the valley and reached into the crystal in part, back in 2003 with Patrick, and so we started pulling these things back and trying to restore into into.
Arthur Merschat: You know where this would go it maybe it makes a better thing for the again the rocks of the grandfather mountain formation and also the glow massey to connect up with something in the in the Mount Rogers formation in the northern part of the French broad massey and also the.
Arthur Merschat: And the basement rocks in the northern part of the French broad massey.
Arthur Merschat: So with that just kind of move into some of the conclusion, again we have Sunday shrimp your aim lead ages from the globe massif.
Arthur Merschat: Again, the following rock I Nice we have ages about 1080 plus minus 10 ma.
Arthur Merschat: We also have three samples of the Wilson creek Nice, the main kinetic phases seen somewhere between 1152 1140 I may, but then the most interesting thing is, again, we found another one of these older 1.3 billion year old rocks.
Arthur Merschat: Which considering the mouth layer Wilson creek nice it's also mapped in the window suggested a significant amount of it in the globe massey and possibly even as kind of what you know Dave was recognized even around the.
Arthur Merschat: The Northern other great smokies there may be more of these layers nice's within our message protozoa base and roxanne we've we've overlooked.
Arthur Merschat: And so kind of gives a very interesting story just with other connections with the mass each and larger connections to the other putting together the picture of Romania and the connections with Amazonia so with their that's i'll stop for any questions.
Ryan McAleer: Alright, thanks are there, there are no questions in the chat.
Ryan McAleer: So, I guess, we can move right along it is 1005 so it's time for the next talk up next we have a talk from brandon Spencer about and we're going to move into a little a little more.
Ryan McAleer: geologically more recent stuff trying to decipher the footprint of the neo acadian metamorphic event in the southern appalachians.
Ryan McAleer: So brandon if you're ready, you can.
Ryan McAleer: share your screen.
Ryan McAleer: and go here alright thanks.
Brandon Spencer: Alright, are we good to go.
Ryan McAleer: Yes, looks good thanks.
Brandon Spencer: All right, wonderful thanks everybody for coming to my talk today, I appreciate the work of the southeastern section and meeting committee the convenience of this session, and everyone put this together.
Brandon Spencer: This talk will present the first set of data came from a collaborative research project funded by the nsf which aims to determine whether the inner Piedmont of the southern appalachians acted as a high temperature origin channel during the neo acadian or rajini.
Brandon Spencer: So the channel for mechanism, essentially, let me choose my laser pointer here there we go the Channel flow mechanism essentially as a mechanism that is invoked to in some origins, to explain gravitational collapse of the system under its own weight.
Brandon Spencer: it's typically assumed to operate in large hot Himalayan style origins, such as we see in this upper figure here.
Brandon Spencer: Significant heating and weakening in the middle to lower crust leads to the initiation of an infrastructure or a channel of ductile material that is extruded from the origin at core.
Brandon Spencer: And such has been has proposed for like the greater Himalayan sequence.
Brandon Spencer: And there are two other distinct parts of the system, first the cold buttress, such as the lesser lesser Himalayan sequence that buttresses the flow of the Channel and then a cold superstructure like the Tibetan plateau that serves as a lid for the Channel.
Brandon Spencer: And so, our hypothesis is that during the neo acadian portion of the appalachian sequence the inner Piedmont actually acted as this week ductile channel.
Brandon Spencer: While the blue Ridge acted as a black dress like the lesser Himalayan sequence, and the Carolina super train acted as the cold or a junk lead, and so the the grass here at the bottom show how the predicted PTT pass of.
Brandon Spencer: differ for the Channel and for like a frontal thrust wedge system, and so in the Channel flow model, the active channel would undergo.
Brandon Spencer: You know, pretty high PT conditions and then some relatively ISO thermal decompression and then rapid exhumation during return flow back to the surface and so you see here very rapid acceleration at the end.
Brandon Spencer: By contrast, the frontal thrust wedge would would undergo lesser burial and a more.
Brandon Spencer: A more steady explanation from its maximum accretion depth and So how do we tell the difference between these systems which one was acting and in southern appalachians.
Brandon Spencer: And what data, do we need to understand which of these is more representative of the neo katie into them so in order to investigate this phenomenon, we need to look at the pressure temperature histories of the origin, so for the rest of this talk i'm going to focus on.
Brandon Spencer: The PTT data that we're using for this project and not in the larger issue of the Channel phone model, but this is the overall motivation for the work.
Brandon Spencer: So complicating Our question is multi-phase origin history to southern southern appalachians like Arthur Arthur mentioned earlier.
Brandon Spencer: The figure shows the composite terrain that was transported during the allegheny androgyny the blue Ridge, the inner Piedmont, and the carolinas super terrain.
Brandon Spencer: Within this larger composite train, there are other multiple domains that contain evidence for organic heating and metamorphosis from more than one more organic event.
Brandon Spencer: The central and western blue Ridge or domain one here is pretty firmly in the iconic date range, as you can see.
Brandon Spencer: From the distribution to the upper left here, but once we get to the eastern blue Ridge this blue area.
Brandon Spencer: And the inner Piedmont this yellow area, there are multiple where i've events represented and each domain and these other distribution pause and So how do we separate the signals in the domains were interested in for our work.
Brandon Spencer: As I mentioned, we need to do is to generate PTC histories for the origin, the PT loop here shows the ranges of pressures and temperatures that can be constrained using different analytical systems are study as a whole as incorporating all of these methods.
Brandon Spencer: laser ablation split stream mondesire geological GEO chronological and chemical data to help define and temporarily constraint that a mark of it metamorphic events.
Brandon Spencer: pseudo section and garnet ISO plus modeling to look at conditions during metamorphose i'm traditional thermo brahma tree to define peak PT conditions.
Brandon Spencer: thermo chronology from the muscovite and Horn blend organ organ systems.
Brandon Spencer: To look at cooling rates on the retrograde path and then finally we'll also look at courts thermometer and papers on a tree, to look at conditions during ductile flow for this talk we're going to focus on number one and number four.
Brandon Spencer: which will hopefully help us delineate these metamorphic events and the thermal history of the region.
Brandon Spencer: So this map does a better job of illustrating the iconic and neo katie and metamorphic course you can see, this iconic core.
Brandon Spencer: up here in the kind of granularity bases area to the West, and then we see the neo acadian so midnight to core over here to the east.
Brandon Spencer: Also on the map are various Jew and thermo chronological dates, such as uranium labs Eric on Mars like chemical dates and muscovite and Horn blend Oregon Oregon data.
Brandon Spencer: This map does not include all of the available data, but it does illustrate one point very well in that data in the area tend to be clustered.
Brandon Spencer: There are several places where research groups over time have for like the del mar group, for instance, have contributed a significant amount of data.
Brandon Spencer: And we've really good concentrations, but then there are large gaps, like the sort of maroon dashboard or here.
Brandon Spencer: Like in the north Carolina and South Carolina Piedmont areas where we do have some certain amount of data.
Brandon Spencer: But we're largely devoid of thermal chronological data that might help us determine when the region cooled below temperatures necessary for Dr flow and or high temperature metamorphosis.
Brandon Spencer: So this gives us a good idea of where to concentrate our efforts for good spatial coverage.
Brandon Spencer: Many of the dates that we do have, in the area can be problematic, at least for our purposes.
Brandon Spencer: Considering long residence times in the mid cross can cause young muscovite dates that may not represent the timing of the actual neo acadian event.
Brandon Spencer: But rather may be more indicative of cooling during surface directed movement during allegheny and defamation, so our research today focuses on the higher temperature and football system.
Brandon Spencer: Which approximately records cooling below 550 BC or closer to the threshold for Dr flow and high grade metamorphose.
Brandon Spencer: So here i'll show you our first round of those data as well as some very recent models, I do chronological data from the laser ablation split stream that we're using to hopefully help constrain the timing of high grade metamorphosis.
Brandon Spencer: So this slide is Martha zero chronology data from the Western, Central blue Ridge thanks to Dave smoker for the use of these samples.
Brandon Spencer: And so, this year from the great smoky group and we see mostly can coordinate data points they're pretty well behaved.
Brandon Spencer: From both samples firmly iconic dates about 450 ma This is consistent with the domain map which has the Western, Central blue Ridge, as the iconic core.
Brandon Spencer: The map also contains metamorphic ice grads and we can see here that these samples are located within a fairly high grade zone of kinda like to sell them a ninth grade metamorphosis.
Brandon Spencer: So these are inverse is a crohn's for am football Oregon Oregon dates from an empty ballistic by a tight Nice in the central blue Ridge and Wilson creek Nice and the grandfather mountain window respectively.
Brandon Spencer: And so, again we have dates that are pre eight neo acadian 494 and 5:11am a lowest low msw D values pretty good fit to the data and so these samples are located within by a tight possibly garnet grade metamorphic zones and so we're probably not reset during the iconic.
Brandon Spencer: This is split stream monetize data from the eastern blue Ridge, and from the two little falls formation again this is consistent with the other blue Ridge split stream data.
Brandon Spencer: With iconic date and very good concordance it's important to note that, of the 40 various amount as it analyzed here the taconic is the only event detected by any of these mana sites.
Brandon Spencer: And this is an amicable Oregon Oregon point from and in February, Nice and the spruce pine area.
Brandon Spencer: While it's still older than the main neo katie impulse at three at ma we do see a younger date here than in the Western, Central blue Ridge, as we approach the provide faults own in this high grade canaanites own.
Brandon Spencer: visit to split stream samples that are located just above the brindle creek fall and the Western or Piedmont from garnet very magnetites of the to glue terrain.
Brandon Spencer: These dates are neo acadian 356 to 359 and ma and are located within the neo katie and core according to the ISO grads and the domain and metamorphic maps.
Brandon Spencer: In a relatively high grade kind I Selma night metamorphic zone, again we see limited distributions with only nine out of 132 mana sites analyzed yielding a date younger than 340 ma.
Brandon Spencer: The first of these Oregon Oregon dates is from the Western inner Piedmont from the typical new terrain, very close to the previous split stream samples just about the brindle creek fault.
Brandon Spencer: The date from this sample is early Neil acadian 375 ma as we move across the train and to the Newton window.
Brandon Spencer: closer to the central Piedmont switcher the two dates in the Newton window give us late neo acadian days of about 330 to 334 and a.
Brandon Spencer: The split stream sample is from a quarter mile and I just west of the central Piedmont switcher near the near the neo acadian core.
Brandon Spencer: And this sample we start to see contribution from two events, the distribution plot has a by modal distribution we do see the neo acadian peak.
Brandon Spencer: similar to the other inner Piedmont samples at around 360 ma in this sample, but we also see effects from the allegheny and start to show up here around 325 ma as we approach the central Piedmont suture.
Brandon Spencer: And finally, these are gone argon data are from the central to Easterner Piedmont from the cost squares rain, the two and the central area, the terrain, the red and white.
Brandon Spencer: are firmly neo acadian 344 ma approximately while the sample closer to the central Piedmont suture again is after the neo acadian approximately 319 ma showing some allegheny and influence, perhaps.
Brandon Spencer: So if we assume that are sorry to recap our current split stream data we do see a fairly clear correlation between date and domain here.
Brandon Spencer: Northwest ever borrowed faults own dates are firm which iconic while once you cross the reward and get into the inner peace of mind, we do see neo katie and dates, with a minor allegheny and component, as we approach the central Piedmont suture.
Brandon Spencer: So if we assume that these models is a reflective of the timing of high grade metamorphose i'm than what we were likely seeing is clearly delineated iconic and neo katie and course.
Brandon Spencer: And this is not a new idea, this has been you know previously talked about it, but you can see it in the metamorphic core maps zone maps from earlier.
Brandon Spencer: But we what we don't see here is any evidence of widespread allegheny and high temperature metamorphose i'm, at least not in the north Carolina portion of the enterprise model we only see that allegheny and and put as we approached the southeast remotes extent.
Brandon Spencer: The Oregon Oregon data show another clear trend with Brittany oh katie and dates northwest of the reward fault zone.
Brandon Spencer: and neo katie into early allegheny and dates, as we traverse the inner Piedmont one thing to note is that the youngest date here 320 ma I slightly further south, then the next youngest date of 330 ma, which is a little closer to neo acadian.
Brandon Spencer: Although they're both pretty similar distance from the central Piedmont suture.
Brandon Spencer: The Oregon Oregon data indicate like I said a pre clear pre neo katie and timing for the blue Ridge and largely.
Brandon Spencer: Neo acadian dates in the rfp month, so that what that tells us is that these rocks have not seen temperatures above 550 see since these dates and therefore health helps us place additional limits on the extent of allegheny and high temperature metamorphic ISM in the area.
Brandon Spencer: So to summarize quickly both of these data sets are the first batches of it will be a large regional data set.
Brandon Spencer: To help further define the neo acadian core these data provide more evidence for the presence of distinct corps for both the neo katie and iconic events.
Brandon Spencer: The monitors like data suggests high grade metamorphosis them in the inner Piedmont was occurring during the neo acadian.
Brandon Spencer: With limited temporal very variation from lower to hire a structural positions.
Brandon Spencer: So there's no indication of high temperature allegheny and metamorphosis in most of the north Carolina inner Piedmont from these models like data until we get to the very southeastern most extent of our data set.
Brandon Spencer: Although the Oregon Oregon data or early allegheny and the southeastern most IP they don't necessarily indicate high temperature allegheny and influence.
Brandon Spencer: Since Oregon Oregon data or on the cooling path of the thermal evolution, these days, could simply be indicative of protracted explanation on a longer explanation time at McChrystal depths.
Brandon Spencer: Longer resident silent McChrystal decks after a peak neo katie and activity, followed by explanation during early allegheny and defamation.
Brandon Spencer: The younger days as we move south, as I mentioned earlier, is consistent with reason data from other researchers that have found.
Brandon Spencer: younger and football and muscovite dates in the inner Piedmont, and so we suspect that, as we continue our work south will see this younger date pattern continue as the ghanian front ships further West.
Brandon Spencer: The next batch of Oregon Oregon samples, which is indicated by the purple circles here is currently being analyzed and will expand this characterization of thermal history of the blue Ridge inner Piedmont contact.
Brandon Spencer: both to the north and it's are tall mountains window area and to the south, as we go into the Piedmont of South Carolina and into Georgia eventually.
Brandon Spencer: I appreciate your time and i'm happy to take any questions you may have.
Arthur Merschat: Thank you brandon.
Arthur Merschat: Excellent talk, I see bill has a question for you so um so bill i'll let you.
Arthur Merschat: Go ahead and ask.
Willis Hames: Oh well, alright, then brandon that was certainly great talk very, very interesting, of course, and really important work um can you just recap for the arc on work was done, briefly, and is it single crystal is a bulk simple incremental eating, how was that done.
Brandon Spencer: yeah so the Oregon Oregon work was multi grain Alec squats usually two to three grain Alec Watts just separated out of bulk bulk rock samples, and then they were done through step eating to fusion at Arizona State University.
Brandon Spencer: right that kept hodges lab right super Thank you.
Arthur Merschat: We have a few more minutes mark also asked by guess the question here about that, I think you kind of answer some we start filling the whole North Virginia North Carolina state line.
Brandon Spencer: Right, so we do we have collected samples from the sorry Tom mountains window that are currently being analyzed and we're moving further south after this.
Brandon Spencer: We are not planning currently to go North into Virginia.
Brandon Spencer: We are planning on concentrating most of this in the southern appalachians and not venturing up into the central applications yeah.
Willis Hames: I think josh pool has a question.
Josh Poole: hi brandon great talk, I was curious um we see somewhat similar dates here down in Alabama and our ice or crohn's generally they seem to the ages get cooler as you work from the from the Northwest down to the southeast sorry my cat is a wants to talk to.
Josh Poole: But so we're kind of seeing two different ages, some of the ages seem to represent just general regional cooling and then other ages seem to represent kind of last gasp of appalachian movement along sheer zones, do you see something similar, do you see a lot of shares up there and.
Josh Poole: So that was that was one question and then to use, I may have misunderstood or misheard but I thought you said and getting your talk channels that I enough you meant like like a tectonic extrusion channel, or maybe I just missed heard us.
Brandon Spencer: Right so for your second question, at least we're talking about kind of an escape flow mechanism similar to what we see and the kind of Eastern syntax of the.
Brandon Spencer: Tibetan of the candle and Tibetan origin.
Brandon Spencer: that's correct yeah and so that's what that's what we're trying to look at here, but obviously this portion of the of the work is not going to answer the whole question so.
Josh Poole: Obviously we've been using that same model here in the southeastern terminus and Alabama and Georgia, as well, we see this very similar thing.
Brandon Spencer: Right and your first question was about whether we see any influence from sheer heating or anything like that we haven't really interpreted that and these data, yet.
Brandon Spencer: To be honest, we just got these split stream data, you know not too long ago and the organ organ data we're fairly new as well, and so these are just our first interpretations from them.
Brandon Spencer: Once we get more information from the chemical data from the mana sites and once we start looking at.
Brandon Spencer: Some of the courts fabrics and things like that we might get a better idea of what stresses were in the area and how we can maybe apply any sheer heating or anything to our model is going forward.
Josh Poole: Excellent Thank you.
Arthur Merschat: Thank you all for the discussion very interesting brandon I know Bart has one more question Barnum asked if you'll kind of send that in the chat it's 1025 so just to keep on time we'll we'll move on to our next.
Arthur Merschat: Our next talk, and that is going to be.
Arthur Merschat: mapping the defamation patterns of the grand greenville one by two degree quadrangle in southern appalachian surface in comparison to size it and such and I saw strappy to predict subsurface dipping thoughts on Michaela Mather and Michael frothing em.
Arthur Merschat: veera shoots with talcum and Kevin mayhem and so Michaela will be presenting.
Makayla Mather: Good afternoon, everyone, my name is Michaela meter I am an undergraduate student at the University of North Dakota.
Makayla Mather: i'm studying environmental geoscience and in the fall i'll be in earth science master's student at Montana State University.
Makayla Mather: This project was based off of and are you we have this last summer, it was virtual so there was a little.
Makayla Mather: complications with that, but it worked out eventually we're working on mapping the defamation patterns of the southern appalachian mountains subsurface continental cross through seismic anisotropy.
Makayla Mather: This work was done in a partner situations and my partner was Juliet Gomez and then we have our three supervisors mentors.
Makayla Mather: I have a little bit of vocab check, just in case, but after seeing some of the sessions I don't know if it's really needed.
Makayla Mather: With seismic anisotropy it's just the variation of velocity through the different formations of rocks this is able to show us the different.
Makayla Mather: The different receiver function, so you can see that there's a little jumps in the red where the contrasts are and so we're able to show our depth that these rock formations are at, but also the dip angle.
Makayla Mather: We also put in our raw data with stereo in it so it's a good way to show 3D data onto a 2d surface and we also map the striking dips which is just the horizontal plane intersection with the degree.
Makayla Mather: A little history of the appalachian mountains, that it was two major plates that collided lauren to and gone wanna and it created blue Ridge mountain and inner Piedmont there's also all these little.
Makayla Mather: Islands that we call them the god smushed and created a nice thrush sheets that we have in our data.
Makayla Mather: So the purpose of this research, study was to correlate the surface defamation patterns with subsurface observed seismic readings, we also modeled the surface data, so we can have like a little accuracy assessment.
Makayla Mather: The importance of this is we digitize them this greenville quadrant, which is to buy one degree.
Makayla Mather: And with digitizing it were able to show a quantitative analysis versus a qualitative analysis.
Makayla Mather: digitizing took a little bit of work we used a program called geology map data extractor.
Makayla Mather: We also use stereo net and then found the averages and plotted them within our key is pro to have some nice figures and be able to compare it.
Makayla Mather: So this is our study area.
Makayla Mather: You can see that this is a fairly large map with all of the different.
Makayla Mather: Striking deaths modeled and the different types of deformations and you can see that this is what we're actually mapping.
Makayla Mather: There are over 6467 points that we mapped in about a week or two during the first week of our 12 week internship.
Makayla Mather: And then we also.
Makayla Mather: had to show all the averages with this.
Makayla Mather: We had two different study areas.
Makayla Mather: One with the seismic.
Makayla Mather: I last slide, but we have two different study spatial analysis one was being 15 minute quadrants to help show the averages a little better, but also the seismic sesame from receivers that are in our quadrangles.
Makayla Mather: The raw data on the left is from the stereo net function, so you can see that only the fully ation is plotted just because.
Makayla Mather: there's a lot of fully ation data and it's a lot easier to see versus the few hundreds of the betting mile a night and all of that.
Makayla Mather: On the right all of the averages are plotted for.
Makayla Mather: My apologies, I have to move this little bar.
Makayla Mather: So on the right, you can see that all the averages for the strikes are plotted.
Makayla Mather: The background of this are the different thrush sheets that are in the area, and you can kind of see some correlation along all of these for the surface geology.
Makayla Mather: And for the seismic stations, we have the raw data on the Left again flooded with a stereo Annette image and we have the averages on the right, so this is the strikes, of all the mile and I delineation fully ation and bedding data that we had plotted.
Makayla Mather: And so we have our model data versus our observed seismic anisotropy data.
Makayla Mather: The black bars are what is modeled at the surface.
Makayla Mather: So we have.
Makayla Mather: similar kind of it's the thicker bars, if you can kind of see it all on your screens and so within the different threat sheets, you can kind of see that it varies a lot on the surface, just because there's so many different rashid's within the 10 kilometer radius around the seismic stations.
Makayla Mather: But with the observed data we can actually see how deep these contracts are.
Makayla Mather: So these green observed data is based off of the depth of these readings are at an angle.
Makayla Mather: Due to there being so much fully ation data, there are over 3000 points within our entire quadrangle, that is what will be mostly looking at for the rest of the presentation.
Makayla Mather: And so, in this right hand side you can kind of see it's off in the same area right within these three four sheets.
Makayla Mather: And so it's kind of Nice being able to have data that is kind of similar to each other, but they're also plotted.
Makayla Mather: very similar to the model data which is good for us, because that is our accuracy assessment.
Makayla Mather: With the seismic stations, we can see that are observed seismic data which should be based off of the subsurface is not very similar to our surface data.
Makayla Mather: That we have modeled.
Makayla Mather: And so you can see that the.
Makayla Mather: orange is the observed data and the black is the model data also plotted with our strike for affiliation.
Makayla Mather: For specifically looking at the seismic stations and so within this 10 kilometer radius around this.
Makayla Mather: Seismic stations united Dean.
Makayla Mather: There isn't a strong correlation between the observed modeled and the surface data.
Makayla Mather: We chalk that up to it being such a small area and so many different spreadsheets and domains.
Makayla Mather: And then, in the lower left hand here Z nine w 30 315 affiliation this all plotted really similar, and it was nice for being able to see that.
Makayla Mather: Overall, yes, are observed data was different from the subsurface but at least the model data we have based off of the surface geology matched and that helps a lot.
Makayla Mather: Some of the future work that they will be doing is looking at the fabric type changes within spreadsheets and spatial data but also modeling the depth of that all of the spreadsheets are at.
Makayla Mather: I like to acknowledge our team that we worked with the summer all virtually over zoom, so this is our nice zoom pictures.
Makayla Mather: Michael frothing ham, Dr Kevin mehan and Dr Barrett shoot pelican this grant was from the National Science Foundation, but also.
Makayla Mather: Our mentors had another nsf grant which you can see, at the bottom.
Makayla Mather: Here, a little bit of our citations.
Makayla Mather: And if you have any questions you can reach out to me or I partner, and these are linked in qr codes if you're interested in taking those at all.
Makayla Mather: If there's any questions.
Arthur Merschat: Thank you carolyn what's up a lot of work.
Arthur Merschat: So, yes there's any questions, I know I have one or two questions as well.
Arthur Merschat: i'll go ahead and ask one first so just also the geologic mapper know you you're doing a lot of data, compilation, what I know I know.
Arthur Merschat: Kevin and avira and Michael have lots of big plans that you're you're starting off with this data, what are we all just going to do with the roadmap data just digitizing all the data distillations seem also doing delineation is that right yeah.
Arthur Merschat: yeah plans for.
Makayla Mather: It was the fully ation the nation, the mile and I and bedding um they were talking about possibly trying to get it submitted to the usgs so that the data is actually available for other people.
Makayla Mather: But it may take a while based off of like quality assessment for it to be publishing publishing is over, like 6000 points.
Arthur Merschat: Good hopefully i'll talk with them more about that to that that's that's good to hear so.
Arthur Merschat: Are there other questions you can just open up in and ask a question if you'd like we're putting in chat I believe.
Arthur Merschat: Our next thing is also will have a break at 1045 so we have a little extra time bar, if you want it, you know if there's any questions from a kayla that'd be good to go ahead and ask that now, or if there's any.
Arthur Merschat: or even anything any other questions back for Dave this morning because we didn't have time to ask Dave any questions we have a little time now and then we'll we'll probably ever break as well.
Arthur Merschat: So another question from kayla go ahead and ask, so how did How did the linear nations matchup for any of the delineation.
Arthur Merschat: Is some places along the bard faults and delineation is is is parallel to the strike with affiliation and possibly shows where you have some the better alignment.
Arthur Merschat: With delineation goes a little bit more down dip or bleak to the to the striker affiliation did did that you have a deal I think i'll have any way to have a qualitative assessment or a quantitative assessment, however, if it's affiliation becomes stronger or weaker with the.
Arthur Merschat: The size, we can assign trophy.
Makayla Mather: um so the delineation that I have for the 15 minute quadrants was my part of the project, so I know that a little better.
Makayla Mather: delineation we have is this red bar.
Makayla Mather: It didn't match a lot with everything else, just because there weren't very many linear nation.
Makayla Mather: readings, so it was more difficult to create the.
Makayla Mather: Like average for that area, the bedding also have that same problem, because there is such some a few of those readings within each 15 minute quadrant.
Makayla Mather: So it didn't really match up well with anything else.
Arthur Merschat: Especially the most of the entertainment then there'd be very few very probably this really could go.
Arthur Merschat: To us, so.
Arthur Merschat: Thank you.
Makayla Mather: Oh Thank you everyone for listening to my presentation of that my RU research this previous summer.
Arthur Merschat: Thank you.
Thanks Michaela.
Ryan McAleer: Right, are there any other questions for any of our earlier speakers.
Ryan McAleer: I guess I have I had one for bill Thomas if he's on.
Ryan McAleer: bill you showed a slide.
Ryan McAleer: And sort of your your overview at the beginning, where you had.
Ryan McAleer: You showed that it would the during the allegheny and maybe the drainage divide was was west of what are sort of allegheny and age rocks.
Ryan McAleer: And so we were mostly shedding older sediments to the West release that was how I understood what you had, I think you also have some data, though don't you some titles are con data in the youngest sediments in the appalachian basin and there are some.
Ryan McAleer: sort of 300 ma zircons making their way out from.
Ryan McAleer: from the East towards the West, suggesting maybe that you know the sediments were being shed all the way from the hinterland out to the West, and then I think even as as sedimentation.
Ryan McAleer: Or, as you go forward in time things I think there's like allegheny and sediments making it all the way out to the grand Canyon or something.
Ryan McAleer: Do you have any comments on I was, I was really interested actually in the data that you have on the youngest.
Ryan McAleer: youngest settlements.
In the appalachian basins.
Ryan McAleer: Was curious if you had any input on that or if you're even here, I could just be talking to myself, which is fun tip.
Arthur Merschat: It builds now you're Maybe someone else has also worked on it may have an answer for that as well or inside.
Thomas: Now i'm here, but I don't know if i'm muted.
Arthur Merschat: If we reveal.
Arthur Merschat: Some good.
Arthur Merschat: Great wonderful.
Thomas: Well, you can hear me.
Ryan McAleer: Yes, okay first.
Thomas: The youngest sample that we have is from the highest bid, we could collect in the Dunkirk basin in the permian.
Thomas: In all of those samples there's a total of seven grains with allegheny and ages, out of 3500 and something.
Thomas: So there's a few elegant and variants but very few That was really the reason for reconstructing that drainage divided the way we did because there's a paucity of.
Thomas: gotten one in age grains Pan African and then, as I mentioned, only seven grains out of 3500 representing the allegheny so just a little bit.
Thomas: gotcha now in.
Thomas: The forecast.
Thomas: For a city Basin and the Western side of the Illinois basin, we did get think it was 11 allegheny and grains, but they are grains that have almost exactly the deposition or age of the sediments that contain themselves, we concluded at those were probably we go when bone volcanic ash.
Thomas: Deposit.
Thomas: I thought there was another part to your question, but I don't remember what it was.
Ryan McAleer: But know that I mean that pretty much answers that yeah I mean I just you know there's yeah the youngest segments in the appalachian base and make their way into the permian and I was just curious about the.
Ryan McAleer: The implications of any young zircons making it there, I guess, I hadn't really thought about some of them, maybe being wind blowing or something like that.
Thomas: And they're very few of those are like three Greens out of 300 and about five samples yeah but you mentioned, also the transport out to the grand Canyon that's actually a project that.
Thomas: drive from a paper by George carrollton colleagues, and since that George and I are actually collaborating on a project right now to try to test that idea.
Thomas: And we currently have a paper in preparation and it's one of those it's dragging on forever, but eventually we'll get it together to look at that possibility, but I think the answer is probably no.
Ryan McAleer: Okay cool great thanks for that.
Thomas: Why don't have the floor, can I add one other thing.
Ryan McAleer: Oh yeah.
Thomas: Now this not to run business to.
Everybody.
Thomas: There was an unconformity in my presentation this morning.
Thomas: Which cut out one comment, I really wanted to be sure, I was able to make and it got truncated That was when I was pointing out that when I started working in Alabama I hadn't.
Thomas: anticipated finding and transition from southeast Northwest from more proximal to more distal and then I discovered that know the carbonate faces on the Northeast and the classic faces is on the southwest.
Thomas: The part that got truncated was it, I was congratulating myself on having made this really interesting discovery, and so I went back to read Charles butts geology of Alabama published in 1926.
Thomas: And discovered, I had rediscovered what Charles butts and discovered.
Thomas: And from Atlanta have gained the wisdom that anytime I think i've found something new and Alabama I go back and recharge much, and then I say okay me and Charles found that to.
Thomas: just wanted to be sure I got that plug in.
Thomas: And marissa Meyer Charles butch in case you haven't figured that out.
Arthur Merschat: I think it's nice also when we've kind of sometimes find the same thing we work back out something the same that even you recognize.
Arthur Merschat: Seeing the someone else's seen it before as well, so it's pretty pretty neat.
Arthur Merschat: So it is, it is approaching 1045 so I guess we'll you know we have a break scheduled here.
Arthur Merschat: Until 11 o'clock.
Arthur Merschat: So I guess we'll allow our 15 minute break and then start back up in at 11 o'clock so thank you all for all the talks this morning good excellent and it will will begin 11.
Arthur Merschat: So take this time again, hopefully, you know if you have questions you remember to put them in the chat or just say you have a question I don't know if we can think we can raise your hand virtually I haven't figured that out, but.
Arthur Merschat: It is there's ways to the we if we need to so when we get down to talks we can we can have the ask questions have discussion about everything that's.
Arthur Merschat: what's being presented, because I guess the, the better we can interact even virtually in this your share ideas, the better the meetings go so.
Arthur Merschat: I think we kind of a one one more minute our next talk is kind of go ahead and.
Arthur Merschat: start to get everybody ready with it again, hopefully, for the speakers, that if we do raise your hand again we're five minutes yeah three minutes, and then you know we can go to kind of get down to that one last minute.
Arthur Merschat: But somewhere, towards the end we'll probably have to.
Arthur Merschat: Somehow have to cut in and.
Arthur Merschat: Say it's time to finish up just to keep everybody online, for you know, keep us on schedule so.
Arthur Merschat: i'm kind of hitting 11 o'clock i'll go ahead and introduce the next speaker.
Arthur Merschat: And it's evaluating the significance of allegheny metamorphosis and the southernmost appalachians by Harold stall and Elizabeth bowen and Harold stone will be presenting so with that i'll turn it over to Harold.
Harold Stowell: Good morning, everybody it's good to be here this this morning and see all of you at least virtually and it's a it's a great pleasure Arthur to have been.
Harold Stowell: have to be in this session, and I must appreciate all of the things that you have done that have helped to make my job, a little easier with this talk, first of all i'm hoping I got a little bit of new data here that's not in butts.
Harold Stowell: That may or may not be the case, please correct me bill but i'd like to thank there's a little bit of new stuff here.
Harold Stowell: i'd also like to acknowledge all the people that have participated, but i'm not going to do that it's a fairly long list of students and other people that i've worked with.
Harold Stowell: If you want to see more of that you want to see the list of people who have worked with this problem and on this project, you can.
Harold Stowell: Perhaps attend the field trip, which is Texan ISM and metamorphic them on a southern most appalachian transact which I think is finally sorted out, it might actually work now, thanks to one of my co workers matt bk who figured this out last night, how to get around some of the problems.
Harold Stowell: So I also think that this this talk is is kind of a nice follow up to brandon's talk earlier, which was on channel flow and the inner Piedmont rocks.
Harold Stowell: But i'm not going to be able to give you much in the way of conclusions or you know new advances that.
Harold Stowell: Tell us, the answer to tectonic problems, instead, what I want to do is motivate more work because there's a lot that needs to be done, in my opinion, in order to solve some of the tectonic questions that are out there.
Harold Stowell: So i'd like to motivate people to collect quantitative PTT data in the southernmost appalachians that allow us to.
Harold Stowell: interpret the tectonics first of all, of course, nomenclature, we all like to use to connick and katie and allegheny and.
Harold Stowell: But I think that some of our authors work fairly recently published in 2017 shows that this may or may not be the right way to think about the thermal history.
Harold Stowell: I don't know if it's the right way to think about or genesis as a whole, I maybe it still is, but.
Harold Stowell: When it comes to the thermal history it's a little bit more complicated and we don't really want to blur things it's very convenient to use these words but, as you can see from this.
Harold Stowell: Age probability plot on the right hand side, out of arthur's publication there's a quite a range of ages and not that many distinct gaps in the ages.
Harold Stowell: So we need to consider that when we talk about all of these tectonic issues when it comes to the southernmost appalachians One of the interesting things that's come out of some around think pens work and other people as well is.
Harold Stowell: Just what is the tectonic sort of model that's best suited for the appalachians and the particularly the Piedmont, but.
Harold Stowell: One probability possibility, of course, is that we have a thickened thermal sort of tectonic wedge, and you know why is it hot and people have talked about this for a long time and.
Harold Stowell: Parts of the Himalaya parts of many parts of the world have been modeled as a thick indoor genetic wedge, which then we see some loading history, and you can see, this over here, where you might see a loading path and.
Harold Stowell: metamorphose um and then return to the surface so that's one possibility The other possibility talk about at some length by brandon was the sort of.
Harold Stowell: crust or flow hypothesis largely becca's that the jamison and bomani Chris Bowman came up with these models.
Harold Stowell: In a sort of quality quantitative mathematical fashion for the Himalaya and it might be some kind of crystal flow mechanism like this, so can I answer these questions today no.
Harold Stowell: Instead, what I want to talk about is some rocks mostly in the southernmost part of the appalachians I did notice that some it appeared to me brandon that you might have just truncated everything at the Alabama state line and for many reasons, that's a great idea, to be honest, but.
Harold Stowell: I would like to say that we can do something with the data from this part of the world and, hopefully, in the future we'll be able to understand it much better i'm going to talk briefly about.
Harold Stowell: Some quantitative PTT pass from these localities duck town Tennessee winding stairs North Carolina standing in the in North Carolina all the way down through this part of the Eastern blue Ridge and Alabama and you'll notice there's still a gap down here with no data.
Harold Stowell: So in the southernmost appalachians one of the nice things that Arthur did.
Harold Stowell: which I think was a great contribution was to start compiling all that data into one map of the origin, where you can actually see metamorphic grade.
Harold Stowell: As its distributed spatially through the mountain belt, and this is what i'm going to sort of build on as we go through this talk and hope to provide some new information.
Harold Stowell: So, again here it is plotted here the data or sorry the data locality, these are the same localities that are discussing in the field trip guide and some detail.
Harold Stowell: So what are we doing well we're going to construct millennial assemblage diagrams, and this is a john Brady term which was from I think northeast GSA.
Harold Stowell: A few days ago, a few years ago and mad or a mineral assemblage diagram is is also known as ice a chemical phase diagram section or pseudo section.
Harold Stowell: And what we do, of course, is mix up a bunch of chemical elements in a beaker so we have a whole rock composition and we.
Harold Stowell: Have a for thermodynamic model where we minimize gives free energy and we try to get to a most stable or low and roast spot in the gives free energy surface.
Harold Stowell: We do this with third act domino that's The model I prefer to use or the program I prefer to use for this, and what that can do, then, is spit out minerals that are stable.
Harold Stowell: In various parts of PT space, you can also of course model chemical space, but for this talk we're going to talk about these sorts of phase diagram sections or mineral assemblage diagrams that look a bit like this and pressure versus temperature space.
Harold Stowell: And that will allow us to produce something that looks like that and and that's a little bit of a headache so we don't really want to look at all those lines, but this is.
Harold Stowell: The raw output from this program and you can see that it produces lots of fields, and you hope not too many of these messes up here where it's having trouble finding a mode zero line or a boundary between these assemblages.
Harold Stowell: And the other part, to these PT diagrams that i'm going to show you is based on samarium neodymium guard at your chronology, and this is done in the UAE red ice lab radiogenic isotope lab where we of course separate elements put them on a filament and then.
Harold Stowell: accelerate ions through a mass spectrometer and determine isotopic ratios.
Harold Stowell: The output from this might look a bit like this and good case or best case scenarios we get ages like these.
Harold Stowell: And in this case we actually have a separate age for the core of a garnet versus the rim of a garnet you can see, they overlap with it uncertainty so it's a very small or brief interval of garnet growth, if you will.
Harold Stowell: But these are nice precise ages and we're getting sort of on the order of plus or minus 1% which is pretty darn good for garnet ice across we also have a just like this, where we can't separate core and room we either physically can't do it, or the ages are identical.
Harold Stowell: So we put all these things together, we can have a quantitative PTT path, why do we do this well we don't want to have any ambiguity in relating the ages to the pressures and temperatures that's why we do this with gartner it negates ambiguous correlation.
Harold Stowell: Right so in the best case scenarios, we might end up with this sort of PT path, this is of course summarize from one of those complex diagrams that I showed you a minute ago.
Harold Stowell: And we might have card at core calibration at some PT condition, followed by remix celebration at a higher pressure and slightly higher someone higher temperature as well.
Harold Stowell: And then we have a retrograde path or a sorry we have a path down to this field, which is the last mineral assemblage we recognize as equilibrium, based on text.
Harold Stowell: So we try to put together all of this, and in this case, we have a garden at age of 357 plus minus three so we also have a good constraint on when that happened.
Harold Stowell: Right okay so good enough that's the interest So what about all these samples, and what is it tell us about the southernmost appalachians.
Harold Stowell: So let's start out at duck town very briefly duck down looks like a big hole in the ground.
Harold Stowell: The they took a lot of copper out of there and they made a mess so there's a lot of prior work here that's been you know tells you something about PT conditions.
Harold Stowell: sort of 540 plus or minus 46 plus or minus one from Nesbitt seeing and then fully guard but tino said that the age must be over 475 ma by a tight closures from da Meyer.
Harold Stowell: Well, we have a new garnered sm end result, which clearly puts this as 449 plus or minus 12 so it's very old it's certainly not allegheny it or do acadian and we would call that to conduct fair enough.
Harold Stowell: For whining stare gap there's also been plenty of work done in the past, excellent work a chronology etc.
Harold Stowell: hey mocha and Miller, published on this and then both right all 2004 and their ages of 458 and 464 zero con uranium lead indicating to conduct ages here.
Harold Stowell: Of course, the PT work goes way back into a former student colleague of mine way back at Florida state Jim Eckert who did some work on on the granular faces metamorphosis here and and estimated about 840 degrees at close to 10 kilo bars.
Harold Stowell: And there's also been some other work done since then, including l shadowy at all 2011 so we constructed a mad diagram for these rocks and.
Harold Stowell: Liz bolin was able to make this new PT path, which is the Gray arrow this this line through here and you'll notice that it goes up to very similar conditions to what's been estimating the past circuit 850 pressures, not as great as those estimated by l sadly and.
Harold Stowell: It could talk about those details, but we think it's probably on the order of approximately nine calabar pressure is the maximum.
Harold Stowell: and reaching these high temperatures, so all of this, of course, is confirming the data that are out there, but this is, I think one of the first, if not the first mad diagram for these granular faces rocks.
Harold Stowell: nearby at standing Indian to the south pretty close to the Tennessee border, we also have done some mad diagrams for.
Harold Stowell: PT path and we've got some new sm end results for this area, and these results from the appalachian trail near Indian standing Indian.
Harold Stowell: show us that we have got at core growth for 40 essentially and rim growth at 411 so this this sort of confirms the older to kind of history for this part of the world.
Harold Stowell: and extends granulated bases metamorphic ISM arguably down to the south, a little ways, this is our PT path reaching.
Harold Stowell: Someone higher pressures, perhaps, than those at whining stare but not reaching the highest temperatures that we're seeing there, so we might only have 775, this is actually a pretty well constrained path.
Harold Stowell: there's a tiny little field in here, which is the garnet core is a plethora intersection from this mad diagram, so this is tracking garnet zoning is tracking the PT history.
Harold Stowell: With some early got it, which probably require liberated by diffusion at those temperatures and then the compressed to rim.
Harold Stowell: The next sample i'll talk to you about is is north of Atlanta, and the pumpkin bone creek formation, where, which is along interstate 575.
Harold Stowell: And in at this locality, we have no new age we're actually working on that now and loose ball is going to talk extensively about this rock and another one nearby the next one.
Harold Stowell: we're not nearby but, in the same sort of stratego fee, so I won't talk much about this, but what we do see is a loading path here and we hope to have an age for this within the next.
Harold Stowell: Well let's see by the time final exams occur it's a class project, so the next sample i'm talking about is is in Alabama finally.
Harold Stowell: And this one is a rock that's in the mad Indian group, and this sample is near micah ville Alabama and we have a PT path and an age, this is the one I used as an example.
Harold Stowell: For our methodology, and this was the garden in line so everything to the right of this red line would have got it, this is the solid us over here everything over here would have melt and our PT pass from the garden core and about 6.2 or 6.3.
Harold Stowell: Here so initial garden grow this one preserves pro grade zoning garnet river calibration much higher pressure nine kilobytes so we see a loading path, and then we see this later so eliminate assemblage down here, which is probably the last sort of equilibrium assemblage.
Harold Stowell: And then near the town of wood alley like Harris just north of without way we see this kind of.
Harold Stowell: PT path that I show here this short.
Harold Stowell: arrow that you see is a loading path for metamorphose, and this was published in 2019 in energy and alyssa sphere, and you can see, this age of 323 to 324 the cores 323 the rim 320.
Harold Stowell: blake's very near the blake's very plutonium, which is a famous locality and Alabama because probably the only place where people have published much on the way of.
Harold Stowell: metamorphic metrology gibson and spirit 1986 published on this, and here we have a garden age of 331.
Harold Stowell: which turns out to be very interesting because that makes it clearly younger than the Pluto one which was dated by standing room at all and.
Harold Stowell: If you go back to the 2019 paper and let the sphere those ages are for the plutonium published so this contradicts that finding of gibson and spear because in this case, what we're finding is the metamorphose is actually younger than the Pluto.
Harold Stowell: We also have some new new results from an old place that i've worked on for a long time, which is gold bill.
Harold Stowell: area, which was a gold mining area in Alabama and we don't have an age from this location, but we have a loading path here as well, for these much lower temperature rock so.
Harold Stowell: Just to emphasize, all of these mad diagrams indicating much lower temperatures than anything that we saw in of course up in whining stare but also lower temperature than what we see at.
Harold Stowell: ashland or microbiome.
Harold Stowell: Finally, in the muck far group a little bit south of gold bill, we see a loading path, also for metamorphic ISM and the josie leg rocks these are coarse grain guarded chest.
Harold Stowell: In which you can see a photograph of students collecting samples here and we have a loading path which extends from approximately six kilo bars up to eight and a half or nine kilo bars up here and temperatures up to about 650 this all this garnett growth is CIRCA 3:30am a.
Harold Stowell: So that we start out with this sort of faded map showing that we know nothing about Alabama and perhaps that's still true but i'd like to say, we know a little i've plotted all of our new and.
Harold Stowell: Published ages for garden here's our duck town sample up here for 50 essentially here are wanting stare sorry this is standing Indian for 42 for 10.
Harold Stowell: And here we have an unknown sample pumpkin bond we're still hoping to get an age for that by the end of Semester, the ashland Mike avail 357.
Harold Stowell: And then these would our group samples, this is the lake Harris 323 320, and this would be our blake sperry 331 and then down here in mcfall group at 330.
Harold Stowell: So what we're, seeing as much younger metamorphosis down here we're not really seeing a great deal of what we might call neo acadian we're seeing this 357 and that's about it so far.
Harold Stowell: We are currently working on this age, as I mentioned, but we also are are hoping to get an age for the curricula shifts down here, which is also in progress, so I hope to be able to report that sometime in the near future.
Harold Stowell: So there's still a big gap down here a big blank, if you will, in what we've called the Piedmont, and I hope that we can fill that in eventually, why did, why is this difficult to do well because there's no money in it.
Harold Stowell: Nobody wants to pay for it and it's very tedious work, but we hope to do this anyway.
Harold Stowell: So maybe we will be able to help with this, and I, you know I just leave you with a few questions you know what what's going on here, what is the extent of this 330 to 300 ma.
Harold Stowell: In quotes allegheny and metamorphosis does it extend into the Piedmont I don't know the answers to this but.
Harold Stowell: I think that this could show something very interesting, which might help us to better understand.
Harold Stowell: The sort of sin formal nature of this part of the world, I mean some of Marks don't impose great mapping and so forth, has showed that.
Harold Stowell: This probably can be a big sin form to to lassie sin forum in Alabama what is, what is the meaning of this structure, what is the significance of it and it might even tell us something about crystal flow.
Harold Stowell: Another question that I like to.
Harold Stowell: sort of resolve which.
Harold Stowell: Is what is the deal with the with our group rocks and some of them are clearly just.
Harold Stowell: Lower amphibian faces rocks and their sandwich.
Harold Stowell: Between higher grade rocks to the Northwest and se, what is the significance of this I don't know the answer i'm hoping eventually we can figure out what this interleaved lower PT belt.
Harold Stowell: structure might be, or at least confirm that it's real so that i'll leave you with that and hopefully we can get new data that can answer some of these questions i'm happy to answer any questions, if I can.
Arthur Merschat: Well, thank you.
Harold Stowell: This is motivation.
Arthur Merschat: And Dave you have one question there and the talk about moving fast just doing Dave if you want to go ahead and.
Arthur Merschat: Ask the question to Harold real quickly.
Dave Moecher Univ. Kentucky: yeah sure, Harold the rocks and when you start gap are pretty pretty heterogeneous, how did you decide on a bulk composition there for your mad diagram.
Harold Stowell: Great question what we did is we tried to avoid those which are partially melted.
Harold Stowell: And that was.
Harold Stowell: With the sample that I showed the photograph that's not what we modeled.
Harold Stowell: Yes.
Arthur Merschat: Alright, thank you again, Harold any other questions I will have put in there just to keep us on time we're gonna get a move on to the next one, but I guess, Harold can prolly this student he'll he'll have to talk with her about whether to take some more time.
Arthur Merschat: So we'll move on to the next talk is a possible neo acadian metamorphic belt in the blue ridge of Alabama and Georgia metamorphic some of the pumpkin vine creek formation in the mad Indian group by Elizabeth bolan Hannah Dixon and Harold stall and Elizabeth will be presenting.
Elizabeth Bollen (she/her): Oh right Hello everybody, and thank you all for being here on this cold but nice morning here in Alabama.
Elizabeth Bollen (she/her): Alright, so Harold gave a fantastic introduction to some of the rocks that i'm going to be talking about today and for my purposes or for this presentation i'm just going to focus on two of them.
Elizabeth Bollen (she/her): i'm only going to talk specifically about.
Elizabeth Bollen (she/her): hold on, let me move some zoom.
Elizabeth Bollen (she/her): windows about the pumpkin vine creek formation in the mad Indian group.
Elizabeth Bollen (she/her): So as Harold just said, we have quite a long way to go before be fully get a handle on the conditions and metamorphosis throughout the Alabama Georgia blue Ridge, as well as the Piedmont.
Elizabeth Bollen (she/her): And this talk is just focused on two of those samples, but I wanted to pull up this map here which does a really good job, this is Michelle 2017 Thank you Arthur.
Elizabeth Bollen (she/her): And it does a great job of mapping out all those index minerals zones showing metamorphic grade and a good broad context.
Elizabeth Bollen (she/her): But what maps like this don't do is they don't have numbers they don't have values.
Elizabeth Bollen (she/her): For instance, garnet can grow over a large range of P amp T conditions, so a garnet zone is useful in a big big broad sense, but we just don't know the precise conditions of all of the garnet zone rocks, for example.
Elizabeth Bollen (she/her): same for kind night store lightness cetera these are large ranges of mineral stability that we're dealing with here.
Elizabeth Bollen (she/her): So maps like this are incredibly useful.
Elizabeth Bollen (she/her): But we need robust PT data to truly understand them and apply them to organic models and organic events.
Elizabeth Bollen (she/her): And this part of the world, so in the blue Ridge we're dealing with the economy, the new of acadian and the allegheny one and as Harold mentioned the new acadian is a bit complicated in a bit loosely defined, especially in this portion of the appalachian or rajan.
Elizabeth Bollen (she/her): Alright, so same APP as before, but now, with the ashland supergroup and the Delano gold belt samples that I will be discussing today labeled on here, but a lot of good gold belt sample.
Elizabeth Bollen (she/her): Specifically, this is the pumpkin vine creek formation and it was sampled from near canton Georgia right off of I 575 it's a beautiful outcrop if you choose to stop there, be very wary of traffic it's a busy interstate.
Elizabeth Bollen (she/her): Fantastic rocks though you'll see why we chose to work on this sample in a moment, instead of an more easily accessible one off a busy highway.
Elizabeth Bollen (she/her): you'll see that it's located at this transition zone from kind night store light to more store light stable assemblages.
Elizabeth Bollen (she/her): Whereas the ashland supergroup is within the this thrust stack here this upper most thrushes that would be the MIC mad Indian group.
Elizabeth Bollen (she/her): Or the ashland supergroup.
Elizabeth Bollen (she/her): they're located approximately approximately along strike, but they aren't slightly different spreadsheets.
Elizabeth Bollen (she/her): And I won't be talking too much about the structural interpretation or left for lack of a better word sugar free of these two units i'm mostly focusing on the metamorphic timing and you'll see why again, as I move on, through this presentation.
Elizabeth Bollen (she/her): Alright, so this is the same map as before, but now, this is or same view different map in this map is just from home to noma and dos 2010.
Elizabeth Bollen (she/her): And it when in their work and and others they are now lumping in or grouping, for, in other words that a lot of gold belt ashland and medallia belt as one similar affinity package of rocks all the way from North Carolina all the way down to the terminus here, and at the coastal plain.
Elizabeth Bollen (she/her): So, if we look at why they group these rocks the way they have and it's mostly due to, as I said, affinity.
Elizabeth Bollen (she/her): So, as you, as you can see here the Funk and vine creek formation is interpreted by many people to be a more more volcanic island Ark affinity.
Elizabeth Bollen (she/her): believed to have been included within this back Arc setting close to deposition or proximal to sources from laurentian creighton crust so more evolve cemetery inputs.
Elizabeth Bollen (she/her): Both the syllabi greenstone which is near the ashland supergroup and closely associated with it.
Elizabeth Bollen (she/her): And the pumpkin vine creek formation share these similarities and that's the basis for the interpretation by these authors have a similar tectonic history for these two units, at least in terms of formation.
Elizabeth Bollen (she/her): The rocks that are or the sediments that are just being shed from the wrench and crust into this back are accessing include the are interpreted to be the ashland supergroup as well as the.
Elizabeth Bollen (she/her): Wood alley and possibly a mcfaul groups as well.
Elizabeth Bollen (she/her): The bunk and fog creek formation and Hello be were interested about 472 for 60 and may based on uranium LEDs are con data.
Elizabeth Bollen (she/her): And those are cons do have evidence for for laurentian Crystal and put.
Elizabeth Bollen (she/her): All right, so i've wax and wane quite a bit about the tectonic history, and that was just to give you guys a taste of what the interpretations for these rocks are so now i'm going to focus on the metamorphosis, which is, I mean what i'm most interested in in this presentation.
Elizabeth Bollen (she/her): So the mad Indian group is part of the ashland supergroup the eastern blue Ridge, the other groups in the ashland include the Po bridge mountain hatchet creek groups, both of which are started graphically or structurally under under late or under underlie the MED Indian group.
Elizabeth Bollen (she/her): The Northern boundary of the ashland supergroup is the hollins line fault, which separates it from the talladega belt to the north.
Elizabeth Bollen (she/her): And the south, the good water and he to chuck co fault separates the ashland supergroup from the medallia group.
Elizabeth Bollen (she/her): To the South and the mad India information is composed primarily it's just some minor fill lights and court sites.
Elizabeth Bollen (she/her): Some of these units, especially those close to the sample here have beautiful magnetite bodies that are host to large kind night and normally deposits, some of these are mind highly.
Elizabeth Bollen (she/her): it'd be great to get into these places, but they are mostly all private owned you can't really access them very easily.
Elizabeth Bollen (she/her): There is one garnet so Monday age that Harold already mentioned in the prior talk that is 357 plus or minus three and may and that's actually published in a past se GSA abstract from Dixon at 2019.
Elizabeth Bollen (she/her): And the samples within the ash or within the sorry getting my units mixed up here within the mad Indian group.
Elizabeth Bollen (she/her): have large Chi night and garnet, and this is the sample that was dated with three at 357 plus or minus three and may, and this is the exact same sample that i'm going to be discussing more details on for the TT history of this rock.
Elizabeth Bollen (she/her): Alright, so the pumpkin vine creek park formation, this one is part of the Delano golden the eastern blue Ridge this unit is mostly may fit nice's uncivilized and some minor shifts the crystallization ages from uranium LEDs are con are for 6064 62 ma.
Elizabeth Bollen (she/her): And there are interpreted as being treated as a modal volcanic Swede within that back Arc.
Elizabeth Bollen (she/her): Now, the only agent metamorphic ISM that we know of, and if you know of another one, please correct us is this 313 plus or minus 10am a for this unit now, this is an Oregon Oregon cooling age so it's not dating peak metamorphic ISM.
Elizabeth Bollen (she/her): And it's referenced as a personal communication and mcconnell 1980 so take it with a grain of salt, we cannot actually interpret how robust this ages all we've got is this role number referenced.
Elizabeth Bollen (she/her): However, if you take this at face value, it would it would indicate that metamorphosis occurred within this group between 460 and 313 ma which could be either Neil acadian or allegheny.
Elizabeth Bollen (she/her): And this is why we chose to work on this sample this is that unit that crops up along is 575 it's an unnamed unit.
Elizabeth Bollen (she/her): And this is the only unit that looks like this within the pumpkin buying create formation, but it's got these large garnet for for glass.
Elizabeth Bollen (she/her): and larger bankable as well with dark really shown well in this photo but they actually form rotated splayed of answerable that have been shared up in this rock.
Elizabeth Bollen (she/her): Also in this photo, which is a little hard to see maybe are these stringers or bands of store light.
Elizabeth Bollen (she/her): Which are shown as this kind of Brown and they're all through here so let's rock is kind of odd and it's mineralogy it has a lot of store light which is not that common in this in this type of composition.
Elizabeth Bollen (she/her): Alright, so both of these units just based on the presence of garnet alone reached and fibula fishes conditions, but just how similar are these conditions.
Elizabeth Bollen (she/her): Additionally, the metamorphosis the ashland supergroup or mad Indian group is 357 but we just don't know what it is for the pumpkin mind creek formation as Harold said, we are currently working on that So hopefully by the end of the spring will have a number.
Elizabeth Bollen (she/her): Alright, so Harold already went through the methods for this talk and i'm not going to go into too much detail, but we use the basics always starting off with Patrick graphic analysis.
Elizabeth Bollen (she/her): Then micro probe analysis of garnet because it's the black box of metamorphic that records P amp T as it grows.
Elizabeth Bollen (she/her): And then we use mads to construct pressure temperature pads using the garnet data and the assemblage data interpretive from PETRA graphic analysis and then finally got it so Monday do chronology two at a time to these PT paths.
Elizabeth Bollen (she/her): Alright, so more detail about the MED Indian group sample.
Elizabeth Bollen (she/her): Again same sample as Dixon adele 2019, this is a garnet kind of bow tie Muscovites just that contains store lights eliminate as well as retail ammonite chorus pledge and chloride, which is relatively minor.
Elizabeth Bollen (she/her): Again, large kind I blame the blades that get up to about a centimeter and smaller garnet which are about roughly up to half a cent half a centimeter at their Max.
Elizabeth Bollen (she/her): Alright, so looking at some photo micro graphs are the MED Indian group on this image Here we see a an angel very ugly store like grain.
Elizabeth Bollen (she/her): That is not shown in this image, but is included within these kind I pour for blessed indicating that storyline is younger or sorry older than the kind I.
Elizabeth Bollen (she/her): We also see some eliminate that is on the borders of these kind nights and these all but up against large garnet for for glass, but this one's mostly out of frame here.
Elizabeth Bollen (she/her): image on the right here is so so eliminate bordering around and then he general kind of grain, as well as some muscovite so eliminate is the is the most is the latest.
Elizabeth Bollen (she/her): i'm going to silicate in the sample.
Elizabeth Bollen (she/her): All right, real quick going through some.
Elizabeth Bollen (she/her): Micro probe data for this same sample, this is a backscatter electron image showing to garnet grains for simplicity sake we're just going to discuss this one up at the top i'm going to ignore this one at the bottom.
Elizabeth Bollen (she/her): This is the location of a quantitative traverse of data points which has shown below.
Elizabeth Bollen (she/her): calcium is strongly zoned decreases from core to rim magnesium increases from quarter him and manganese is a bit more complicated it decreases from quarter Ram which it was struggling indicates pro grade growth, but then it also has an increase at the rim again.
Elizabeth Bollen (she/her): Now, if you look down at this orange line here with labeled manganese I can see this in greater detail, you can see the manganese does decrease indicating progress growth.
Elizabeth Bollen (she/her): And then, it increases again before decreasing at the outer rim, this could be indicative of a complex growth text history either punctuated garnet growth or due to consumption.
Elizabeth Bollen (she/her): By minerals, such as store light in regrowth of that garnet along a single PT path and that's our interpretation for this particular zoning profile.
Elizabeth Bollen (she/her): Alright, so this is the PT path of the MED Indian group.
Elizabeth Bollen (she/her): We start off with a 6.25 kilo bar 550 degrees Celsius garnet core collaboration and that's from composition of garnet predicted by this mad diagram.
Elizabeth Bollen (she/her): garnet rim acrylic rates at the highest pressure and almost the highest temperature of this sample at about nine killer bars 625 or so degrees Celsius.
Elizabeth Bollen (she/her): Following this, though we have resumption of that store like growth of kind i'd into our peak assemblage field shown and read.
Elizabeth Bollen (she/her): And our peak assemblage is the kind of stable zone.
Elizabeth Bollen (she/her): going down that decompression path within stabilized eliminate into our last observed equilibrium assemblage card it's eliminate bow tie muscovite courts pledging routine.
Elizabeth Bollen (she/her): Alright, so the pumpkin find creek formation again gorgeous nice here it's a kind night store like garnet Horn blend nice it's a bit of an oddball.
Elizabeth Bollen (she/her): It has a lot of Horn blend It could almost be classified as an herbalife.
Elizabeth Bollen (she/her): It does have minor ortho affable as well as courts pleasure eliminate routine and some minor calcite now on this particular photo there is a rather large ish not so minor courts and calcite vein.
Elizabeth Bollen (she/her): But I want to stress that this was avoided when sampling for modeling for this particular rocket it spoke composition.
Elizabeth Bollen (she/her): so thin sections for pumpkin vine creek formation so show large warm blend for full blast as well as various sizes of garnet so there's, not just those large rotated port for blasters also smaller ones.
Elizabeth Bollen (she/her): And, and the matrix there's also an ortho at football, which is relatively minor but does a good job of helping to constrain the PT path for this sample.
Elizabeth Bollen (she/her): This image shows a garnet that has overgrown starlight indicating that storyline is earlier than garner growth.
Elizabeth Bollen (she/her): And finally, we have kind night most evident and the pressure setters of garnet, and this is interpreted as the most recent or the latest crystallizing index mineral for this sample.
Elizabeth Bollen (she/her): All right, very quickly through running out of time from confined creek has beautiful inclusion trails that are rotated within here and a possible rim overgrowth with no inclusions.
Elizabeth Bollen (she/her): These two maps and magnesium and manganese indicate that discarded has grown during pro grade growth zoning mostly from manganese decreasing from quarter rim.
Elizabeth Bollen (she/her): But we don't have any quantitative zoning date data yet to help her find a PT path for this sample.
Elizabeth Bollen (she/her): The mad diagram for this sample is more simplified as a result of that from garnet in we first reached or light stability.
Elizabeth Bollen (she/her): We pass into eliminate eliminate reaction line and into routine stable space up in here.
Elizabeth Bollen (she/her): We end up reserving the kind of that store light has been grown more garnet.
Elizabeth Bollen (she/her): We would come into ortho rentable space and then into kind nights stability at the very top at about nine kilowatt hours.
Elizabeth Bollen (she/her): Comparing these two they have very similar histories nine kilobytes 650 to 675 degrees Celsius so so far, so good they're rather sort of similar, but what about the timing.
Elizabeth Bollen (she/her): So the mad Indian group sample and the pumpkin vine creek formation sample this one, we have a great age for 357 plus or minus three but we're still waiting on this one could it be neo acadian or allegheny.
Elizabeth Bollen (she/her): Alright, so back to the title of the talk a possible neo acadian metamorphic belt and short maybe we're waiting on that one data point from pumpkin bind creek to come out of the tim's lab.
Elizabeth Bollen (she/her): The PT conditions are similar for the to the timing is unknown if you believe this 313 to my age that could indicate pig metamorphosis and the pumpkin vine about a new acadian or allegheny and, but if you look at this map which shows all the garnet ages for this southern appalachians.
Elizabeth Bollen (she/her): We don't know if there's a sharp break between the new acadian age and the Vitaly among small groups to the south, and we also don't know what's happening between here.
Elizabeth Bollen (she/her): Alright, so with that I will take any questions I think i'm out of time, but we just don't know what's happening between pumpkin vine creek and the rest of what we know about the seven appalachians in Alabama.
Arthur Merschat: Thank you Elizabeth very, very good to talk and excellent job yeah I think you're right there's there's some interesting, there is a dragon there.
Arthur Merschat: of how all these things.
Arthur Merschat: hold together, you know, and also with arrows kind of blurring together some of the thermal histories and are we missing any structures or other units in these.
Arthur Merschat: Are there if anyone has a question, we do have about a minute for a question for Elizabeth.
Arthur Merschat: If not, I may, I have one or two mass.
Arthur Merschat: So one one question that like in dating This may also with with Harold in dating the gardens.
Arthur Merschat: Do you ever see any come, you know from the show the microphone data that you don't have any, but do you ever see any like composite garnets that would be possibly from two different gross gross histories.
Definitely.
Elizabeth Bollen (she/her): The problem is getting to those zones to actually be able to date them because the way garnet geology works, we can't pinpoint discrete growth zones that are too small for the for the for the method.
Elizabeth Bollen (she/her): So we're restricted to dating large grains and that pumpkin vine sample that is being done it's being dated but for core and for rim, to get at that inclusion rich rotated inclusion trail core and that overgrowth inclusion free rim, maybe it's two different ages, maybe it's not.
Arthur Merschat: Well, I guess we're Thank you again Elizabeth excellent talk a lot of interesting data and I guess we'll be ready to move on to our our our next next speaker.
Arthur Merschat: is going to be.
Arthur Merschat: Uranium LEDs work on age estimates from metamorphosis of ashland supergroup Eastern blue ridge of Alabama records die actress metamorphose in the southern appalachian Piedmont by a daily honest I Enescu and Matthew mckay Delhi will be presenting.
Adelie Ionescu: Okay, can everyone hear me.
Adelie Ionescu: So hello, my name is natalie I Enescu I am a graduate students at Missouri State University, and this is my research this study will focus on metamorphic H constraints in the coosa black of the northern Piedmont province in the southern appalachians.
Adelie Ionescu: So first i'd like to thank my co author, Dr mckay as well as usgs bed map and Missouri State University for funding this project with special thanks to Dr Barry socialist at the University of Arkansas and Robert mill step from hancock natural resource group.
Adelie Ionescu: So the ashland supergroup located in the eastern blue ridge of the northern people aren't is a high grade metamorphic sequence that records mid crystal conditions.
Adelie Ionescu: The rocks within the ashland are separated from rocks in the structurally underlying talladega group and overlying rocks of the valley group by the holland's line and good water and needed taco fault systems respectively the talladega Belt is a lower grade middle.
Adelie Ionescu: horrific sequence that words peak metamorphosis between 334 and 329 that's from mcclellan at all 2007.
Adelie Ionescu: The medallia mcfaul Belt is a similar lower grade sequence that records peak metamorphosis between 331 and 320 a day, and this is from stillwell at all 2019.
Adelie Ionescu: So already, the issue is how does a higher grade sequence get sandwich between to lower grade sequences so since metamorphosis isn't increasing towards the south east like it was previously got for the Piedmont.
Adelie Ionescu: Our hypothesis is that the thresholds could be breaking backward, meaning that defamation is migrating towards the end killin or it could be out of sequence.
Adelie Ionescu: So some basic overview the appalachians contain evidence for for paleozoic organic events, the taconic acadian neo acadian and allegheny and.
Adelie Ionescu: These are our journeys are defined in the appalachians but not substantiated along the entire length of the mountain chain.
Adelie Ionescu: So the acadian rajini occurred between 410 and three at na in the northern appalachians but, as I mentioned there's there's less evidence for it and the southern appalachian since defamation of course later and is referred to as the neo acadian.
Adelie Ionescu: The decayed Ian bus a consonant consonant collision that produced a huge mountain belt that's can be traced across the modern Atlantic Ocean and is equivalent to the Caledonian originated in Europe.
Adelie Ionescu: So in the southern appalachians the neocon you know rodney began about 375 ma or so and continue until the beginning of the allegheny and rodney which is around 325 ma.
Adelie Ionescu: This event was marked by textural strikes let kinematics that are associated with a few hundred kilometers of to rain transport.
Adelie Ionescu: And finally, the alligator rajini is the last major event that affected Eastern North America during the paleozoic.
Adelie Ionescu: it's marked by the collision of North America with Africa which transported the blue Ridge Piedmont megathrust at least 350 kilometers towards the North American krypton and this event was complete by about 265 and they with the formation of pangea.
Adelie Ionescu: So the northern Piedmont province, also known as the blue Ridge is separated from the appalachian fold and rust belt by the talladega carter's built fault.
Adelie Ionescu: In the Northwest and from the inner Piedmont by the River our fault so to the southeast.
Adelie Ionescu: The units in this region have undergone various pulses of metamorphic ISM and gluten ISM and it's divided into three structural blocks the talladega comes and tells the blocks.
Adelie Ionescu: The northwestern most portion of this region is the talladega structural block which is characterized by the low grade medicine or memory units of the talladega belt with the better volcanic Hello be green stone at the structural talk.
Adelie Ionescu: So hollins live fault marks the boundary between the talladega block and the coosa block or the western and eastern blue retrospectively.
Adelie Ionescu: Where the ladder contains the high grade units of the ashland supergroup the strategic griffey of the talladega block can be linked to lorenza while the units in the crystal black may represent suspect terrain that constitute the laurentian outer margin.
Adelie Ionescu: So good water and need to chop co faults marks the boundary between the black and the southeastern most portion of the northern Piedmontese the telcos have block and this block contains, though, what dally and.
Adelie Ionescu: The timing of last displacement along the good water in each shop cobalt is constrained by 327 and they asked by ages so early allegheny and or so.
Adelie Ionescu: And because the good water need to chop co fault cuts the underlying Collins line faults, the hollins line fall is interpreted to predate the good water nia chocolate.
Adelie Ionescu: So that ashland supergroup is a middle to upper and public facing sequence that makes up the acoustic structural block and is the hanging wall of the holiday delightful.
Adelie Ionescu: It contains two units, the lowest unit strata graphically is the coverage mountain group, and this unit is separated from the overlying that Indian group due to the presence of uncivilized.
Adelie Ionescu: Otherwise, the Po bridge now group and the mad Indian group if they're marked by a diverse array of mythologies.
Adelie Ionescu: And proto lists this unit are most likely you met a P like Meta Gray wacky and ocean floor basalts which suggests that the actual super group was formed in a continental slope and rise along or repeated margin.
Adelie Ionescu: So ages of 1.1 GA to 964 and a from dos 2006 are typical of laurentian grenville basement and just suggest that the ashland settlements were supplied from laurentian margin.
Adelie Ionescu: And metamorphic ISM in the mat Indian group as Elizabeth just mentioned.
Adelie Ionescu: occurred, possibly during loading from nine or 6.5 to nine kilo bars and at 515 to 650 Celsius with peak conditions at about 357 at night.
Adelie Ionescu: So for methods six samples or collected from the ashland supergroup on the Claremont springs 7.5 minute quadrangle where we also did some geologic mapping, to have a structural context.
Adelie Ionescu: Their cons were separated from the samples with standard mineral separation techniques and analyzed at the La ICP Ms laboratory at the University of Arkansas.
Adelie Ionescu: The grains were are mounted on tape and along with depth profiling, this allows for better better spatial resolution and the acquisition of.
Adelie Ionescu: rim and core ages, so the metamorphic because our Conference where singled out by uranium thorium ratio is greater than 10 which reflects metamorphic overgrowth in the appalachians.
Adelie Ionescu: katie diagrams were created for the full population of zero con and each sample normalized 2.1 with a bandwidth of 25.
Adelie Ionescu: weighted mean age class were made for all of the suspected metamorphic rinse and each sample and certain populations were singled out in order to obtain a more representative agent metamorphosis and get a more reasonable and.
Adelie Ionescu: And we're aware that we could still be mixing some material here.
Adelie Ionescu: So samples 57 and oh to our medium grains belts bath anxious with garnet muscovite and minimal by a tight from the Polish mount group sample Oh, to provide a 35 grains with ages that ranged from 240 ma to 2.4 GPA, with a significant peek at 378.
Adelie Ionescu: Though weighted mean age blocks of 11th or conference yielded a being of 351.
Adelie Ionescu: sample 57 year old to 18 grains with ages that range from 318 ma to 1.5 GPA, with a peek at three ATMs and the weighted mean H plus of forums show a mean have 366.
Adelie Ionescu: sample 58 is a garden courtside from the pole bridge mount work that yielded 121 grains with agents that span from.
Adelie Ionescu: With a major peak occurring at 420 a day, those are called room ages from 27 grains hat on mean of 347 ma and from these 27 grains have waited mean age plot of the 60 youngest Greens.
Adelie Ionescu: yielded a mean have 293 a day and a third weighted mean age plots takes out the sixth grains and you'll find mean of 367 am a with a more reasonable msw D and this age is interpreted to be the most representative, since the higher other studies you likely indicates mixing material.
Adelie Ionescu: So samples 54 and 01 our medium to coarse grained muscovite by a tight garnets and kindness just from the mat engine grip sample 50 for ages that range from 361 ma to one point 48 from 22 grains with a peek at 389 and three rim ages, how to mean a free seven DNA.
Adelie Ionescu: sample one yielded 136 grants with ages that spans from 230 to ma to 2.6 GPA, with a major peek at 358 and 29 rent ages had a mean have 336 ma.
Adelie Ionescu: And again from these 29 grains weighted mean plot of the six youngest grains was created and yielded a mean age of 274 and a while a third way to mean age clock omitted these six youngest grains and yielded a mean of 348 and a with a more reasonable amnesty.
Adelie Ionescu: And finally sample 53 is a tonal light that interests them at Indian group it yielded 121 total grains with ages spanning from 310 ma to 1.5 GPA, with a significant peek at 350 ma and 19 rim ages, how to mean of 348 ma.
Adelie Ionescu: And this.
Adelie Ionescu: This specific sample this age could be also the age of and placement.
Adelie Ionescu: So the weighted mean H plus of the totals are con rooms for each sample Ulan ages that range from 340 723 71 and they went, the statistical rejects were removed, and this reflects mainly Neil katie and metamorphosis.
Adelie Ionescu: The meat ages of the youngest grains the 16th grains and samples 58 and 01 given their reasonable msw could suggest that the rocks are recording two distinct events.
Adelie Ionescu: or possibly just one event either way it's still shows diaphanous metamorphosis as I just mentioned, notably sample 53 the futon records and age that could be the timing of its in placement as well.
Adelie Ionescu: As I mentioned in my intro for the talladega belts, most of my data yielded ages between 334 and 328 which are interpreted to reflect peak metamorphosis.
Adelie Ionescu: And coincide with the earliest allocating and that data is from mcclellan at all 2007 again the sequence is also lower grade than the actual supergroup so.
Adelie Ionescu: This information illustrates that the rocks in the hanging wall of the hall and slide fault, which are the ashland rocks.
Adelie Ionescu: Were metamorphose before the rocks in the foot wall, and so the hollins line for most be most 340 in a sense, the actual supergroup rocks would already be metamorphose but the.
Adelie Ionescu: Underlying rocks are not so pigmented Wharf ISM for the overlying we Dolly and mcfaul belt, as mentioned is constrained to 330 123 28 from stu well it all 2019 from the garnet Sumerian music in data, and this is also the earliest allegheny and.
Adelie Ionescu: Meaning laptop good water, I need to chop co fall needs to be post re 20th a.
Adelie Ionescu: it's also possible that there's some complex partitioning of defamation that was first active in the ashland and then migrated into the hinterland at borland so that's why those areas reach peak metamorphosis almost the same time.
Adelie Ionescu: So in conclusion the six samples collected from the ashes supergroup yielded ages that's adjustment and morph ISM occurred mainly during the neo locating the rodney.
Adelie Ionescu: But also illustrate that activity continues into the allegheny university so continue this kind of the key word here.
Adelie Ionescu: We could just be one of the better it could be interpreted as two distinct events, so the early allegheny and constraints that are found in the surrounding units.
Adelie Ionescu: Those are interesting because those units are also lower grade rocks and also seem to have reached peak metamorphosis after the fashions supergroup.
Adelie Ionescu: So this could mean that the holland's line fall and the good water need to chop cobalt, which lie on either side of the ashland they're not getting younger tours of portland so they're either breaking backwards or they're out of sequence.
Any questions.
Arthur Merschat: So, yes, we have we have time for any questions.
Arthur Merschat: None have been posted in the chat.
Arthur Merschat: About I guess that I have, I may have asked a question on so it seemed like you also had some Zurich on remains is that we're almost either back to about 400 are a little older than 400 to where division age.
Arthur Merschat: yep and I looked like some of those also had your low thorn uranium values, what do you, what do you think for some of the the older those older ages are they discordant and overlapping cores or do you think it's an earlier event.
Adelie Ionescu: Oh it's possible that there earlier event I know we've kind of been looking for that kind of data kind of for 15 or so.
Adelie Ionescu: So I don't know if I really analyze that side of things as much as I would like to, but that will for sure, be interesting because there's I definitely have like a good spread that.
Adelie Ionescu: From 400 to like 250 per some of the samples, where I got a lot of Greens there's definitely a good chunk of of rims in there.
Arthur Merschat: So, are there any other questions, I may have one more to ask, as well.
Ryan McAleer: um I had a quick question so you said, these are um.
Ryan McAleer: You do depth profiling is that is that right that I catch that and so, then, do you sort of split the data up like bye bye cycle and you look for a sort of like several cycles in a row that have the same isotopic ratios when you because.
Ryan McAleer: Like if you're drilling through multiple rams or whatever I was just curious how you assess what to include when you determine each age with the death profile.
Ryan McAleer: I don't know you know.
Adelie Ionescu: Usually when i'm in I lie it's like there's a certain I guess shape i'm looking for I should have added a picture of that in here but usually it like the squiggle looks in a way, where.
Adelie Ionescu: there's a certain you know I can put a certain.
Adelie Ionescu: Whatever it's called a bar where the it's around.
Adelie Ionescu: One da or so and then there's like another population for and then i'll get to ages for the one grain.
Adelie Ionescu: I don't know if that really answered your question.
Ryan McAleer: Okay, thanks yeah I was just kind of to arthur's point I just and to the point that you also notice sometimes it's hard to know whether or not you're you're mixing isotopic signals.
Adelie Ionescu: Oh no.
Ryan McAleer: You have a spread from 250 and 400.
Ryan McAleer: You know the the way that you interpret.
Ryan McAleer: The data is.
Ryan McAleer: or there's there's a lot of wiggle room.
Ryan McAleer: Dan how you how you decide what's geologically meaningful.
Ryan McAleer: pathak thanks.
Arthur Merschat: let's see, we also have I guess uh oh hi Ryan is Ryan there's also an extra extra answer for your your talk there from Matthew okay as well, so.
Arthur Merschat: And matt if you want to you have one minute, if you want, and you just say that Ryan as well.
mck11: Oh yeah we just want to.
mck11: Do the depth profiling we collect the data and were able to go through and see the the time since the beginning of the analysis and where we see the age of the ratios jump after we process, the full data set were able to go back and reprocess it.
mck11: And split out any different age domains, and we try to.
mck11: skip are not analyzed breakout that mixing zone where we see the age change from something.
mck11: Significantly younger and then it jumps old we try to get rid of that mixing zone, although we're almost certainly mixing some sort of material in there, but we try to limit the amount of mixed age we get.
Thanks.
Adelie Ionescu: So.
Arthur Merschat: Well, I guess, we will go ahead and two minutes behind we'll go ahead and move into our next talk.
Arthur Merschat: It is geochemistry in mineralogy of may 5 intermediate and fellowship rocks of the north Florida volcanic series or Ryan dd.
rdeasy: Either can you hear me, can you hear me yes.
Arthur Merschat: We can hear you right.
rdeasy: Okay that's that's good news i'm going to share this screen here.
rdeasy: And then i'm going Can you see that screen.
Arthur Merschat: it's it's starting to share we see your screen.
rdeasy: Okay, my input on.
rdeasy: That do this just do it there, we go do you see that full screen now.
Arthur Merschat: Now we see the side.
rdeasy: We see the what.
Arthur Merschat: We see the side by side, we see the.
rdeasy: We don't want that we don't want that.
Arthur Merschat: If you have to.
Arthur Merschat: Make sure you.
Arthur Merschat: Share like screen sear that's the PowerPoint here.
rdeasy: Okay let's just try this again.
rdeasy: New share we want screen to and here, that is, and how's that.
Arthur Merschat: still looking at Paul secures this the presenter screen one.
Arthur Merschat: I found it when I had to do it, I had to make sure it was it was looking at instead of doing like screen to actually just doing the PowerPoint window that has the presentation in it like actual presentation view of the of it.
rdeasy: was just stop sharing i'll share again.
rdeasy: sorry about this.
rdeasy: Has that.
Arthur Merschat: Yes, that's.
rdeasy: Okay, good Okay, as our Thank you are there for the introduction, my name is Ryan mendenhall fellow with the usgs based out of the Florence baskin geoscience Center in reston.
Arthur Merschat: Virginia.
rdeasy: And my co author Mary beth Lupo is with the.
rdeasy: Florida geological survey.
rdeasy: i'll be talking about some preliminary results, we have from the north Florida volcanic series which is some of the Crystal and basement substructure under.
rdeasy: Some unknown portion of Florida, and I will draw your attention to the disclaimer language of the bottom left here that this is preliminary data not please don't share this just yet.
rdeasy: Moving see here click okay good Okay, what is the north Florida volcanic series well it's.
rdeasy: My definition here is a late it's the late neoproterozoic exclusive component.
rdeasy: Of the locked in a swanee terrain, which underlies the coastal plain and much of southeastern most us, including maybe almost all of Florida and it's of course never exposed it's all underneath coastal plain rocks it's not only from cuttings and core collected from depths you see there.
rdeasy: And what, so why do we care about this well the the basement structure here comprises.
rdeasy: it's the basement of the whole coastal plain and whatever history it brought in North America is set the stage for all subsequent sedimentation drifting and everything else, so we might learn a lot about.
rdeasy: All of the US and North America from from knowing some of this stuff this figure on the left is a very conservative figure from hetherington at all.
rdeasy: depicting the distribution of known North Florida volcanic rocks here on of course there's no boundaries between that anything else, so we don't really know the extent that hopefully will add some clarity to that here in this talk and, of course, this project.
rdeasy: here's another image of that suwanee terrain from another paper reference there in the bottom left.
rdeasy: And I show you this, to show you the what's the real distribution of the of the Loch Ness train the swanee we don't really know but there's a.
rdeasy: geophysical feature here that provides northern boundary to what's probably all this stuff.
rdeasy: And how do we know that the swanee terrain, is a locked in as well it's it hasn't gone one and offensive the established by a wealth of fossil evidence Paleo magnetic evidence and some nicer icons from both the swanee base and sediments and from the.
rdeasy: Volcanic rocks from the north Florida organic series a little bit from other associated futons.
rdeasy: So we know it blow it once belonged to guana, and now it is here.
rdeasy: here's a reconstruction of Don bwana at 500 million or so, and you can make out the profiles of modern Africa Arabia here's South America.
rdeasy: And it's not called suwanee train in this paper they call it Florida, but of course the 500 million years ago, nothing that anyone would call Florida is there, so the swanee train.
rdeasy: Otherwise, is really cool figure.
rdeasy: And to go on a little about the background what what we think happened.
rdeasy: Is in the allegheny and Roger navy during the assembly of pangea swanee docked on to North America and then with the opening of the Atlantic Ocean rift it along something like that margin to lead swanee train on the edge in North America and to be segmented upon and give us Florida.
rdeasy: Okay here's a map of a couple things going on here, first of all, all those dots are the locations of wells, which have penetrated pre middle Jurassic or pre coastal plain sedimentation rocks.
rdeasy: And i've also put on here this color pattern is the a raster extrapolation from each of those well depths where those depths penetrated.
rdeasy: Pre coastal plain rocks and I just raster interpolated through those with some hard boundaries from what we think we know the substructure, this is the southern edge of the early mesozoic drastic drastic rift basins that gave us.
rdeasy: I guess you might call this the south Georgia refer the tallahassee Robin or has it has names, but it's contemporaneous with.
rdeasy: Traffic basins in New England hartford basin and New Jersey, for example.
rdeasy: Another hard constraint, we have is this Bahamas fracture zone that's thought to be a.
rdeasy: transform fault associated with the opening of the Atlantic Ocean and there's believed to be in a little bit of evidence from from the well.
rdeasy: it's a sample right here, where the swanee basin rocks are on top of Crystal and rocks in the interpreted vault contact there that age that don't know but it's younger than devonian so there's some hard boundaries here between the.
rdeasy: demarcating the raster interval extrapolation rather um but what you notice is that the swanee that this is shallow his basement here.
rdeasy: It continues to be a little bit Shell here and that's about two or 3000 4000 feet depth below sea level and gets much, much deeper towards the south, and of course in these rift basins in the Northwest under the panhandle very much deeper there as well.
rdeasy: But if we peel that so this this surface here is the depth to what might be called the fall line unconformity that's the bottom of coastal plain segmentation.
rdeasy: But, depending on how we define basement maybe that's not really basement let's think about the Crystal and rocks and, if we look at the depth of Crystal and basement well very few holes have gone that deep.
rdeasy: Mostly because they're all oil, gas or maybe water wells, and once they hit Crystal and rocks they don't go any farther Why would they.
rdeasy: But these are the all the holes that have penetrated that deep and what you see now is I kept the same hard boundaries and the raster interpolation now shows that we have Highlands or shallow lands.
rdeasy: And this area of peninsular Florida getting deeper to the south and the bottom of the swanee base and here is pretty deep at 8000 to 10,000 feet and very, very deep again i've been in the Northwest.
rdeasy: So here's here's a map now of again all the wells that penetrated Crystal and rock under Florida.
rdeasy: The larger black black and colored dots are the wells that have been sampled for the study i'm conducting right now, and the thoughts with colors in them are the wells, from which I will be presenting some new data today.
rdeasy: And i'll give you a little bit of a breakdown of the basic structural domains here.
rdeasy: From little we know there are in the south here some.
rdeasy: Early mesozoic volcanic we only have a couple of ages from those from whole Rocker barium strontium data from 60s or 70s, so who knows what those.
rdeasy: Who knows what that really means, but a little bit of work i've done looking at the sample right here, I believe they are mesozoic based on the.
rdeasy: comparatively little degree of alteration and the persistence of ortho clays felts bar, in contrast to microclimate, which is what you see everywhere else in the older rocks.
rdeasy: South Georgia rift up here in the north that's that mesozoic really messes up, based on I was talking about earlier and those contacts are.
rdeasy: are pretty good after hefner's good geophysical PhD study 2013 the gasping entries and complex up there, we don't really know anything about that there is one.
rdeasy: Whole rock testing on age neoproterozoic that since age 7709 or so um but again horak naseem argon who knows what that means, and then there's a nearby zero con from 625 but again that's there's a lot of geology going on here to hang much on those two dates.
rdeasy: Moving on to the swanee basin is in this area here, these are the ground one sediments cambrian to devonian sediments based on fossil data.
rdeasy: And the north Florida organic series is a sub crops here under coastal plain rocks and probably extends underneath the swanee basin and maybe there's a little clip of swanee base and stuff here and organic stuff here as well.
rdeasy: And then, this other Granite wide complex the osceola i'm telling you about all these other structural domains, besides North Florida volcanic series because i'll come back to them briefly at the end.
rdeasy: Alright, so, as I mentioned these rocks are only known from corn cuttings here's a couple of examples of what we're actually working with here.
rdeasy: And like I said when drillers penetrate these rocks they don't go very much farther it's not what they're looking for.
rdeasy: So all of rocks that we know, have down here are represented by 10 or a few 10s of feet of cuttings which recovered a few grams, maybe a few 10s of grams of material.
rdeasy: In a couple of cases those people penetrations when a few hundred feet and which case we have a few hundreds of grams of sample but, nevertheless, we have to be extremely deliberate, especially with deep destructive analyses, how we handle these what we can learn from them.
rdeasy: Okay, moving on to some geochemical results.
rdeasy: About that major element geochemistry of these rocks.
rdeasy: This triangle tip tribe go here in the top Center are.
rdeasy: This is the abundances of courts Alkali felts bar and pelagic is as determined by ci pw norm calculations on whole rock chemistry Okay, and what you see in here and in these.
rdeasy: afm triangle is that we have in the north fork for volcanic rocks a complete range of may fake intermediate and fell sick rocks.
rdeasy: I should mention that the new data and presenting are in these filled symbols and I have some legacy data here, most of the legacy data is from is in the fell sick rocks here and actually all these red guys are from the same well.
rdeasy: The purple ones with the salts are from those four different wells and those intermediate proxy right here there's a this blue sample here is another fell sick rock I separated by color because it's special and we'll talk about why in a little bit.
rdeasy: The so we have full range of volcanic compositions and they fall in the FM and a cow calculus trend, except for a couple of outliers.
rdeasy: As for the trace elements geochemistry it tells you about the same same thing the whole rock does as far as.
rdeasy: make a rock classification and that's good, because these rocks are pretty heavily altered and there's potential for better semitism of the.
rdeasy: Major elements may be more than some of these trace elements are Kony and titanium I will be Atrium.
rdeasy: Our contract normalized earth patterns in the bottom here they're all light rare earth enriched and it excludes a more upsetting or depleted mantle but melt setting for all of them tells us we're not probably not dealing with a light here or anything like that.
rdeasy: i'm sticking with those rare earth patterns, the similar pattern across all the.
rdeasy: mythologies suggesting a common tectonic tectonic setting and or melt source conditions.
rdeasy: However, the overlapping rarest concentrations in May for info SEC rocks suggests the probably not related by fraction nation else the filter would be much more enriched and perhaps that means there's multiple discrete melt sources.
rdeasy: course this is covering a wide area of couple hundred kilometers breath so that's not surprising that's all permissive that these rocks belong to a common subduction art, which is the.
rdeasy: hypothesis model we're moving forward with.
rdeasy: another couple observations, the European no anomalies, whether there is none the European values, especially the big rocks are just about exactly one indicating there's been no plans for action ation contributing to the.
rdeasy: epigenetic history of this rock slight plan a slight europium depletion in the felt sick rocks suggests that there is some logical extraction Asian in their history, so these are not be as somewhat differentiated melts more so than the salt.
rdeasy: I do want to draw an observation to the the uniform composition and this intermediate unit and what's really interesting about, that is, this is the one.
rdeasy: Hope one well that penetrated something like five almost 500 feet of volcanic rock and these three analyses and then one legacy analysis from an adjacent well I pulled.
rdeasy: These three analyses from the three analyses from across about 470 feet of recovery and they're all flat compositionally with respect to rare earths trace element ratios and to go back to the major elements that they cluster pretty tightly there too.
rdeasy: Okay, so i'll move on to a little photography and some observations about the mineralogy we see alteration mineralogy everywhere we look, we see pretty pretty good mathematics structures and no metamorphic sharing or strain fabrics.
rdeasy: These may think rocks have life like pleasure clays and.
rdeasy: Climate Pyrrhic seen a massive texture cut by several generations of veins this this name contains carbonate print it a little bit courts.
rdeasy: Harrison backscatter images of.
rdeasy: same rock and again, you see last like plastic ladies massive texture relatively fresh client appearing same and in some some sample some classmates we have a Z analysts angular two somewhat rounded incorporated in that matrix.
rdeasy: Here, a couple other examples of may 5 rocks with similar textures Here we see maybe a little bit more of a magnetic fully ation to the orientations of the pledge lads and we have one a legacy image over here from this assault assault take rock.
rdeasy: it's hard to make out what exactly is going on, nobody looks like again massive texture with with.
rdeasy: political Islam last.
rdeasy: So to summarize that these Celtic arts I don't know if they're I doubt they're there you know that's this is there 200 kilometers apart there's it's not likely to be a single flow, but they may be related as part of a common Arc.
rdeasy: The intermediate rocks that's from these greenwell's here, this is the one that penetrated 500 or so feet.
rdeasy: The textures are just gorgeous.
rdeasy: Really heterogeneous fragments with elliptic fragments Tetra with internal fabrics here's an interesting class with sewn recreated porphyria texture inside really fascinating stuff um and, here are some backscatter images of the same same thing you see.
rdeasy: This is.
rdeasy: backscatter on the Left sorry and photo luminescent on the right, and you see class again with internal fabrics and bright courts and seashells just interesting stuff.
rdeasy: And, of course, with these heterogeneous tougher it's indicating multiple generations have.
rdeasy: Multiple eruptions multiple flows and evidence in some classes for poly phase magnetism with little cyclists inside.
rdeasy: The the welded.
rdeasy: classic texture.
rdeasy: So what does that mean well, this is the, this is the sample that's 450 or so feet of compositional a uniform and.
rdeasy: texturally very different rocks so it's possible that this whole 477 foot interval is a single eruption from a very big volcano that did all the mixing of material for us and that's why it's all compositionally.
rdeasy: The illustration of these rocks is variable depending on where you look but but strongly altered in all samples 50 to 100% metamorphic minerals, the.
rdeasy: Specific alteration mineralogy is variable both within and among samples but generally we have low temperature low to moderate temperature print is compelling I.
rdeasy: corn fells to very lowest screenshot species conditions and and then a variable died genetic over print On top of that quartz and chloride, of course, everywhere everywhere, replacing things.
rdeasy: alibi carbonates print it later also common moderate temperature replacements, and a lot of alteration intervals minerals are only found in single 10 foot or 40 foot intervals and there's a list of those right there.
rdeasy: Local Evans higher temperature alteration with these sample in episode four for blasts and very weird magnetite titan night simplex tights that.
rdeasy: I don't know what temperature those grow at wherever it was it was in their way out of equilibrium now, because these are just really, really cool solution textures.
rdeasy: So, all in all, what does that mean I my interpretation right now is that there is there isn't a metal regional metamorphic.
rdeasy: Is not original metamorphic over print in North Florida volcanic rocks that all of these are localized hydrothermal alteration probably associated with the the heat of.
rdeasy: magnetism of the volcano volcanic activity, so what i'm trying to say is alteration mostly contemporary contemporary this with volcanism.
rdeasy: Lots of veining though and.
rdeasy: it's my dog be quite a lots of adding and multiple generations of means are evident from the Cross cutting curse episode vein cut by court vein, and you can see, in other cases that vein was reactivated to precipitate a series of minerals, so a lot of brittle defamation, but not.
rdeasy: high temperature.
rdeasy: Moving on to the fell sick rocks we have this is this rock here is really interesting rock mostly because we have really good.
rdeasy: isotopic evidence for his age, which i'll get to in a second but we support Frederick rock we have fan of Chris of that was probably a failed Spar of xena lists and fine grained matrix.
rdeasy: what's really interesting about this is that matrix is totally totally Sarah sanitized and, in fact, in whole rocks whole rock X Ray diffraction patterns, there are no fields bars left in this rock whatsoever, which makes it a great it's a great potential for.
rdeasy: White Mike on aren't thermo maybe GEO chronology.
rdeasy: And what makes that especially wonderful for this rock is this is the one sample of the north Florida volcanic series that has a really good radio metric age on it 552 plus or minus eight.
rdeasy: So if we're able to date, the growth of lights parasite in this in this rock, though, that would be a really nice control point for the evolution of the swanee train.
rdeasy: So.
rdeasy: From looks.
Arthur Merschat: Like we have about 3030 seconds left.
rdeasy: Okay, so i'll just skip some of the rest of the stuff except to say that, and this is a preliminary talk I don't have much in the way of conclusions, but I will tell you where we're going with this.
rdeasy: we're taking white micah and K felts bar separates to constrain the thermal evolution through 300 hundred degrees or so of these rocks from you know predators out to hopefully cretaceous time.
rdeasy: This is the distribution of case bars will also get some mono as it ages, these are metamorphic mountainsides girls have magnetic ones, hopefully get some zircons.
rdeasy: And all told these data will constrain the timing floating and uplifted swanee train.
rdeasy: confirm challenger at nuance to the structural boundaries that we've interpreted and explain apparent absence of allegheny information swanee rocks because here they are right there in the middle of the permian are in the middle of the pangea and took no hits.
rdeasy: That I will thank you and take any questions.
Arthur Merschat: Thanks Thank you RON I guess we'll have to move on to your sub coastal plain trains are always so interesting because there's so much limited knowledge that we have, so thank you very much.
Ryan McAleer: Thanks Ryan.
Ryan McAleer: Yes, so we're on to the last talk of the morning session i'm switching gears a little bit here heading down to.
Ryan McAleer: Antarctica.
Ryan McAleer: And the talk is going to be given by don john yes are and we're going to let him take it away and then, if there's any anybody wants to ask questions for any of the talks following this one, we can do that so thanks everybody for a great morning session.
Can you see my screen.
Ryan McAleer: yeah your current you're in the presenter view right now, so we can see that.
Better thing right.
Sandor Ricketts: share your other screen you're sharing your presenter screen.
Ryan McAleer: There you go looks great.
Hello everyone.
Dogancan Yasar: i'm chef from the Department of geosciences auburn university i'm a PhD student of Dr James today I will share my answer degree search.
Dogancan Yasar: And we focused on this study on the Miller and geologists ranges from the central transantarctic mountain range and i'm going to talk about our single crystal are going are going ages and their implications as well.
Dogancan Yasar: As this billion photo is from Dr good us to any to any paper, and we are looking towards the nimrod Galicia gledhill and getting a glimpse of the geologists range we actually have some samples around this belt.
Dogancan Yasar: I will first start off by pointing out some analogies analogies between Ross origin and the southern appalachians then give a brief info about the turns Antarctic mountains and the Miller and geologists Rangers.
Dogancan Yasar: Then I will talk about the missing pieces of the puzzle in terms of cooling rates then move on to our analysis introduce our samples and data and then some of it, our conclusions for the terminal evolution of central transantarctic mountains so far.
Dogancan Yasar: Ross origin and the southern appalachians have several things in common, but the main six pointers if we have to narrow them down.
Dogancan Yasar: would be that they formed they bought formed from chronic fragments of riff riff that rodia they have approximately hundred million new mere a million year cooling histories.
Dogancan Yasar: With respect to Oregon Oregon system and they both are very good, representatives of successor bazan importance in organic evolution.
Dogancan Yasar: They have a power surge any existing extension that led up to big news province and placement camp in the appalachians and for our magnetism in the transantarctic they bought to present various aspects of our continent and continent continent collusion tectonics and they are comparison.
Dogancan Yasar: brings a lot of possibilities and other thing is they bought have a similar scale if you.
Sorry.
If you would.
Dogancan Yasar: If I were to emphasize the scale bar is hundred kilometers and they both have a similar scale.
Dogancan Yasar: And the most notable difference between them is, although we observe a stage of drifting after the great admiration of the appalachian obliging units we don't observe such an event in the Antarctic, there is no referring between the East Antarctic and the vast Antarctic at a later stage.
Dogancan Yasar: The transantarctic mountains.
Dogancan Yasar: have a very long and complicated history but main events would be that they it start everything starts with them archaean juvenile crystal magnetism.
Dogancan Yasar: which was followed by numerous origin me during the formation of Columbia supercontinent, then we have the stage of Romania supercontinent which includes a crust formation stability time time frame and then erosion, then we have the raw storage any.
Dogancan Yasar: That.
Dogancan Yasar: During to go on one, at a time and which includes the battle several bottles and placements related volcanism high pressure high temperature metamorphosis and respective.
Dogancan Yasar: Their formation stages, following that during the permian time we have during the pangea we have the ground, one I tectonics which which ended with em placement of for our metric magnetism.
Dogancan Yasar: The final stage is the formation of the modern transantarctic mountains, as we observe them right now, which includes uplift and animation Dan glaciation some alkaline intrusions and.
Dogancan Yasar: most recent MAC moda volcanism.
Dogancan Yasar: Ours study.
Dogancan Yasar: At the moment we focus on Miller and geologists Rangers we have several samples.
Dogancan Yasar: Cross cutting the general trend of the art grubs.
Dogancan Yasar: And we.
Dogancan Yasar: The aim of this is to be able to.
Dogancan Yasar: Provide contour.
Dogancan Yasar: thermal contours for the better understanding of the terminal evolution of the area.
Dogancan Yasar: A.
Dogancan Yasar: Good window Meyer at.
Dogancan Yasar: That they presented their data from 92 and incorporating the Fitzgerald and stump appetite ages as well, and they provided a constraint to high temperature.
Dogancan Yasar: temperature and very low temperature events and yet these data are mostly potassium argon instead of Oregon Oregon and have a very.
Dogancan Yasar: wide range of ages results.
Dogancan Yasar: Because of that, mostly and then the missing piece of this puzzle appears as the bite ages and potassium felts for ages, which which would provide us approximately the events between 300 and 220 and 100 degrees Celsius and the respective 500 to 250 million year history.
Dogancan Yasar: Our samples are from the Argos chests and.
Dogancan Yasar: We try to select our samples, you know to to just to.
Dogancan Yasar: represent units variables, therefore, we have shit samples some artificial lights and and and to Nice samples, we also have the.
Dogancan Yasar: crowd we have we also have a sample from the Cross cutting grenades harbor interested in order to constraint that event as well and core and compare with metamorphic basement.
Dogancan Yasar: The one of the first things we did is to look at micro potassium distribution and try to characterize our michaels, as you can see in these backscatter photos.
Dogancan Yasar: Some Moscow item bites may appear as fractured or may have some inclusions in them as well, but the overall potassium distribution is observed to be homogeneous throughout.
Dogancan Yasar: and distributed uniformly this indicated that, if there were an argon diffusion would be towards the coverage planes and also we determined, they are half it's for the closure temperatures of these.
Dogancan Yasar: phases, as well the mineral chemistry results revealed that Moscow Whites are near and member and biocides, have a flood quite content between 35 to 60% indicating Granite again pennant paralytic rocks as for the.
Dogancan Yasar: For the Origination rather than metamorphic sources We calculated the closure temperatures us using the parameters provided by Harrison at all 85 for homeland McDougal and Harrison 88 for biotech and hams and boring 94 for muscovite calculations, using the dotson's ad for.
Dogancan Yasar: Closure temperature model.
Dogancan Yasar: Our Oregon Oregon data.
Dogancan Yasar: We start off by doing incremental heating of single homeland crystals.
Dogancan Yasar: which we got the ages of five 524 and ranging up to 519 million years and there is also.
Dogancan Yasar: Inter inter crystalline green tea green variation in the amount of extra genius are going 40 in crystals from single samples.
Dogancan Yasar: As we would expect, mostly from homeland crystal there is access are gone and this access argon is observed to be released, mostly during the first step of.
Dogancan Yasar: incremental eating with just 10% of laser power if we integrate the first step of incremental eating as well, then our total gas and ages ranges up to 700 million years.
Dogancan Yasar: Another way to look at this is the.
Dogancan Yasar: Total fusion and second step age distribution in a probability diagram and we can also see here that.
Dogancan Yasar: The second step, the distribution of second step ages.
Dogancan Yasar: Are.
Dogancan Yasar: 92% of them are.
Dogancan Yasar: younger than 600 million years and they are very close to the plateau ages, we got from respective samples, but if we integrate the first step of eating to that calculation as well, then we get to total age total gas ages ranging up to.
Dogancan Yasar: Very all older.
Dogancan Yasar: Older ages as well.
Dogancan Yasar: This actually reveals very clearly the contribution of access are gone and how.
Dogancan Yasar: We should be careful during their our interpretations of search results.
Dogancan Yasar: When we consider the incremental eating of single bite crystals.
Dogancan Yasar: We got 515 2470 million years of ages and we also realized that total fusion ages.
Dogancan Yasar: tends to lower the age of it because of our gun laws in these phases and.
Dogancan Yasar: The, as you can see, completely opposite of farmland, we have our gun laws, creating this.
increment implementation leading up to younger ages.
Dogancan Yasar: When we consider the age distribution of makers as a whole, we observed that both when we compare them with homeland our homeland plateau ages.
Dogancan Yasar: We see that for most of our samples the homeland ages are the oldest one compared to Moscow and phases and pass the biotech phases, which we would expect because.
Dogancan Yasar: The homeland will reach their closure temperature early in the stage with higher temperatures, then we would have the Moscow is then we will have to buy a tights.
Dogancan Yasar: And also considering the our gun laws on by a tights this skewing towards the younger ages are expected as well, yet in two samples, it was clearly observed that somebody a tight.
Dogancan Yasar: Analysis revealed older ages than the Horn blend plateau ages.
Dogancan Yasar: and
Dogancan Yasar: When we when we compare our Moscow item buyer agents with with this way of probability diagram floating.
Dogancan Yasar: We see the younger.
Dogancan Yasar: The skewing towards younger ages in most of our bow ties with some of them skewing towards older ages and we interpreted this as inheritance X axis are gone in in the bio tights originated from the portal it.
Dogancan Yasar: Overall, when we combine.
Dogancan Yasar: Our new data and newly published data by brown at all 2020 last year and.
actually just came out.
Dogancan Yasar: Within the last two weeks.
Dogancan Yasar: These two papers provides the high temperature events and.
Dogancan Yasar: For both phases zero con and retail.
Dogancan Yasar: We observe a very abrupt change in temperature within 10 million years of time.
Dogancan Yasar: And our homeland ages, managed to come come.
Dogancan Yasar: managed to.
Dogancan Yasar: better identify.
Dogancan Yasar: The events of.
Dogancan Yasar: 500 degrees Celsius compared to older virgin demeyer 96 paper and with better analytical capable capabilities we also managed to increase our position in Moscow ice ages as well and combining these two we identified and continuation of rapid acceleration.
Dogancan Yasar: In the central transantarctic basement which was followed by relatively.
Dogancan Yasar: slower cool and great following the posture of storage any along the endurance interest, where most of our samples are from.
Dogancan Yasar: And the Thompson adult 2019 Paper provides oriented toward them helium zero con ages, which it which.
Dogancan Yasar: which characterizes hundred and 50 degrees Celsius events, and then we still use the Fitzgerald and stop 92 appetite ages for the very law.
degrees.
Dogancan Yasar: And the skewing towards younger ages in our biocide samples we actually interpreted that as due to the placement of grenades harbor into reserves which may have prolonged the metamorphic ISM.
Dogancan Yasar: And because because of their overlaps in the ages, they must have been placed wild Metamorphoses metamorphic ISM was still ongoing.
Dogancan Yasar: And also, we concluded that settlements that would be derived from the basement of central transantarctic mountains would mostly contain ages of cambrian which would range up until permian.
Dogancan Yasar: We still are going to date are fell sparse they're coming very soon and we will be able to identify what what is going on around this region as well.
Dogancan Yasar: um.
Dogancan Yasar: Thank you for your attention and i'll be gladly answering any questions you may have, thank you.
Ryan McAleer: Alright, thanks thanks don john.
Ryan McAleer: There any questions from the audience.
Ryan McAleer: um I had a couple questions.
Ryan McAleer: One is i'm not that familiar with Antarctica what's the.
Ryan McAleer: How long has an article being glaciated do you know, like when the onset of glaciation supposed to be.
Ryan McAleer: I actually don't know.
Ryan McAleer: yeah me neither yeah I was just curious because it looks like.
Ryan McAleer: There was really rapid exclamation or cooling up until I forget the numbers now maybe like 250 million years ago, and then it was like nothing happening.
Ryan McAleer: And then, just over the past couple million years, maybe there's a lot of wiggle room there with appetite helium ages, but I was just curious.
Ryan McAleer: yeah the increased exclamation coincided with onset glaciation or something like that.
Dogancan Yasar: yeah actually there has been several geophysical applications that are trying that.
is working on that one of makers 2017 paper is very good for that.
cool.
Willis Hames: Now those are things.
Willis Hames: That we that we wonder about as well john and I have um are keenly interested in that and there's been a lot of work there really low temperature and.
Willis Hames: Which is all quite younger, this is one of the cases where climate and thurber chronology meet particularly well because it may be the loading of ice host in a candle leverage sort of fashion the translator Arctic mountain some.
Willis Hames: And when the I started to accumulate I hear you know, perhaps figures of 30 million years ago um but there's a there's a big unknown swap of time for sure.
Ryan McAleer: And then, I have one more question did you did you also look at the the bio tights and like potassium type maps or the bites maybe in cross section I was just curious if they.
Ryan McAleer: You know if if you see any evidence of corporatization or anything like that and that could be correlated with some of the.
Ryan McAleer: variation you see in the vital.
Dogancan Yasar: As far as we have examined so far.
Dogancan Yasar: They are this is from by a tight and the potassium distribution seems to be more or less homogeneous, but we are to make more analysis on these.
Ryan McAleer: cool yeah it looks like really, really good and careful work thanks for your talk, thank you.
Arthur Merschat: yeah I guess for break if there's any other questions for the presenters we can ask that now, or I guess the bill, how long winter winter, the the afternoon session startup.
Willis Hames: Our schedule has, as I see it, that we begin again at one o'clock and there are approximately 10 talks this afternoon with a general Q amp a session at the end of the day, as well.
Dave Blake: So that'll be two o'clock Eastern time.
Willis Hames: Yes, yes, thank you i'm central.
Willis Hames: Time in my head so everything will begin two o'clock Eastern.
Ryan McAleer: yeah so please come on back to be great talks we had a massive showing this morning let's let's keep that going right.
Willis Hames: And God officially I think of well I don't know if I should say, but I can't say officially, but just looking around we've had a very well attended session, thank you all.
Dogancan Yasar: I think there's a question.
Arthur Merschat: From josh pool yes josh did you have a question go ahead and mute nass Thank you.
Josh Poole: yeah hey everyone great talks by all of you, this is a been super super insightful.
Josh Poole: So I actually had a question for for Liz and Harold, and this may be opening a can of worms and I apologize, this is not meant to be.
Josh Poole: igniting anything.
Josh Poole: But I was looking in your talks and I haven't watched your filter video, yet I just haven't got around to it, but I look forward to it, the the gardens and the data, you are showing from from the josie leg.
Josh Poole: Just just from you know your your short overview of it that to me that looked like with our group, and I was just.
Josh Poole: I guess maybe I didn't see it clearly on the map, but I guess if you guys could just clear that up on.
Josh Poole: On your distinction of the josie leg of the mcfaul versus what looked like to me that the modality and then it'd be perfectly fine to to not answer this question, but I just kind of generally wanted to get your thoughts on the the Alexander city shares own fault zone.
Josh Poole: Again, I know it's probably opening some words.
Elizabeth Bollen (she/her): So that last questions out of my wheelhouse.
Elizabeth Bollen (she/her): The I don't think Harold is on right now okay.
Elizabeth Bollen (she/her): I can speak a little bit about josie leg, are you referring to the map.
Elizabeth Bollen (she/her): where he wasn't in the right unit.
Maybe.
Josh Poole: yeah maybe.
Elizabeth Bollen (she/her): It is, it is really close to the word alligator that suggest over the contact, however, you wanted to find that content.
Dane VanDervoort: I mean if i'm time and there's just some contention over what the definition of the contact between the with alley in the call is the josie What if you can hear it, the JESSICA leg versus timber gut and whether they are.
Dane VanDervoort: What is what has been mapped recently as josie like historically didn't map is with our group.
Dane VanDervoort: there's just some contention on what what that distinction is between those and where this contacts actually fall into Australia graphic contact or structural contact and does Alexander city fault exists or does it not exist or is it a continuation of the overall fault.
Dane VanDervoort: So that's kind of.
Dane VanDervoort: I think what we're.
Dane VanDervoort: curious about.
Dane VanDervoort: You know the age date that you guys showed for the fall and the way that we were essentially the same.
Elizabeth Bollen (she/her): yeah there.
Elizabeth Bollen (she/her): You know, definitely within uncertainty.
Elizabeth Bollen (she/her): We know.
Dane VanDervoort: Until yeah that was just I guess josh i've been kind of talking back and forth just.
Dane VanDervoort: clarify that stuff but.
Elizabeth Bollen (she/her): And those are mcfall garnets or josie leg creek garnets.
Elizabeth Bollen (she/her): are big and they were a dated for core and rim, and had the same age.
Elizabeth Bollen (she/her): Sure very, very little difference networks plotting two different agents recording rim.
yeah.
Josh Poole: yeah Okay, and I just, just to clarify and i'm not we're not trying to hijack this conversation by any means we can you know we can talk about this separate later.
Josh Poole: But your I saw your ranges for for years and harold's ranges for the for the garnets from like 350 to all the way down to like 323 13.
Josh Poole: Those lower dates like 322 313 seems similar to our.
Josh Poole: muscovite closure closing dates, so do you think that's like the waning metamorphic.
Elizabeth Bollen (she/her): that's 13 I think was the pumpkin vine.
Josh Poole: Oh okay.
Elizabeth Bollen (she/her): Was that Oregon Oregon ha, it has to be greater than that if.
Josh Poole: That yeah.
Josh Poole: that's what I made sense, did you guys differentiate between like and again this may just I may have missed this but, like Cinematic versus like pre or post kinematic garnets or did you notice a difference.
Elizabeth Bollen (she/her): The pumpkin vine is definitely at least pre Cana or sorry sin kinematic.
Josh Poole: Okay, what about these are blue Ridge stuff.
Josh Poole: If you don't remember this.
Elizabeth Bollen (she/her): I want to.
Elizabeth Bollen (she/her): Say most of its host but I can't recall.
Elizabeth Bollen (she/her): No, no, no, just a leg has good rotation inclusion trails within it to.
Josh Poole: mm hmm OK cool.
Elizabeth Bollen (she/her): They could be.
Elizabeth Bollen (she/her): Again, to post.
Josh Poole: This wasn't confrontation, or anything I was just genuinely curious because you know we just see a lot of those good garnets and we've been seeing some and I sent you some really phenomenal garnets in the medallia from our drug war and so.
Elizabeth Bollen (she/her): yeah we still have that pile of stuff collected from you guys.
Elizabeth Bollen (she/her): yeah.
Josh Poole: I appreciate the.
Josh Poole: You guys just letting me me and Dane, and was was chat real quick son again not trying to hijack.
Dane VanDervoort: Thanks Elizabeth for sure.
Elizabeth Bollen (she/her): Now.
Willis Hames: I can't resist show up again a little bit of wins and Harold have really enjoyed I enjoyed all the talks in the session but I like seeing the garnet on.
Willis Hames: thurber Rama tree in one of the characteristics of some of the garden paths that you showed us that is a thermal decompression.
Willis Hames: sort of leg for the garnet growth, and I think that makes perfect sense and i'm, in which case at cooling age ought to be this might be very well the same as the current age, everything is sort of happening with that with that final decompression perhaps and.
Willis Hames: A lot of fun to see.
Elizabeth Bollen (she/her): yeah what's interesting is that along that path for that one sample that has that well defined decompression there's garnets not growing along that path.
Elizabeth Bollen (she/her): Ah it's nearly parallel to the mode mode lines.
Elizabeth Bollen (she/her): So it's just pretty much stagnant growth.
Very cool.
Arthur Merschat: Well, I think.
Arthur Merschat: Again, thanks everyone for a great session and I guess ever ever since i'm getting hungry.
Arthur Merschat: seem there.
Arthur Merschat: Hopefully, more ways to chat but uh.
Arthur Merschat: That, I think, will may may adjourn for until lunch and.
Arthur Merschat: Come back at 1pm to 2pm so Thank you everyone, it was a great great start.
Arthur Merschat: see everyone in our. 1412