Lisa Davis: Okay, so with That being said, our first speaker is going to be presenting through recording his name is brad Johnson is from the Davidson college of environmental studies.
Lisa Davis: And he'll be speaking about dance farmers and legacy sediments the messy drivers of stream incision in the north Carolina people.
Lisa Davis: My name is brad Johnson, and what I want to present today is the results from a number of different projects that are really weren't even part of the same project, but it kind of come together through the time and lots of this data was collected by students, and so I want to.
Lisa Davis: Mention.
Lisa Davis: None of them are necessarily collaborators, because a lot of.
Steph Shepherd (she/her): Sound just stop for us.
Steph Shepherd (she/her): Probably cuz you muted yourself.
Lisa Davis: probably seen it looks something like this, so this stream is incised somewhere between two and four meters oftentimes about three meters in this area and.
Lisa Davis: Through time that has robbed it have access to its floodplain and so cleaned up at the top here.
Lisa Davis: And because of incision it's cut down that much and the Stream is kind of trapped in its own channel here and we see this throughout almost the entire area.
Lisa Davis: And when I was new to the Piedmont over a decade ago there was kind of an assumption from the people I talked to a lot of this was probably the result of processes, similar to what Walter and merits had identified in the mid Atlantic.
Lisa Davis: It made a ton of sense right it's a similar landscape.
Lisa Davis: incision is a big part of it, and so people would have come in your American settlers would come in and build build dams and then after those million per breach we we've gotten.
Lisa Davis: incision and Carl even prove something similar worked pretty well out on a coastal plan, and so there wasn't a real good reason why it wouldn't have worked here.
Lisa Davis: However, the more we examine this landscape, the more we noticed that a lot of those features that we saw in the mid Atlantic aren't here, especially buried soils aren't clear at the bottoms of these things, and so.
Lisa Davis: I started out to do, kind of more systematic study of whether or not this was possible, and the first step for that for my first student work on this hand writing.
Lisa Davis: was to actually start to figure out where we had dams in this area and I oftentimes still say millions, but a lot of these dams weren't build dams, this one on the right here that she found in a newspaper.
Lisa Davis: was, but a lot of these other ones are irrigation dams, and so I try to say small bands, but oftentimes say mill them so.
Lisa Davis: Hannah went for the four counties around Davidson college rowan to Paris aridol in Mecklenburg.
Lisa Davis: And went to the archives free to those and in each archive the record looks quite different in the best case scenario, you get something like we do it ironed out here.
Lisa Davis: Whereas basically essentially just a map in other areas, their lists and the streams there on.
Lisa Davis: parcels their days into in Mecklenburg Mecklenburg is the county that charlotte's in today, and a lot of those have been destroyed, so much of this is focused on the three counties further into the rural area with a few still in Mecklenburg.
Lisa Davis: The result of that early research from Hannah was that she found over 150 damn locations over the four counties, this is like when we're done here is, we only have a couple that remain there.
Lisa Davis: And then she sub selected sites, based on accessibility basically a lot of these are on private land today farmers are somewhat reluctant to have you recommend, on their land and so.
Lisa Davis: Basically, whatever was adjacent to public land are the ones we went after first and that each site what we wanted to know.
Lisa Davis: Is do we see the sedimentary wedge that we see in the mid Atlantic associated with with breached mill dams so in order to figure out and it would go out to each site.
Lisa Davis: And measure incision upstream of the dam and then again downstream of the damn.
Lisa Davis: If the dam is missing, she would walk far enough in each direction to know that she got at least one that was upstream in one that was downstream and then while she was there, she would clear one of the banks and examine soul, development and some of.
Lisa Davis: The results or something like that so she made each of these figures on the right here, and you can see many of them have kind of a damn in the middle.
Lisa Davis: And then there'll be incision measured on one side and decision making on the other side, and what she found pretty quickly.
Lisa Davis: Both in places where we knew exactly where the dam was and in places where it was hard to locate the dam.
Lisa Davis: Was the incision was about the same upstream and downstream, which is very different than what you see in the mid Atlantic.
Lisa Davis: And in fact incision seems to be controlled primarily by depth of bedrock not proximity to a damn so in the bottom left corner here, you see, one of the streams that we examine.
Lisa Davis: That was not in size and the reason it's not in sizes, because you have a shallow depth the bedrock compared to most of the people.
Lisa Davis: And for a stream this small there's just not enough stream power to move all the sudden model, and you can see, this is mid summer and the intermittent stream, and so the Center ministry was moved away this large some.
Lisa Davis: After Hannah finished, we got better lidar for this area, and so I went back and did additional sites that she wasn't able to see, this is a.
Lisa Davis: stream reached that has four dams along it once you get zoomed in here there's only two visible, but this Gray blob here is one of the dams.
Lisa Davis: This Gray blob here the other than I am, and so we can take profiles above the dam and below them above them and loving them and what we see is very consistent incision between three and five meters.
Lisa Davis: And all those sites, even the ones that are right downstream.
Lisa Davis: And in fact this is a slope map and the primary goal here was to show you how steep the banks are to show you that this incisions consistent and you can do the same thing if you just look at the DM.
Lisa Davis: Is notice how significant and consistent this incision is along entire distance and this is a site closer to the College itself.
Lisa Davis: One where the dam is still present here, so the dams, in the middle and so using lidar i've taken cross sections in four places to upstream and downstream.
Lisa Davis: And again, you see the same thing about three meters of incision a little bit more in some places the width of the Channel varies, but the depth of incisions consistent with the damn being right.
Lisa Davis: So the incision doesn't match the pattern, we see in the mid Atlantic, but what about the settlement itself and I pulled this figure from walters paper.
Lisa Davis: And i've always loved this diagram because it shows very clearly kind of pre euro American dream settlements below with this history saw with tree trunks still in it at the base and then a nice column of mill them sentiments basically what country and southern moving up.
Lisa Davis: above that buried soil.
Lisa Davis: So what do we see, is it, similar to what they see there.
Lisa Davis: And i'll be the first one to admit that when I came to the southeast it took me years to even train my eyes to understand a bank like this and everything just kind of let's read, is it separate lines and sediment.
Lisa Davis: But after a while you start to be able to see these and the first one, you see here and i'm sure you guys stay tuned this line here is a true dividing line.
Lisa Davis: And below this dividing line we get fined during settlements occasionally laminated but not significantly so in many places, and then above that we get sandy Solomon sometimes those sandy segments for prospecting.
Lisa Davis: and in other places they're just kind of a massive sand.
Lisa Davis: And sorry question again this is kind of the opposite of what you see in the mid Atlantic the question again, what is the nature of this dividing line here.
Lisa Davis: And we haven't had a ton of deadwood material, but the data will material we've had is in this lower material and it all dates to pre your American arrival, so your Americans move into the Piedmont of Western or central Carolina about.
Lisa Davis: Of the oldest settlements and area, and so the sediments below this appear to be the fine grained stream sediments of the natural background stream pre your American settlement, which would make all this stuff on top.
Lisa Davis: Some sort of legacy Center and so, then I guess the question becomes, what is the source of his legacy sediment.
Lisa Davis: You see a similar one here right so below the knife right we see those finer grain settlements above the Nice we see significantly coarser sand your writer.
Lisa Davis: And the answer, in my opinion, from both my work and work of others, is that this is the sediment that comes from the upland so.
Lisa Davis: Another one of my students Rosalind spell work on goalie formation Doug so pits on olivia fans at the base of these galleries and when she found is that.
Lisa Davis: Because these landscapes are predisposed to erosion, because of how much clay, they have at the surface.
Lisa Davis: As soon as your American settlers start cutting down trees golly start forming almost immediately, she would get bazell ages in louisville fans.
Lisa Davis: From the 70s and most immediately after people arrive, and we had originally thought it would kind of be these with form during peak agriculture 1850s 1860s but every place we found dates.
Lisa Davis: golly started forming significantly before that and it's not just the goalies it's also the uplands.
Lisa Davis: Trimble showed in this area of quake conclusively in the 70s, that we've lost almost a full of top so much of the opinions of the pima.
Lisa Davis: derman in jamestown similar legacy segments industry values recently in South Carolina so this isn't totally shocking to think that all of this settlement that was on these options has settled down into.
Lisa Davis: Some figure fee that looks something like this, so is another one of these bottom half fine grain clay and so rich sediments dividing line with the upper half here.
Lisa Davis: Being sandy even some find your apples in there to zoom in you can see some cross betting so much higher energy environment than that stuff.
Lisa Davis: I do want to point out and i'm not going to mention it again because it's kind of an aside, but I do want to mention this dark spot at the base here, because our original idea was that these were buried a horizon, similar to what we've seen in Linux.
Lisa Davis: However, our testing of this shows that it's not high and organic matter anywhere that it shows up.
Lisa Davis: In fact, they tend to coincide with where ground water seeps out of the banks of the River leading us to believe that these are actually Hydra logic future features either.
Lisa Davis: Reducing conditions, a stage of glossing or maybe even manganese that you see in the walls here, so these look like very soul, but they don't actually seem to have any features and I want to mention they do show up.
Lisa Davis: Okay, so i've answered the question about aggregation but we haven't addressed what the cause of pema incision is here so so let's let's circle back to that what is the cause of.
Lisa Davis: incision in this area, so this is a great stream, for example, because this isn't the summer, this is an intermittent stream, with no water in it, and yet we have almost two meters.
Lisa Davis: And that brings us to one of what we think is a primary cause here and that primary cause is significant changes in surface hydrology specifically.
Lisa Davis: These landscapes, are very flashy partially because they have clay at the surface and also because they've been developed over the last few years, and as we get increased impervious surface, we got more and more flashiness and higher peak distorted so.
Lisa Davis: here's a forest stream on the left, during a summer summer summer storm about an inch for in 35 millimeters or in, and you can see, the response on these tiny first order streams, is we get over 100 CFS.
Lisa Davis: And for these winter events we see something similar.
Lisa Davis: But even more, we did extreme flashiness in the winter, even in forested areas because there's so little topsoil is soak up some of that water.
Lisa Davis: But that's not the only reason we see a number of other reasons as well, for instance.
Lisa Davis: I pulled the 1938 aerial photos for the region, this is the first stream if you went South from Davidson college.
Lisa Davis: And these aerial photos are harder to get because they're in the national archives and what we see is a stream that is consistently very straight indicating the farmers have already been straightening streams as early as the early 1900s.
Lisa Davis: And you can actually see that very clearly in these cross Sections I made earlier.
Lisa Davis: These cross sections in to the side of them, you see what looked like natural levees but they're not actually natural on these what they are is oils pile So if you dig into these you don't get any sold about their spoils files from when these channels were significantly deeper.
Lisa Davis: And if we go back to the modern lot are, this is the same stream, we were looking at a minute ago nice straight stream it's it started to get a little meandering through time.
Lisa Davis: But not only do you see streaming streaming and evidence stream straightening farmers were very aggressive about digging side channels which you can see, near.
Lisa Davis: and dear to drain the lowlands in order for these side channels to drain downhill, you need to dig the main channel down even deeper.
Lisa Davis: So you did these main channels down very deep and then you think the side channels down and all that would train these these bottom lens essentially the flood plains.
Lisa Davis: And in draining those floodplains you have significant or farmland and you not only see this in the entire region, but farmers have explained to me how their grandparents done these out and how they maintain the side channels to keep the bottom lands nice dry.
Lisa Davis: So what would streams have looked like before your American side there's a few of these left and they always look pretty similar to this and a NASA moving stream low energy multiple channels oftentimes in a forest fine grained sediment.
Lisa Davis: But these are very much threaten So when I took this picture that you see here, I also took another picture I rotated 180 degrees, so this is looking upstream.
Lisa Davis: And I rotated 180 degrees in the picture downstream and the picture downstream is this one.
Lisa Davis: And this is clear evidence of active incision and that active incision has started at Nick point and that Nick point will move through the system very rapidly.
Lisa Davis: Because the substrate is mainly soil and once it gets going it's very hard to stop it so i've mentioned numerous causes of incision.
Lisa Davis: But also it's important to recognize that, once the incision starts in one part of the landscape, it will move through the rest of the landscape quite rapidly.
Lisa Davis: This is the lidar from that exact same site, so this is the insides channel down here that Nick point was right here and upstream if we draw a little.
Lisa Davis: Cross section, what we see is no incision less than half a meter multiple side channels and Eskimos, this is the what I think that historic floodplain would have looked like before these these rivers got trapped in their own.
Lisa Davis: In their own incision.
Lisa Davis: And in fact I had point that Nick point I had a student get interested in a few years ago he went out in May, before the summer and.
Lisa Davis: surveyed it in using a total station So these are all in meters so it's about three meters deep on these are just kind of random X and y axes of meters.
Lisa Davis: And we thought this would move a couple meters per year, and so we didn't serve a very far upstream and by the time you came back by the end of the summer, it had already moved seven meters Edward.
Lisa Davis: Two months later, after hurricane season had moved another five meters and by February, not even a year later, it had moved almost 20 years 25 meters.
Lisa Davis: So this kind of rapid incision shows that once you get incision in one place it's going to move throughout the rest of the landscape extremely quickly.
Lisa Davis: And, and so basically you don't need incision happen everywhere one farmer to deepen their stream and then that signal would move throughout the rest of the system at least upstream.
Lisa Davis: So let's let's build a little conceptual model here so underneath these things sometimes you see him through the bottom of the stream, we did a some sort of strategy built into the separately and I don't know any details about that, but you see it once in a while, so it must be.
Lisa Davis: And then we get a natural aggregation in the Holocene a associated with these massive building streams and find great segment with multiple channels.
Lisa Davis: Then we get a period of euro American settlement and legacy segments coming down and burying the entire floodplain.
Lisa Davis: And then we get incision for a handful of reasons including reduction of sediment supply as the upland stabilize increase urbanization flashiness stream straightening Edward erosion all of those things come together.
Lisa Davis: And one of the ways that we know that this the mill dams are often are generally not the cause.
Lisa Davis: Is that every meal damn we found is actually inside incision indicating that incision occurred before the mill damn was built.
Lisa Davis: And in places we can take these little tabs to about 1900 there is one in the area that behaves exactly like it does in the mid Atlantic, and that is one of these were the exception basically kind of proves the rule for all the other sites.
Lisa Davis: So some conclusions here there's a single mill damn in the area that fits the Walter and marriage model but otherwise like legacy settlements are nearly ever present.
Lisa Davis: incision seems to be the result of complex overlapping sort of energetic impacts and a little bit more dating is required to understand policy and aggregation and to put a firmer line on the pre colonial postcolonial so.
Lisa Davis: With that I do want to recognize students who worked on this through time, each of them worked on a different part of it, a lot of these I didn't think were part of the same project to begin with.
Lisa Davis: i'm hoping to be present for this presentation, so I take questions if i'm here if i'm not here, please feel free to email me i'm happy to answer questions.
Lisa Davis: Thank you all for your attention, I really appreciate it.
Lisa Davis: So that was brad's presentation and I don't think brad is with us i'm just looking through the list of attendees brad if you're here, please you know.
Lisa Davis: make yourself known but I don't think he didn't make it, so I think we will we can discuss what we saw but uh you know, and if you have some pressing questions, we can certainly address those by email with them.
Steph Shepherd (she/her): I get super excited when I see anything related to this work, because my first job was to I was Dorothy merits sabbatical replacement and the work that.
Steph Shepherd (she/her): He showed i've stood in that stream with her and her students.
Steph Shepherd (she/her): And gotten to see it in person, so I get excited when I see more of this type of work because it's a way her her that paper and what brad is doing shows how much more complicated this understanding stream morphology through time is way more complicated than we ever thought it was.
Lisa Davis: yeah I spent some time working in streams in the Piedmont and insights channels, in particular, looking at incipient floatplane formation and these overriding channels and.
Lisa Davis: it's just with unconsolidated materials it's so there's just so many degrees of freedom for changes to occur.
Steph Shepherd (she/her): yeah.
Lisa Davis: It does make it far more complex, you have, like many different you know layers essentially or you know contingencies of things that have happened over time so.
it's very.
Lisa Davis: Interesting I would love to ask him about whether or not he has found any of these sort of incipient floodplain features in his insights.
Lisa Davis: channels that.
Lisa Davis: correlate to kind of bagful stage, essentially, so he mentioned in the beginning, that you know they're essentially decoupled from the main valley flat, which is like the hallmark of like you're going to develop a new inset pipeline so.
Lisa Davis: it's interesting.
Lisa Davis: anybody else here work in the people.
Lisa Davis: Okay well we're now at 155 and.
Lisa Davis: So it's actually time for our next presenter to.
Lisa Davis: To start their presentation, which is Michael obvious.
Lisa Davis: From the centers research in Stanford Connecticut and the presentations title dough lines and Carolina based on the data city playing an unconventional hypothesis for conjoined to morphology so i'm going to go ahead and i'm no longer sharing, so you should be able to share your screen.
Michael Davias: You got that lady.
Michael Davias: Already.
Steph Shepherd (she/her): Already, so we actually see all of the everything, so I don't know if you just want us to see your slides because.
Steph Shepherd (she/her): I see the.
Okay.
Lisa Davis: yeah if you just go to slide show.
Steph Shepherd (she/her): yeah.
Michael Davias: that's helps to.
Michael Davias: accept that still not right, unfortunately, because I lose my text on the wrong side I don't know how I did that hold on a.
Steph Shepherd (she/her): Second.
Michael Davias: I have to start again.
I understand.
Steph Shepherd (she/her): the joy of small screens.
yeah.
Lisa Davis: Too many options.
Michael Davias: yeah i'm.
Michael Davias: Just okay this.
Michael Davias: Not only that, not me not just me simply knowing what to do, i'm going back to zoom here to share, I think I need to share my desktop to, which is what I wanted to share.
Michael Davias: How about that.
Steph Shepherd (she/her): Much better, I see this this slide.
Steph Shepherd (she/her): And sorry read it that's.
Michael Davias: that's what I want yeah that's, the important thing.
Michael Davias: um so um.
Michael Davias: it's my pleasure to talk to you today about my Carolina based survey, along with observations deductions and some pretty wild speculations.
Michael Davias: i'll share with you my unconventional hypothesis for pleistocene doherty plane this came out of the door the playing group that never.
Michael Davias: I guess coagulate into enough people to have their own session, but it also addresses the hydrology issues that this group is looking at right now.
Michael Davias: And I want to socialize a geo chronological tool that may help constrain North America, over the last 5 million years and perhaps tickle out some of these issues about all it sediment Honda both on the Piedmont and and the coastal plain.
Michael Davias: I propose the Carolina bay's we're not excavated from coastal sediments not by wind and wave, not by direct or secondary cosmic impact and that the base our fire fire older than contemplated by students of the coastal plain.
Michael Davias: All of that informs the speculative catastrophic hypothesis that will get into the liens, of course, are well documented subsiding the sinkholes caused by a fusion of underlying my pitch your pictures are in the way here.
Michael Davias: carbonate bedrock on the dirty plane, the bedrock agency is the late you've seen oh color limestone.
Michael Davias: Now i'm.
Michael Davias: there been a lot of mapping effort to document 1000 so sinkholes across the dirty plane, a few of them are old boys, but otherwise they're pretty jacket.
Michael Davias: linear sequences of buildings are considered control by underground drainage channels or by bedrock fracture patterns.
Michael Davias: On the Carolina bays in the 1940s Douglas Johnson documented to Carolina base shapes each found in unique territories one oval one teardrop found embedded in a wide pediment that ran from beta Bay or beta plane.
Michael Davias: Has a head of Columbia university's geology department Johnson asserted that he had not encountered a problem so difficult is Carolina bay's unless it be that have submarine Kenyans.
Michael Davias: Now those Kenyans are explaining GEO one on one these days, but science and johnson's error was smitten with land bridges, because he could not tolerate the constants went crashing through the oceans.
Michael Davias: And I consider the wind and wave solution for Carolina base to be analogous to land bridges gradualist solution that allows a difficult problem to be dismissed with a wave of a hand.
Michael Davias: Well, I have identified six pieces of base that except for the bay oval possess a signature flattening.
Michael Davias: johnson's plan form Bay Carolina and based south are highlighted here all six are found within exclusive territories on the continent.
Michael Davias: These templates are used in a measurement for the length and width can be shrunk or stretched to match a given bay.
Michael Davias: But otherwise is subtly at unique modification from a pure oval are maintained now here's a table that shows simple averages of spatial size in essence pretty.
Michael Davias: SN tricity by plan form type and those to the bay south of a Carolina represent 90% of all bays mostly in South Carolina North Carolina.
Michael Davias: While the bay shape changes some metrics they persistent this histogram demonstrates the size distribution of 50,000 bay's.
Michael Davias: over various ranges of elevation above sea level are all exactly the same now, despite their prolific presence on the coastal plain.
Michael Davias: The story and smithsonian magazine, is the only article discussing Carolina base in a major public consumption scientific periodical nat GEO discover all scientific American right nope.
Michael Davias: Only one those few days remaining and it near natural state or national treasures impenetrable enclaves rich environment by ever diversity.
Michael Davias: The lowest level of organic deposits in these land forms is typically carbon bed carbon dead suggesting, they are over 50,000 years old.
Michael Davias: featured in the smithsonian story is antioch Bay in North Carolina a truly beautiful Emerald gem on abroad fat into flavio terrorists that topography of the land form is apparent in the lidar.
Michael Davias: revealing and close hydrology within an overlay depression now despite is protected status, there is artificial training here.
Michael Davias: The custom color ramp on the Left cycles every 10 meters so elevations can be interpolated modular 10 meters, the total relief on this image is under five meters.
Michael Davias: So my protocol for the elevation model is to pump up the hill shading by 20 times, making such subtle relief look substantial and it ain't.
Michael Davias: The imagery tiles in the cloud or rendered at 150 centimeter spatial resolution a trade off between detail and download bandwidth now, this is a significant catchment basin each meter of water in the basins holds 200,000 cubic meters of water.
Michael Davias: Is antioch and unusually large Carolina pay well actually no.
Michael Davias: backing out with antioch in the Center there are many of similar sizes, the survey documents over 10,000 babies that have a main axis of over half a kilometer.
Michael Davias: And within that the average size is 955 meters like antioch a meter of standing water and all of those would yield a total of over 1.6 million acre feet of potential runoff catchment.
Michael Davias: The high rez typical topographical model i'm using here lubricates the actual plan form of the base without the OPS vacation of all the foliage.
Michael Davias: could extend the seamlessly across the entire survey scope this image covers 200 square kilometers you have to train has a relief across all of this of only 25 meters.
Michael Davias: so sadly 99% of these bays identified in the survey have been ditched and logged in the vast majority drained and converted to human users.
Michael Davias: This 1930 aerial photo documents obey with a major access of over a kilometer.
Michael Davias: And Google historical imagery provides us with this view in 1999 with graceful parkways through the long leaf pine forest in wilmington North Carolina by 2011 the camera and art museum had built on the bay, along with the park and a pretty little pond.
Michael Davias: By 2011 by 2014 lidar we see what's under the foliage lots of drainage after 25 years of D watering it was ready for development in 2016 satellite views.
Michael Davias: Today it's a bustling community of homes apartments shopping offices, the requisite cineplex and acres of asphalt parking and.
Michael Davias: So I often contemplate with the flow rate of rivers look like in today, after a major hurricane relative to after a similar storms centuries ago when all these enormous Cashman basins were buffering that hydrology.
Michael Davias: Now I have been doing the geospatial survey of Carolina base for the past decade.
Michael Davias: I currently have 55,000 basins represented in this heat map view across 201 degree quadrants and image and over 3001 quarter degree by one quarter degree high resolution topographic digital models integrated all into Google Earth.
Michael Davias: You might ask who inspired me to undertake all this such obscure research, while it was GSA fellow and usgs hydrologist extraordinaire William rasmuson.
Michael Davias: He was a GSA fellow there he stated that they're very randomness of grouping and scatter demands an explanation as a statistical phenomenon.
Michael Davias: They deserve to be studied statistically, so I thought i'd do that let's take a, but we need data to do that so let's take a closer look to the southeastern us zooming in tighter on a digital elevation model regions of solid color denote low relief, where I go looking for Carolina base.
Michael Davias: As in the area highlighted.
Michael Davias: Now this area concise coincides with the ACF river basin those superimposed image is derived from Google.
Michael Davias: zooming in further to doherty plane as a subset of the ACF from the fall zone to the elements carpet now i'm going to activate the survey data set.
Michael Davias: At this field of view the orange outlines and white placements of when degree quads are showing.
Michael Davias: The course heat map of measure base shows a zone of days in the ACF question for today is are those domains or Carolina bays we will be zooming into a suspect Carolina Bay where the phoenix city, making both in and way cross quads me.
Michael Davias: As a viewer moves in closer the survey presents place marks for the largest 10% of base in each quarter degree sub quadrant outlined and read their that topographic model begins to load in the field of view.
Michael Davias: Note that the do not enter icons to note quarter to quarter degree closet don't contain basin measured basins anyhow but i'm always looking now zooming in further even high res maps higher res maps load and, along with the next 40% of days.
Michael Davias: Along with the smallest 50% of bays the measurement overlays are beginning to become more visible here sub meter lidar is only available west of the flint river to the east disperse 10 meter which doesn't show us much at all.
Michael Davias: The primary land form here with a major axis of 926 meters like antioch is considered by me to be a Carolina Bay a week to its robust conformance to the plan forum and orientation that is consistent with its neighbors.
Michael Davias: Now the value of Sub meter lighter becomes apparent when viewing the gentle arcs of irrigation rigs and other anthropological alterations the available ortho photography clearly cannot assist in discriminating the actual rim from the wetland.
Michael Davias: Located 34 kilometers to the West is another well sculpted day again about 900 meters and major access note the similarity unplanned form, but the different essence.
Michael Davias: Now it looks to be natural drained by head word stream erosion, which gain entry after being rebuffed.
Michael Davias: Along 800 meters of its axis of it so what's the eastern boundary there now this Bay has been measured previously let's let's back up and have a look at my Bay measurement protocol.
Michael Davias: First, a new first a new image overlay is added to the directory of metadata we provide a name and a URL to the template image it's instantiated with the arrow pointing due north.
Michael Davias: It is an edited with the corner and rotation handles.
Michael Davias: To help fit the template to the bay rim, while some of the outcome is subjective the subtle variation of the archetypal vocal help block in the result.
Michael Davias: template and provides a price precise and reproducible measurement protocol, while measuring while remaining highly efficient compared to the manual tracing the goal is to encompass the rim under the dotted line done.
Michael Davias: Now a ground overlay is not a graphic image it's text in a markup language, we can read it, the base South overlay URL is identified rotation from do North reports debase orientation, the lat Lon box coordinates.
Michael Davias: which are quite precise there's five decimal places there, which gives you about a one meter accuracy.
Michael Davias: They create a bounding box defines with a bit of trigger the major and minor access to the bay Bay Center in an approximate surface area, the boxes defined at zero rotation and it's then reapplied by Google earth when its displayed.
Michael Davias: Now the survey can be accessed it since those.org slash survey were to download links are available first will deliver a tab separated text file with 55,000 plus rows.
Michael Davias: And each contains metrics for a specific bay and a field which contains kl to view the bay on a Google folder globe, you can copy it out of the spreadsheet and pasted into Google Earth.
Michael Davias: The second link on the page will deliver a lightweight starter camellia file to load the geospatial server you've been looking at into Google earth and from there all the survey loads from the cloud now.
Michael Davias: As the second one here.
Michael Davias: Now North Carolina geologists gamble Daniels and wheeler spent a decade scouring the coastal planes trying to identify the Providence of undefeatable.
Michael Davias: Deep superficial sediments in this paper they made the assertion that has frame my entire 15 years of research as the opening sentence, the Carolina bay's of coastal plain of North Carolina our surface features form during the deposition of the superficial sediments.
Michael Davias: In the intervening five decades, no one has undertaken a comprehensive follow up using today's jiuquan tools to date, those settlements.
Michael Davias: I maintain the Carolina based are not ephemeral wispy land forms but rather are the artifacts of a massive sedimentary deposition event.
Michael Davias: i'm not looking to get into the physics today just exploring with you the possible implications of such an event on the GMO ufology the dirty plane or the coastal plain or the Piedmont, for that matter.
Michael Davias: The hypothesis has numerous challenges which had been debated in many venues, I maintain that most of these are incorrect or irrelevant.
Michael Davias: In the context of the hypothesis, but let's look at the last two they don't look that old well many days, many of the base in the survey have kilometer scale natural drainage.
Michael Davias: What does that tell you about their age, on this pool table top table smooth topography that's been there since the cretaceous.
Michael Davias: There are no deposition or sheets across the terrorists boundaries well as assertive by Daniels and his buddies 50 years ago with a brandy why ankle hearing and Sunderland Ms us are delineated largely.
Michael Davias: On the basis of the Kenyan Wilson bill scarves but little proof is presented, that the indicates, one way or the other, what happens to the units across the scarves.
Michael Davias: We believe the surface deposits in the middle coast, the plane in our area or one formation not three what goes across three different terraces.
Michael Davias: The literature contains numerous examples of excellent research in this post miocene deposit from Maryland all the way out to Louisiana.
Michael Davias: Each ending with a call to do further work to identify their temporal and deposition all aspects but they're there so it's there right I sense the same issue on the dirty planes rose idiom.
Michael Davias: Now, allow me wishes back that mid pleistocene 800,000 years ago when an ancestral drainage dendritic drainage pattern had expanded North from the Gulf.
Michael Davias: Across the dirty plane topographic province now I invoke my catastrophic event which resurfaces the plane, with one to 20 meters of regolith currently characterizes resilience.
Michael Davias: That deposition is in blankets, finding upwards and it's conformal to Paleo terrain features Carolina babies are manifested in the new terrorists surface turning a significant percentage of the landscape into hydraulically closed capture basins.
Michael Davias: terrain and deranged drainage evolves it's my interpretation that base do not develop on into flu fields, but rather that the flavio evolution is constrained by erosion resistant Bay rims and drainage develops around the Carolina base.
Michael Davias: My speculative event has implications for the dirty plane drainage evolution, first of all, the Paleo drainage channels all get buried.
Michael Davias: The presence of numerous Carolina Bay catchments reduces rain and run off any erosion.
Michael Davias: The range drainage network regrows across the resurface plane deflected around the erosion resistant base and occasionally capturing antecedent drainage.
Michael Davias: That results in insights channels implication for the dirty plane d'alene evolution many domains for him and new sedimentary blanket through normal so fusion.
Michael Davias: Carolina base holding concentrate standing water encouraging cars penetration into the call a bedrock.
Michael Davias: Carolina beta floors which you have suffered anthropological modification may effectively puncture any developed Avatar and accelerate the lean development in the recent past.
Michael Davias: Barry channels offer alternative mechanism for the north, south delete alignment now the hypothesis, I have here is falsified if GEO chronology of previously unavailable.
Michael Davias: Post miocene sediments do not document a significant anomalous pulse of superficial regular aggregation 830,000 years ago.
Lisa Davis: I got two minutes okay i'm sorry.
Michael Davias: Thank you i'm almost done i'm i'm at the fall suffocation that's the end right.
Michael Davias: And assessment that can be accomplished with brilliant dating now so beryllium aluminum dating I don't know if you're familiar with it, but it's it's a great geological deposit.
Michael Davias: measurement of Joe was deposit of measuring the dating of geological deposits, by looking at a pair of rare nucleotides.
Michael Davias: They are caused during correct cosmic Ray bombardment of a courts Barry mineral target of which there's a lot out there, so um I encourage more research just don't researcher to delve into this dating technique i'm always asking people to.
Michael Davias: So self serving thing.
Michael Davias: There would be more examples, such as these i'd like to see Belka noted in anomalous regolith loading in glacial till's deposited eight 800,000 years ago.
Michael Davias: Anthony notice a widespread singular appalachian drainage basin aggregation signal at 800,000 years ago del vecchio identified a sudden onset of regolith.
Michael Davias: About 750,000 years ago in a central appalachian by trout previously only accumulating separately, so these things, of course, are considered by products would admit pleistocene climate transition which nobody knows what caused.
Michael Davias: In another Daniels and Gamble and wheeler paper they investigated this 10 meal meter high 20 kilometer long range of monotonous, and can they containing Carolina based they struggled to identify it's deposition regime.
Michael Davias: This is their closing sentence.
Michael Davias: But until much more is known about the middle coastal plain the goldsboro bridge will remain in the last analysis and enigma.
Michael Davias: And 50 years ago geology only allowed gradualist mechanisms to be tested against for depositions regimes, the coastal plain deserves an extension extensive.
Michael Davias: effort to contain its temporal aspects over the last 5 million years and this would be a great place to do it across those two transcripts so there's my summary, I have a I have an abstract that's definitely pros I hopefully even read it.
Michael Davias: So that's yeah.
Lisa Davis: it's great Michael awesome job getting that succinctly wrapped up.
Michael Davias: And thank you for your patience i'm.
Lisa Davis: know you presented some really interesting concepts there, and unfortunately there's not time for questions, right now, but we do have a break coming up and so people want to hang out after that.
Lisa Davis: feel free to do that and or you can direct message Michael your questions Okay, so our next speaker is Joseph holdings from the Department of geology and geophysics Louisiana State University.
Lisa Davis: You will be presenting on characterization of preferential subsurface flow paths in a mantle cars terrain so i'm going to turn it over to you, Joseph.
Joe Honings: Okay, do you guys see my full.
Joe Honings: PowerPoint Nada stuff on the sidebar cool.
Joe Honings: Well, thank you.
Joe Honings: i'm Joe i'm a PhD candidate at LSE Oh, and I work at the john Center ditch way to present a little bit of my dissertation work and which i'm using some geophysical methods to characterize preferential so surface flow paths in a mantle cars terrain, such as that already.
Joe Honings: So the main motivation for this research.
Joe Honings: You orient yourself to the bottom left image, you will see several circular features, if you haven't been through the door the plane or this area, those are Center to the irrigation systems that became a prominent practice in the late 1970s and continue today.
Joe Honings: As these became more prominent groundwater is being extracted and sometimes over extracted therefore disputes have arisen for decades related to resources, both locally and nationally.
Joe Honings: Even state to state the superficial hydrology has been diminished, which therefore affects the hydrological ecosystems that depend on them and by about mid century groundwater extraction is expected to increase in the area by about point 4 million cubic meters per day.
Joe Honings: The.
Joe Honings: The aquifer itself is the upper Florida and aquifer which is within a car system.
Joe Honings: As Michael actually alluded to, and in his presentation prior there is.
Joe Honings: A fracture system that's been identified and hypothesized in in previous research by Kathleen regal and back in others.
Joe Honings: indicating that this fracture system in the carbonate could be controlling some surface streams and the ground water flow.
Joe Honings: However, with cars is difficult to characterize how water flows through because of the high secondary ferocity and heterogeneity of these systems.
Joe Honings: Recent work in the door, the plane and the john Center have been a recent efforts have been focused on identifying recharge hotspots.
Joe Honings: To the article for for forest management decisions and restoration, but how these hotspots are connected to.
Joe Honings: The rest of the aquifer and the surface streams, is relatively unknown so are there surface pathways are perhaps sudden surface flow paths that connects these recharge areas to discharge points.
Joe Honings: So some of the objectives with this research are to inform groundwater models that will improve the sustainability of the aquifer so.
Joe Honings: Around the MID 2000s are when capabilities to put cars features into models like MOD flow, the US, yes, my flow equation.
Joe Honings: Where were initiated in yet look the battle has been, how do you how do you put a conduit in other than just making it a simple straight pipe in your bedrock.
Joe Honings: And so, current research has been aimed to constrain the geometries and parameters around these conduits or cars cavities or continuous.
Joe Honings: That are otherwise difficult to automate, and so we are using shallow.
Joe Honings: shallow subsurface geophysical methods to hopefully constrain these kinds of geometries their location, therefore, improving model calibration and accuracy for the region.
Joe Honings: Additionally, if we can locate these features, it would help us further understand the connection of these recharge hotspots to subsurface flow.
Joe Honings: And therefore, identifying those flow paths would inform land management decisions groundwater modeling projects and even a future implementation of Center pivot irrigation systems on these flow pads increasing overall efficiency.
Joe Honings: So the study area so i'm not sure how many of you have been to the john Center this way but it's a beautiful property.
Joe Honings: safely forest city ecological preserve the boundary is indicated in this image by the light is green, as you can see immediately outside the property boundaries it's densely irrigated by Center pivot irrigation.
Joe Honings: There are several cars class features present at the surface, but also beneath the exams in clays at the gen Center most of them are sinkholes and the patterns in which these sinkholes are.
Joe Honings: aligned in arranged on the landscape are indicative of those fracture patterns identified in previous research, most recently Kathleen regal worked with a john Center identifying those fractures in stream bank outcrops of a creek its way not to a creek on property.
Joe Honings: To start this process.
Joe Honings: We use lidar imagery and some aerial photography and a little bit of actual physical on the ground.
Joe Honings: reconnaissance but.
Joe Honings: Digital train models produced from lidar courtesy of mian mian did a flyover of the john Center and the digital train models which are basically bear earth models, you said you eliminate the vegetation and can't tree canopies and you're visualizing the bear geology essentially.
Joe Honings: We examine those for patterns and.
Joe Honings: came up with a couple of continuous features, but, most notably this this longest.
Joe Honings: line here, extending from the creek in which, in this actual stream bank, you can see dissolved fishers of the ocala limestone.
Joe Honings: In the stream bank and the orientation of those fishers are such that it is aligned with this lineaments of sinkholes and i'm not sure how how your screen quality.
Joe Honings: is really turning these out, but there are several sinkholes along this gentleman about 600 meters long an additional one and another smaller one all converging in this one area.
Joe Honings: And so, this is a Paleo stream Valley, but the sinkholes are aligned in such an intimate that we want to do, investigate if this is where a subsurface flow path actually exists.
Joe Honings: Beneath the sinkhole funnels essentially.
Joe Honings: They do that ground penetrating radar we completed several trans sex cross that feature but.
Joe Honings: Typically ground penetrating radar is used to understand the subsurface stratigraphy and any defamation specifically for this car stuff formation and the subsurface.
Joe Honings: electromagnetic waves are transmitted into the subsurface and reflected back to a receiver which records travel time.
Joe Honings: The difference and the dielectric prime activities of geological us so in this case, like a sand and clay overlying limestone bedrock is one surface, that would be reflected.
Joe Honings: Cars features that would be reflected would be any combination of sediment in filling dissolved limestone and water and air reflections.
Joe Honings: With something if we're working with the conceptual idea of a pipe in the bedrock we oriented the surveys perpendicular to the pipe such that we would cross that feature several times and therefore.
Joe Honings: interpret the geometry from the Cross sections produced by the gdpr data and just recently we we all created some software and actually are able to convert the Cross sections into dust slices to view the entire survey area as a whole and see how.
Joe Honings: Just the dynamics between different depth slices through the landscape to visualize whether or not there's connectivity.
Joe Honings: So this is the same view I had shown earlier just with the Trans tax identified as a B and C transact a is towards the in the southwest area of the of the feature, where we have these lineaments converging.
Joe Honings: Cross section me that will follow is kind of in the middle of our conduit so speak men see is in this area where it's possibly I mean.
Joe Honings: they're all big sinkholes but this looks like one of the oldest sinkholes and in the field, you know it's about two and a half, three meters deep.
Joe Honings: With several older trees growing out of it it's a pretty prominent one and we focus a lot of our other surveys around that one as well and i'm going to show you just how those looking cross section in sequence, and then we'll look at the feature as a whole.
Joe Honings: So this is that Southwest transact and very clearly there's reflections.
Joe Honings: On the conservative side of things about 10 meters wide that continued from about two and a half meters deep.
Joe Honings: Well into the subsurface beyond where the survey imaged when I know that these are a little hard to see and the software doesn't really let you.
Joe Honings: play around with how big these axes are, but this is about nine meters deep the bottom of this image and so at about two and a half meters deep, is where we have.
Joe Honings: A point hyperbolic reflector and then another one that follows that indicates, you know this here between two sinkholes this is this is solid ground is a kind of a continuation of the cars, between those two sinkhole features.
Joe Honings: As we work our way up valley and upstream it's not quite as obvious, but again about two and a half meters deep in this part of the image.
Joe Honings: We are seeing somewhat of a funneling of sediments and stacked hyperbolic even though they're a little fainter here reflectors into the subsurface.
Joe Honings: We work our way completely off the valley this survey was designed to completely pass the largest single by several meters and you know when we've been looking at this, these data and interpreting this cross section, we can see the funnel shape beginning.
Joe Honings: On look to your left in this image.
Joe Honings: That right here is where reflections are indicating that there can be like buggy karst or.
Joe Honings: Air pockets in the in the host bedrock but not necessarily a full on collapse, however, when I went out to the field and hand auger this I.
Joe Honings: stood about right here at the about close as close as I could get to halfway through but I had an air pocket with the hand auger that immediately caved in upon itself in the field so we're looking at this two and a half to three meter.
Joe Honings: covering of sediment says, like the zone of interest to finally entering the current regime of the region.
Joe Honings: And so I put together a little video, and this is my first time ever, trying to put in a video into a conference presentation so let's see if it works.
Joe Honings: um the you're going to be viewing depth slices in quarter meter increments the first meter is going to be mostly blues, and that is not indicative necessarily have sediments but just the.
Joe Honings: The direct surface way from the gdpr it comes out in every data set so we're going to start looking at about the one meter and slice where everything kind of goes red and that's considered like our baseline for settlements, so to speak, so.
Joe Honings: let's hope this works.
Joe Honings: But here, is where we pass those artifact data.
Joe Honings: Now you're going to start seeing some not red colors emerge.
Joe Honings: about here is where we've, you know as we're interpreting these data about five meters deep.
Joe Honings: Is where we really see in the opening and things changing to blue indicating the best probably are our cavity or our cavernous rock and the this a continuous reflection in all of the Trans sex leading towards the Cree.
Joe Honings: The i'm sorry the surface water body to the Northeast.
Joe Honings: So, working with the these ongoing interpretations, the implications would be that, yes, we were imaging.
Joe Honings: This feature that we believe is continuous through the landscape that we.
Joe Honings: And it's a long one of these fractures this northeast Southwest manner that is identified in previous research in the area.
Joe Honings: we're beginning to constrain the dimensions and the connectivity and therefore continuity slice to slice through the landscape and this is resolved with the ground penetrating radar.
Joe Honings: And what I think is really neat about this also is.
Joe Honings: You know a lot of this was explored on the desktop looking at lidar data and aerial photography so if we can feel verify.
Joe Honings: This conduit or this this subsurface flow path we can use these clues whether it's with singles or further offline where there's more mental cover over the cars.
Joe Honings: To key in on where these flow pads actually exist without having to physically dig for them and whatnot so it's it's more or less confirmed a pattern and hypothesis of the car string.
Joe Honings: With that I plenty of people to thank my advisors, the john Center for.
Joe Honings: Their funding as well router Richter who pulls the front of the gdpr card he's not pictured in any of these but he's a field technician and i'm very.
Joe Honings: very grateful for router it's hard work i've received some other funding advice from people that deserve thanks.
Joe Honings: And with that i'll turn the questions over to you guys I do, I have a hearing loss and it's been very hard for me on zoom to like get questions coming through with microphone feedbacks and stuff so honestly I prefer to read them, but thank you very much.
Lisa Davis: Great presentation, though that was really interesting yeah So if you have questions we actually do have time we have a couple minutes here before the next presentation needs to start So if you want to use the chat box joking read your questions and.
Lisa Davis: And we can.
Lisa Davis: Take it from there if you've got questions.
Joe Honings: Then refer to some literature by James Jamie Thank you James i'll definitely check out that paper by George brooke.
Joe Honings: there's a question on which one came first the flow or the same coals and that's.
Joe Honings: that's kind of in one of our well how long a year ago I was in a committee meeting in which we cut that out of my dissertation which I did want to investigate kind of like a.
Joe Honings: Tony one.
Joe Honings: Down cutting method versus the groundwater sapping that you know flowing to.
Joe Honings: Bigger pores and you know that being like a car model for dissolving along the fractures and whatnot so that's that's an ongoing question in the area that i'd like to investigate it's just.
Joe Honings: Where i'm at I need to I need to kind of pick one thing and stick with it for right now but um that's definitely a question we we work with.
Joe Honings: yeah Thank you James I see your your comment here too and i'd be definitely happy to discuss my ongoing work with you outside of this I know the field trip fell through so I was kind of disappointed we didn't explore points of that but.
Joe Honings: Yes, thank you.
Lisa Davis: Okay, with that i'm going to include Question Time and again we got a break coming up, so if you have some other thoughts and you want to revisit these topics with the presenters please save them for the Question Time awesome job.
Lisa Davis: Joe our next speaker is Nigel gross right from Virginia Polytechnic Institute, he will be speaking about analyzing time series data of K drips and James K Virginia implications for storage and recharge and appalachian cars systems.
Nigel Groce-Wright (he/him): awesome thanks so much Lisa.
Nigel Groce-Wright (he/him): get started here.
Nigel Groce-Wright (he/him): hi everyone and welcome to my presentation analyzing time series data of cave drips in James K Virginia implications for storage.
Nigel Groce-Wright (he/him): And recharge and appalachian car systems i'm Nigel prostrate and with my co authors josh Benton Nick hammond and Dr Madeline treiber we'd like to welcome you to this year se GSA and to this presentation.
Nigel Groce-Wright (he/him): Cars deserves to attention from the scientific community, since 20 to 25% of the world's population acquires they're drinking water from cartographers.
Nigel Groce-Wright (he/him): The appalachian valley and rich province has a high concentration of limestone formations which carry inherent risks of sinkhole formation and further cave development.
Nigel Groce-Wright (he/him): As we can see in the bottom right photo sinkhole information can be dramatic and rally and rich province.
Nigel Groce-Wright (he/him): The concentration of limestone formations proves to be of economic importance for the valley and rich in that they provide tourism water resources and mining resources, which are key in cement creation.
Nigel Groce-Wright (he/him): And the Left photo, we can see natural bridge state park and on the top right luray caverns both popular tourist attractions.
Nigel Groce-Wright (he/him): The zone of soil and weathered bedrock above a cartographer is referred to as the EPI cars.
Nigel Groce-Wright (he/him): The F E commerce makes up the perched on saturated aquifer which contrasts and hydraulic conductivity to the more competent bedrock aquifer below in this diagram soil and weathered bedrock makeup the EPI karst in transport, water downward to the cave passage in the cartographer.
Nigel Groce-Wright (he/him): reach out recharge to the cartographer occurs as water infiltrates through fractures as quick flow and through the weathered bedrock matrix as diffuse flow K passages tend to live below the EPI cars and above the saturated aquifer as can be seen in this diagram.
Nigel Groce-Wright (he/him): Historically spring discharge measurements at the surface, are used to quantify the storage and recharge properties of these groundwater systems.
Nigel Groce-Wright (he/him): cave measurements provide a method by which to acquire data representing direct recharge to the cartographer these data can also indicate the exchange between the transit storage and water in the EPI cars and recharge to the cartographer.
Nigel Groce-Wright (he/him): to examine recharge and appalachian value rich type karst we instrumented James cave in pulaski county Virginia.
Nigel Groce-Wright (he/him): It could be seen from the geologic map of plasticky county that James cave is formed in the cambrian age cannot get cheap formation heavily dominated by dolomite and limestone.
Nigel Groce-Wright (he/him): located in the southwest corner of other Virginia value rich geographic province James cave proved to be a suitable location to collect representative hydrological data.
Nigel Groce-Wright (he/him): From the cave survey of James cave three study sites were located for studying cave ceiling drip water, as well as identification of the cave stream location.
Nigel Groce-Wright (he/him): The overlying landscape has patterns of sinkhole formation, which lead to issues regarding groundwater contamination and infrastructure damage.
Nigel Groce-Wright (he/him): We can see from the bottom right photo that the entrance to James cave has been created by the formation of a sinkhole is common to see these features in the surrounding landscape, due to a lack of force cover since the land is huge primarily as pasture for cattle.
Nigel Groce-Wright (he/him): The data for this study was collected using three locations in James cave where the cave ceiling drips water at those three is three locations a drift tarp was installed by will orndorff and Benjamin Schwartz the photograph on the right, shows the drip tarp assembly.
Nigel Groce-Wright (he/him): The drip tar collects the water as it drips down from the Overhanging spiel do things.
Nigel Groce-Wright (he/him): The plastic to be seen here attached to the speed of fans directly was installed to collect geochemical data, which will be presented here.
Nigel Groce-Wright (he/him): The photo on the left, shows the data collection simply below the drip tarp a standard tipping bucket re engage reported water levels every 10 minutes to a hobo where data shut off.
Nigel Groce-Wright (he/him): We see additional instrumentation instrumentation in this photo used again for geochemical analysis not presented in today's talk the instruments were installed in September 2007 and removed during summer 2019.
Nigel Groce-Wright (he/him): Care we can observe the seasonal pattern of TRIPS from trip site one the plot shows the rate of TRIPS in millimeters on the y axis and the date of record on the X axis the drip record less from September 2007 to August.
Nigel Groce-Wright (he/him): The cave consistently drips in a seasonal had in from the month of December to July.
Nigel Groce-Wright (he/him): during July until November the cave is not tripping and goes to try period.
Nigel Groce-Wright (he/him): We can see a large spike and drip rate during the winter months of 2015 but due to instrument failure, there are gaps in the drip record.
Nigel Groce-Wright (he/him): One of these guests can be observed during 2012.
Nigel Groce-Wright (he/him): When compared to the drip data set the precipitation exhibits seasonal highs during the recharge period and lower precipitation during the latter months the precipitation data shown here in the bottom figure.
Nigel Groce-Wright (he/him): was collected from the nearby Dublin Airport in Dublin Virginia about 10 miles away from James cave.
Nigel Groce-Wright (he/him): The characteristics of precipitation often exhibit similar behavior to the connect to the characteristics of TRIPS indicating the potential for an exchange between the two systems.
Nigel Groce-Wright (he/him): In 2015 there's a visual maximum for both precipitation and TRIPS, but again due to instrument failure, many of the drip readings from that period are lost.
Nigel Groce-Wright (he/him): So what can we learn from these drip discharge observations to better understand the cars groundwater system.
Nigel Groce-Wright (he/him): will attempt to answer questions such as does recharge occur through the EPI karst primarily via fast flow through fractures or primarily through diffuse flow and pores.
Nigel Groce-Wright (he/him): will be able to that will ask how much water volume is stored in the EPI cars and does that volume very temp Orleans spatially and finally we'll ask what's the relationship between the input precipitation and the output of drips.
Nigel Groce-Wright (he/him): To try and answer the questions posed the most useful methods will be recession analysis and time series analysis recession analysis involves investigation of the receding limb of drip Hydra graphs over a period of data collection.
Nigel Groce-Wright (he/him): Recession coefficients can be calculated for time period through linear regression correlation of drip brain to previous drip rate and slope of the exponential decay of drip rain.
Nigel Groce-Wright (he/him): Time series analysis involves comparing the response characteristics of TRIPS with the input characteristics of precipitation.
Nigel Groce-Wright (he/him): These analyses can be used to identify and evaluate the different flow paths within the EPI cars these time series and analyses can also be used to examine the drivers of recharge such as precipitation and if apo transpiration.
Nigel Groce-Wright (he/him): Through a session method for this study investigates the receding limb of event scale hide your graphs.
Nigel Groce-Wright (he/him): The equation for exponential decay to acquire their session coefficient for defined period is shown here where cutesy is the discharge at time T choose zero is the initial discharge and alpha is a constant, also known as the cutoff frequency.
Nigel Groce-Wright (he/him): This equation is optimal for homogenous aquifer but since this charges, a result of an in homogenous medium alpha most very during the recession period.
Nigel Groce-Wright (he/him): The semi lot plot of discharge versus time is used to identify individual recession segments, from which the recession coefficient can be estimated as the slope of the linear regression line of the recession segment.
Nigel Groce-Wright (he/him): The exponential function of the recession is used to relate the recession characteristics of the aquifer in terms of darcy and matrix flow to the coefficient for a session.
Nigel Groce-Wright (he/him): The term erase to the negative alpha is replaced by K, which is a recession constant for the selected time in its recession period tells the turnover time of the ground water storage defined as the ratio storage to flow.
Nigel Groce-Wright (he/him): As shown in Luke 2016 multiple methods can be used for estimating the recession constant K here the correlation method in the magic strip method will be used.
Nigel Groce-Wright (he/him): The correlation method involves rearranging the exponential model qt a recession constant to be expressed as a function of the slope of the correlation mind Q over Q zero.
Nigel Groce-Wright (he/him): And the lag interval T.
Nigel Groce-Wright (he/him): The recession constant K is the slope between the current discharge queue and the previous discharge cutie at the previous time interval T.
Nigel Groce-Wright (he/him): The correlation method plots are session segments on natural scales plotting the current discharge against the discharge at some previous fixed time T.
Nigel Groce-Wright (he/him): The matching strict method is based on the exponential model cutie where all the recession segments are plotted on one semi logarithmic scale and shifted until the tail parts of their sessions overlap.
Nigel Groce-Wright (he/him): From there a common set of lines is established in a main line through the lower tales yields the recession constant K.
Nigel Groce-Wright (he/him): using an our code, I can identify and separate individual trip Hydra graphs from the data set as can be seen here during an event exhibiting recession from trip site one in the recharge period of 2013.
Nigel Groce-Wright (he/him): The Middle finger shows the receding limb maps to more clearly identify the point at which they discharged from drips.
Nigel Groce-Wright (he/him): reaches the peak value and begins decreasing.
Nigel Groce-Wright (he/him): According to the correlation methods shown by Lou.
Nigel Groce-Wright (he/him): The figure on the right, shows the plot of drip rate versus leg drip rate which yields the recession coefficient K when a linear regression line is plotted for the data.
Nigel Groce-Wright (he/him): This initial analysis allows for the characteristics of a session to be established for the EPI cars during different precipitation events for drip site one this identification can then be made across drip events and across the three trips sites.
Nigel Groce-Wright (he/him): The results of their session coefficient analysis for James cave at drip site one, two and three are shown in the table.
Nigel Groce-Wright (he/him): By utilizing the previously mentioned approach K was estimated using trip data from January to June, which is the noted recharge period for James cave on each period of record.
Nigel Groce-Wright (he/him): Due to the prevalent data gaps every year does not contain three or more Hydra graphs that can cannot be estimated for those time periods.
Nigel Groce-Wright (he/him): These results show that there is useful information contained within the James Cape drip record, despite the gaps in the data created by instrument failure.
Nigel Groce-Wright (he/him): Storage vine can be calculated from the derivation of the Alpha coefficient for defined period alpha is calculated, first by applying linear regression to the long log transform discharge rate.
Nigel Groce-Wright (he/him): The storage volume for time period is then estimated by defining the drip discharged to die by the Alpha coefficient, as shown by amid at all equation three.
Nigel Groce-Wright (he/him): This volume has been estimated for events containing sufficient data for the analysis.
Nigel Groce-Wright (he/him): As we could see from the figure a little left event scale volumes were Apps for the present data set considering the data gaps, the estimated volumes for drip sites 123 during the recharge periods, where all three sites contain Hydra grass with receding lands are presented here.
Nigel Groce-Wright (he/him): The immediate next step for this study is to compare the time series of precipitation and drips with precipitation as the input drips being the output.
Nigel Groce-Wright (he/him): The lag between the responsive drips and the input of precipitation suggests the degree of weathering in the EPI karst.
Nigel Groce-Wright (he/him): correlation models aid and quantifying the relationship between precipitation and drips which allows for the determination of the dominant recharge processes which will be quick flow through conduits or matrix flow as base flow.
Nigel Groce-Wright (he/him): Identifying the dominant recharge processes and the degree of car certification allows for improved management of car stock or first for water supply these statistical analyses will be performed with assistance from when you go to Virginia tech department of statistics.
Nigel Groce-Wright (he/him): And with that i'd like to acknowledge committee members doctors Pauline Stewart will orndorff Catarina thicko and Tom Alabama of the Virginia DC are.
Nigel Groce-Wright (he/him): When you gals of Virginia tech department of statistics and, finally, the Virginia tech department of geosciences Thank you guys, for your attention and i'll take any questions.
Lisa Davis: great job.
Nigel Groce-Wright (he/him): questions.
Lisa Davis: And i'm gonna say i'm hearing a little bit of feedback, so I think if you're unmuted or maybe you want to turn down your volume.
A bit.
Lisa Davis: I have a question, maybe, while others are thinking of theirs of what actually caused your instrument failure, did you does it that just frequently happen i'm not at all familiar with that kind of experimental setup.
Nigel Groce-Wright (he/him): So yeah and the cave environment, due to the high amount of moisture and the low amount of airflow the electrical electrical connections get heavily corroded really quickly.
Nigel Groce-Wright (he/him): So it can be hard, it was hard to predict when and when or when and where those instruments would fail, and so we have these data gaps that are kind of sporadically throughout the data set.
Lisa Davis: What is the next thing will.
investigate.
Nigel Groce-Wright (he/him): um yes so we're going to be looking farther into the storage volume analysis, improving those numbers, making sure that we're extract every event every Hydra graph to look at the.
Nigel Groce-Wright (he/him): spatial and temporal distribution of storage, whether that occurs at different rates throughout the year, based on.
Nigel Groce-Wright (he/him): The water coming in and comparing that to the precipitation does the cave trip only when we have precipitation or is there enough pressure built up in the recharge period that we do get drips.
Nigel Groce-Wright (he/him): So that's that's kind of like the direction that will be headed in next on and be able to put some put some hard numbers on there.
Nigel Groce-Wright (he/him): And yeah just continue the analysis, because with such a large data set there yeah there's definitely information to be gleaned from and like I said courses important and i'm sure everyone in this session can relate.
Nigel Groce-Wright (he/him): On some level that that courses are really dynamic system and anyone who's studying hit completely understands.
Nigel Groce-Wright (he/him): The different the different factors at play there.
Every trade.
Lisa Davis: So we're now at 252 and we have Thank you so much Nigel that was great presentation, we have a break coming up at 255.
Lisa Davis: So we can go ahead and condense that break, we will stay on schedule, so that other people joining us from other sessions will be able to anticipate the timing of presentation, so our next presentation will start at 310.
Lisa Davis: I will fire back up my video and everything at 305 so I can go on and have a bathroom break and i'll be back.
Lisa Davis: But if you guys want to hang out and continue to discuss i'm not going to actually do my screen.
Lisa Davis: i'm not gonna share my screen in my absence, just in case people want to talk to each other and catch up okay so i'm going to depart for now for bathroom break and maybe others too, but i'll be back at three or five our next speakers at 310.
Lisa Davis: Thanks so much for all the speakers from the earlier portion of the session that was really interesting work and well done in terms of the presentations and I appreciate everybody sticking to the schedule we're doing an awesome job on timing.
Lisa Davis: Try one more time unmuted okay everybody welcome back from the break it's been a minute before our next presentation.
Lisa Davis: which actually is going to be presented by clifton berna coastal science and engineering incorporated in Columbia South Carolina.
Lisa Davis: And the topic of the presentation is what mechanisms trigger coastal flow sides slides so i'm going to allow you to go ahead and put up your presentation, please clipped in if you will.
Okay.
Lisa Davis: Sorry for butchering your title, you may want to give it.
Patrick Barrineau: Perfectly fine.
Patrick Barrineau: Great.
Patrick Barrineau: Well, thank you for joining me everyone, my name is Patrick Baron our work for crystal science and engineering.
Patrick Barrineau: clifton is my legal first name, so I go by Patrick we're located in Columbia South Carolina and it's where i'm coming to you from although.
Patrick Barrineau: As an alum I wish we were in auburn it would be nice to get a chance to go down to the plains again.
Patrick Barrineau: i'm talking about coastal flow slide on that occurs repeatedly on seabrook island in South Carolina which is which shown in this photograph here.
Patrick Barrineau: From the air seabrook is about halfway between charleston and savannah and what happens, there is also known as a retrogressive breach failure right so it's like a sub aqueous landslide.
Patrick Barrineau: You have a lot of deposition of 10s of hundreds of millions in some in some locations of cubic meters of sand down on the lower shore face that you can see in this upper figure.
Patrick Barrineau: Driven by density current stupidity currents along the shore face and manifest on the upper short face on the beach as.
Patrick Barrineau: A scarf or rather dramatic scarf that poses a hazard for swimmers and beachgoers but it's also a an interesting scientific conundrum because.
Patrick Barrineau: it's difficult to predict your observed these they they tend to occur on in locations that are a little bit harder to serve a like and let channels or.
Patrick Barrineau: canalside locations with Steve shore faces and it's difficult to identify the controlling mechanisms as a result, not least of all as well because well we don't always have data on specific say rainfall totals or a specific.
Patrick Barrineau: geotechnical qualities of the material on these slopes, that would be the controlling factors in traditional hailstones failure.
Patrick Barrineau: So these occurred globally on they're all over the place there, and on all populated continents on some of them historically like what's shown here and bevel end on the upper right.
Patrick Barrineau: have moved millions of cubic meters of material over the course of a few days, which is a significant concern if you're living near that shoreline or, if you have an interest in your that shoreline.
Patrick Barrineau: The commonalities between all of these locations in these events are fine water saturated sans relatively fine, that is.
Patrick Barrineau: gravity driven durability currents occurring along the shore faced where you have an original section and adapt positional lobe.
Patrick Barrineau: Some sort of title or flu, the old influence that causes current switching back and forth along the lower short face.
Patrick Barrineau: And finally, relatively steep short faces like I mentioned a lot of these will occur on in live shorelines like it seabrook.
Patrick Barrineau: or on on dredged canals like you see an ambivalent.
Patrick Barrineau: I believe the example shown here in Queensland Australia is also on an unlit highly influenced shorelines this there's a few commonalities but.
Patrick Barrineau: Again there's not that much that's known about them because they're hard to observe now that there have been a few laboratory based studies.
Patrick Barrineau: That have tried to determine the controlling factors and the actual mechanisms that lead to these events.
Patrick Barrineau: And, in general, the controlling factors are presumed to be similar to what controls sub area hill slope failures, so you ever reduction in soil cohesion with an increase in poor pressure due to moisture.
Patrick Barrineau: You may have liquefaction leading to density currents or density flows moving down the hill slope.
Patrick Barrineau: If the slope is steeper than the native angle of repose it can it can trigger failures.
Patrick Barrineau: And then in sub aqueous environments Added to that is the Trinity current which can result in large quantities of sediment being lost from the bottom of the slope and can lead to this sort of tagging type motion that you see here in the.
Patrick Barrineau: Sub sub figure be.
Patrick Barrineau: The problem again with these is that because the deposition occurs mainly underwater.
Patrick Barrineau: The most of the events you know we may not even see happen it's only whenever they breach, to the extent that they begin to cause scarfing on the upper beach that they actually become noticed by people.
Patrick Barrineau: So let's talk about seabrook island a little bit it's a mixed energy barrier islands very similar to what you see up and down the the Georgia coast and the South Carolina low country um, it is a strongly beach Ridge type morphology, as you can see from this slide hardy and.
Patrick Barrineau: it's also rather steep short face because it's located right on the North at Mr river and live, which is a fairly large and let's system.
Patrick Barrineau: You know that the River at that point is close to a quarter mile wide at least.
Patrick Barrineau: So there's a lot of sediment moving around on the shore face, but it is rather steep because, as you can see, on this image here.
Patrick Barrineau: Right up against the short face kind of in the middle portion of the image there's a secondary title channel that cuts right up against the beach, and there is on a small show that you can also see there in dark blue.
Patrick Barrineau: That sort of serves to keep that title channel squeezed up against the beach so it's a rather steep shoreline right there, to the point that as i'll show you in some images later on.
Patrick Barrineau: there's really isn't much of a beach in this part of the island it's actually just a wet beach, generally speaking, you can't even sit out there, unless it's it's a low tide that spring tide.
Patrick Barrineau: So the development of seabrook has occurred, mainly in the past 50 years in the 70s, it was designed as a plan unit development, you can see, this before and after the top image is from the 1940s and the banners from 1983.
Patrick Barrineau: Before 1983 there were some issues associated with the small inlet system, you see, on the right, and these images called Captain sands and let.
Patrick Barrineau: It would migrate rather rapidly channel switching would cut into some of the uplink properties that were planned for development on seabrook.
Patrick Barrineau: And it would occasionally release packets of sediment through a process known as show bypassing.
Patrick Barrineau: That would then attach to the island and feed the beach further down short and keep things in equilibrium, but after development again with the Channel switching cutting into some of the uplands.
Patrick Barrineau: My company coastal science and engineering was actually.
Patrick Barrineau: contracted by the town of seabrook island to begin in late relocation projects at Captain sam's and let where we cut a channel that's labeled with a in the bottom panel.
Patrick Barrineau: And then we'll actually close the Channel labeled be the old Channel with some of the sand from the new channel.
Patrick Barrineau: And reset the inlet cycling process so that keeps both islands happy and it keeps beach sand feeding down shore.
Patrick Barrineau: The problem is, once you get over to the western end of seabrook on the left hand side of these images, you can tell the development is right up on the beach and there's a rocky resentment they call a seawall but it's it's just a rap rap or Batman.
Patrick Barrineau: That leads right down to a wet beach, and on top of it, you have their beach club it's actually one of the only places in South Carolina where you can have.
Patrick Barrineau: A meal up on a beach and look out over the ocean sitting outside at a restaurant, because most of our islands have had dunes and homes built up right on the ocean, but this is kind of a unique situation.
Patrick Barrineau: And that location where the island does sort of been up against its own shoreline the development part of the island, the development of the island is is where we're looking at this retrogressive beach breach failure.
Lisa Davis: bicoastal flow slots.
Patrick Barrineau: So here's a post event D and we collected on after the.
Patrick Barrineau: event showing you can see the scarfing.
Patrick Barrineau: towards the Center right portion of the figure the beach surface goes from you know positive to positive three feet down to negative 20 feet relatively quickly.
Patrick Barrineau: produced a hole on the beach on the order of.
Patrick Barrineau: 50 to 75 meters along shore and you can actually see the deposition alone down in the bottom of the D and where that 40 foot contour and the 30 foot contour.
Patrick Barrineau: Both kind of bulge C word and that's the sediment being deposited down on the bottom of that inlet channel that's right up against the island.
Patrick Barrineau: Now there's been several of these events at seabrook, and this is why they asked us to look into it, because.
Patrick Barrineau: Every time, an event occurs it gets a little bit closer to that resentment and eventually could cause undermining and, as you can see there's there's houses built right at the top of that resentment so that that just won't work for them.
Patrick Barrineau: And there's been five of these events in the past year or in the past five years, excuse me.
Patrick Barrineau: Three of them between July 2016 and July 2017, which is a very high frequency and then to since.
Patrick Barrineau: And so we've we've begun to sort of tease apart what's what's been happening here and it looks like it's a mixture of factors, so, if you look at the history of profiles.
Patrick Barrineau: beach profiles along seabrook island, you know right there at the breach failure, you can see there's a very steep short face on the.
Patrick Barrineau: shoreline featured a relatively wide each five foot contour extends out 200 feet from the baseline which is basically on top of the resentment in that location.
Patrick Barrineau: And then, by you know January of 2018 you can see a large noticeable scarf in the beach days, all the way down to negative 25 feet, which is persisted.
Patrick Barrineau: Whereas a little bit to the left and that image on top, you know profile number five very, very, very flat short face that's where the English Channel isn't quite as squeezed by the title shoals.
Patrick Barrineau: And there's a little bit more of a free exchange of sediment in the across or longshore directions.
Patrick Barrineau: Now what's interesting about this profile number nine is the elevation at which it Stevens, so if you'll notice from the y axis between about 25 and 35 feet below zero.
Patrick Barrineau: It almost becomes vertical compared to what you would normally see for beach profiles in this area, and if we looked at an older study.
Patrick Barrineau: miles Hayes from university of South Carolina where they actually put some rather the pores around seabrook in succession.
Patrick Barrineau: you'll notice there's there's pleistocene moral van at about 30 feet and Center there's a chance that there's over steepening of the shore face due to this traffic control, you have relatively cohesive material down there towards the bottom of the Channel.
Patrick Barrineau: That can withstand the title flow, but if sand piles up on top of it to steeply it may eventually fail and spill out into the deeper portions of the Channel.
Patrick Barrineau: what's more this portion of of the beach.
Patrick Barrineau: In the near surface has a little bit higher fraction of fine grained size material, so, if you look at the light RD and up close here the star indicates, where the breach failure has been occurring.
Patrick Barrineau: it's located on on a low spot actually you can look to the left, look to the right and there's the dune ridges that that meet the shoreline that indicate former shoreline positions and that's what these lines actually show you.
Patrick Barrineau: And if you look at the orange shoreline in particular that's from the 1920s um it looks as though there was there was a rotating spit with perhaps a marsh creek behind it.
Patrick Barrineau: That would have flushed out some fine sediments right to that portion of the beach on seabrook and, if you look at the image on the Left from 1948.
Patrick Barrineau: By you know the MID century that had closed it had been covered up with beach sand, but that would have been just sort of the veneer.
Patrick Barrineau: On top of what's ultimately marshy kind of sediment that could hold a lot more water than most beach sands would so we're we're looking at an overstatement shore face way beyond the angle of proposed for sand in this area we're looking at potentially saturated material.
Patrick Barrineau: That that is more more prone to saturation because of its grain size.
Patrick Barrineau: And then finally there's meteorological controls that we began to notice now unfortunately there aren't any weather station rain gauges on seabrook island, but there are several.
Patrick Barrineau: Cocoa rods network Members on nearby islands, and there are weather service stations in charleston and buford that we can kind of interpolate between get a picture for how much rain was occurring.
Patrick Barrineau: And, and in reality in all five events we saw a rainfall total within five days of the event that exceeded 70% of the daily record so in all five events we experienced heavy heavy rain in the week leading up to these these breach failures occurring.
Patrick Barrineau: And and what's more three of the five events occurred at spring tides which on this part of the coast is significant, those are more than two meters title amplitude.
Patrick Barrineau: And so there is a lot of flow moving in and out of the Channel at those times, so what we're seeing here holistically is there's a combination of stratigraphy.
Patrick Barrineau: Smaller sediments that retain more moisture as well as that place to seen semi bedrock it's just moral down at about negative 30 that overstepping the shore face.
Patrick Barrineau: Then you have rainfall excessive rainfall, reducing the soil, cohesion and the days leading up to the event on the relic English Channel may actually serve as a bit of a conduit for groundwater flow on to the lower short face.
Patrick Barrineau: And then, finally, you have this title prism question where at spring tides or mid cycle tides.
Patrick Barrineau: You have a river flowing down the beach it's not like a normal beach that you think of whenever you think and barrier islands it's much more.
Patrick Barrineau: riverine have an environment and so again, all these things sort of holistically come.
Patrick Barrineau: Now you know if we're going to make recommendations to the speech about how to address these problems, because they are, they are problems like like you saw in the picture there's there's properties privately owned properties basically a Jason for this feature.
Patrick Barrineau: And so they would love to come up with a solution, but the best thing that we've been able to come up with was you know, this is the Atlantic Ocean we're on the east coast they're not going to let us put toe protection in a title and let.
Patrick Barrineau: That that just wouldn't work with the regulatory agencies, to put it lightly I don't think they would be okay with that we don't have the confidence that that would even.
Patrick Barrineau: be a reasonable solution get in this environment it's um it's a very energetic active title influenced environment so take.
Patrick Barrineau: Take a lot of money and material to actually implement that sort of solution, so one of the things that we're trying to encourage is they have so much sand over on the east side of the island, that you can see here labeled and yellow.
Patrick Barrineau: That they may want to think about using small excavators and trucks and trucking sand around the corner of the island to keep that part of the beach less steep.
Patrick Barrineau: Historically, the shoulders labeled here in dark green that sort of keeps the title inlet channel pinned up against the island.
Patrick Barrineau: has been dredged for nourishment projects, but these days with habitat, there is a particular concern and essential fish habitats.
Patrick Barrineau: Again, the regulators are not too keen on that being a good solution, so I think at the moment.
Patrick Barrineau: The best that we have to offer is basically keep the sand moving so that way there's enough material to feed these events down the lower short face without completely stopping the beach all the way back to their investment and undermining the uplands.
Patrick Barrineau: they're very unpredictable events, but it does seem like this combination of meteorological and strata graphic controls are affecting the timing of the events.
Patrick Barrineau: And so we're working with seabrook island to get some get some sensors and cameras put up in the location, so that we can really get a good beat on what's happening in the days leading up to the events, because at this point.
Patrick Barrineau: we'll just show up to work and we'll get a picture, like this one in our email telling us that hey it's back.
Patrick Barrineau: And so we have to sort of do all this work after the fact, and we'd like to get out ahead of the problem, a little bit more.
Patrick Barrineau: um i'll just leave you guys with this to another really nice aerial shot, this was the 2017 event in July 2017 it's one of the smaller events.
Patrick Barrineau: One of the other concerns with this is that it seems like every time they have an event the scarf gets a little closer to the rebellion and so it makes everyone a little more and more nervous.
Patrick Barrineau: So it's a very interesting system very, very interesting geological questions i'm happy to take any questions from you all, thank you.
Lisa Davis: Nice job centric um well questions for Patrick.
rkvance: We have.
Lisa Davis: We have some time for questions.
Lisa Davis: And of course you can unmute yourself raise your hand.
Lisa Davis: You know, physically raise your hand or your virtual hand, or you can use the chat box.
Lisa Davis: i'll ask a question, maybe what others are thinking or typing.
Lisa Davis: What do you think about trying some sort of living shorelines approach, so you can get some of that armoring.
Lisa Davis: effect that you would you know, without having sort of a hard engineering solution so i'm thinking like maybe create sort of like a machine marshy kind of habitat that might give a little bit more resistance, when these you know, triggering rain falls occur.
Patrick Barrineau: yeah that's that's a really good idea so so one thing that we have talked about if the Community is because this is right on the open ocean, it does face the Atlantic.
Patrick Barrineau: You know, installing a marsh type habitat probably wouldn't be very effective, however, we have talked with them about trying to use some sort of de watering.
Patrick Barrineau: Technology on top of the resentment in order to facilitate drainage after these rainfall events on but, again, we want to get some sensors in the ground first so that we can really determine if that's a you know, a controlling mechanism first.
Lisa Davis: Wave action so relentless i'm sure, and with the small size sediment you know it's so transportable you're really it's kind of an upward battle is you know.
Patrick Barrineau: Oh absolutely keeps us busy.
Lisa Davis: yeah okay well thanks so much great presentation our next speaker is Robert Vance I believe is from Georgia southern university and he will be speaking about a geologic framework and anthropogenic impacts.
Lisa Davis: On the hydrology and ecology of St catherine's island Georgia so staying on our coastal thing.
rkvance: I need you to cut off your screen there.
Lisa Davis: yeah i'm actually not sharing so that's Patrick screen so.
rkvance: don't me out Patrick.
rkvance: how's that.
rkvance: Good go.
rkvance: This is a project i've been reporting on periodically at GSA meetings and so i've been coming to running progress report on this work.
rkvance: We were talking about car systems earlier there, so it may surprise you that that topic may pop up again here during this talk.
rkvance: i'll start off by acknowledging my colleagues i'm just part of a research team that consists of myself Jim riker Jackie Kelly, Brian Meyer and Fred rich and also want to acknowledge our host site St catherine's island and our supporters here.
rkvance: So let's get into it.
rkvance: If you're not familiar St catherine's island on the GA coast it sits between us ball island and black beard okay and it's composed of applies to same core that's flying down the South and North ends by Holocene region swell deposits, we also have some Holocene alien cover on the island.
rkvance: That alan's been inhabited and pretty heavily work by human beings for over 5000 years according to American museum of natural history research.
rkvance: This one some classic diagrams and the work of plate and hales.
rkvance: plan view map you're showing you some of the Paleo shoreline systems there's a silver bluff applies to seeing shoreline complex here St cat sitting right here.
rkvance: And if you look at the Cross section will do that, you can see, we also have Holocene lapping up on an eroded see side of that and again we have some Holocene aeolian cover over that as well.
rkvance: Top of graphically the highest part of the island is on seaward side is light our map shows that in brown here some elevations up to almost eight meters and height you're not going to get nosebleeds from it that's pretty good for one of our barrier islands here.
rkvance: The sharp break here we go to the green topography that indicates a lower elevations on island and our light our code here, and some of those are quite low very close to sea level.
rkvance: This is just kind of another view Allen kind of blowing up on a few sites in here down in the.
rkvance: southern part of the islands so again the brown the higher elevations here we have greater thicknesses of superficial sand there and some cases 11 meters thick and part of that is due to Holocene cover.
rkvance: which again is sticker on the side of Alan you drop over across this boundary to the Western side and that's santana pretty dramatically in some places, less than two meters thick on the far Western side.
rkvance: This little image here I included, this is a blow up of lidar rendering Brian Meyer did produce a slope aspect mount.
rkvance: And it's from the area just south of the image, you see, on the right and it actually season, the maritime for us and you can see what looks like some nice Dean, for showing up in that particular image.
rkvance: it's it's pretty cool when you're able to see through the forest like that to slide our systems.
rkvance: So a classic bit of history, this journal X art is often referred to from 1753 and in that Jonathan Brian on a visit to St catherine's describes these extensive freshwater wetlands and interior darlin the also refers to these crystal strains and springs and are feeding those wetlands.
rkvance: In our initial work an island, we were using vibrant cores and some of the wetter areas on Allen and Fred rich did the bell and logical analysis from that and aplenty flora.
rkvance: indicated that these were indeed freshwater wetlands and it was an open type of environment, not a sort of thing we see today that's forest in another supporting evidence for that or the distribution of these heidrick Mandarin rutledge type soils that you'll see on the usda soil maps.
rkvance: And this is an example of some of those early course we took vibe records.
rkvance: Pretty tickles you see the upper part of the core here and meter meter and a half thick very black organic with sentiment and that's what our Fred did some polenta flora work.
rkvance: But you get a couple of meters down and we run into these guys, these are go shrimp borrows see some nice longitudinal sections, so that really marker low tide line if you're on the GA coast today.
rkvance: Now, just to get into some the controlling factors and so some of the images from krauss randolph's publications from the usgs hydrological work.
rkvance: If you look at the 18 at math areas are teasing flow are shown and blue.
rkvance: This is a potential metric contour surface on the upper Florida knock for system and back in 1880 St cats would sit between the 40 and 50 foot 10 geometric contrary.
rkvance: If you roll the clock forward to 1986 development has resulted in these huge cones and depression and that potential metric surface and, if you look at St cats.
rkvance: or 919 86 excuse my tongue we're sitting right on the zero 10 geometric contour line, and I believe the last artesian well ceased flowing about 1970 on St catherine's here so nice archival photos from SAP Hello Alan to the south they're showing one of their artesian wells.
rkvance: So it's been a business of drying continuously since the industrialization has dropped that potential metric surface.
rkvance: And this older map, you can see some of the former wetlands in here today, this is what they look like they're just remnants of their former glory here so they're almost forced it in in many places.
rkvance: This was a very extensive part of the March systems southern invalid today part it's still alive, because it's fed by overflow from a pond it's pumped up from Florida and well, but if you look at the southern end of that you can see it's just an ephemeral wetland now.
rkvance: So we had this transition from open wetlands to swap type conditions and now to maritime for us.
rkvance: So our work and here it's been kind of multitasking we started off by recording we eventually got a tractor amount of GEO probe.
rkvance: Which is great because we're able to get that thing around in the woods, we can do coring well installation.
rkvance: So we established a network of shallow whale systems on island to look at the shallow off for systems there.
rkvance: And then we're supplementing network with ground penetrating radar and resist activity profile it's the lab and we got our water chemistry.
rkvance: Fred riches Palin a logical studies and if we were lucky enough to pull up a chunk of old wood and some of our course here we send it off to paid analytic radio carbon work.
rkvance: it's just show some of our crews work, this is our hundred megahertz gdpr which is gets us to the deepest we can, as far as gdpr here's Jackie Kelly, and her students laying out and receptivity line.
rkvance: So when you think about those crystal streams and springs at Brian described back and 1753 to get artesian flow at the surface, you absolutely have to have some kind of breach in the confining layer of the upper Florida and offer it's a prerequisite.
rkvance: So we've been looking for structural evidence on island and also studying water chemistry, particularly.
rkvance: Jim reichert and Jackie Kelly looking for water chemistry.
rkvance: So here's a image, where we superimpose coastal plain structural features that have been.
rkvance: delineated by Jerry Bartholomew and co workers work in various parts, the coastal plain.
rkvance: And one of the things I want to point out is that his in one land lines up pretty nicely with a bunch of these old ponds and wetlands on Highland.
rkvance: there's some other limits right angles also line up with a few features, but we also have this general sort of north east, south west strike here, and that also coincides with the.
rkvance: fault trend it's been postulated from well mossley and prowse work goes back to 1988 and kind of coincides with the Atlantic coast fault system.
rkvance: We also have an actual one joint exposed up on the yellow bikes bluff and places saying that the lines up pretty well with it to.
rkvance: The triangles that you see here and read are saying structures that have been discovered by gdpr profiling on the roadways on the hour and we're going to look at that.
rkvance: And this is what those things look like and profile, you can have about a two meter substance and send formal feature here and interests and and feeling with the younger seven and above that.
rkvance: At the bottom there's a double one here from down South invalid, and you can also see a few displacements, in return, signals on the gdpr here and we're interpreting some of those things as a false place.
rkvance: As some of the sideshow direct evidence to former drainage systems there's a really nice little segue structure up here off the.
rkvance: Southwest side of the road way appear that we've run gdpr over and there's an old drainage network that starts there and runs down through here, as you can see, by my errands again, this is a light our map.
rkvance: drainage is still there and still flows during heavy rains but nothing from a spring in this case.
rkvance: So our interpretation of this as that decide features basically cars type features, but we believe they were generated, or at least I believe that are generated by hygiene system.
rkvance: Because of that strong up flow producing those artesian sprains we developed caverns and collapse those things resulted in savings at the surface, so they were also discharged points and pre industrial times.
rkvance: Roll the clock forward and post industrial conditions, and now that.
rkvance: Pressure services is about 20 to 30 feet below the land surface here, so now the gradient is downward and no so side features.
rkvance: Of these things are still occurring and the Georgia coastal plain, this is England, but this isn't bullet county few years ago nice fresh one just starting up here and the guys, because an orchard.
rkvance: His House would have been just over to the left here, and as soon as this thing appeared.
rkvance: Their water turn muddy and that's enough for Florida and well tap water supply.
rkvance: So, Jim reichert has done a sampling of the upper Florida and Wales and island you're shown in blue here.
rkvance: And it turned out, they have some salt water intrusion and nose and his interpretation of that was it is due to upcoming from the lower Florida and system now just to what we have brunswick.
rkvance: And this is one of his Piper diagrams, these are the upper Florida and Wales shown in blue here, and this is some of the water chemistry from one of the lower Florida and Wales taking from the literature and they really define a mixing line.
rkvance: we've established a pretty extensive shallow whale network and i'll now, you can see, the data on that and to right here, this is just a snapshot of.
rkvance: Some chloride concentrations from some of those whales back in 2016 and you see there's a spotty appearance of these chloride Spikes in these wells it's not a.
rkvance: Uniform pattern from shore line to the insurance volunteers it's very locally concentrated and we're trying to explain this and we believe structure has a lot to do with it, this is one of Jackie kelly's receptivity profiles that we lined up with our.
rkvance: Side structured on the southwest part of the island here, and you see the side also shows up in this.
rkvance: Resistance zone at the top here, but the ocular system under this shows a much more pronounced development in areas that site structure, so we think that's probably enhanced permeability due to solution or collapse in that area.
rkvance: couple of other profiles here, this is one over a little farther East here, and you see to offer systems, this is our water table author shown and the reasons 20 profile and a slightly deeper symbol, I can find off for in here and they're separated by Monday sand and clay bed.
rkvance: So in this particular area there's not much.
rkvance: Communication between these two offer systems, if you look at the sampling of water, at the same time, from both these offers here notice there's a difference in the chloride content and knows.
rkvance: it's not the case and in all areas here, these whales are individual they all have some interesting behavior to them.
rkvance: So this is one a little farther to the east longer same well traverse here okay here's one of jackie's a receptivity profiles, so we have one whale shallow well tapping the water table system and another tapping the slightly deeper semi confined system and the.
rkvance: raises the profile definitely shows us and communication going on and that's supported by the water sampling analysis, at the same time, of course contents almost identical and decide.
rkvance: This is the gdpr profile that's lined up with the resisted it profile there's a side of the whales right there so they're aligned and the scale is is pretty much the same in this particular setting here.
rkvance: One of the few structural hands and fair with the gdpr it doesn't quite get as deep as we need really be nice tested seismic lines, but we do see some small offsets and some of the reflectors and the deeper part of these profiles and I interpret those things as part of false flags.
rkvance: When you look at fault systems if you go over 30 meters deep, you can start getting into more concentrated fault planes, but when you start getting into semi consolidated segments studies and various areas, show that these break up and displays.
rkvance: One more look at this Piper diagram Jim riker put together and the black cross as you see here are sampling of our shallow well systems and notice their show contamination by seawater if you look at our key here.
rkvance: The red x's in here are from our symbol, I can find off for system you notice they spread out a little bit different so we see a little bit different the water chemistry knows, except for those two sites that have showed.
rkvance: And here's the shallow well three a deeper well in here, so their chemistry is pretty similar.
rkvance: If you look at these two oddballs over here, these are in the semi can find system Those are all in the Western side of the Allen and most of the only.
rkvance: whales, we had actually screened out and some Shell rich material so they're picking up some calcium from that Shell material narrative that's making them look a little more like our upper Florida and Wales.
rkvance: So conclusions.
rkvance: We believe we have contamination is the lower of the upper Florida and system St catherine's my upcoming of sailing waters from the lower Florida and system.
rkvance: Are shallow offer system includes about the water table system and a deeper semi can find system and locally, they show some communication in there.
rkvance: The shall offer system show a very focused response and we get these chloride Spikes in there when we have King tides and storm surges.
rkvance: And their responses different among those whales as well, some so very strong quick response and it's a little slower, but it definitely isn't a uniform response from the island margins, and so we believe these are structurally control.
rkvance: So the shallow water.
rkvance: salt water contamination matches up with the current see water chemistry.
rkvance: And when you look at the big picture here this former artesian springs requires some faulting in there, you had to have something to break through the confining layer
rkvance: And locally we've actually found a couple places where we have a decent marsh mud or Paleo marsh Bud marker layer in it actually showed us them all sent across them on those limits.
rkvance: And just a final acknowledgement, here again, our supporters benefactors and finally.
rkvance: Just a big thank you to all the students we've involved in this project they've gotten to go out and market the geo probe do well installation and do coring.
rkvance: Do geophysical profiling so it's been a huge plus to put on the resume so it's been a really good project for them, and thank you.
Lisa Davis: So much Robert great presentation we.
Lisa Davis: Take a minute for questions the audience have any now would be a good time to put them in the chat box or you can raise your hand visually or virtually and and speak up.
rkvance: goes pretty fast I didn't want to eat into tony's talk there I know he'd give me a hard time with that they.
Get Gray.
Lisa Davis: hair and I will say I was kind of curious you mentioned about the the sort of the Eco tone that exists there across the island, you have to the maritime forest and different types of environments, they are How have they transitioned in time with the changes.
Lisa Davis: You know, to more elite water at the surface.
rkvance: Of a can't really see or make a positive correlation with some die offs and trees and stuff like that, and the surface in there, I don't think it's been that extreme.
rkvance: I think more the Diocesan senior probably related to drought events, when you start going back and looking at the various years and there but.
rkvance: it's probably coming sea level rising and we were very rational Alan we lose about three meters or shoreline per year on average on St catherine's and if you get one hurricane it does that in one event.
rkvance: So the erosion is dramatic and it's going to be interesting to see how these changes progress, you know, over the years is that shoreline continues to erode landward.
For sure.
Lisa Davis: Okay, well, there are no questions.
Steph Shepherd (she/her): I have a quick one actually.
Steph Shepherd (she/her): So so looking when you talked about the the basically the sinkhole style situation with the sinks that there's there's large or some sort of macro piping below it that's leading to the sinks at the surface, have you published on that because.
Steph Shepherd (she/her): i'm looking at something similar potentially but next to a river where seawater isn't an issue but it's farm fields auburn farm fields and the guy that runs the farm is keeps asking me if i'd come out there and figure out why these are forming in his fields.
rkvance: And we were we were jumping into some writing there right for the coven hidden and that ended up calls knows a lot of extra work.
rkvance: yeah with the classroom and so forth, so that's something we want to get back into the summer get get some more of this out and publication in their gym publish some information early on in southeastern geology on the upper Florida work in there, but we need to get the rest of the sale.
Steph Shepherd (she/her): Well i'd be definitely interested in reading it, because, if I can show that.
Steph Shepherd (she/her): there's an examples of this in other situations and maybe I can convince some other people to take a look at it with me, you know that's one of those things it's in my back pocket as a project eventually for students and myself.
rkvance: I grew up in cars typography and Kentucky and so i'm used to seeing these sort of features up there, but you know, when I look at some of those maps and say cats and all those little elongate freshens in there, it looks like parts of Florida.
Steph Shepherd (she/her): yeah and I grew up in cars, too, but here it's where the field broken or probably all soft sediment so it's gonna be a different mechanism, but I think it's still some sort of my macro piping underneath that.
rkvance: Thank you we're looking at big.
rkvance: caverns collapsing in the upper floor to five dissuaded surface there's some neat engineering studies show that claps of deep mind started 400 feet.
rkvance: will give you just a couple of meters of substance at the surface interesting.
Steph Shepherd (she/her): Well i'll turn it over now i've run us over time.
Lisa Davis: So it's still salvageable it's okay nipped in the bud.
Lisa Davis: So it is time for our next speaker.
Lisa Davis: To come forward and that's to it's Tony Martin from the Department of environmental sciences at emory university will be speaking about ethnology as a tool for understanding, ecological and geological changes of the Georgia barrier islands.
Anthony Martin: Okay, well, thank you very much it's great to be here and i'm really happy to be presenting in this session.
Anthony Martin: So yes, acknowledged as a tool for understanding, ecological and geological change means that we want to think about uniting.
Anthony Martin: The sciences through technology is kind of a way to be able to have a perspective from both disciplines.
Anthony Martin: i'll start out with the acknowledgments and there have been many, many people who have helped me over the years in my work on the Georgia coast.
Anthony Martin: Over the past 20 plus years but I always like to thank my former students for always keeping me on the ball whenever i've taken them in the field, down to the Georgia coast, and of course I always think the trace makers as well.
Anthony Martin: So we're talking about how acknowledged, it really is a good representative science for uniting II II college in geology most of you are geologists.
Anthony Martin: Some of you may do some ecology, some of you may be colleges to do a little bit of geology that's why in technology, I like to think that it's easy to bridge all of those sciences.
Anthony Martin: Through the study of traces so it really does give us a good perspective than for geologists any colleges, particularly using the Georgia coast, because of the Orange coast is.
Anthony Martin: In my opinion, and i'm biased is one really the perfect place to do that kind of intersection.
Anthony Martin: So let's use an example from the title slide this picture, which is on SAP little island showing.
Anthony Martin: A wash over fan storm wash over a fan that it's overlapped with the MARS, but you can already see that the ego tone.
Anthony Martin: between those two what we would normally ecologically separate as environments is being merged and that's because of bio debaters.
Anthony Martin: You get organisms from either of those environments that in that transition between the soul marsh and the storm wash over fan.
Anthony Martin: The burrowing tends to mix up those sentiments, so the sentiment mixing in each of these ecosystems is also representing how we're getting this blurring.
Anthony Martin: Of those ecosystems, thanks to the burrowing so these organisms all the interactions that are happening in these respective environments, as well as the nutrient cycling it's all being driven by burrows in this instance.
Anthony Martin: So those burrows actually if they fossilized you could separate them, and this is thanks to the neo ethnology study of the new traces on the GA coast.
Anthony Martin: That we can say this is a sand fiddler crab borough, this is a mite fiddler crab borough they normally would be in separate environments, as a result of their divergence in their evolutionary history, so these burrows then are good identifiers that we can use them in the fossil record.
Anthony Martin: But when we look at salt marsh you may just see this part time, you may see the maritime forest off in the distance.
Anthony Martin: You may not think of it as an ecological landscape have to this talk, I hope you do, because it really is an technological landscape.
Anthony Martin: That, if you had the world's biggest die katana or a ginsu knife and you cut through the Marsh.
Anthony Martin: You would be able to see all of the distinctive burrows that mark which part of the environments you're looking at that all of these traces are going to be diagnostic of those environments.
Anthony Martin: And even when you look at the mud, even if you're not seeing.
Anthony Martin: The traces within the mind itself the mud is a trace in that what you're looking at our feces and pseudo feces that are produced by suspension and deposit feeding organisms.
Anthony Martin: Bio deposition that's responsible for the mud even getting deposited in these, and this is work that originally was done with Jennifer Smith and Bob fry in the 1980s and then has been worked on ever since.
Anthony Martin: So here's some representation of summit in pseudo feces that you might have whether these are these little sand balls from scrapings by.
Anthony Martin: fiddler crab sand fiddler crabs or some of the mud fiddler's that you might have in those transitional zones that are between the sandy and the muddy environments in the marshes so you can get a drone view of this, landscape and again I see traces there are traces everywhere.
Anthony Martin: So again, if you're thinking about a Georgia barrier island and you this is basically a where's Waldo but there's no Waldo in it.
Anthony Martin: In that it is nothing but traces going from the maritime forest from the terrestrial ecosystems to some of the few fresh water environments, that we still have in the barrier islands.
Anthony Martin: Going into the marginal marine environments, as we get more toward the coast and then to the more fully marine that are off shore, then we have these distinctive suites of traces that are in each of these respective ecosystems.
Anthony Martin: I always like to preach and, yes, you were all being converted to the Church in technology in this talk, I always like to preach the Holy Trinity of acknowledge.
Anthony Martin: That we have substrate anatomy and behavior that all are the gestalt that give you the traces that you see whether that's a trace Basile wore a trace in a modern environment.
Anthony Martin: So, for instance in this trace where we have a y shaped barone that's cut through in a coastal dune the trace maker, is our favorite trace maker on the GA goes to goes crab which also makes a lot of other traces as a result of its behavior but it uses the same anatomy and each instance.
Anthony Martin: So the history of technology actually the Georgia coast is integral to that in that technology was applied very early on in studies of the Georgia coast.
Anthony Martin: and applied in a way, so that it contributed to understanding the geologic history of the lower coastal plain in the islands.
Anthony Martin: And we know, of course, now that the islands represent the southern islands, at least composite barrier islands in that you have a place to seeing core to them, but then the additional whole scene sediments recently and these different.
Anthony Martin: Regions San ridges that we have in these environments are representing those past shorelines.
Anthony Martin: So, for instance, if you look at St catherine's island on the left, you have the difference there between the Holocene and pleistocene shoreline, as we saw in kelly's talk.
Anthony Martin: Just before this once you get north of there to awesome ah that's where the divergence happens between the shorelines were with the place just seeing it goes up to scare away and the Holocene shoreline would go up to La sigh and.
Anthony Martin: We know this thanks to go shrimp and that goes for IMP today at the theory deeper as I go down to two three to four meters, but we see these little volcanoes at the top that represent the eruption of the material being.
Anthony Martin: pumped out of the borough, and this is where you see the magical chocolate sprinkles do not have your students paste these.
Anthony Martin: These are fecal pellets, and this is how mud is also deposited in these intertidal environments has traces the mud is being deposited though as hydro dynamically equivalent to sand.
Anthony Martin: If you go further down into the borough system, then you were seeing how.
Anthony Martin: The money exteriors of these burrows they're heavily armored, and this has good preservation potential in the fossil record and sure enough on the West side of.
Anthony Martin: sample island, I saw this specimen there and the raccoon bluff formation shows you where the shoreline was during the place to seen this then was used in the 1960s by hoyt.
Anthony Martin: Henry and others to be able to map where these ancient shorelines were on the lower coastal plain.
Anthony Martin: So University of Georgia, Athens Marine Institute is integral to this history and my former thesis advisor dissertation advisor at university of Georgia pop FRY.
Anthony Martin: was also integral for this history of how we're we're able to demonstrate this intersection between ecology and geology via technology.
Anthony Martin: So this then also contributed to the activations concept in order in which the Georgia coast in these traces or models really or analogs for what we could see.
Anthony Martin: With these traces going back into the geologic past so, for instance on the GA coast, you have very nice suites of traces that go from dune to burn.
Anthony Martin: down into the beach transitions and these trace assemblages then as you go more offshore from more of the high energy near shore into the subtitle offshore gives us an idea and and a model for what we might recognize the geologic record.
Anthony Martin: let's let's get the fresh water and i'm glad again Kelly mentioned some of the fresh water resources that are in some of the interiors still on the Georgia coast, despite.
Anthony Martin: The cone of depression that's been happening over the past few decades.
Anthony Martin: And with fresh water environments, you could particularly look for wherever you have fresh water crayfish burrows and i've seen these on for of the Georgia beer islands that's an interesting.
Anthony Martin: ecological problem in itself How did the crayfish get there, but they do demonstrate that you have fresh water environments in the interiors.
Anthony Martin: Of the islands, as a result of that water being there for them, they cannot live in salt water So these are good freshwater indicators.
Anthony Martin: Much easier to recognize are these large alligator dens this is on St catherine's island, you can sometimes find Nice in the middle of the woods and actually the Dan on the Left did have a very large alligator in it.
Anthony Martin: You can talk with me later about that about how that happened but nonetheless these alligator dancer again going to be good freshwater indicators and there's a close up, yes, I took that with a telephoto have a big pharma using her den for raising her brood there.
Anthony Martin: Now what's really cool about alligators as trace makers is that they are face she's crossing, they are not freshwater only they will go across dunes, they will go out into the water.
Anthony Martin: into the surf zone, and they will go up and over beaches and dunes leaving their traces as well, and I have been seeing their traces on Georgia beaches for well over 20 years and I was quite thrilled a couple of years ago to finally see an alligator in the surf So there you go.
Anthony Martin: Now here's another way that we can use technology kind of on a broader scale of thinking about how with invasion ecology, by looking at traces.
Anthony Martin: left by these animals, we can actually look at how they are interacting with those ecosystems, as well as how they might be actually modifying the ecosystems and I have examples here of mammals.
Anthony Martin: That leave their traces and the various islands, but the larger trays makers are, of course, the easiest to be able to detect via their traces and then how these traces.
Anthony Martin: Maybe representing their behaviors on the island, so on sample island, there are Feral cattle, for instance.
Anthony Martin: That will be leaving traces and sometimes and unexpected places such as here on the beach i've only seen that twice in all the years i've gone to South flow.
Anthony Martin: But it does show that they do go to the beach occasionally and then of course the infamous horses that are on Cumberland that go across all of the environments there and modify the environments there, so I actually had a.
Anthony Martin: Senior honors thesis student at emory a couple of years ago arbor guthrie who presented this at southeastern GSA.
Anthony Martin: A couple of years ago in charleston where she actually mapped the horse trails and determined that yes, the trails increased in length over the years and they actually did modify.
Anthony Martin: The geology of the southeastern corner of the island that these were actually geologically significant as an invasive species.
Anthony Martin: And these are traces you can see from space so it's an example of how a technology can go all the way from the go shrimp borough all the way to mapping these sorts of trails.
Anthony Martin: So, of course, the big elephant in the room is going to be climate change on the Georgia coast and with this illustration i've shown.
Anthony Martin: What we can expect to happen in which these laterally adjacent face she's are going to seek see one another vertically and we will see hypnosis know sees these traces and trace assemblages that are going to go from.
Anthony Martin: more of a dune environment to the berm to the inner title to the subtitle as sea level goes up over the next hundred years or so.
Anthony Martin: And with this we're seeing more of the so called spring what are they called the.
Anthony Martin: These flood ties that are becoming much more common King tights I knew i'd remember it eventually yes these King ties that are becoming much more common.
Anthony Martin: On the Georgia coast, this is from one of the ones in 2015 on sample island where we got some drone footage from above there, and some of the soul marshes on the West.
Anthony Martin: and East end of the island and, of course, some of the predictions made University of Georgia for what's going to happen say one meter rise at sea level how all of these hypnosis no seas are going to shift, as a result, or actually modify the environment as they shift.
Anthony Martin: So I like to use storm wash over fans has an example of how these ecosystems can literally change overnight one hurricane can change that ecosystem, where you have that laterally adjacent.
Anthony Martin: More sandy offshore environment is now over your marsh so with this we actually have instances of that on jackal where some of the.
Anthony Martin: The breaching of the maritime forest there on the North end of the island, as also.
Anthony Martin: them now going into some of the salt marsh there, and that means those trays makers are being displaced that were originally in the money salt marsh now you have those inhabited.
Anthony Martin: By more of the same love trace makers and that's happening rapidly on the Georgia coast, and these are ecologically.
Anthony Martin: Significant environments, the storm wash over fans, so a couple of years ago I gave a talk co authored again with Andy rensburg.
Anthony Martin: Where we are discussing how you can recognize these through looking at the modern traces and there's handy for scale on one of the storm wash over fans on St catherine's.
Anthony Martin: Where we also interpreted from the silver bluff formation place to see information.
Anthony Martin: At on St catherine's we were able to look at the traces and interpret this as a storm wash over deposit using the modern traces for.
Anthony Martin: As a model So these are ways in which these modern traces and how they represent interactions of.
Anthony Martin: The modern foreigners and floors with those environments can be used to be able to retro addict and better understand what we're seeing in the geologic record.
Anthony Martin: Which Then again, we can use to predict what may happen with climate change on the Georgia coast now also what's going to complicate this is, as we go into the future thinking about how.
Anthony Martin: Human Development of the coast and trace making how Sometimes these are not going to mix, for instance, this is probably the.
Anthony Martin: worst situation possible if you have let's say an island that has a Georgia sea turtle Center as a tourist attraction, where you have done shoreline development.
Anthony Martin: In a way, that sea turtles cannot nest there, and you cannot have shorebirds nest there so that trays making for those nasty invertebrates is now severely limited as a result of.
Anthony Martin: This kind of development, now, this is a better way to do it, this is on tybee where you have doing restoration you're trying to have more of a natural doing restoration.
Anthony Martin: And this is a very low tech very effective very inexpensive way to keep people off the dunes and their dogs off the dunes I hail you sign maker of the venomous snake nesting area.
Anthony Martin: So just to review we can have technology as representing intersections of geology and ecology, the Georgia coast is by far the perfect place most perfect place to ever for being able to show these intersections.
Anthony Martin: and technology than can't provide perspectives poor both geologists any colleges studying the GA coast.
Anthony Martin: So if you can please visit the GA coast atlas, this is a five plus year project i've been doing with my colleagues.
Anthony Martin: At emory Georgia coast atlas.org i've written a few books about the Georgia coast, so you can read up in those two or at least put them in your university libraries and that's all I have for you, thank you.
Lisa Davis: Well, thanks so much I think that's definitely a different take on coastal environments for many of us, so we since we got started a little bit late on your session, you know how about one or two questions minute or so.
Lisa Davis: Center questions.
Lisa Davis: Okay, I guess, I have you all to myself, I, so I actually work.
Lisa Davis: In rivers.
Lisa Davis: And I work with colleges all the time, and particularly when we look at fresh water muscles and their biogenic effect on me dynamics and things, and so I know with fresh water muscles, a lot of their functional traits that would affect that emits.
Lisa Davis: Our species dependent, what about in coastal environments how close in association is it by species or can we make kind of broader conclusions.
Anthony Martin: yeah, of course, fresh water muscles have these integrated relationships with the fish that help them with a reproduction, as far as I know, the muscles that are in the salt marsh environments.
Anthony Martin: The rib muscles that they have their good kinsey a dumb so they don't have that sort of relationship with the fish, although.
Anthony Martin: i'm not an F theologists i'm a technologist, although I have done fish traces which would make being a theological acknowledges in that respect, anyway, I digress I don't know of any such relationship with the muscles that are in the salt marsh is on the coast.
Lisa Davis: Really cool looks like they happen in significant densities, the communities there, I mean they may be.
Lisa Davis: doing things like creating resistance to sentiment transport a whole bunch of different things I know some of that fit investigated and kind of history and environments so.
Lisa Davis: So anyways it's fascinating Okay, since you know we are sort of at the end of the session are approaching it, we have one final speaker it's an easy poster presentation and so.
Lisa Davis: I believe, how this will work is that I will share my screen, I will initiate the poster.
Lisa Davis: The authors are here, the first presenters jameson braun from auburn university and the second presenter is stephanie shepherd our session co chair.
Lisa Davis: And so there will be time and availability of the authors afterwards for questions, so I will go ahead and get things going with sharing the screen.
Lisa Davis: and
there's a button i'm looking.
Lisa Davis: Of course, this will work, exactly as it did before.
Lisa Davis: My name is Jamie Brown and i'll be giving you a short summary of my thesis project today entitled using ground baseliner analyze factory characteristics as possible controls.
Lisa Davis: On the variability of value morphology the buffalo river watershed Arkansas start off I like to give a little information about the background for this project.
Lisa Davis: The buffalo national river is a bedrock river that flows from east to west across the southern extent of the ozark down.
Lisa Davis: As it meanders it alternates between narrow and white balance not traditionally rivers start off by being narrow at their headquarters and become progressively wider downstream.
Lisa Davis: The buffalo national ever does not follow this form so current research in the area has been devoted to figuring out what is the primary reason the rubber just not having more traditional morphology.
Lisa Davis: My research is specifically focusing on analyzing the fracture characteristics of the boone and every Informations.
Lisa Davis: The Buddha information tends to form wide valleys and the average information tends to form a more narrow balance and Lessing fractured characteristics, such as spacing orientation.
Lisa Davis: And termination index will potentially identify primary cause for the development of the valley form.
Lisa Davis: And combination of field methods and remote sensing techniques, we use to gather data about these fractures Next, I would like to give some more information about the integrity of the study area.
Lisa Davis: Every information was deposited in the ordovician and it's predominantly composed of sandy limestone.
Lisa Davis: gallstones and the massive sandstone with the Newton sandstone remember after the ordovician there is an unconformity where there is no evidence of deposition during the salary and for the devonian.
Lisa Davis: And finally, we have the information which was deposited during the early mississippian this formation is known for his limestone as well as it's highly fractured chart it's moving on.
Lisa Davis: This map depicts the buffalo river watershed the field size for factors happen sample and locations where a separate field team used a like a terrestrial lidar scanner to scan blood, so the average information and the information.
Lisa Davis: About also contains various pictures from the field as well as a sample of a scan from the average information.
Lisa Davis: In order to sample fracture characteristics in the field, the linear scan line method was employed.
Lisa Davis: And this is balls pinning a measuring tape to the surface of the Rock outcrop were fractured are visible and easily accessible.
Lisa Davis: After that each faction that cuts across the measuring tape is noted at the distance it crosses the day in the orientation of the fracture is taken using a button compass.
Lisa Davis: The length of each fracture is also measure, if possible, in order to analyze fracture characteristics, using the letter scans a program called split and sex with us.
Lisa Davis: split effects is a program that has been developed specifically to analyze fracture orientation.
Lisa Davis: Here we can see a 110 meter section of the row our bluff, which is a large exposure of the average information.
Lisa Davis: The red bounding box shows a portion of the scan that has been enlarged to show a sample of fractures identify within the Program.
Lisa Davis: The purple ellipses represent those fractures wants to fractures have been identified a program will automatically calculate orientation data such as strike that in depth direction.
Lisa Davis: Moving on this section shows orientation data for fractures sampled in the field and those exported from split effects.
Lisa Davis: rose diagram a shows orientation data for fractures within the average information rose diagram be show the orientation data for the average information exported from split effects.
Lisa Davis: rose diagrams see shows orientation data for fractures that were collected by the usgs during the mapping of aka quadrangle.
Lisa Davis: And finally, rose diagram D shows orientation data for fractures sample within the information for extra orientation collection of the field generally lana well with fractures that were identified use explain effects.
Lisa Davis: record of the average information generally follow in north east, south west strength and those for the information strike north, south.
Lisa Davis: table one shows fracture characteristics measure for the boone and evers Informations across five different field sites.
Lisa Davis: spacing as an important characteristic to record for fractures within information, this is simply just a measure of the distance between some secret fractures along a stand line.
Lisa Davis: fractures with within the bone formation are closer together than the average and with a boon having a 11.2 centimeters spacing, on average, and the average and having a 16.5 centimeters facing.
Lisa Davis: The termination index is a quick measurement of how connected a fraction network is the higher the percentage, the less connected the fractions are.
Lisa Davis: While the everton and boom formations both have relatively low termination indexes on average.
Lisa Davis: The termination index for the boom is substantially lower which indicates a highly connected fractured network in conclusion.
Lisa Davis: and understanding of the distribution of fractures within formations is essential to forming an understanding of balance morphology.
Lisa Davis: Preliminary results from the field indicate that the clothes spacing of fractures within the information delineates on the weakness better a primary control on the evolution the wind balance of buffalo river, thank you.
Lisa Davis: Okay, great job wow i'm at work very well because it just paying the worst and It all went off without a hitch Okay, so we have plenty of time for questions.
Steph Shepherd (she/her): People gonna be nice to us wait.
jamiebraun: Yes, I had my fingers crossed for hoping that presentation format would actually work I spent a long time getting it to like jump back and forth in those sections to kind of show what I was trying to talk about so i'm glad it worked out.
Lisa Davis: It paid off, you did that, like expertly That was really good.
jamiebraun: Thank you.
Steph Shepherd (she/her): Well i'll give just a bit of context is what Jamie is working on is actually part of a much larger project that's been going on for about 10 years I know Lisa you've heard me talk about it, five or six years ago.
Steph Shepherd (she/her): But the exciting thing is a lot of our students at my colleague amanda kinsey Burt and I have worked on this together for about 10 years and.
Steph Shepherd (she/her): A lot of our students now are producing this great work along with what Jamie is doing, and one of them, and his PhD students just sent me a paper for review that's going out for publication.
Steph Shepherd (she/her): And she did the we have terrorists deposits and she did dating on the terrorists deposits, at the same locations and more to.
Steph Shepherd (she/her): Have Jamie scans and the exciting thing is the dates on the terrace deposit suggest that there is greater lateral erosion in the boone than the everton.
Steph Shepherd (she/her): Based on the timing and so her dates based on rsl samples and also some cosmic genetics match what we were arguing just based on the nature of the Rock layers that's kind of exciting actually a big cool.
jamiebraun: yeah that's great.
Steph Shepherd (she/her): yeah Jamie hadn't heard that, yet I.
Steph Shepherd (she/her): Just read the book no I just read the paper like two days ago, three days ago.
jamiebraun: So what I saw in the field it's mostly in the business specially the chart.
jamiebraun: formations they're like highly fraction highly appreciated and then you have the limestone that area that will you know dissolve pretty readily and that's what the student before me kind of worked on was analyzing the.
jamiebraun: How easily stuff would you know kind of a road in that in that regard so hearing that is actually super cool i'm glad we got to talk about just know.
Lisa Davis: This is sort of I know you were talking about the terrorists environment, the extra channel zone but i'm curious about what this.
Lisa Davis: Additional kind of valley like this unconfined valley setting no upstream relative to downstream conditions, what does that do to the bed forms, I mean do they is there, different sort of bed form formations as a consequence of this, you know spatial heterogeneity in the geologic substrate.
Steph Shepherd (she/her): know that we have noticed, I mean and amanda and I grew up on that river, so we have years and years and years of floating it looking at it so there's the visually no but scientifically we have documented some differences in terrorist development and the modern gravel bars.
Steph Shepherd (she/her): What isn't different is the material the material is not local it's coming from upstream in all in all, the way upstream to downstream it's not it's not coming just off the slopes it's coming but.
Steph Shepherd (she/her): The terrace distribution and the gravel bar development is different so.
Steph Shepherd (she/her): And now i'm going to struggle with exactly how to tell you what's different about the gravel bar, because we have such a giant data set I hadn't looked at that recently, what I can tell you is there's more steps terraces so there's steps in the valley in the everton.
Steph Shepherd (she/her): With the narrow Valley, you have steps in the boone you have much wider lot bigger cliffs although you can have clips and everton to and you only have maybe one terrace because the others are either not never were created not preserved or been washed away.
Lisa Davis: sounds like a perfect environment for slack water sediment preservation Paleo fled reconstruction.
Steph Shepherd (she/her): We we haven't gotten to that, yet I haven't even looked at that we have a lot of landslide data, so we have a student out of Oregon that's been looking at landslide ages okay.
Lisa Davis: And so, some of those tears to sound like they could be original treads not necessarily deposition features.
Steph Shepherd (she/her): So they're strapped tears, so you have bedrock some regolith and then a super thick deposit and one of the big things of Kathleen is the student out of d-ri.
Steph Shepherd (she/her): University Nevada that's her paper we're we're finishing up her paper republication it should be out we're sending the spl they can be slow we'll see what happens.
Steph Shepherd (she/her): But one of the things that she's proven with the she's done heavy dating like concentrated dating in the.
Steph Shepherd (she/her): In the multiple terraces and and so these are not you know we sometimes think of this model of like you have your rock and then you have your over bank deposit you think of that is like a package.
Steph Shepherd (she/her): of time, but the problem is what she's seeing and what multiple dating methods are showing is these these packages of sediment represent massive packages of time there's a huge amount of time collected there so.
Steph Shepherd (she/her): For so that shows that, like individual dating of a large terrorists you're not getting you know you only you don't know how old it is you don't.
Steph Shepherd (she/her): Look, you might you might know it's if you get down towards the regolith you might have a good age, but where we have some stepping of the bedrock under the terrorists those have vastly different ages, even though they're mostly one package of sediment.
Lisa Davis: says, maybe some discontinuities they are creating your time.
it's interesting.
Lisa Davis: Okay, so Questions for our presenters, this is the last presentation of the session
Lisa Davis: I want to go ahead and just i'm not saying we have to conclude now, but before I forget, I want to thank all of our presenters in the session today you guys do an awesome job and I learned a lot and I was totally.
Lisa Davis: You know, interested in every single one of the presentations that we had so my compliments to all of you for a job well done.
Lisa Davis: And I want to thank our session participants for hanging through the session and doing such a great job of moderating yourselves and making this pleasant experience for everyone involved, we do have time for discussion i'm going to open the floor for any sort of.
Lisa Davis: Questions or topics to revisit from everyone in the session that's remaining doesn't necessarily have to be related to the last presentation, but any of the presentations in the session today or this afternoon.
jamiebraun: I actually had a question for Dr band, Sir, Mr Vance.
jamiebraun: You mentioned during your presentation something about you were looking to do some seismic surveys and i'm just wondering if you had a chance to do that, or if that was like on the list of things.
jamiebraun: You wanted to do, because I was thinking it was like the perfect thing to kind of look for.
rkvance: yeah it would definitely be nice to have some of that future because.
rkvance: Now, with the gdpr we're just kind of getting to the very top of what you might see as far as the defaults place, but if you can get deeper with the seismic that you may be able to see some of the main parts and salt systems in there yeah.
rkvance: yeah.
Steph Shepherd (she/her): What is that 200 megahertz approximately antenna y'all were using.
rkvance: The one we were told him was a 100 megahertz okay.
Steph Shepherd (she/her): it's still it doesn't go nearly deep enough.
rkvance: For us, you can really.
rkvance: If you get really dry sand you, you know you may get down to 25 meters or or something like that, if you're really lucky, but you know typically 30 feet, or something you're you're done very good.
rkvance: We go into some money sands and.
rkvance: It does show you places where you hit salt water, though, because you get into salt water that attenuate signal very quickly so.
Steph Shepherd (she/her): We had trouble with water.
Steph Shepherd (she/her): And dvr sorry go ahead.
Lisa Davis: I just curious I don't really have a lot of experience working in seismic seismically active.
Lisa Davis: sediments, what does the strategic griffey look like, I mean what's the bedding line where that happens, they solved splay I mean sorry the sand slides you were describing or they just sort of lenses or how what's the morphology like.
rkvance: Are you asking a question.
Lisa Davis: yeah i'm sorry yeah.
Lisa Davis: yeah.
rkvance: What we would hope, I guess, it is just to see some offsets sunday's reflector when you look at.
rkvance: GP er and size, make it looks a lot of life and the processing is pretty similar.
rkvance: In that but.
rkvance: You know you got a chance of getting much deeper with that, and you can recognize.
rkvance: sides, and you know.
rkvance: channel scars and things like that, with with the seismic there's been some some real work done by.
rkvance: Jim Henry and co workers and Jim was at skid way and then mark it down and coast, he had some nice profiles that showed some psychic structures that were also probably related to that.
rkvance: brunswick fault system in there.
rkvance: Jim riker you know thanks that these are probably basically just reactivation of some of the old basement faults, which makes good sense, you know we're sitting on a raft and margin so.
rkvance: You know those things are going to be stressed, as you go through loading or unloading on the coast there, and so they shouldn't move again.
rkvance: And you know, we do have a size of its own up the charleston it was a pretty big quake up there, it busted up buildings and savannah and you know I haven't seen any Santa Claus yet on knowledge they're not.
Steph Shepherd (she/her): That the Sam blows are things that one of jamie's colleagues Stephen Matthews, one of our Grad students is doing some work on Sam blows and.
Steph Shepherd (she/her): In the new matter of timing down there, I will, and I, my in my master's thesis I worked in advertising so so I ran into Sam blows a lot they're they're interesting structures, if you run into those.
Steph Shepherd (she/her): First off the the geo probe the getting's if you have a getting drilled probe or whatever your job won't go through them.
Steph Shepherd (she/her): you'll get refusal.
rkvance: We do we drilled once we do that spring here, where I showed you the.
rkvance: You know the little baffled the drainage coming out of that we decided to put the geo probe right in there and we got down to about 20 feet or 22 feet in that and got refusal it just Pack.
rkvance: The sand was so all sorted and find it packs so tight, we could not go any further.
rkvance: yeah.
Steph Shepherd (she/her): We get that when we hit Sam blows because it was just so well.
Steph Shepherd (she/her): It was, such as uniform grain size and the drill just couldn't get through it, it just compact you're right, it would just compact and compacted.
rkvance: We actually had a jeweler weren't warned us about that, when we were asking you know how well the same goes to client settlements and he said done one thing you'll have trouble with is when you get into super fine sand.
rkvance: is right.
So.
Michael Davias: If I may i'd like to continue that discussion about the breathing beryllium dating with the.
Michael Davias: Entire audience to.
Michael Davias: really consider that when you're out there, talking, I was talking about those stress deposits and things like that up in the.
Michael Davias: In the ozarks I mean those all those things may actually you know so come to beryllium dating Looking back over the last 5 million years.
Michael Davias: Always sell only goes 100,000 years I mean it and then from there to the myo seen or or two when there is a heterogeneous fossils which often there aren't there's no other way to look at it, except the brilliant dating and it really, really is great stuff.
Steph Shepherd (she/her): It is, and we know we know we've gone past the rsl capabilities and some of those sites and luckily my colleague amanda kinsey runs the dry lab the luminescent lab at d-ri but she is good, she got in with the crowd with darryl granger and so darryl granger has.
Steph Shepherd (she/her): actually been helping us.
Steph Shepherd (she/her): and helping our students do brilliant work, you know, and he he kind of knows his stuff on that, so we were sold on it, we think it's a great tool to use.
Michael Davias: Looking for whatever I got I mean.
Steph Shepherd (she/her): it's great.
Michael Davias: You know.
Michael Davias: If there is any merit to to my crazy idea, there may be, you know, two or three meters of of impact regolith on top of the some of the stress at the top highest peaks of ozark that hasn't washed away yet.
Michael Davias: I know that's a that's a concerning thing, how did some of that stuff get way up there, and why is it still the way up there after what 40 million years.
Steph Shepherd (she/her): They used to say that weren't.
Steph Shepherd (she/her): terraces and in that part of the ozarks and we're like except we're looking at river cobbles you know meters and meters and meters on this somewhat flat surface were like those are river cobbles guess what.
Michael Davias: Well yeah everything was a lot higher at one time and there's an awful lot of a lot of.
Michael Davias: You know just stuff that's laid there after everything eroded away and they stayed just.
Michael Davias: In the River channels.
Lisa Davis: Sorry.
Michael Davias: river channels out in Arizona that were there 3 million years ago as a pilot cobbles.
Lisa Davis: Michael I was thinking about your presentation and during your presentation and sort of like your your ballpark ideas about what we're sort of.
Lisa Davis: The sources of those features It reminded me a little bit about it wasn't a big impact that happened in central Germany and didn't they have like i'm wondering if you found some other sort of analogous locations where there were similar remnant features from that and.
Michael Davias: What I would what I would say is the one thing i've always felt needs addressing is the fact that there is there should be an awful lot of really we call it call my new to.
Michael Davias: rock it gets spread out and when they look at impact of craters they use it looking for shock courts and things like that that show you know definitive impact very high pressures, you know.
Michael Davias: 10 gig apostles or whatever, but there should be tremendous volumes, maybe tremendous volumes of just sand or you know grapples that just gets shipped out.
Michael Davias: When they talk about the.
Michael Davias: chicken loop structure and the sand deposits along the Gulf of Mexico, some places there 2030 meters deep and they sit on top of.
Michael Davias: The katie boundary and some people say what it means to katie boundary really isn't where it should be well that all that boat could actually have come from the kt impact.
Michael Davias: But they don't you know and liquefaction just compacts it like crazy it's almost you know sandstone but it's viable.
Michael Davias: um no fossils in it, you know there's no way to date it and they think maybe landslides and things, but I think it just may be distribution of.
Michael Davias: These co minute at sediments but I don't know if we can sit you can't trace it back it's going to be hard.
Michael Davias: The only thing I think about it is when like things like at least the over the last 5 million years if we've got wi fi brilliant dating enough, we can find large areas that all seem to have.
Michael Davias: You know at 2.3 billion, years ago, all of this 10 meters of sand got here, we could start saying well, maybe, that was a catastrophic event but that's about all will be able to tell it.
Steph Shepherd (she/her): To wait for better tools.
Michael Davias: And there will be better tools, I mean we wouldn't have plate tectonics self if we didn't have all those better tools that for both are didn't have.
Lisa Davis: cool well, I think we are the last ones remaining.
Steph Shepherd (she/her): Active.
Lisa Davis: In the session so if our questions are satisfied um I think we, we can call it and not session.
rkvance: So thank you good job running the shoulder appreciate.
Lisa Davis: You guys for hanging in there with.
Steph Shepherd (she/her): US yeah maybe you'll see some of you guys tomorrow, I am going to show up for some stuff tomorrow, although I do have to do a few other things that's the hard part of doing these meetings from home life gets in the way when you're at the meeting you can just be at the meeting.
Michael Davias: around with your iPad.
Right.
Steph Shepherd (she/her): Actually I can't my kindergartener came home and he ran off with my.
Steph Shepherd (she/her): so well.
Steph Shepherd (she/her): yeah they later.
Lisa Davis: Alright, thanks everybody. 1005