Ann Ojeda: Alright, it seems like our numbers are growing a little bit we have 16 participants logged in.
Ann Ojeda: So if you haven't already please we'll welcome first of all, and then while we're waiting for everyone to join, please connect to the poll everywhere there's a link in the chat and the question is what one word comes to mind when you hear isotopes.
Ann Ojeda: Okay, so we have one more minute we're gonna start thing on time, because we have a jam packed afternoon so.
Ann Ojeda: First i'll just spend this last minute to say, welcome to everyone that's here thanks for coming on this should be a fun afternoon.
Ann Ojeda: If you know everything about isotopes then please lead this course, and if not, then we hope you take something away with you today.
Ann Ojeda: Even if it's just one or two references, so I do want to set the stage to that to that point and say we're not going to cover every single isotope system.
Ann Ojeda: Every single isotope and every single application I think even our careers can't do that.
Ann Ojeda: We had all the time in the world, but what we will do today, our goal here is to highlight some of the isotopes and the isotope systems that are used in our research and in broad application so we've split this up into the workshop up into several chunks and we will.
Ann Ojeda: kind of work through those through the schedule and there's going to be plenty of time to ask questions during our individual sessions and, at the end of the.
Ann Ojeda: workshop as well, so if you have questions, please do write them down, and we can address those.
Ann Ojeda: And, first I want to say, thanks to GSA and thanks to our convenience for this workshop we do hope to make this a respectful and inclusive event so here are some guidelines set out by GSA and we are.
Ann Ojeda: it's our duty to uphold these guidelines as individuals and as a collective group, so please, of course, contact me if you see actions that are contrary to these guidelines, and we will take steps, and if you want to elevate somebody's voice, please do.
Ann Ojeda: That as well, and if you see someone that excels in these categories we're happy to give commendations were there to serve as well, thanks.
Ann Ojeda: So just a few housekeeping things I know we've spent a year in zoom.
Ann Ojeda: But one thing I think zoom updated and it changed my view so maybe it changed here as well, here's as well, but here you have your mute button, you should all be muted on Upon entry and we will unmute to ask questions and then mute again.
Ann Ojeda: Thanks and we'll use the step forward and step back model as well in our discussion, so that if you have a burning question.
Ann Ojeda: Please do bring that forward and then, once that question is addressed, please step back so other people can step forward and also ask their burning questions i'm done here's your video, we would like to see your faces.
Ann Ojeda: I feel like we're all in you know locked dungeon sometimes in zoom, especially with the sea of black boxes.
Ann Ojeda: So i'll keep my video on the whole time, you can see my reactions when I get really interested or confused i'm not very good at hiding my reactions my facial reactions, so I encourage you to put your video on to so you can have that personal interaction.
Ann Ojeda: down here in the middle, should be your chat button will use the chat i'll have the chat open the entire time.
Ann Ojeda: and be monitoring for questions i'll also use that poll everywhere link as well to gauge your questions, then up here in the right hand side is your view, so this is the feature that I think I upgraded in zoom so you can have side by side speaker views or.
Ann Ojeda: A gallery view so if you want to see everyone, please do put it in gallery view, if you want to just see who's speaking speaker view as well, so i've also pinned several of our hosts and I.
Ann Ojeda: I hope we'll wait a minute we'll be able to introduce everybody.
Ann Ojeda: And kind of give you a brief background on the workshop leaders today so here's our schedule and we'll try to stick to this very tightly I am a person of order, so I will.
Ann Ojeda: start our isotope fundamentals at 110 and then we'll have a break, so one of the critical things we built into the schedule our three breaks to give us time to digest think about your questions grab a coffee grab some water.
Ann Ojeda: Let Mother Nature call, so please do use those get up out of your chair rotate your ankles really a shirt shoulders back and relax a little bit because we'll be here from one to five.
Ann Ojeda: So during these breaks, we will also have the option for you do go into breakout rooms randomly assigned breakout rooms So hopefully this kind of nucleus those networking opportunities that we miss in traditional conferences, you know the regular Conference, we would go up and.
Ann Ojeda: You know walk around meet people talk to people that were sitting next to us and in the zoom world that's a little bit more difficult so we're going to try.
Ann Ojeda: The breakout rooms during our 10 minute break sessions don't feel like you have to attend that breakout room.
Ann Ojeda: The whole time, but it would be nice if you could pop in introduce yourself say hi and get to know people from all over southeast GSA.
Ann Ojeda: So with that I will open the floor to our other hosts so i'll be do my name is Anna theta i'm an assistant Professor here in geosciences at auburn.
Ann Ojeda: And my research is about fate and transport of organic contaminants and water and sediment so most of my isotope world is down here, in the light stable isotopes I use carbon and hydrogen.
Ann Ojeda: And sometimes nitrogen to understand trans rotation and degradation of contaminants in the natural environment.
Ann Ojeda: So Laura would you introduce yourself.
Laura Bilenker: yeah hi everyone i'm Laura blinker i'm an assistant Professor here at auburn also and my background is.
Laura Bilenker: In studying how metals move and become concentrated in the crust primarily in higher temperature environments like manganese and volcanic systems and.
Laura Bilenker: Also in the context of or deposits my sort of GEO chemical weapon of choice is non traditional stable isotopes and so i'll be talking to you guys about metal stables around four o'clock today central.
Ann Ojeda: bill.
Willis Hames: hi thanks him my name is phil hames i'm a professor at auburn university, where I teach into research and mineralogy and metrology I.
Willis Hames: was trained originally I suppose and metamorphic metrology tectonics and I learned Arc on 4039 baiting fairly early on and it's stuck with me and I.
Willis Hames: haven't a laboratory here at alternative will speak about later in the presentation, most of my research work is either metrology or argon 4039 data which gets me into problems he has spent morphic and 70 rocks thanks.
Ann Ojeda: Great thanks bill and brennan.
Brennan van Alderwerelt: hi i'm brennan van all the world i'm a lecturer with auburn university geosciences right now.
Brennan van Alderwerelt: And my training as an igneous metrology I like to wield trace elements.
Brennan van Alderwerelt: And do a lot of mineralogy and I in fact to not really do age dating because i've mostly worked with extremely young volcanoes so i'm interested in isotopes as tracers of igneous processes throughout the system so.
Ann Ojeda: Running Could you also introduce the.
Ann Ojeda: Our other convener that is not present.
Ann Ojeda: Okay, yes, he is Oh, I see you go ahead and pins you.
Haibo Zou: know.
Haibo Zou: I names or however, though i'm professor of geology or brown university.
Haibo Zou: i'm interesting is to put chemistry, especially new the most rational laddie or anyone see whether you're a new land and I also interesting active volcanology and geochemical modeling.
Haibo Zou: So thank you.
Ann Ojeda: Great Thank you this is your isotope team, am I call this is the top performers in our flyer I don't know if anybody caught that I thought it was clever.
Ann Ojeda: But that's essentially the same molecule with an isotope in a different place so that's kind of what I envisioned our team, as is, we are all researchers that use isotope different isotopes and different isotope systems in different ways, so thanks for joining again today, and I appreciate.
Ann Ojeda: Your time and feel free again to pop questions into poll everywhere, or the chat Okay, so let me go back to sharing my screen, so this is the latest poll everywhere answer.
Ann Ojeda: let's see if I can do all of this, then.
Ann Ojeda: So what what one word comes to mind when you hear isotopes so i'll give you a second to digest this.
Ann Ojeda: So to me this looks pretty evenly distributed in this type of word cloud.
Ann Ojeda: The bigger the word, the more often it's used so all of these words look like they're in the same size font so it looks like we have a wide range of experience with isotopes and interpretations of isotopes.
Ann Ojeda: Again, one of the goals today is that we are able to see connections between different isotope systems, how we can use isotopes in different ways to feed into our knowledge of.
Ann Ojeda: earth system processes, so thank you for participating i've advanced the poll everywhere and currently exit out of this, so the poll everywhere, right now, should look like this.
Ann Ojeda: What isotope fundamentals, what are your outstanding questions so as I go through the next section, which is isotope fundamentals.
Ann Ojeda: If you have a question that comes to your mind, please type it here and other participants will be able to have those questions that they also have and.
Ann Ojeda: From that collection of knowledge i'll be able to decide which questions, we should answer, where we kind of missing the mark and what things.
Ann Ojeda: will make sure to catch up on before we move into our specialties does that make sense, are we okay feel free to use your emojis your votes your updates.
Ann Ojeda: audience participation in.
Ann Ojeda: zoom world is always a challenge and it looks like I have three votes, so we will move on.
Ann Ojeda: And right on time, so you told you it's 111 and we're starting today.
Ann Ojeda: So.
Okay let's see swap presentation.
Ann Ojeda: Alright, so I still find a middle section, this will only be a couple of minutes long, I think.
Ann Ojeda: Exactly 30 minutes long, and I hope to leave the last 20 minutes or 10 minutes for questions, so please do use that that function.
Ann Ojeda: The questions I hope to answer in these fundamental the fundamental section is what is an isotope so we have a whole conference on our workshop on isotopes but let's start at the very beginning.
Ann Ojeda: To ask what are they and what are the differences between stable isotopes and radiogenic isotopes, so there are two big categories of research, and we have representation from both sides in our workshop leaders.
Ann Ojeda: So setting that foundation of the difference between the systems and when they're used and how they're used is quite important.
Ann Ojeda: And then we'll finish on how isotope ratios are measured, so this is quite important for us to really do the research that we do, and we must be able to measure these isotopes at really high precision and with high accuracy, so that is quite important and we'll touch on that as well.
Ann Ojeda: This was.
Ann Ojeda: My attempt to put together a brief history of time in isotope in the isotope world I learned a lot putting it together so i'm going to give you a minute to digest this timeline starting from the sixth century BC or this sixth century at sorry to the early 40s.
Ann Ojeda: So we get a word for Adam from the Greek atmos which means indivisible, and we know now that that is not true, the item is divisible into some parts and that's a pretty good understanding of the basic building blocks of all of our materials and then an.
Ann Ojeda: Dalton came up with the modern theory of chemical compounds and then we have the discovery of radioactivity and the curious work with radium.
Ann Ojeda: And so, this actually is a movie if you haven't seen this 2019 release radioactive um it's it's pretty good, and then we can move on to different concepts of radioactivity or advancing the concept of radioactivity and rutherford, so this is rutherford here.
Ann Ojeda: introduced introduce the concept of the half life he's made better know him with the gold foil experiment.
Ann Ojeda: And discovering the nucleus after jj Thompson discovered the electron So these are all those components of the atom and this discovery is.
Ann Ojeda: kind of digging deeper into the physics and chemistry that make our our world possible and the first radio with metric dating of geologic samples was referred in Saudi.
Ann Ojeda: And it was pitch blend so we have this history of radioactive dating and geology that are.
Ann Ojeda: it's a quite tight connection, this has been used since the very first understanding is of radioactivity and its use for us to understand the world around us.
Ann Ojeda: that we can move a little bit too I tried to add in some light stable isotopes here so Harold Yuri was the first person to distill.
Ann Ojeda: liquid hydrogen and discover deuterium so stable isotopes of hydrogen here, and then we move on to the stabilizes topic compositions of pitchman, which is a natural product from.
Ann Ojeda: petroleum and coal.
Ann Ojeda: So, moving a little further will closer to modern day give you a second to digest this.
Ann Ojeda: So we have the the late 40s and discovery of the sea 14 clock radio metric dating with carbon really, really revolutionized us understanding these biological processes and how to use these time scales of different time scales to understand more modern.
Ann Ojeda: materials and then of course we have exploration of the Lunar rocks and always bring something back from weird places I was on to analyze them and see what information can they tell us about.
Ann Ojeda: about our system, and these little rocks led to the impact hypothesis for the formation of the moon so that's kind of a hallmark of how we've advanced in this.
Ann Ojeda: Radio metric dating also lead isotopes um I added this one in here it's quite nice gives us the beginning of environmental forensics so understanding how these things that we create.
Ann Ojeda: Then can contaminate the world around us and what techniques, we use to trace that contamination so that's really started in leaded gasoline and the 1960s and 70s.
Ann Ojeda: And then the 1990s on the ice core was drilled in the Greenland ice sheet and we were able to look back and onto earth's past climate through isotopes and these scores.
Ann Ojeda: And then he'll pop back over to modern and say carbon and nitrogen isotopes were established as ways to understand.
Ann Ojeda: organism dynamics and trophy level changes within within ecosystems.
Ann Ojeda: which has important implications for reconstructing diets like the iceman would see and understanding how these these processes these isotopic processes can reveal the history.
Ann Ojeda: Of the earth.
Ann Ojeda: So we have to stop here and say the evolution of this isotope chemistry or isotope geochemistry is tightly coupled to advances in instrumentation.
Ann Ojeda: So this on the left hand side, we have one of the first mass spectrometers, and this is from 1954 and it's set up very similar to the mass spectrometers of today, and this is a gas mass spec so it's analyzing carbon dioxide gas.
Ann Ojeda: But, essentially, we have a source a magnet and a collector symbol and, if you look at some of the.
Ann Ojeda: Mass spectrometers today they have essentially very similar inner workings with slightly different or improved technologies.
Ann Ojeda: So really these mass specs that measure isotopic abundances have will say a couple of different configurations and the configuration is based on what type of sample you're trying to analyze so we have gas or some aspects that analyze gases like CO2 or hydrogen.
Ann Ojeda: And then we have thermal ionization that measure I isotopes of solid samples and ICP Ms inductive Lee coupled map plasma mass spec can analyze liquid samples or solid samples and then bills animal can also analyze argon gas, so we have a couple of different.
Ann Ojeda: instruments and your when you think about doing isotopes one of the limiting factors is how are you going to measure the isotopes that you have of interest right, so all of these come into play for different isotopic systems and for different.
Ann Ojeda: different reasons Okay, and again, though.
Ann Ojeda: The basis of our isotope class is the periodic table, and we must consider this atomic accounting, so what is an isotope.
Ann Ojeda: So we have an elemental symbol here, this may be old hat, for some people, we have their elemental symbol and then we have our mass and we have a number of protons this is how our isotopes are usually labeled so see 12 has a mass of 12.
Ann Ojeda: And six protons right, and so the difference between the number of your mass number and the number of protons is the number of neutrons and that's how isotopes are formed.
Ann Ojeda: Right, so we have carbon 12 is different than carbon 13 has the same number of protons but one extra neutron carbon 14.
Ann Ojeda: has two extra neutrons compared to carbon 12 so they're really kick the kicker to remember here is that isotopes are not bigger Adams okay in general they're not bigger Adams they're heavier atoms and that makes a big difference when we talk about isotope fraction ation.
Ann Ojeda: So the read, so in this case, we have a couple of stable isotopes and then we have one unstable isotope so what's the difference between a stable and an unstable isotope.
Ann Ojeda: Well it's really the binding energy of the nucleus, so how well these.
Ann Ojeda: subatomic particles can stick to each other, and now, if you really like this topic, you could have you could go into physics and have lots of fun discovering.
Ann Ojeda: All the different energies and all the different relationships between your subatomic particles, but essentially the big idea that comes out is some things are just more stable than others, and most of the time it's due to.
Ann Ojeda: The number of protons and the number of neutron so we come up with this magic number, where you have unusually stable elements.
Ann Ojeda: That have even numbers of protons and neutrons and then calcium actually has calcium 40 is doubling magic because it has the same number of protons and neutrons and that stability is resistant to nuclear decay So what do I mean by nuclear decay well.
Ann Ojeda: The rules of thermodynamics the laws of thermodynamics are set so that things proceed to become a more and more stable state right, so if we have this line of nuclear stability anything that is unstable.
Ann Ojeda: admits particles or mitts energy to fall into this line of stability so that's where we get nuclear decay or radioactivity and nuclear decay.
Ann Ojeda: So if you see here on the X axis, we have in right which is our number of protons.
Ann Ojeda: No mass mass number sorry our mass number here and Z is our number of protons we have this this linear relationship of stability and then anything that lives outside of that we have a nuclear decay to fall into this valley of stability.
Ann Ojeda: So radiogenic isotopes become more stable by emitting energy and particles right we're pretty familiar with carbon 14 and uranium and lead stable isotopes live their best life Okay, they don't decay.
Ann Ojeda: But we have stability of different isotope system so carbon 12 and carbon 13 or two examples of the same element that have to stable isotopes.
Ann Ojeda: So we're talking about these radiogenic isotopes we can achieve stability and a number of different ways, so if you're, and this is.
Ann Ojeda: quite important and told when you're tracking these radioactive series in geologic materials is understanding what types of particles are emitted at different times so this gives you a nice diagram of the different decay patterns for.
Ann Ojeda: A nucleus, and we can of beta decay alpha decay and electron capture essentially again moving from this unstable nucleus to a more stable state.
Ann Ojeda: One of the hallmarks here of radioactive decay is defining the rate at which it decays and we define that through the half life.
Ann Ojeda: So one of the important things to understand here is this decay constant and again we hope it is a constant and i'll go into that in a minute.
Ann Ojeda: But essentially we have decay of that parent nucleus, and we have production of a daughter nucleus so going back here.
Ann Ojeda: We would call this the element that you start with is your parent and then whatever you produce is the daughter OK, so the relationship between the parent and daughter.
Ann Ojeda: um it's quite important to define and then to understand the decay constant the rate at which that daughter nucleus is formed.
Ann Ojeda: i'm not going to go to this I wish I did have time, but this is a really nice simulation and interaction and, if you would like to dive further i'll put this in the chat.
Ann Ojeda: about different isotopic systems and simulating radioactive decay identifying parents and daughters in this little cutie game, I think it's cute.
Ann Ojeda: Okay, so if we look at that same diagram we looked at earlier, and now we can put a few elements within that kind of colorful picture we saw a few slides ago.
Ann Ojeda: The things in blue here are stable nuclei right we're familiar with carbon 12 and carbon 13 hydrogen one into, and then we have again increasing our atomic number here and increasing our mass on your y axis, and you can see.
Ann Ojeda: All these other elements are color coded by half life.
Ann Ojeda: So we can use this relationship between the half life of our radioactive.
Ann Ojeda: material, the concentration of our product of our parent and of our daughter, to understand the age of material, and this is the ultimate age equation for that's utilized and a lot of our radioactive.
Ann Ojeda: Radio metric dating and geologic timescales so i'm going to leave this here.
Ann Ojeda: And our bill and bring it and maybe bill and Hypo will pick this one backup and start with the raid the age equation, and their discussion of radioactive dating or do chronology Maybe I should say that GEO chronology.
Ann Ojeda: There are some assumptions that we have to make, and I want to reiterate this that all of our isotopic measurements and our assumption.
Ann Ojeda: Are underlying by assumptions about our system okay so for this age equation, there are a couple of assumptions one is that our Lambda our cake.
Ann Ojeda: Our decay factor here is a constant and that we can measure our isotopes right, we can measure these products, and we can measure the daughters and that we have a closed system between this parent and daughter relationship so those types of assumptions.
Ann Ojeda: Are spelled out right here for the age equation, but I want you to keep that in mind as we go through other isotopic systems and ask yourself what are the assumptions that would be relevant for one on so topic system over another.
Ann Ojeda: So now we'll just kind of breeze over a couple of different applications of radioactive decay schemes, so we have their.
Ann Ojeda: Broadly used in chemistry geography GEO chronology Providence studies tracers and temporal changes and geo archaeology so here in the table, one I have a list of the parent isotope the daughter isotope the decay mechanism, the decay constant and a half life.
Ann Ojeda: What you can see from the half life is that there's different rocks for different clocks right, we can use different isotopic systems.
Ann Ojeda: in different ways to understand different temporal changes within these earth's surface processes.
Ann Ojeda: So here is another set of radioactive nuclear ions here, so we have the isotopic system on the left hand side, we have the half life, and then we have common applications.
Ann Ojeda: Again, these are broad applications, these are atmospheric instead of looking at our rock record, we can look at our rock record related to our atmosphere with some of these systems as well.
Ann Ojeda: Then the last example of radioactive decay schemes are really related to.
Ann Ojeda: The atomic bombs in the.
Ann Ojeda: 40s and 50s and atomic bomb testing Okay, so they produced really kind of unique and interesting isotopes that wouldn't have existed, if these atomic bombs were.
Ann Ojeda: tested and put into our atmosphere these isotopes weren't loaded into our atmosphere, but since they're there, we can use them to trace many different.
Ann Ojeda: Different timescales related to processes that are happening since.
Ann Ojeda: Their explosion.
Ann Ojeda: So one of the critical things about isotopes isotope systems in general is the way that we reference and report, and this is a big difference between our.
Ann Ojeda: radiogenic systems and our stable isotopes systems so most radiogenic systems are reported by the ratio of the daughter of a radioactive decay over the stable isotope of the same element, so, if you look down here at this table table 8.2 and you can see some common values that are reported.
Ann Ojeda: But sometimes if that sometimes this epsilon notation is used, if this is topic variation is very is really small and i'll Contrast that with our.
Ann Ojeda: stabilized scope system in a second.
Ann Ojeda: Okay, so now we're going to move on to stable isotopes we have our atomic accounting, and these are most of the elements used in stabilize took geochemistry.
Ann Ojeda: there's two main types of fractures nation, when we talk about stable isotopes one is mass dependent vaccination.
Ann Ojeda: And these vaccinations scale in proportion to the difference in isotope masses, so if we look at hydrogen hydrogen is to stable isotopes.
Ann Ojeda: Hydrogen deuterium so actually deuterium is twice as heavy as hydrogen Okay, so we have 100% difference in the mass difference between our isotopes carbon.
Ann Ojeda: Has isotope so stable isotopes carbon 12 and carbon 13 the difference between carbon 12 and carbon 13 is only one 12th of the mass of the.
Ann Ojeda: The lower mass stable isotope so the mass difference in those stable isotopes mean that hydrogen is going to fraction a typically faction eight and a much larger scale than carbon will.
Ann Ojeda: Okay, and we have two types of.
Ann Ojeda: infraction ation where you're there's equilibrium established between two different phases, or two different materials.
Ann Ojeda: Or you have kinetic fraction nation that's established based on reaction rates typically tied to biology biology has a preference for.
Ann Ojeda: living things have a preference to do less work right, you would never do more homework than you are asked so biology has the same preference they prefer light stable isotopes compared to heavier ones, and you end up with a fraction ation based on that.
Ann Ojeda: and generally it's because that these heavier isotopes form stronger and stiffer bonds than our light isotopes.
Ann Ojeda: So this is an example of mass dependent vaccination So here we have water, and here we have carbonates we have isotopic exchange between the.
Ann Ojeda: oxygen isotope and water and the oxygen isotope in carbonate okay so that's what this alpha, which is the fraction nation factor so here in the products we have our.
Ann Ojeda: Are heavy oxygen that's been incorporated into that carbonate structure.
Ann Ojeda: And the degree to which we have this isotope exchange is dependent on temperature and the composition of water, so this is kind of an example of that fraction ation happening over time Okay, so if the equilibrium is here, and our initial.
Ann Ojeda: isotope ratio is here, we have.
Ann Ojeda: A simulation of that isotope signature based on this this exchange.
Ann Ojeda: So the second type of stable isotope vaccination is mass independent vaccination and so that fraction ation does not scale with different tonight so masses so.
Ann Ojeda: Laura will talk more about this i'm especially applies to a lot of our transition metals and also applies to sulfur sometimes the sulfur system and actually mass independent fraction ation is how we can learn more about the great oxidation event.
Ann Ojeda: So this is a really foundational paper and so understanding the great oxidation event, if you're interested in that.
Ann Ojeda: Well, essentially because these atmospheric reactions are photochemical and there's their mass independent and then, once bugs start growing there's a vital effect there's a preference for light isotopes and you can see that in the isotopic record of sulfur.
Ann Ojeda: That switch between photo chemical reactions and biology.
Ann Ojeda: So in stable isotopes again our reporting, we have the same language but a little different dialect courtesy of brennan and our talks.
Ann Ojeda: Is that we report relative to this delta notation where we have our isotope ratios relative to an international standard and that you purchase.
Ann Ojeda: Times 1000 because usually these numbers are the difference in our isotope ratios are really, really small so we bring them to a scale that we can talk about.
Ann Ojeda: And again, that fraction ation factor is another critical element.
Ann Ojeda: of comparing the degree of fraction ation or the degree of that equilibrium or kinetic fraction ation.
Ann Ojeda: So in our world on these reference materials come from international agencies that agree on isotope values and agree on selling these to each other, essentially.
Ann Ojeda: So some criteria for those reference materials are that they are abundant and available not always the case and i'll talk about that in a second.
Ann Ojeda: And that they're homogenous so any sample that you get is the same in one lab as another lab that purchase it 30 years later.
Ann Ojeda: it's also well characterized and that value is agreed upon and also a reasonable range of isotope composition, which is not always the case think ptb, which is the carbon.
Ann Ojeda: So PD bell might so this ptb is actually much, much heavier than most everything else, so all of our carbon numbers end up being negative and relative to ptb.
Ann Ojeda: Nitrogen is one of the most homogenous isotope signatures in the atmosphere and it's actually a reasonable comparison, so we end up with some numbers that are positive and some numbers that are negative.
Ann Ojeda: But just to show how kind of practical, this can be our standard for water or for oxygen and hydrogen is actually standard mean ocean water that was collected outside of scripts so they went and picked.
Ann Ojeda: A bucket of water brought it back to the lab and say yep that is now the international standard, and it is the same standard.
Ann Ojeda: That we use today with a couple of other trips to the ocean.
Ann Ojeda: So this i'll leave you with just a few kind of a.
Ann Ojeda: flow chart of the different ways we can use these isotopes and each one of our session leaders will.
Ann Ojeda: kind of dive deeper into these applications that if we don't hit on an application that you're interested in.
Ann Ojeda: And we have a couple of references and that will share with you at the end of the session one is the sharp 2017 book i'll put a link to that in the chat it's actually free and downloadable so.
Ann Ojeda: You can dive deeper into this, if you still have questions okay so i'm going to stop sharing my screen.
Ann Ojeda: take a deep breath.
Ann Ojeda: And now we'll answer questions, we can talk deeper about any of these topics any of the slides that I entered happy to bring those back up I don't see any questions and pull everywhere.
Ann Ojeda: I know that was like quick and dirty you know really quick, but if you have any questions or want to bring something up you have your panel of experts to lay the foundation.
Ann Ojeda: Do we need the jeopardy music before somebody asked a question.
Elyssa Rivera: So I have a question just on a term that i've never seen before um what exactly is a chemistry geography.
Elyssa Rivera: If you know.
Brennan van Alderwerelt: I can take that one if you want and.
Brennan van Alderwerelt: yeah so so in particular grippy you need to correlate your different strata right and so there's things like bios particular feet, which is connecting fossils across units to to.
Brennan van Alderwerelt: Essentially, give them relative ages and so key monster to a goofy is the recognition that there are different chemical conditions of the earth throughout time that can also be used the correlation griffey, for example, the isotope content.
Brennan van Alderwerelt: Something well i'm kind of biased, but like strontium and the ocean has changed with time due to relative input of whichever rocks were currently weathering and different aeons and so you can actually.
Brennan van Alderwerelt: track those isotopes and sediments to the ocean chemistry at the time, which allows you to put it in its track record place.
Brennan van Alderwerelt: And I shouldn't say it's not all isotopes there are people who do chemo stratigraphy with other things like calcium magnesium ratios and carbon X and whatnot.
Ann Ojeda: Get separate and that was my thought is.
Ann Ojeda: i'm looking at some of these transgressive regressive cycles.
Ann Ojeda: And you can really see.
Ann Ojeda: Those quite clearly in.
Ann Ojeda: Chemical ratios essentially.
Ann Ojeda: Thanks alyssa was that you appreciate the question.
Elyssa Rivera: No problem.
Ann Ojeda: Any other questions or maybe I brings up a good point was anything new to you that you hadn't considered or thought of before that you want to know more about.
Ann Ojeda: Isaac asked if you will have access to the slides later on, and the answer is yes, we have, if you registered for the course we do have your email address associated with that and we'll work to send out a packet.
Ann Ojeda: For.
Ann Ojeda: Each section, including references, if we can, if I can get my act together.
Ann Ojeda: audrey This is also being recorded yeah so you'll have access to this.
Laura Bilenker: For a year right audrey or an.
Laura Bilenker: Access for a whole year, I think, to the recording.
RISE- Audrey Heun GSA: That is correct yep as long as you've registered for this meeting.
RISE- Audrey Heun GSA: Then you can go in at any time and watch any short course field trip session everything's being recorded.
Ann Ojeda: fabulous.
Ann Ojeda: Okay, so.
Willis Hames: I have a question.
Willis Hames: yeah I i'm great presentation on I.
Willis Hames: Oh, but I was not so great hair and and I I was around some stabilized system labs they had um they're pretty complicated and they had things set of them if people said Well, this is jet fuel, and this is, and so, how do you how do you survive, is it do you have these.
Willis Hames: Complex labs with very dangerous compounds are house, the state of the art today versus what people might have seen before, it also the question could be about sample size how smaller sample can you analyze today versus something that people might have worked on before.
Ann Ojeda: Right so and that's a good question so if you're specifically looking at contaminants there's several pre processing steps.
Ann Ojeda: You have to if you're looking at water, you have to get rid of all the water and then just analyze your compound of interest which can take a little bit of time and that's usually where the complex materials come in.
Ann Ojeda: And, especially if you have to do offline preparation and our instrumentation is advance, so that you can do online.
Ann Ojeda: isotope ratios, which is quite nice but yeah we can analyze pretty small concentrations I work in the parts per billion and parts per trillion range.
Ann Ojeda: In water and in sediment most of that is legwork getting it out of the water and sediment so that you can analyze the material but usually we're injecting.
Ann Ojeda: liquid samples or gaseous samples in the parts per billion parts per trillion range and it isn't asked you stuff right you look at an oil spill we're looking at all the oil residues we're looking at all industrial chemicals and things like that.
Ann Ojeda: Okay, so we're right at 142 so i'll let you take a break we'll take a 10 minute break and then come back and.
Ann Ojeda: Let me double check my count my.
Ann Ojeda: Oh, my last one thing.
Ann Ojeda: Okay, so we have.
Ann Ojeda: A 10 minute break i'm going to put everybody into breakout groups, if you want to join and say hi to people meet some people and that's great if not.
Ann Ojeda: i'll close the breakout groups, a minute before 150 and hi Bo is going to pick up with uranium theory and lead and uranium series in general okay.
Laura Bilenker: How does it break down number wise to how many people are are any true.
Ann Ojeda: Okay welcome back team.
Ann Ojeda: I will show you the results from the how are you feeling, you know um.
Ann Ojeda: So it looks like.
Ann Ojeda: Those that responded are feeling pretty good, which is a good a good sign, so hi Bo you got him in a good mood you know.
Ann Ojeda: we're ready to keep going Okay, so the next section is have so he'll talk about uranium series and uranium thorium and uranium lead dating so.
Ann Ojeda: Thanks hi Bo.
Haibo Zou: see my screen now.
Haibo Zou: Let me say.
Ann Ojeda: Yes, I see your screen.
Haibo Zou: Okay, let me start yeah.
Haibo Zou: So i'm going to talk about the uranium lag and uranium series isotope Oh, my name is our hybrid though and.
Haibo Zou: So, in terms of for you're only allowed we talked about your renewal and you, essentially, we have two clocks uranium to 38 all the way to lead to six, the other clock is uranium to 35 all the way to lead to seven, so this one has a special system, it has two clocks your anywhere.
Haibo Zou: In terms of uranium series was a series, then we have a multiple know when we talk about your renewal land where you know the intermediate I suppose.
Haibo Zou: When we talk about your annual series we pay attention to the intermediate why these are the important ones for geologists.
Haibo Zou: Uranium to early fall you fall into 30 ready on to do six in this you're earning 238 decay series and for the uranium to 35 DK series this one's important a PA 230.
Haibo Zou: So follow your own online they work for old rocks for uranium series they work for young rocks so depends on the applications depends on the knee.
Haibo Zou: See.
Haibo Zou: So if I want to know a little bit more about your own to 38 DK know this, the uranium to 38 so we know that the decay, is the half life, as I mentioned.
Haibo Zou: So for uranium to 38 decay is pretty slow it's easy to remember the half life is pretty similar to the age of the earth so so far.
Haibo Zou: you're earning 238 the earth last half of its original you're down to 30 day so there's a middle intermediate I suppose.
Haibo Zou: I like a Ruby the instructions Mera new DEMO Now this is called a series, so the daughter has daughter, you know granddaughter and a grand grand daughter, and all this way if we work, how long older us, you know we can ignore we can ignore the middle middle.
Haibo Zou: intermediate isotope but if we're working on wrong young rocks we take advantage of this intermediate isotopes.
Haibo Zou: So this the old line you're only allowed two clocks uranium to 38 you're earning 235 this is special.
Haibo Zou: And so we first talked about the common ladder dating you know common ladder means a whole rock us a whole rock lana lana dd.
Haibo Zou: And, and then we go to minerals first mineral this Glynn you can see from the formula, a lot of land, you know not you know it's the latter dominant so this for this one, we can do the ladder ladder model ages.
Haibo Zou: And then we go to work on this is a great great work for the dating and on zero con this one.
Haibo Zou: has a high uranium lead ratio, so I like a cleaner cleaner that's lad reach for circle uranium range.
Haibo Zou: So you can use this to clocks know Amazon has advantage of all the hierarchy, because their account doesn't have a lead at the beginning, and so we don't have to worry about initial ratios too much you know.
Haibo Zou: And then we can also use the two clocks to Cox this thing i'm not going to talk about I just mentioned, you know zarqa also has a half now I stopped know pretty.
Haibo Zou: For provenance studies and based on a half and I still and Austrian isotopes you know you can data with this so Oregon has a very simple.
Haibo Zou: Chemistry now so that matrix if there is not a big deal, so you can do the option, I still in situ analysis and avail we move on to uranium serious this one only works for your rocks.
Haibo Zou: So your end users are focused on foreign to 30 know this one, so the application includes a whole Arc and zarqa again sorry, no.
Haibo Zou: hierarchy you do the carbonate and agricultural Oh, and you can do the suitcase.
Haibo Zou: On a zero con is a silicate so different from the whole rock analysis this why you have to do the chemistry for those are called you can do that in situ analysis for your own series, you can do the youngs or across you know I will show you that.
Haibo Zou: Sometimes you can get as far as the as the 700 years old, oh.
Haibo Zou: that's the best you can do so you're in your life, I suppose, now there is a urine in 238 lead to six you run into 35 lead to so.
Haibo Zou: Now you have another one that called a foreign foreign to 32 it's the latter two eight you know, this is the fall around 232 for the uranium series that that's foreign to 30 you know they're different so we care about it or anything, I suppose, because.
Haibo Zou: You know you're already on that's for geophysicists and I he producing elements, you know, important.
Haibo Zou: For the thermal budget of earth now another thing you look at the decay Constance so they are very precise and very precise you don't have to worry about.
Haibo Zou: You know, a big uncertainty is the front of the constants when you get the ages of the rocks.
Haibo Zou: And again, you know for any radio Danny guys to ups, you know you're essentially you know, this is the one we measure today, this is one of the major today, you know.
Haibo Zou: So they are a function of the initial ratio the apparent this like.
Haibo Zou: You can see parent order not exactly you know parent order element ratio and and then time know some people want to see the present day measure, the ratio represent a time integrate you know, in this case, you are no matter ratio oh.
Haibo Zou: And, first of all, we go to the common law, you know whole rock lana lana dating you know, this is a property well certainly one of the biggest achievements for geochemist audiologists you know, is about dating of the age of earth now.
Haibo Zou: let's clarify doesn't know yay 1956 publish a paper E G chemical cosmic chemical actor that's the age of the earth, based on the lead lead isotopes you know from.
Haibo Zou: Our own and Estonia meteorites and have some earthen materials, you know the form so quality essentially no so this why you got an age of 4.55 you know.
Haibo Zou: So it's very remarkable considering the quality of mass spectrometers as their time and also you know so many years afterward people can only add.
Haibo Zou: To the third decimal place that's a you know still this number of holds true now, which is very remarkable work this about it, based on our lead lead isotopes.
Haibo Zou: So that's a Clara partisans world now you know I already mentioned, you know partisans work with the gasoline lighting the gasoline you know before 1970s, but the rhinos are letting the gasoline you know that's part of the work by.
Haibo Zou: Claire Patterson know this is the based on the light isotopes you know you can track your contract the so origins of.
Haibo Zou: Land, you know from the gasoline you know purposely folks and this material.
Haibo Zou: You know, to increase the vehicle performance and the fuel economy but it'll cause pollution know and with the isotopes as a tracer the latter tracers you know people campaigned on you know you know the source of the polluted the lead in the environment.
Haibo Zou: and burn out we'll talk more about the you know prominent studying facing my only slides I mentioned the Clare practices, so I stroke color and pregnancy.
Haibo Zou: So we go to another mineral color gleaner you know this one's a ladder he cleaned his spirit forward, based on the formula, you know, this is the land of the major element in this mineral oh.
Haibo Zou: So this is a different from the age of earth when you do the age of the earth, you know this thing grow all the way to today right, so you go this year oh over here you have a song like a different to militarize different meteorites you know you have a different meteorites know.
Haibo Zou: And over here gleaner the different you know if you fall in the gleaner right here, for example, 3 billion years old, oh.
Haibo Zou: This lead us to the ratio of stopped growing because you have too much to learn, you can do the uranium decay and a little bit later it doesn't matter, no.
Haibo Zou: So so that's thing you can date the formation of cleaner right, just like this one, you know, so the age of the earth you grow the age of greener and then you stop growing you know.
Haibo Zou: So essentially this the equation for this work you compare the previous equation for geographic essentially you know previous one, I measure today the whole wrong, so you just replace this term destroy the law now you get the same equation, and I show you.
Haibo Zou: The same equation right just a Wah Wah you know your interest to replace replace that by the angel for this.
Haibo Zou: Galina Galina the special because too much flat, you know you start growing this ratios.
Haibo Zou: So that's the gleaner but in terms of the precision is not that great it's good to follow the evolution of the earth, but in terms of presentation, now that great.
Haibo Zou: Value came this George where the rails you're only allowed Sarkar you know this one has a lot of uranium so you'll have two clocks you have to class and and then whether we'll put them together you got to this Concordia.
Haibo Zou: You know, and also because of the different decay House and you know the, this is not a straight line, but a whether it's a.
Haibo Zou: You know concave earth or concave down depends, you know so right here as a concave down, so it is you know second derivative work, you know, this one is less than zero because alumna to 35 is always less than Lambda to 38 you know So these are the concave down always.
Haibo Zou: Available application, as well as the application to date all dark on all the titles are on this one, you know you can go berserk on this earth materials and not a meteor is right, you know your data is our quality can get into 4.4 billion years you know from the jack hill.
Haibo Zou: of Australia.
Haibo Zou: And then we move on to the shortly of astral uranium series of your rocks you know, this can only work on your ass you know previously when the rocks are too young.
Haibo Zou: you're only allowed you know cannot do it, but you know you can use the uranium series so there's the time scale, you know tend to the privacy this word meaning, yes, you know you do the same, the last night when meeting so that authority into 30 ready on two to six.
Haibo Zou: And again, you know, based on Woolsey burger.
Haibo Zou: opinion you know different roster different cost, I can add a little bit about different processes different clocks you know it depends on your goal depends on your goal.
Haibo Zou: And allow you to log into the system, you know this, we work on the slope, you know the slow slow, please call 080 slope equals one infinity.
Haibo Zou: But for uranium series of infinity means a greater than zero point for many years, anything older than.
Haibo Zou: 0.4 million years before on this line, but over here, we take advantage of this area right so that's all I go 1000 years to you know less than one meaning, yes, this is a larger scale know so.
Haibo Zou: Again, it was a difficult that beginning, you know stock people got stuck you know for several decades, because of the limitation of the Alpha counting the method original muscle, you know.
Haibo Zou: So what can you do this was in burger from caltech oh so hey developer high abundance sensitivity and mass spectrometer within your technique.
Haibo Zou: And certainly much better or 10 times smaller and a sample size for 40 times smaller than traditional African you know this is how you develop science know Edwin science.
Haibo Zou: And then there's the way important occasion collaboration with carbon 14 no Karma 14 was a method was a big you know winning the Nobel Prize.
Haibo Zou: But if you go more details you look for the production with Karma 14 by the cosmic rays it's not a constant know so you need to collaborate by.
Haibo Zou: Other methods that while we can do the triggering triggering can on a girl much older than 9000 years so beyond a 9000 years you use your own series like calibration.
Haibo Zou: So this is the wire allocation, the other application is a core role, you know, so in this way, you have a million college cycle you try to figure out, you know, this is a.
Haibo Zou: record on this call role growing the high C level, you know you want to check, you know if this Cora also to age of the Koran is also consistent with a prediction, you know or here's a consistent now supporting this.
Haibo Zou: will encourage cycle, so this is the uncertain any small uncertainty, you know this old measurement you know older measurement don't have the resolution.
Haibo Zou: There you go to observe how young you know young zircons, these are the different instrumentation secondary mass spectrometry this law, you have to add USA you know.
Haibo Zou: Because this you need a high abundance sensitivity and also the energy focusing oh for the normal mass spectrometer.
Haibo Zou: So false work on this, so this is a big development, you know she'll work on the young zones at the different eruption ages, but as a youngster dessert my age is kind of a seminar showing that, although different eruptions but underneath the the share the same Long live the magma chamber.
Haibo Zou: And then came in my work, I use the application now to work on this dark on the front different places.
Haibo Zou: And then got two PICs know so there's a 95 on a day you got around 40 you know there's a 5055 pig now and also already here, you see the room is so small.
Haibo Zou: Now, so this the spot of the beam know so you cannot measure this So here we got a little bit you know crazy so.
Haibo Zou: Traditionally, you do the Polish Polish those are called here we are, you know we decided not to Polish it just to measure this part you know.
Haibo Zou: put up being over here and then there's a small change, you know produce accidental results when our visitors are coming surface dating and politicians are gone, you know, so we got ages like this now there's a 5455 confirming that this small peak is for real.
Haibo Zou: And then my student, you know these are the first first circle uranium Syrian surface ages, you know.
Haibo Zou: This brick thrall didn't rely on the mission at events you know renovation it's just that simple preparation, you know different thinking different ideas.
Haibo Zou: So these are the data from another world handled by my student former student Tucker again, you know traditionally you Polish the door cons, but sometimes you do the the room, the soul small you do the unpolished the room.
Haibo Zou: This is a show some additional work, you know over here, you can get a 0.708 you know your option 1.0.
Haibo Zou: OK so it's essentially you can data darkened room now and the user option at this, I like a 10,000 years, these are the 97,000 years oh.
Haibo Zou: I need to submit a you know there's another one you do the circle room, this was important and because of geophysical geomagnetic is crushing.
Haibo Zou: you'll want to do this, initially folks at 120 3000 years by 2014 my number, I gave a 12 plus months one another one from Wisconsin got a 17 plus minus one, these are the Oregon Oregon so so both.
Haibo Zou: shows data they are much younger than 120 3000 years about there's a discrepancy, but only recently there was constant girl updated their analysis, you know 10.2 plus or minus one which is a consistent with the dark ages.
Haibo Zou: So.
Haibo Zou: These are the some of the references no and I welcome questions Thank you so much.
I miss the I stopped for sharing.
Beth McClellan: Can you explain in more detail what you're looking at To date, the geomagnetic reversals.
Haibo Zou: Okay that's a good point yeah initially folks have found the Germanic reversal that they see this, a young very young, in the lower.
Haibo Zou: know and allow our original people measure the ages, but that's an Oregon we got 120 3000 years near the reversal know I know there are the the desert young zarqa another girl at the Oregon.
Haibo Zou: And then we got a much younger but there's still there's some difference, but they are the lab realized that the need to.
Haibo Zou: You know, get a better machine your work and then right now the ages are are consistent, you know within 1000 years yeah so as far as I know this, the the the youngest the gym enacted reversal default, so you know what can you what can allow a near the border of China and North Korea.
Haibo Zou: Initially I didn't know his work he did I know my work.
Haibo Zou: To 40 and power to pay for his a paper published in geophysical research lateral miserly resource, you know it's kind of I didn't know you know you know he didn't know awesome yeah.
Haibo Zou: So that's what I expected I expected you know work that's a lot that's allow you allow they can preserve this thing pretty well you know.
Haibo Zou: and also the day that you're off sure it works better with the pumice know the palm is probably doesn't work well with a geometric next gen magnetic reversal but i'm pretty well with you know with with a lot of stuff.
Haibo Zou: Thank you.
Haibo Zou: Did I answer your question.
Beth McClellan: Yes, thank you.
Haibo Zou: Thank you.
Haibo Zou: So my time is up, looks like.
Ann Ojeda: Okay, great Thank you so much Kevin I think up next is brennan and he'll talk about fingerprinting.
Ann Ojeda: With radiogenic isotopes.
Brennan van Alderwerelt: Is there.
Brennan van Alderwerelt: there's not a break okay.
Brennan van Alderwerelt: Let me see.
Just really quick.
screen share.
Brennan van Alderwerelt: Alright, I lost my chat window, so if somebody somebody asked a question someone stopped me.
Brennan van Alderwerelt: Great.
Brennan van Alderwerelt: Okay.
Brennan van Alderwerelt: So I wanted to cover the use of a radiogenic.
Brennan van Alderwerelt: isotope systems as as tracers and I decided, the best way to do this was to focus on the system i'm most familiar with, which is the rubidium strontium system, which is a very, very cool system for a bunch of different reasons.
Brennan van Alderwerelt: Among them are that they're not restricted only to igneous systems strontium is present through out geochemical reservoirs it's in soils it's a water it's living things as well as our hard rock minerals.
Brennan van Alderwerelt: And so, an understanding of the system can actually be applied to either dating or tracing processes or provenances across the greater earth sciences and not even just hard rock geology.
Brennan van Alderwerelt: All right, I am screen sharing right can I get a thumbs up all right good Thank you Okay, so this is very odd.
Brennan van Alderwerelt: yeah I think you know that you can see that i'm sandwiched between two different mostly dating focused ones, but this is where we are in the periodic table we're dealing with.
Brennan van Alderwerelt: The beta decay of rubidium into the element strontium which is number 38, so this is right here what I just want to make sure everyone recognizes us that we're dealing with a decay.
Brennan van Alderwerelt: Where while we are changing what element we're dealing with the atomic mass is actually the same so there's no mass fraction nation when we're when we're experiencing.
Brennan van Alderwerelt: The decay we're actually looking at different chemical behaviors between parent and daughter.
Brennan van Alderwerelt: And i'll come back to this later, but what's really interesting is that is that strontium has a very similar Ionic radius and the same charges calcium, and so it actually can sort of track the movement of calcium throughout systems.
Brennan van Alderwerelt: All right.
Brennan van Alderwerelt: What else, I have to say.
Brennan van Alderwerelt: Great okay and.
Brennan van Alderwerelt: let's see So this was originally used as a system, mostly for dating and kind of the traditional way up until about 1960 when there was this fellow Paul gassed who recognize that this could make great tracer and geochemical systems.
Brennan van Alderwerelt: And he started with igneous systems, specifically with trying to kind of fingerprint the mantle but since then use of rubidium and strontium or i'm just going to call it the strontium system.
Brennan van Alderwerelt: At 786 has expanded to to cover things like tracking the origins of different ions and and weathering into streams all this kind of surface process stuff.
Brennan van Alderwerelt: At the surface of the earth mineral weathering rates have been and laid out using strontium isotopes.
Brennan van Alderwerelt: we've looked even at how ecosystems get their nutrient based like the bottom of the traffic level how that gets contributed to from a whole bunch of different sources, because you can track those sources.
Brennan van Alderwerelt: With these isotopic characteristics and and the 2010s and onwards we seen the system also applied it's it's entered the.
Brennan van Alderwerelt: world of archaeology so archaeologists have been using it for all sorts of things, the most successful been tracking human migration, although I recently saw one where they were like trying to figure out where a.
Brennan van Alderwerelt: shipwreck came from by looking at the strontium isotopes and the ship.
Brennan van Alderwerelt: Would the, what are the ship which included this extra consideration of weathering exchange with the seawater and the ship so there's there's a lot going on but.
Brennan van Alderwerelt: The geochemical behavior of strontium is pretty well understood so even in these complex intertwined systems, you can extract a little bit of information, which makes it really, really interesting.
Brennan van Alderwerelt: And let's see what else I have chemistry geography relative ages and and the last thing is so much more because there's a lot of cutting edges and.
Brennan van Alderwerelt: use it this this group so, so why the strontium system is so useful across many of these as i've mentioned in.
Brennan van Alderwerelt: Its present and a lot of different systems, the geochemical behavior is really well understood there's also a very nice database of different.
Brennan van Alderwerelt: reservoirs oh strontium you can go online and look up and not even a single database right, you can look up in water databases, you can look up in GEO rock is things like that.
Brennan van Alderwerelt: Nice flat clean numbers of what kind of ratios, you should expect between the radiogenic isotope 87 and one of the stable isotopes at six, which also those two so 86 is not the main staple isotope it's actually one of the.
Brennan van Alderwerelt: lesser it's about 10% of strontium while at seven is about 7% of strontium so it also makes it easy to talk about because the radiogenic isotope and the stable one half of similar.
Brennan van Alderwerelt: abundances so we don't have to deal with epsilon notations or delta notations we can actually just report that straight up ratio and it's usually like 0.7 something something something so it's a it's a manageable number.
Brennan van Alderwerelt: All right, and then finally we're not dealing with a lot of mass vaccination and this largely has to do with the fact that these.
Brennan van Alderwerelt: These atoms are so big that the mass differences between different isotopes is really, really tiny, so the mass vaccination effect is very small, you do correct for it during analysis but.
Brennan van Alderwerelt: i've done a few different strontium isotope analyses and never had the correction really changed the numbers in the end in a major way.
Brennan van Alderwerelt: But yeah, I think, maybe I have too many slides backing up each of these bullet points but they're just right there is is the relative abundance of strontium and rubidium in the upper crust compared to other elements, you can see that these are not as trace.
Brennan van Alderwerelt: As as the phrase trace element might might suggest they're pretty up there, of course, only under the big the big common ones as far as abundance goes.
Brennan van Alderwerelt: So all right also worth pointing out that the decay system is pretty hammer down, we know how it decays we have a good, well constrained Lambda and half life.
Brennan van Alderwerelt: as well and, and so it does make a useful dating technique and and follows a relatively simple age equation, if we have a nice clean well constraints system.
Brennan van Alderwerelt: Where it's usually reported this way where the slope of this.
Brennan van Alderwerelt: Of this line over time gets us ch but I don't want to focus super hard on that.
Brennan van Alderwerelt: One thing I do want to point out is that the amount of this radiogenic 87 strontium, meaning that the strontium that is entirely developed from radioactive decay of rubidium.
Brennan van Alderwerelt: can be understood as as being the result of really for other factors, which is the initial isotopic composition, the current amount of rubidium versus strontium in in whatever you're looking at.
Brennan van Alderwerelt: That decay constant of 87 rb and the time elapsed since this material was initially formed, which is the text version of this equation here, but what makes strontium a pretty useful fingerprint, among other things, too, is that if you're dealing with young materials.
Brennan van Alderwerelt: You can see that this last.
Brennan van Alderwerelt: chunk of the equation disappears and we can often for a lot of material just use the measured 8786 ratio as a fingerprint of the initial ratio in the rock.
Brennan van Alderwerelt: But otherwise we'd have to know the time independently and then we can adjust that measured ratio to understand what some initial ratio was and that's what we're really interested in is the initial ratio.
Brennan van Alderwerelt: And i'm going to talk about this a little bit in the context, starting with magnetic systems.
Brennan van Alderwerelt: So we do have a idea of what the initial ratio of parent to daughter would be for the entire Earth.
Brennan van Alderwerelt: From the Celtic a contract meteorites so kind of how we imagine the planet form that allows us to in fact this is one thing that can be used to differentiate.
Brennan van Alderwerelt: earth rocks from from sort of extra solar rocks but we got a good starting point and let's see where is my yeah there is, and so in a simple system, we would expect this to decay, or the 87 to accumulate from decay of rubidium and a predictable way over time.
Brennan van Alderwerelt: Which is cool for age dating but what's really interesting is is that in reality it's not that clean.
Brennan van Alderwerelt: You can see that we started with some initial ratio right about Point seven and, since then, different components of the planetary system have followed different in growth.
Brennan van Alderwerelt: evolutionary paths, like the amount of 87 strontium over time has developed differently in these different systems and what we're really looking at here is the geochemical.
Brennan van Alderwerelt: behavior of the parent rubidium because it is what we call in geochemistry a highly incompatible element and so.
Brennan van Alderwerelt: Hopefully you've heard that phrase before, but if you haven't that got really compressed on.
Brennan van Alderwerelt: Essentially, what that means is that when you have some sort of melting event that rubidium highly incompatible means that gets.
Brennan van Alderwerelt: concentrated in the melt is not compatible with the solid phases and so that means every time there is a partial melting of a rock say the upper mantle and which other materials extracted through this.
Brennan van Alderwerelt: planetary process of differentiation rubidium is progressively being concentrated in the outer crust so we can actually use this ratio of how close we are to this initial value.
Brennan van Alderwerelt: The following this 8786 ratio kind of follows how evolved, we are from that primary primitive mantle or original earth value so if we have.
Brennan van Alderwerelt: magma is that are extracted from say this upper mental line if you can understand where you are along this line, you know your starting point is so you can do things like understand the degree of partial melting that would have dumped that parent rubidium into the system.
Brennan van Alderwerelt: And you can also use this 8786 ratio as a standard for how evolved away from that initial system, you are so you'll find volcanic.
Brennan van Alderwerelt: magnetic margins of some sort or another well you'll have these assaults that are really close to the mantle.
Brennan van Alderwerelt: they'll have a ratio of like Point seven one, and then the the more evolved intermediate to even fell sick rocks will have like a point 710 or a point 713 giving you this this evolutionary spectrum.
yeah.
Brennan van Alderwerelt: So here's one somewhat famous example, who I forgot to credit it but it's originally from a 1986 paper in which someone looked at.
Brennan van Alderwerelt: This this isotope ratio and use it to connect different.
Brennan van Alderwerelt: oceanic basalts to what they propose as a variety of unique mantle reservoir sources sort of trying to use basalt at the surface, to understand how the mantle is GEO chemically heterogeneous.
Brennan van Alderwerelt: beneath the surface very cool stuff this has since been expanded on a lot and gotten a lot more complicated than this diagram right here, but I thought i'd show this one, because it's I think it's pretty neat.
Brennan van Alderwerelt: And one thing I do want to point out is is that, like most isotope systems, you never use it in a vacuum that's kind of bad practice so here they've paired it with the happy medium neodymium system which is reported as an epsilon.
Brennan van Alderwerelt: To to sort of have this duel isotope system, helping you understand what's going on.
Brennan van Alderwerelt: All right, I know i'm talking a lot of vagaries so I thought i'd bring in a case study to.
Brennan van Alderwerelt: I swear it's just coincidence that it happens to be something that I recently published on, but you can check out this article, if you want, and let us it just came out.
Brennan van Alderwerelt: Like last week officially published on this on this, the rocks of this mar amar real quick it's a one off okay know when rising madman hits the groundwater and explodes creating a crater it's not a long sustained volcano.
Brennan van Alderwerelt: And so, this looks like it's erupted a really, really primitive material that should give us information about the mantle underlying this region of the central andy's.
Brennan van Alderwerelt: But this is actually a relatively of all the Celtic and despite despite what my little flag there says.
Brennan van Alderwerelt: And that is a little bit of an issue and trying to understand the central and ease, which is a very act of modern magnetic argh because that's the most primitive the most may 5 Rock in the entire volcanic arcs since the last 25 million years or so, when it was a different machine.
Brennan van Alderwerelt: So there you can see it in context there's the Mar in the bottom right of that field photo black.
Brennan van Alderwerelt: crater right there, and you can see it sitting on top of this right elliptic ignore bright from from.
Brennan van Alderwerelt: crystal melt super eruptions and then there's all these and acidic volcanoes around there's there's just.
Brennan van Alderwerelt: No deep earth signals here in the deepest signal that we get is just still a result aganda site so it's still evolve.
Brennan van Alderwerelt: And in this region that means we've always had this question of what's down there is the mantle look like it looks under the southern andy's or does it look the way that it looks on into the.
Brennan van Alderwerelt: Pacific, is it a contaminated mantle is it an ancient mantle that's been re mobilize and is all depleted and all these different things.
Brennan van Alderwerelt: Over the decades there's been a lot of hypotheses and none of them have really been able to be confirmed what the nature of the mantle is like in this area until now.
Brennan van Alderwerelt: So this diagram here is showing how it's a super duper thick crust and there's a lot going on that's an ultra simplified view.
Brennan van Alderwerelt: But one thing to point out is i've labeled where inclusions have been trapped, and so this Sarah Vera lava is special because it shut up along a fault or crystal weakness, however, you want to describe it.
Brennan van Alderwerelt: And so avoided a lot of these processing centers in the crust not all of them.
Brennan van Alderwerelt: it's still got of all to have assault aganda site, and it has a strontium isotope characteristic that's closer to an Anti site.
Brennan van Alderwerelt: But within this lava are all of these and inside the all the veins are melt inclusions glassy silicate melt inclusion sometimes a single single large one and I like using this example, not just because I did it but.
Brennan van Alderwerelt: but also because it really shows the power of understand are using strontium isotopes because so in all of the strontium doesn't fit into the crystal lattice anywhere just does not.
Brennan van Alderwerelt: go into those those minerals, so if you take that material.
Brennan van Alderwerelt: All have been with a large inclusion in it in you dissolve it and you extract the strontium for something like column chromatography.
Brennan van Alderwerelt: You can make the assumption that that strontium is entirely from the material that was trapped in the inclusion.
Brennan van Alderwerelt: Which is really cool getting isotope values from a magnetic melt inclusion, really, really sweet stuff there and.
Brennan van Alderwerelt: So not everybody gets a single inclusion i'm going to skip the crystal growth thing so.
Brennan van Alderwerelt: yeah so that's what we did, and one great thing about strontium, this is what i'm getting at is that you don't actually need very much of it to analyze to be able to get a good viable understandable ratio off of that analyses so.
Brennan van Alderwerelt: long story short, can skip that one what we found is that I went and did this work at new Mexico state with this tim's a thermal ionization mass spec.
Brennan van Alderwerelt: Oh hang on.
Brennan van Alderwerelt: Which is an interesting I type of mass spectrometer I think it might be one of the older ones.
Brennan van Alderwerelt: I think it might be the oldest non gas one, but if I remember correctly, but essentially you dissolve your sample and you try it on a little filament it's like.
Brennan van Alderwerelt: A light bulb filament but it's Mediterranean and really, really, expensive and then you send some voltage to that Ionized is all of your sample goes through the sector magnets and then you get your different.
Brennan van Alderwerelt: Ion separated by mass to charge ratio and because the strontium atoms are pretty big it's it's relatively easy to get those faraday cups that detectors you physically move them, they can be they are relatively far apart, to look at these isotopes of strontium.
Brennan van Alderwerelt: And that's actually why we talked about this in ratios, because you don't measure the actual amount of strontium you measure.
Brennan van Alderwerelt: The ratio of the different ions of the different isotopes that are coming through the system in the mass spec so the ratio thing is partly in.
Brennan van Alderwerelt: an analytical reporting but anyway, the bottom line is that this worked with sometimes only 10 or 20 nanograms of strontium extracted from inclusions like this, I was able to pick up a signal that showed.
Brennan van Alderwerelt: Approximately mantle like strontium 8786 values that were lower than any other recorded across the entire central andy's before this work.
Brennan van Alderwerelt: And so the the punch line to kind of have this great long debate about what's the mantle like under the central andy's lands on kind of maybe the most boring.
Brennan van Alderwerelt: But still useful answer of it's a relatively normal mantle, and all this evolution that we're seeing of these highly evolved isotopic really evolved law of us on the surface is all due to live a sphere processes which I think is really, really neat.
Brennan van Alderwerelt: let's see I think i'm pretty tight on time and someone tracking this better than I am.
Brennan van Alderwerelt: So anyway.
Ann Ojeda: You have just say wrap it up.
Brennan van Alderwerelt: yeah okay so i'm wrapping it up, maybe i'll publish the slides because I put some other neat examples in is the thing is that you can.
Brennan van Alderwerelt: follow these different rocks and kind of relate them to how they've moved away from the mantle through time by tracking their strontium isotope ratio and on the flip side of trying to you know.
Brennan van Alderwerelt: Peer into the mantle you can also try to figure out which rocks are weathering away and contribute into systems such as this combined input, there is fan or so it's seawater which is mostly going to be getting up or mental derive rocks and produce our crust.
Brennan van Alderwerelt: Most places, but not everywhere and so i'll close it off really quickly with isotope chemo stratigraphy bunch of different inputs, giving us a consistent ocean residents, time is longer than the mixing time so.
Brennan van Alderwerelt: isotope ratios of the ocean are sustained over long time periods which allows us to create something like this, which is a curve that follows that isotope ratio throughout time.
Brennan van Alderwerelt: Old stuff kind of a little sloppy and confusing, but I want to notice that here, you want you to notice that here in the tertiary it's really, really tight.
Brennan van Alderwerelt: Not only as a tight is that once you get to about 40 million years old or younger you really don't have very many opportunities to accidentally.
Brennan van Alderwerelt: Put your settlement or whatever material you're analyzing into the wrong age group based off of the isotope ratios like not even using dating techniques, not even using it to convert into yours, you can.
Brennan van Alderwerelt: Put your sediments into strata graphic relationship by looking at these changing isotopes that represent different inputs over time okay.
Ann Ojeda: Thank you Brendan.
Ann Ojeda: yeah that's wonderful appreciate the dive into strontium isotopes I didn't know much about them, and now I feel like i'm enlightened so thank you.
Brennan van Alderwerelt: it's a huge world I cook.
Ann Ojeda: Okay, so next up is bill and he'll talk about.
Ann Ojeda: argon dating and some other fun activities so thanks.
Willis Hames: Thank you and and everyone i'm going to get a presentation set here and.
Willis Hames: wish that my pointer option, with the.
Willis Hames: Cooperating with me, which I think it has we are to the point in our overall presentations to think about the potassium mark on method one.
Willis Hames: i'm not, by any stretch really the oldest but a venerable method and another.
Willis Hames: technique which you tend to hear about more today the arc on 4039, but they are, in fact, the same thing it's all everything i'm going to talk about state is going to be in regards to potassium Arc on dating.
Willis Hames: Either traditionally or with the variation that we call our gun 4039 So here we go i'm excited to be with you today, again, my name is phil aims and i'm.
Willis Hames: going to pay homage to those who have come before the technique for potassium archive dating actually goes back to al Amir.
Willis Hames: and others discovering that potassium kind of radioactive isotope but it a laboratory of john Reynolds in the mid 1960s, a lot what's going on, it was in the department of physics at Berkeley.
Willis Hames: And it was said the dawn it was in the mercury, you know era for NASA dawn of Apollo Sputnik era and.
Willis Hames: It was a hotbed of activity and what was discovered there they were working with nuclear reactors that are radiating samples of meteorites.
Willis Hames: And for some of the students in the slab some of the more famous individuals that was their primary focus was planetary geology and and the study of cosmic chemistry and interaction with the solar, wind topics like that.
Willis Hames: Now up what Dr Reynolds head is students do was measure everything, even though they might be interested in a particular isotopic system it to students in particular i'm.
Willis Hames: Correct Mary few in greenville Turner realize hey in a nuclear reactor we make.
Willis Hames: Arc on 39 for potassium 39 that sounds like something useful, and it is this is how it works.
Willis Hames: i've got a portion of the new Clyde chart that man represented so ably for us at the beginning of our presentation today and the isotopes that are stable are shown in blue.
Willis Hames: You can think of this as a valley energy things that are in the valley tends to be stable and if you're outside the valley they're going to change in the balance of protons and neutrons to come back into this Valley.
Willis Hames: And right smack DAB in the middle of the valley is potassium 40 a special gift to us because it ought to be stable, it ought to be perfectly stable like we heard earlier about calcium 40.
Willis Hames: What can be wrong, well, you also heard reference in DR as talk to magic numbers and.
Willis Hames: potassium 40 is under a bad star it Scott odd number of protons and an odd number of neutrons and because of that.
Willis Hames: it's unstable, but with a very long half life, the half life actually is 1.25 billion years very long amount of time, but potassium is of nature element so potassium.
Willis Hames: decay in a lots of materials is enough to make a measurable amount of the daughter Arc on 40 so this technique has application to.
Willis Hames: The oldest meteorites that are known oldest materials we can get our hands on to well just to show they could do it one.
Willis Hames: A given Berkeley many years later, Paul rainy and overstated, the lobbyists at pompei so they can write a paper and science to say they were calibrating their work and gets plenty of the younger.
Willis Hames: that's pretty impressive well here's the equation that you were presented with a couple times today, it is exactly the same.
Willis Hames: with one exception here's the daughter we've got a proxy for the parents this just would be an equivalent sign for radiating a sample of artificially making some argon 39 but we turn it into an equality bye.
Willis Hames: Putting in the number chain just a mathematical manipulation this come down here again for a second if we put a sample in a nuclear reactor, the way the shorthand works, a neutron comes in a fast neutron and interacts with 30 potassium a proton leaves.
Willis Hames: If you lose approach on.
Brendan Soles: But you.
Willis Hames: gave a neutron you move.
Willis Hames: From.
Willis Hames: here to here and now, we could do our hd work all on archive easy easy to measure it's a gas heated up crush it melted get the gases of the best spectrometer it just measure the archive isotopes that are there.
Willis Hames: 37 is also beta is a byproduct from test, so we just have to measure these two and it works mathematically if you put this metric called J yeah it's a.
Willis Hames: Quality i'm turn in a proportionality now how do we do with shave it out, we figured this out well very few returner said.
Willis Hames: it's it's easy just take this expression and rearrange it and solve for che but now what you do is you put in monitor minerals, with your sample.
Willis Hames: That you know the age of it that you hang the results on I think I know the J value for the spot at the nuclear reactor.
Willis Hames: let's go there next we have an image of a provided from a paper by dalrymple at all by TD one.
Willis Hames: These individuals were meticulous and they wrote an exhaustive paper, the usgs professional paper and they went through everything about how the nuclear reactor worked and preparing their samples, this is a picture from a front speech effect effect work.
Willis Hames: A nuclear reactor, by the way, is about the size of a modest trash can in your office, if I had a I could hold it like this big it's it's not very big.
Willis Hames: And what is done is a package with your samples is lowered to the Center of the reactor, ideally, and the very central position in the stack.
Willis Hames: And they literally and some reactors, they do with a fishing line and they've got a piece of chewing gum or something attached to the line something know how far to lower it.
Willis Hames: And what they aim for, is to get to the middle of the middle of the fuel rods, and when i've got to the lower right kind of encapsulated underclass which are glass blower here does it.
Willis Hames: operate university maybe only charges 25 bucks nobody telling you don't charge enough and V.
Willis Hames: we've got samples from one layer here and look at that, I mean.
Willis Hames: A jewelry store with looked at the stuff we've got some pink K felt Spar we've got some black by a tight, there are some to grab fragments of assaults.
Willis Hames: Then we've got some minerals that are wrapped in aluminum foil each of those is in a unique position along with monitor minerals, so the monitor minerals are.
Willis Hames: are shown with them, so what we do is we map out and solve what's the che value for a layer
Willis Hames: And we do that for every layer of central position radio positions, and then we go up up up and we measure the chain value for the whole package, the value we showed there that's a plus or minus 0.1%.
Willis Hames: i've got kind of get fired up pure because because other people have done such a great job of I have taught kind of fired up about this that's one per mil precision in measuring our teeth.
Willis Hames: Now you'll never do better than you do when your standards, so the best you could do, on your standards is about the best that you can that you could crow about and we could go.
Willis Hames: To about.
Willis Hames: Point 1% that's makes us happy we want, we like that so.
Willis Hames: This is the lab overall.
Willis Hames: And the what do I have to say, well it's a fun place we got a lot going on the overall lab is called we.
Willis Hames: Spent lots of money on this so with focus groups and polling and it's called the auburn noble isotope mass analysis lab just rolls.
Willis Hames: off the Tongue that's the whole caboodle the machine that's closest we're going to look at in more detail it's called the glm 110 and if you wonder what glm stands for.
Willis Hames: It stands for great little machine and that's it because you can't call it it's by homemade mass spec that you're an idiot I mean I can kidding me so so now it's it's the GL everyone now there are other machines properly made in England, but they're ma p.
Willis Hames: there's one that's blue that's Duncan those what that's with a green electromagnet that's called see these are for people who set them up and various labs and we have gone and got them in brought them into our lap of the customer to doing stuff with them and.
Willis Hames: Now I think about.
Willis Hames: For fans of history, the ultimate reductionist was Julius Caesar but somebody's breaking it down and saying here are the parts now.
Willis Hames: we're enlightened, we know that the sum of something can be greater than its parts, but let's break it down on mass spectrometer system you've got to have a way to get samples in the system.
Willis Hames: For sampling we use some laser you've got an extraction line that's going to handle the gas and then you've got a mass spectrometer system to measure isotopes by masses we've discussed so Caesars right.
Willis Hames: complex system three parts well, even the mass spectrometer we can break into three parts as well the mass spectrometer has got a source.
Willis Hames: it's got something to separate mass in our case it's in most cases it's a whopping big electromagnet you can have other ways of sort of separating mass also.
Willis Hames: Keeping kind of us time and distance, which is cool but um we have a detector so this portion see over here is to indicate the mass spec itself that's the deal language and.
Willis Hames: And it's got a source and analyzer in a detector charged particles entering a magnetic field are reflected in proportion to their mass and their velocity or.
Willis Hames: Potential difference and the strength of the magnetic fields, so we just buried the magnetic field keep the source at one potential and we bring things into a catcher's mitt to catch them and measure them and it's really simple it actually is.
Willis Hames: Now fun, if you have ever imagined or been me a little kid with a magnifying glass out of the playground.
Willis Hames: And there were ads and you chased the ants and you fry them with a magnifying glass, did you know how this works, we can use a laser to heat stuff up the latest or it's just giving us a particular wavelength for the fun thing is there are different wavelengths.
Willis Hames: UV visible infrared sometimes we heat a sample sometimes we melt a pit sometimes we have late and just go straight from solid into vapor we use different lasers for different purposes um.
Willis Hames: And i've got a collection of them here, this was an accommodation that came out just just recently and it'll be in our reference list.
Willis Hames: I could say a lot more, but I want to move alone we in dealing with noble gases, they can be lost from a phase of high temperature.
Willis Hames: So an extremely high temperature even moderately high temperature let's say about 300 degrees see above 400 degrees see mid cross all kinds of conditions, perhaps.
Willis Hames: of minerals can be open system with respect to the archive daughter product, so it may not be retained, what dodson envision envision back in the 70s, and this is important broadcast chemistry.
Willis Hames: At a high temperature, you may have an open system, but a sample may go through a closure interval and then retain a daughter isotope fully when it's cool enough.
Willis Hames: And if you have a graph stowing apparent age or daughter carrot ratio and time you don't really accumulate a ratio initially.
Willis Hames: But as soon as the daughter product begins to be retained, you transition to a closed system of behavior.
Willis Hames: So we can kind of extrapolate back from that using dotson's way of thinking, to get to a closed room temperature and that construct is useful and it varies for different minerals, maybe.
Willis Hames: 600 degrees centigrade in the case of our gun at our upper limit, perhaps to maybe 200 degrees see the lower limit.
Willis Hames: i've got some data here and well, I wanted to say first of all that the easiest thing in the world to date are rocks that cool fast and nothing happens to them.
Willis Hames: i've got data on this page like that 17 is shown, we fuse single crystals and take a mean of those it's very nice very precise we've got one single sanity and crystal that we step heating.
Willis Hames: It up a little bit measure different amounts of guests that are released in a sequence if all the ages of the same we call that a plateau and some people like that it's useful.
Willis Hames: These are data for an older by a tightness a standard in Australia again all the ages are the same, with an uncertainty.
Willis Hames: The power of the method really is not just for really simple samples that cool fast, but what about samples that didn't cool quickly.
Willis Hames: um these are two different crystals from ones rock that used to be used as a gold spike standard, and now we went back at fish kV and 17 standard and realized a.
Willis Hames: it's kind of a mess up there, we get different ages for different crystals out of this one ash flow tough and it's because some of them state hot last gas.
Willis Hames: lost Ark on Chung ma who is Scott and appearance of a field trip this meeting i'll speak about this work in a second.
Willis Hames: These are crystals of muscovite that he said he did in the lab that have an age range from 200 million years to 300 million years is probably reflecting when the source of the crust.
Willis Hames: was in the middle Cross access archive well documented, you can have Arc on trapped in fluid inclusions are defects.
Willis Hames: And the left and that can be a parrot with incremental eating on as for us and other chauffeur of Galapagos island basalt and of Jordan and rainy show another effect called recoil which happens is an artifact of the radiation self if you have things that are grown at a micron scale.
Willis Hames: We can measure grains in situ, and I think this is where a lot of the future is.
Willis Hames: Here we've analyzed the senators and edges of crystal some centers are older edges are younger, because our God is leaking out and sensor Fusion is preferential along the cleavage children micah.
Willis Hames: And here's a photograph of one with a twist that are shown for spots, the laser we're using is kind of caught up a heavy doll instrument at this point, and you get these little percussion figures.
Willis Hames: around it, those are a function of the lattice of, but we can measure 425 million years two 365 again we interpret that to be when this rock was hot, and while it was hot it gives us tectonic information.
Willis Hames: and Dr ma will speak and part of a field trip that you can download and look at anytime for the next year.
Willis Hames: In honor of Dr mark so bowl he collected, a number of samples from a sheer zone in the hanging wall and serious of itself about 283 going to samples.
Willis Hames: An earlier share that's cod and in the foot wall to 88 to 90 or they statistically different yeah they are and and we think that this is a time and given roofing an exclamation for.
Willis Hames: A.
Willis Hames: Piedmont exposure just south of us here in auburn that's part of ongoing work a Dr Dean, will speak on Friday.
Willis Hames: These are samples from a set of integrity, based in India, we can use single crystals of muscovite to look at the provenance of sand stones and.
Willis Hames: determine ages for about 100 different micah's individually from one sandstone and look at the variation of them.
Willis Hames: And a field trip that will be on Saturday looks at that kind of exercise the strata graphics section in Alabama we look at different signatures of age distribution for to tribal minerals.
Willis Hames: going through a strata graphic sequence tells us about tectonics tells us about base in evolution and segmentation.
Willis Hames: And the overall timing of these things and I just put a kitchen for our students, they help us to.
Willis Hames: Get out of bed in the morning and to what to do this, you know, sometimes it's sometimes it's kind of challenging but.
Willis Hames: The students are fun and we don't limit ourselves to students who are only auburn university students, we have students who visit.
Willis Hames: And we have colleagues that we visit with and visit us and we can encourage for work in all the labs that we were speaking about today, and some of the lab facilities that are are not presented here today, we really thrive upon and.
Willis Hames: And, and look forward to even more collaborations and I have some references that I can provide and put that out make available to you became a our method is still around.
Willis Hames: It very importantly, if you need to know the answer for something tomorrow you better use kr because we have to remediate our samples.
Willis Hames: And if you want to put it on a space probe and landed a little planet and determine the age of rocks on another planet well that's been done by Ken farley and others.
Willis Hames: bunch of others paper like that um but but institute dating as possible, but the key art method and it's being used i'm some review Article circular small classics or here.
Willis Hames: i'm concerned about my.
Time.
Ann Ojeda: Perfectly on 250 so thanks.
Willis Hames: And I observed for you to be very punctual so i'm gonna do i'm gonna try to live up to that.
Ann Ojeda: Thank you okay that's great um thanks bill.
Ann Ojeda: If you'll stop sharing your screen, do you mind.
Ann Ojeda: I I posted another poll.
Ann Ojeda: we're feeling after radioactivity, we have a 10 minute break so get up stretch your we've almost made it halfway.
Ann Ojeda: So take some deep breaths do some shoulder roll some ankle roles and we'll meet back here at 3pm.
Ann Ojeda: And i'll talk about light stable isotopes i'm going to send you to breakout rooms again feel free to walk around take a break and then get to know the other participants that are here as well.
RISE- Audrey Heun GSA: Hello again.
Ann Ojeda: Okay welcome back everyone pop pointing in and joining us after a little bit of break, I hope you could.
Ann Ojeda: take a deep breath and relax we're halfway there you know this is gonna be gonna be fun we're moving into stable isotopes which.
Ann Ojeda: is a departure from radiogenic so i'll show what the um let's do so i'm gonna share screen one and say all right, this is our current poll results.
Ann Ojeda: So, most people are doing half are feeling good retail enough and I hope that the 10 minute break or an eight minute break gave you a little bit of energy to keep on going, and we have one more break.
Ann Ojeda: And one more session before closing remarks okay so where we're headed now is into stable isotopes.
Ann Ojeda: i'll talk a little bit about some light stable isotopes and then Laura will have a break and then Laura will come in and.
Ann Ojeda: ooh can I do this Okay, and then Laura will come in and talk about transition metal stable isotopes then we'll close it out with some question and answer I have the remarks part is false, I have nothing to say so, if you have any questions, we can answer those there.
Ann Ojeda: Right first thing I want to point out if most of the figures that i'm about to show come from this amazing free, open source of isotope information from Zack sharp okay principles of stable isotope geochemistry goes through a lot of different stuff.
Ann Ojeda: I think somebody put this a link to it very kindly in the chat a little bit earlier, so if you scroll up, you can have direct access to this book.
Ann Ojeda: So today i'll talk about a couple of isotopes you know it's really hard to choose which ones, you want to talk about because they're you know they're all your favorite.
Ann Ojeda: And, but really that's not true, I like carbon and hydrogen so we're going to focus on those and i'll kind of throw in some other isotope systems that are used as well, but when we talk about light stable isotopes you're talking about these guys.
Ann Ojeda: Really ch in ios are the popular ones um chlorine and bromine also have stable isotopes most of these guys are used in contaminant studies or in chlorine can be used in some of the some of the Rock stuff but i'm not as familiar with that, compared to the contaminant stuff.
Ann Ojeda: Okay, so um stabilized job ratios can provide evidence for a range of processes, this figure is actually from zach sharps book and this just gives you an over kind of an overview of what different processes, we can use.
Ann Ojeda: We can investigate using these stable isotopes systems and again this is just hydrogen carbon nitrogen oxygen and sulfur.
Ann Ojeda: So the first major isotope system that i'll talk about is oxygen hydrogen and i'm departing from minerals here okay.
Ann Ojeda: This is oxygen and hydrogen isotopes of water, and so the background I also made all of my slides really vibrant to try to keep us all awake So there you go um.
Ann Ojeda: So we're talking about oxygen hydrogen isotopes of water and fraction ation mostly equilibrium fraction ation between.
Ann Ojeda: The light and the heavy stable isotopes of these two elements Okay, and one of the dominant controls on that equilibrium fraction ation is really the relative.
Ann Ojeda: matt so, given the air is the mass fraction of vapor that's remaining in your original pool of material, so you can imagine, here we call the Ocean is our standard mean ocean water okay if we call that zero then that fraction ation process into vapor.
Ann Ojeda: Is favoring the light isotope over the heavy isotope so we have a fraction ation of 13 per mil and then as that vapor moves across land, you have.
Ann Ojeda: A newly formed phase right, so the newly formed phase in this case would be water, the newly formed face that that's water is actually lighter than what is in the residual pool Okay, so that means you have this fraction ation as your life phase drops out of your vapor face here.
Ann Ojeda: Okay, and that's the really model that we see here, so if we have the fraction or meaning is one one or hundred percent here are delta goes down our isotope value decreases as we end up with zero.
Ann Ojeda: percent of the water remaining so that ends up playing out in a couple of different ways that are really impactful.
Ann Ojeda: One is that we have a very defined relationship in our water samples between oxygen and hydrogen Okay, this is delta D or deuterium okay you'll see this sometimes is a two H or.
Ann Ojeda: Oh sorry.
Ann Ojeda: If you're an auburn we're in the middle of a thunderstorm and that was crazy.
Ann Ojeda: Oh, my goodness.
Ann Ojeda: Anyway, so standard mean ocean water and speaking of precipitation right so actually we have this relationship between oxygen and hydrogen.
Ann Ojeda: To where most meteoric waters most precipitation the stable isotopes of hydrogen oxygen at both precipitation follows a very nice linear relationship, and that is based on this idea of really fraction ation so the further you are away from the ocean.
Ann Ojeda: You have this fraction nation happening over and over and over, meaning that.
Ann Ojeda: You have warmer low latitudes coastal regions with higher or heavier water than you have cooler high latitude inland processes Okay, so we have this.
Ann Ojeda: fraction ation that happens to lighter waters inland and which has some really neat really, really neat implications first.
Ann Ojeda: This is kind of a global meteoric waterline, so this is an average of all waters around the world, you can actually have pretty localized meteoric water lines that deviate a little bit from this path, but because we have this global.
Ann Ojeda: relationship we can actually map this across space, and this is called the ice escapes because this is water isotopes around the world that are sent into the University of utah.
Ann Ojeda: And they create these really high resolution maps of water fraction ation of the water isotopes around the world, and we can see that this global meteoric line plays out pretty nicely in this map right we have really um.
Ann Ojeda: So here we have negative point two is oxygen isotopes right, so we have negative point to around the latitudes and then the further inland the lighter we get that's kind of neat.
Ann Ojeda: i'll come back to this and why it's important with some applications in just a minute so hold on to your hat.
Ann Ojeda: And the other isotope will talk about a little bit today is carbon, so I don't work in D time I work in very, very recent time mostly looking at materials.
Ann Ojeda: That cycle through the earth related to living things so plants, and we have several different types of plants here see three and see for plants, we also have methane's organic carbon as a whole reservoir has a wide range of ice topic signatures are CO2 in the atmosphere currently.
Ann Ojeda: Is can vary quite a bit based on different CO2 inputs.
Ann Ojeda: And then you can get back to talk about some of the rocky stuff up at the top, if you're interested in that, but today i'll talk mostly about plants and animals and how they really prefer see 12 oversee 13 and the neat implications that can.
Ann Ojeda: Come because of that.
Ann Ojeda: So nitrogen is another really powerful isotope, not only do living things rely on carbon but we very much rely on nitrogen.
Ann Ojeda: So that nitrogen isotope signature can be preserved in a lot of earth processes and biological processes as well, so we'll talk about traffic levels and specifically today and ways that nitrogen isotopes can be used to unravel.
Ann Ojeda: ecosystem dynamics.
Ann Ojeda: So this is a key point that I want, if you take nothing else home, just like zoom in for just one second and remember this key point.
Ann Ojeda: When people talk about light stable isotopes, especially of carbon and nitrogen and oxygen.
Ann Ojeda: there's really two versions, that we can talk about we can talk about bulk isotopes where you process, the whole material and you get an aggregate signature of all of the carbon or all of the nitrogen in that sample so you can imagine, take a lake sediment or you take a.
Ann Ojeda: Okay let's do like sentiment and you can have all of the carbon that's in that lake sediment you can get their averaged isotope signature of that or of nitrogen.
Ann Ojeda: And we do that, using an elemental analyzer so essentially burns the sample converts it to CO2 gas and the CO2 gases measured on an isotope machine, this is quite cheap I would you know you can do this for about eight bucks a sample eight to 10 bucks a sample.
Ann Ojeda: But again, the downside is that you're getting an average signature of all the carbon in that material.
Ann Ojeda: The second, the second option is to do compound specific isotope analysis, where you measure the isotopic composition of a single molecule within that mixture so say you had a lake sediment.
Ann Ojeda: there's all kinds of molecules in there, you can imagine all the living things all the molecules kills their bills of there's plant material all the molecules the plants are built up.
Ann Ojeda: And so compound specific analysis would tell you Okay, there was a leaf in that plant material and there was a leaf wax that's preserved in the sediment.
Ann Ojeda: Using compound specific isotopes, we can say the carbon and hydrogen isotope signatures of that leaf wax that one compound, in particular, and what that does is gives us more detailed information about the.
Ann Ojeda: about the input, the material that was inputted into the sediment relative ages of that material and maybe some diabetic history of that like sediments well it's more expensive and critically this uses a gas.
Ann Ojeda: chromatograph to first separate your materials, and so this is how CSA measurements are done if you want to do bulk isotopes.
Ann Ojeda: Just replace this essentially with an oven, and then it's the same process okay before it compounds specific isotope So the first use a chromatography column to separate all of the mixtures in your lake sediment or in your water sample.
Ann Ojeda: into these individual compounds the individual compounds are then burned in a combat combustion oven, and we produce.
Ann Ojeda: gases that we can analyze on the isotope machine, we can analyze carbon and hydrogen and hydrochloric acid is really you can do it it's not fun.
Ann Ojeda: Because it's corrosive so you have to replace a lot of your instrument parts quite easily are quite frequently when you do that, but essentially burn these compounds produce a measurable gas, and then you can analyze that gas on an isotope ratio mass spec.
Ann Ojeda: I have, I don't have sulfur here, but this is the exact same process you do for sulfur and nitrogen those aren't listed here, but you.
Ann Ojeda: produce gaseous forms of those two elements as well and measure those.
Ann Ojeda: they'll get into some applications, and this will be a popcorn of applications on one slide per topic it's again really hard to pick.
Ann Ojeda: What you're going to talk about, but I My guiding principle here is things you should at least hear about as a geology student or someone that's in the geosciences.
Ann Ojeda: So one is the Greenland ice core project grip and where they drilled a 3000 meter core into the Greenland ice sheet to learn more about earth past climate and stable isotopes especially hydrogen stabilized sips of water.
Ann Ojeda: of hydrogen and oxygen told us a lot about earth's past climate some of the surprise, so this is one example of a surprising result here, if you look on the right hand side we have.
Ann Ojeda: The isotope ratio of oxygen and then here we have the amount of dust that they found in the ice core as well, so you can see.
Ann Ojeda: And this is, of course, and the depth is related to the age of the high score, we can see it, this really interesting interval we have an excursion Okay, we have a rapid change in our isotope signature.
Ann Ojeda: And what that means is, we can relate the change in that isotope signature to a change in the climate.
Ann Ojeda: A temperature change in the atmosphere at that time right because fraction nation, as I said in the introduction, vaccination is related to temperature and isotopic composition of your starting material.
Ann Ojeda: So we assumed the water has the ocean had a pretty homogenous isotope signature, so the only driver for this really big change in isotopes here is a change in temperature is inferred as a change in temperature.
Ann Ojeda: And this was much, much more drastic change in temperature than we had seen before.
Ann Ojeda: Okay.
Ann Ojeda: So another application of the stable isotopes is finding our place in the clouds Am I like if you ever seen Lego movie benny is one of my faves so he had to go on here um, but these.
Ann Ojeda: So here's some raw.
Ann Ojeda: values for deuterium, so this is for our stable isotopes of hydrogen, for a number of galactic or solar system of bodies.
Ann Ojeda: Okay, and one of the points I want to make here is.
Ann Ojeda: These definitely have different isotope values but they're all measured using different techniques so we've talked about different techniques in a couple of other sections of this.
Ann Ojeda: One you can measure these very similar lita how I introduced it earlier, we can do bulk isotopes on materials that we can hold like the earth materials or the moon materials.
Ann Ojeda: But we can also measure stable isotopes of these light elements using lasers that are aboard the Rovers and spacecraft and there's actually a tenable laser on the Rover that's on Mars right now that's doing some really cool.
Ann Ojeda: isotope work for oxygen and hydrogen.
Ann Ojeda: on Mars, which is quite new.
Ann Ojeda: The other idea to bring up here and I think Laura will go into this a little bit more is that some of these isotope ratios, we have to experimentally determine.
Ann Ojeda: We can predict what the isotope ratios would be on.
Ann Ojeda: uranus and Neptune based on temperatures and pressures that we know existed during the formation of those planets so we can do those experiments in the lab and then predict what we see and then go out and measure it using.
Ann Ojeda: lasers from a spacecraft so there's this idea that our lab experiments can also tell us these isotope ratios that are really difficult to measure in some cases.
Ann Ojeda: So i've talked about this a little bit earlier in that biology has an extreme preference for light isotopes most of the time I shouldn't say all the time, because then you're just.
Ann Ojeda: you're setting yourself up for failure, but most of the time biology has a preference for breaking light so bonds of light isotopes and that really comes out in things like organisms.
Ann Ojeda: organisms biology when we secrete set or organisms secrete shells that are out of equal equilibrium with ambient water, so this is an example of.
Ann Ojeda: an organism producing light shells relatively light carbon and light oxygen shells or heavy carbon and oxygen shells compared to the surrounding.
Ann Ojeda: P CO2 or the carbonate system that would be in the sea water.
Ann Ojeda: And this diagram is showing that not all organisms have the same preference I think that's a critical thing to consider as well that some organisms green algae have one preference.
Ann Ojeda: And our red algae have a different preference, so we can use those differences in our vital of the vital effect and based on those enzymatic processes can really tell us what organisms what's happening at those.
Ann Ojeda: enzymatic levels.
Ann Ojeda: So the other cool application on carbon hydrogen nitrogen isotopes sulfur isotopes are used a lot in regulation.
Ann Ojeda: For natural products, so you might have heard of a adulterated wines or olive oils, and this is a really big issue when you start talking about really expensive bottles of wine and olive oil, so we can actually use.
Ann Ojeda: The stable isotopes of carbon and hydrogen, especially oxygen and hydrogen right because they're connected to that meteoric waterline we can geographically place wines and olive oils.
Ann Ojeda: In a region and verify that they are authentic and we can also identify any products because of that distribution of carbon and the isotopes of carbon, we can identify.
Ann Ojeda: Products that are made from petroleum versus biomass because petroleum has a very different carbon signature than something like a plant a living plant so because of that isotopic difference we can find adulterated products.
Ann Ojeda: That have a petroleum or synthetic chemical instead of a natural product and that's this example in the crawling and thanks to bring in for pulling this up for me it's really cool.
Ann Ojeda: And one of the other really popular if you Google carbon isotopes in popular media you'll come up with a doping examples of doping, so this is what the.
Ann Ojeda: Olympic Committee and a lot of regulatory bodies in sports use to identify those that.
Ann Ojeda: Athletes that use synthetic steroids take a steroids or synthesized from petroleum products.
Ann Ojeda: right they go through this chemical manufacturing process your body goes through a different process and synthesizes your own testosterone from the food that you eat so those two isotope signatures can be very different.
Ann Ojeda: and actually the carbon isotope signatures of testosterone took floyd landis and we're part of that.
Ann Ojeda: The claims that floyd landis and lance Armstrong were doping for the.
Ann Ojeda: Tour de France kind of neat.
Ann Ojeda: Another great example of this, and this pulls right back to the meteoric waterline is.
Ann Ojeda: And so, this example is the bottled water controversies so this steady here on the right hand side, this is by earlier at utah.
Ann Ojeda: They did the what measured the hydrogen and oxygen isotopes of bottled waters across the world and found that most of the bottled waters, so this data is the purchased versus.
Ann Ojeda: Where are we, the.
Ann Ojeda: purchase, so the bottled water value versus the source Okay, so this would be the where the bottle claims they got their water from the source of the water.
Ann Ojeda: Or the location that they purchased the water Okay, so this is the delta value of the bottled water that they sampled versus.
Ann Ojeda: The hydrogen signature from the claimed source and the hydrogen signature from the purchasing location and what they found that most bottled waters reflected the location of purchase, no matter what the claim was or where you purchased it, which is quite astounding when you look at.
Ann Ojeda: managing water resources and especially related to producing these.
Ann Ojeda: Massive amounts of bottled water where they're drawing their water how they're using it and how it's being distributed has some pretty significant implications in that respect.
Ann Ojeda: So, again I want to focus on biology and maybe some things you don't hear a lot about.
Ann Ojeda: In the geosciences but really these five synthetic pathways matter so here we're talking about plants, the carbon signature of plants we have.
Ann Ojeda: See three plants there's a difference in there's really two different bio synthetic pathways to fix carbon and plants see three plants use the Calvin cycle.
Ann Ojeda: This is most of the plants in the world is the Calvin cycle, there are some really special plans that have a different bio synthetic pathway called the Di carb oxalic acid pathway, and these are especially adapted to low water conditions, so these guys have a.
Ann Ojeda: have less of a preference for see 12 then see 13 so you end up with see for plants, having a slightly.
Ann Ojeda: heavier signature than our see three plants Okay, and this is statistical difference and because of this, we can actually reconstruct some Paleo vegetation, based on the those specific molecules that are related to plants in our rocks and sediment right so here, you can see.
Ann Ojeda: In this example we start with a pretty classic see three signature here or.
Ann Ojeda: Relatives is a bulk signature so it's aggregate so it's not going to look the same number is this is so, we have some things that are kind of included in there too.
Ann Ojeda: So we have this this this signature is what most of our sample is going back in time and then at some point about 7 million years ago, we have a drastic increase in the amount of C 13 oversee 12, and this is interpreted as the evolution of seed for plants in the.
Ann Ojeda: In the in the area.
that's kind of.
Ann Ojeda: So we also have this terrific shifts we can use carbon and nitrogen isotopes to understand trophy shifts and diet so most of.
Ann Ojeda: Our hope we all know, these amino acids, that are the building blocks of your proteins, the building blocks of all organisms have.
Ann Ojeda: A lot of light stable isotopes and they have oxygen they have carbon and they have nitrogen and hydrogen, so we can use these stable isotopes to understand something about organisms.
Ann Ojeda: organisms biology and diets and shifts so I wanted to bring this figure out this is from the usgs and they actually sampled fingernails from usgs visitors over several years that visited the.
Ann Ojeda: The the usgs Center, and so what we can do is take.
Ann Ojeda: The isotope signature of a bunch of different.
Ann Ojeda: Food stuffs So here we have fruits and vegetables and grains they're plotting round here right very near RC three plants signatures are see fours or corn or sugarcane they're plotting a little bit higher a little bit heavier in that carbon isotope signature.
Ann Ojeda: And then we have right the connection between our so the dotted lines here the blue lines are the connection between the source and the animal that eats it Okay, so we actually see.
Ann Ojeda: Most of the time we see this enrichment.
Ann Ojeda: In our diet, based on the diet that we that we have and that's again because we prefer our body prefers to process the see 12 and see see 12 oversee 13, so we are progressively getting lighter in carbon or lighter.
Ann Ojeda: or hip sorry heavier in carbon I heavier nitrogen and lighter in carbon So these are very specific, you can see these arrows are in different ways.
Ann Ojeda: they're different arrows in different degrees of the arrow and thats related to again the biology of the organism has a different preference for see 12 oversee 13 and we can use that to reconstruct.
Ann Ojeda: Reconstruction diets we also see this our relationship between C 13 and C and nitrogen.
Ann Ojeda: And enrichment of our.
Ann Ojeda: Along these traffic levels in our from our primary producers like phytoplankton all the way to our fish, so we can a lot of biologists use fatty acid methyl esters.
Ann Ojeda: And amino acid analysis carbon and nitrogen amino acid analysis to understand where a fish or an organism lies along this terrific relationship.
Ann Ojeda: So I just have two more sections here one is petroleum geochemistry this is kind of an interesting application of our carbon in.
Ann Ojeda: Mostly carbon and hydrogen isotopes at their essence oil and gas or natural products because they are produced by life.
Ann Ojeda: they're mostly algae and algae are made of carbon and hydrogen and these chains of fatty acids that are preserved in the rock record and that's really what we're extracting when we're looking for petroleum and because those organisms are specific to.
Ann Ojeda: A certain most likely a certain age or a certain diet genetic pathway based on how those molecules change over time and we can use these organic compounds as oil and source rock correlations.
Ann Ojeda: And we could also get information about maturation thermal history, migration and accumulation from these isotope ratios and i'll give you some examples.
Ann Ojeda: So here's an example of the.
Ann Ojeda: Of.
Ann Ojeda: isotope ratio of several different crude oils from around the world.
Ann Ojeda: And then on the right hand side, you can see, we have a differentiation between Alaska and our South Asian or South America oils and on the.
Ann Ojeda: left hand side here, usually we fraction eight these oils into different molecular categories so it's not really that important that you understand what these are, but the whole oil is this this bar here and then different fractions concentrate different.
Ann Ojeda: molecules and have a slightly different isotope signature, but you can see that whole profile is quite different, moving to different basins in the in the world and also our ISO carbon isotope signatures can be used as.
Ann Ojeda: Evidence for deposition of some of these.
Ann Ojeda: source rocks and because our carbon isotope signature changes with time.
Ann Ojeda: So here's another example again we're getting back to biology has has a preference, so we have.
Ann Ojeda: Light isotopes here and heavier isotopes as we go this way, so this axis is a little flipped and then on the left hand side we have methane, which is the first carbon card so.
Ann Ojeda: Carbon and hydrogen ch for over ethane and propane which are also produced during.
Ann Ojeda: thermo genet cracking of gas, so if we can use both of these parameters to understand the source of natural gas and oils so, for instance, really light signatures, with a high proportion of methane is indicative of biogenic gas a little bit heavier signatures low lower proportions of.
Ann Ojeda: Methane over propane so essentially you're increasing this denominator are thermo genet gas indicator, so this is a really good example where we have isotopes that are combined with another parameter.
Ann Ojeda: That give us indications of source and these thermal maturation pathways.
Ann Ojeda: So the last one that i'll talk about today is environmental forensics and essentially the question here is who's going to fit the bill, and most of the time and environmental forensics we're looking at chemical spills.
Ann Ojeda: That are then regulated by the EPA, and the question is who's the EPA got to sue to get their money back for cleaning it up.
Ann Ojeda: um so here's a really good example of how we can use isotopes to differentiate sources of contaminants in the environment, for instance.
Ann Ojeda: This example is looking at brand a gasoline and brand be gasoline and these two gasoline is have two very different carbon and hydrogen isotope signatures.
Ann Ojeda: Right, going back to well we've already seen these can be connected to the location and age and these maturation processes that produce these slightly different signatures.
Ann Ojeda: So in this study, they took well samples around the gas station and found that all the groundwater contamination was very similar in signature to brand a gasoline compared to brand be gasoline so in this case brand a fits the bill.
Ann Ojeda: Another example of phaeton transport is looking at some emerging contaminants or chemical contaminants like trichloroethylene or benzene, you may have heard of be tex before and that's been that's.
Ann Ojeda: been seeing 20 means eileen um but, again, these are all industrial chemicals or household chemicals that gets filled and then enter our environment, we can use isotopes again to figure out their fate and transport.
Ann Ojeda: So here's another great example PC perchloroethylene is a solvent used in.
Ann Ojeda: Industry for cleaning materials used in the military for cleaning lots of.
Ann Ojeda: tanks and D greasers decreasing guns and things like that, and the runoff from all these large scale processes it's not very well regulated.
Ann Ojeda: or managed so we end up with a lot of perchloroethylene in our groundwater near these still sites, so in this case on the plane migrated off base, and I was threatening.
Ann Ojeda: indoor air quality, from a neighborhood So the question was is the PC and the House actually coming from the plume or is it coming from these products in your home that include PC like.
Ann Ojeda: If you owned a gun and you may have done cleaner in your home that's a source of PC So how can we differentiate between these two sources.
Ann Ojeda: Carbon and chlorine isotopes for a really powerful to do that, so if you see here we have carbon on the y axis chlorine on the X axis and our indoor source.
Ann Ojeda: of VOC so our indoor air is the triangle, the indoor source and the subsurface source are quite different so in the example a.
Ann Ojeda: We could assume that the indoor source was controlling the air quality, an example be, we can see the subsurface source would most likely control the air quality and the.
Ann Ojeda: source of PC in your air, and so this is the real data from that study, you can see here's the carbon signature for the range of consumer products and that indoor air residence was very similar to the groundwater plume signature, so in this case that's.
Ann Ojeda: a pretty good idea of the source of PC in their home is coming from this indoor plume instead of the gun cleaner in their closet.
Ann Ojeda: Okay, the last example that i'll show is one about bio degradation of contaminants, so this is monoclonal benzene or really kind of nasty chemical that's used in a lot of synthetic dyes.
Ann Ojeda: The synthesis of synthetic dyes and we installed a penis called a peeper we installed a paper in the canal.
Ann Ojeda: To try to understand okay what's happening in the subsurface related to constant concentration of MTV and what we found is that oh.
Ann Ojeda: As we get closer to the settlement water interface, we have decreases in concentration of MTV that sounds great fabulous one of the problems is we didn't know why is it really just migrating and.
Ann Ojeda: diffusing out of the sentiment and it's actually going into the water or is it being five degraded by the indigenous microbial community.
Ann Ojeda: So, again we rely on this isotopic preference for bugs microbes to consume things of exclusively light isotopes compared to something with a heavy isotope and then you can see, here we have the isotope signatures of carbon where we have this big enrichment.
Ann Ojeda: That is correlated to decreases and contaminant concentration, so this is one line of evidence that the microbial community is transforming this really toxic nasty substance into see oh two which is non toxic and protective of the environment.
Ann Ojeda: Okay.
Ann Ojeda: So that is all of my slides just a brief foray into.
Ann Ojeda: Environmental isotopes or light stables, I want to open the floor up to questions, and if you have any please ask them i'm not guaranteeing I can answer them, but I will do my best.
Ann Ojeda: Nothing, not one.
Ann Ojeda: We have like I we had.
Ann Ojeda: I left a lot of time.
Joel Lerner (he/him): Could you pull up the slide from near the beginning of your presentation from the Smith book just about the different fields that aren't isotopes could be that I still like tracking to be instead.
Ann Ojeda: Sure yeah let me I did something weird with my sharing at that point.
Ann Ojeda: let's see.
Ann Ojeda: screen share screen one okay that zach sharp book this one.
Joel Lerner (he/him): yeah.
Joel Lerner (he/him): I just thought that might inspire some questions on my own behalf.
Ann Ojeda: Oh great thanks.
Willis Hames: I have a question i'm.
Willis Hames: kind of confused, since I go out to the grocery store to buy water.
Willis Hames: and
Willis Hames: You seem to show tatum that.
Willis Hames: I must be confused the.
Willis Hames: Its most recruiters characteristic is actually where you purchase it.
Ann Ojeda: Any.
Willis Hames: Other source does it change when it's bottle.
Ann Ojeda: So those there's two different ideas there one is i'll bring that up.
Ann Ojeda: swap one is that it's being produced very close to where it's sold.
Ann Ojeda: Ah yeah.
Willis Hames: So they tell you it's from our T shirt and water, and so you know to soto's exploration in Florida, but but no.
Ann Ojeda: So there is this paper there's a caveat for some of the.
Ann Ojeda: exotic waters, there are some there's some distribution in this.
Ann Ojeda: In this plot for exotic waters, you know the Fiji water or something like that.
Ann Ojeda: And, but in general, most of the waters are produced and sold locally so high consumption of this bottled water product is really high demand on your water resources and typically pulled from the same source as your municipal source.
Ann Ojeda: So it's a.
Ann Ojeda: Good.
Willis Hames: thing isotopes don't lie.
Ann Ojeda: No, no, no, ask.
Van Burbach: Her.
Van Burbach: To look at the actual municipal water users and see if these people were simply selling municipal water.
Ann Ojeda: Yes, actually that's been done quite a few times and it's true they do sell municipal water and they pay for it from the municipality bottle it make profit on it.
Ann Ojeda: it's very common there's.
Ann Ojeda: Well, I teach this in my environmental geology course but I don't have the slide ready and there's actually a quite a bit of research that's done related to bottling and drought conditions.
Ann Ojeda: Because the production doesn't change based on drought conditions, because they are pulling from that municipal water source and municipal usually isn't regulated like irrigation or something like that is so there's kind of a an interesting.
Ann Ojeda: Economic loophole that seems to be there, especially if you look at some of the bottled water that's happening in California.
Ann Ojeda: Joel did you have a question.
Joel Lerner (he/him): I was going to kind of ask and pick your brain a little bit about what the possible implications could be of like utilizing this like approach to investigating like modern changes in climate like it with the hydrological cycle.
Joel Lerner (he/him): So, could we possibly like observe a change in like isotope concentrations, or would it be a much longer time period that that change quick.
Ann Ojeda: Sure, so i'm going to point you towards another reference, and that is this ice escapes reference we.
Ann Ojeda: All go back to the meteoric waterline.
Ann Ojeda: So this is the ice escapes reference.
Ann Ojeda: I can throw this in the chat real quick for you.
Ann Ojeda: But there are seasonal changes and I can't find my chat where's my chat.
Ann Ojeda: there's i'll go back to the mediocre waterline fluctuations, there are seasonal changes.
Ann Ojeda: And latitude changes, and so you have several variables that are acting upon that fraction nation to really explore recent exchanges, a maybe a little difficult because you're working within a much you have a certain amount of air associated with your.
Ann Ojeda: Your measurement and then looking at changes have to be outside of that air of measurement does that make sense.
Ann Ojeda: But there are a lot of investigations into local meteoric water lines and how those deviate from season to season.
Ann Ojeda: But I again i'm going to point you towards the.
Ann Ojeda: ISO escapes and they have a really nice time series of changes in that.
Ann Ojeda: Essentially, this figure as a function of time, going back to 2016 I think.
Joel Lerner (he/him): which may be giving you so much.
Ann Ojeda: yeah of your modern more modern changes.
Sara Speetjens Gilley: To the question about i'm kind of going back to the bottled water source and I hope that this sound quality's Okay, the rain is really loud where i'm at right now on, but so if you live in a part of the world.
Sara Speetjens Gilley: Say like anniston Alabama or you know anywhere else, where there's questionable water quality, but legally the drinking water still meet our standards.
Sara Speetjens Gilley: Are you better off just putting a brita filter on your water at home than buying bottled water from the grocery store says it's probably or possibly still source from the same like is there any i'm sure.
Sara Speetjens Gilley: that's a good question anything you can say about that I don't know that's.
Sara Speetjens Gilley: A very interesting insight I guess.
Ann Ojeda: So one of the things I will say is I do organic contamination analysis for a living and I have a brita water filter on every one of my sources of water it's just safer That way, there are minimum and maximum or maximum contamination level limits set by the EPA for a lot of our.
Ann Ojeda: contaminants in the water and Britta filter takes care of most of them.
Ann Ojeda: Most of the manufacturing for bottled water does go through a secondary treatment process, so they may you know you look on the label it'll say reverse osmosis or.
Ann Ojeda: Carbon filtration most of them do have a step after source extraction wherever that's from whether it's municipality or groundwater or a spring usually they do have a second step of filtration it should they're legally required to say that, on the bottle.
Ann Ojeda: But in my experience i've tested, a lot of.
Ann Ojeda: tap waters and a Brit I rent it before and after a brita filter and it's.
Ann Ojeda: Fine, for organics after Britta filter.
Sara Speetjens Gilley: Thank you.
Ann Ojeda: yep Cindy do you have a question.
Ann Ojeda: Oh, I can't hear you.
Ann Ojeda: I cannot hear you.
know.
Ann Ojeda: Maybe, could you type it in the chat great Thank you.
Ann Ojeda: So while waiting for Sydney i'll bring up one other example of weight, since this is just sitting here that we can utilize the C three and see for differentiation um it's a project that I have going right now, which is.
Ann Ojeda: Related to tracing poop and water so managing fecal contamination any cola and water is a big deal going back to this water quality.
Ann Ojeda: Management stance and because we have this differentiation in our diets between usually chickens and cows and humans and chickens are usually fed see for corn.
Ann Ojeda: Cows usually eat see three plants exclusively and humans eat a mixture of these that biological signature is carried in our isotopes and especially in our sterols like cholesterol.
Ann Ojeda: it's reflective of our diet and we can use that.
Ann Ojeda: to trace sources of sewage pollution in waterways and we can differentiate like contain feeding operations of a pig versus a chicken versus inputs from alyssa dumping or sewage from humans.
Ann Ojeda: Okay Sydney is there a signature for the carbon dioxide in the atmosphere from anthropogenic sources absolutely let's go back to this carbon.
Ann Ojeda: This carbon diagram.
Ann Ojeda: So one of the things that.
Ann Ojeda: We.
Ann Ojeda: relate is that CO2 in the atmosphere thats related to any fossil fuel burning.
Ann Ojeda: it's going to have a different isotope signature, because it has a different source.
Ann Ojeda: Right, so we have a little bit lighter source here for our coal ignite in petroleum compared to the average CO2 in the atmosphere.
Ann Ojeda: Right, so we can actually detect how much.
Ann Ojeda: CO2 is input from burning the fossil fuels, compared to the background CO2 signature without input from those sources absolutely.
Ann Ojeda: Any other questions.
Ann Ojeda: So need you some question are you.
Ann Ojeda: You just raising the roof.
Ann Ojeda: Maybe no I feel like that's still in my generation, I can do that.
Ann Ojeda: let's see.
Ann Ojeda: Any other questions, I mean if we don't i'm happy to stay on, and if you want to take a break you're more than welcome to.
Ann Ojeda: Or, I can keep talking about contaminants i'm one of the big ones that people always they want to throw money at you throw money at you to figure out sources of.
Ann Ojeda: These forever chemicals P us per floor unaided out kills rate, have you heard of these that are everywhere, the EPA is wants to know where they're from and manufacturers don't want to find them in their.
Ann Ojeda: Products are in the water that they're touching ever the part of the problem, these are ubiquitous now we finding them in all drinking water sources are finding them and all surface water sources and sediments everywhere, even where they're not supposed to be.
Ann Ojeda: And these are the relics of industrialization and producing things like teflon right Gore tex your non stick pans.
Ann Ojeda: we're all used these per floor native compounds were used to produce that kind of stuff and now they're getting into.
Ann Ojeda: Our service and our sentiment and they're not going away, one of the weird things about these guys is they don't degrade at all.
Ann Ojeda: Carbon fluorine is one of the strongest bonds in chemistry and bugs don't like the strong things right they prefer, we always move to a state of lower energy.
Ann Ojeda: So they don't want to break these bonds, so they don't touch them in there forever because they don't degrade or degrade.
Ann Ojeda: You have to essentially don't degrade so one of the questions we hear in the isotope world all the time, is when are you going to do, carbon isotopes or hydrogen isotopes or oxygen isotopes.
Ann Ojeda: Of these per floor unaided compound to tell us the source right if your job as a isotope geochemist is to do source appropriation, you can always tell us you know who's to blame.
Ann Ojeda: Who spilled this stuff can you analyze these P Fos compounds and blame somebody and the answer is no, not really in part because of this carbon flooring bond and the pyrolysis product, so if I go back up here.
Ann Ojeda: Right, so the way that we measure these guys is to separate them on the juicy fine no problem, then we burn them.
Ann Ojeda: If you burn these are fluoridated compounds, one of the byproducts is going to be hydrochloric acid hf.
Ann Ojeda: Which is incredibly corrosive if you've ever done sediment digestion right it eats everything it dissolves everything.
Ann Ojeda: So you really don't want high concentrations of hf in your very sensitive analytical equipment so that's kind of an interesting point here that, although it would give us really good information.
Ann Ojeda: we're gonna have to have some really big analytical leaps in order to do.
Ann Ojeda: compound specific isotopes on these PR fluoridated compounds.
interesting.
Ann Ojeda: Okay, so that's 350 we're gonna take another 10 minute break and then Laura is going to.
Ann Ojeda: Talk about transition metal.
Van Burbach: Stable isotopes.
Ann Ojeda: And some of the.
Ann Ojeda: Applications that we have for that.
Ann Ojeda: Right.
Ann Ojeda: I have.
Laura Bilenker: Okay, so welcome back from your breakout rooms and from break.
Laura Bilenker: So here we are in the schedule we're.
Laura Bilenker: In the homestretch essentially so i'm about to tell you a little bit about metal stable isotopes and then we'll just kind of wrap things up as a group.
Laura Bilenker: There we go so just to introduce myself again, my name is Laura blinker and I am an assistant Professor here in the department of geosciences my background is in more higher temperature systems.
Laura Bilenker: And I do more on the non traditional stable isotope end of things, with a focus on metal stable isotopes that's because I am an economic geologist.
Laura Bilenker: And geochemist, and so what i'm going to tell you about in terms of metal stable isotopes is going to focus more on the high temperature.
Laura Bilenker: or forming system side of things, but will also touch on the more environmental side of things, and hopefully from this presentation.
Laura Bilenker: Like what we've been emphasizing all along you'll get some good references and resources and use this as a jumping off point to maybe learn more about metal stable isotopes or see if you can apply them in your own research.
Laura Bilenker: I also want to take a minute to acknowledge that a lot of what i'm going to present, especially when I talk about mass spectrometry.
Laura Bilenker: Is stuff that I learned, because people welcomed me into their labs for hands on experience, so the University of Michigan University of Illinois at urbana champaign and the University of British Columbia and also the factory at new instruments.
Laura Bilenker: All graciously hosted me in their labs to do, science, and so I know we have a lot of students and I think that.
Laura Bilenker: You know it's a it's an opportunity to not take for granted if you're able to to.
Laura Bilenker: Work in in a local labs work with instrumentation hands on or go outside of your your institution to get this kind of experience.
Laura Bilenker: Okay, so just some context for metal stable isotopes it's a relatively relatively new in the past decade decade and a half branch of isotope do chemistry.
Laura Bilenker: they're called often called are used to often be called non traditional stable isotopes.
Laura Bilenker: But they're becoming more and more utilized, and so the the traditional end of things, the non traditional end of things is actually maybe not so accurate anymore.
Laura Bilenker: But I wanted to off the BAT point to to really great resources if you want to learn more about metal stable isotopes.
Laura Bilenker: So they're both from reviews and mineralogy into your chemistry, so the geo chemical society is a way to access them and the first was their volume that they put out in.
Laura Bilenker: called the geochemistry of non traditional stable isotopes so that's valid volume 55.
Laura Bilenker: And then the more recent one is volume at to where they kind of caught up.
Laura Bilenker: In those in that decade or so.
Laura Bilenker: 2017 actually a little over a decade what more had been developed and, at the time of the 2004 chapter, the editor in the preface actually writes this long.
Laura Bilenker: description about how he never could have imagined that there would be an entire volume just on these stabilizes folks so things like iron chromium molybdenum copper zinc.
Laura Bilenker: Simply because the instrumentation hadn't been good enough to really fully develop those isotope systems as tools in the geosciences.
Laura Bilenker: And so that's just that's a little background on metal stable isotopes and why you might hear the term non traditional stable isotopes and then also these these really two great.
Laura Bilenker: volumes for reference.
Laura Bilenker: going to collapse your faces there we go.
Laura Bilenker: So today we're going to focus on more the transition metal stable isotopes.
Laura Bilenker: And just to start off, so why measure the abundance is a metal stable isotopes To begin with, so first there's a wide range of concentrations in geologic materials.
Laura Bilenker: there's a range and chemical characteristics as well, so volatiles refractory.
Laura Bilenker: metal stable isotopes can be read ox sensitive biologically active and they have different bonding environments compared to the traditional stable isotopes the lake stable isotopes the analysts focusing on.
Laura Bilenker: They also often have more than two stable isotopes in the system, which can be really useful.
Laura Bilenker: And so, because of these characteristics.
Laura Bilenker: It makes these elements susceptible to different fraction nation mechanisms and then, by extension, their unique tracers of different cosmic chemical geological.
Laura Bilenker: biological and environmental prophecies so when we study stable isotopes systems, what we're doing is studying the processes that fraction ate those isotopes.
Laura Bilenker: Which means.
Laura Bilenker: That we can apply these in new and exciting ways so things like economic geology environmental tracing bio chemistry and even medicine and geo archaeology.
Laura Bilenker: So when should you use mental sniper stable isotopes as a geochemical tool there's a few times a few suggestions.
Laura Bilenker: First, is generally to just study the behavior of metals, so this can be in the context of or deposit formation so metal concentrations within the crust that's what I do primarily that's also what you see in the background of this slide.
Laura Bilenker: This is all magnetite so iron oxide.
Laura Bilenker: You can also use them to study the behavior metals as environmental tracers contamination and pollution.
Laura Bilenker: You can study them to understand planetary accretion and evolution and biogeochemical cycling and I mentioned a case actually where these two things overlap.
Laura Bilenker: You might also use metal stable isotopes if you don't have any other ingredients to work with so, especially in the case of something like an order deposit so again what you see in the background.
Laura Bilenker: In this case, really, all we have to work with our iron in oxygen and maybe traces of other elements and so.
Laura Bilenker: Economic geology and places where we have metal concentrations in the cross become really great new laboratories for testing out different metal isotope systems, basically, because the ingredients are abundant.
Laura Bilenker: You can use solid or liquid samples, but you might need to isolate the element of interest and i'll talk about that.
Laura Bilenker: In a in some methodology descriptions and then you can also study metal stable isotopes as bulk as a bulk of a sample.
Laura Bilenker: or in situ and whether you do one or the other, is going to depend on your research question, and also whether the melt method development exists so also talk about that a little bit more coming up.
Laura Bilenker: So.
Laura Bilenker: we've just heard a really great description of how late stable isotopes fraction eight and can be applied in the geosciences.
Laura Bilenker: So now, just to kind of give you a baseline here we can compare light and heat heavy stable isotopes so heavy is going to be more of those metals.
Laura Bilenker: And how much they are actually in terms of their magnitude, but also the ranges that we're talking about so here on the left these elements are plotted by atomic number just going to switch my daughter.
cool.
Laura Bilenker: My atomic number increasing towards the right and on our y axis, we have this delta em over average em, and so what that showing is the difference in mass between two isotopes of an element.
Laura Bilenker: divided by the average mass of that element so as Dan was saying deuterium and hydrogen so masses to in one have a very large percentage wise relative difference between the two of them, compared to something like iron where we're thinking about masses 56 and 54 or 57 and 54.
Laura Bilenker: And as that mass difference gets smaller.
Laura Bilenker: It becomes more challenging for us analytically to analyze vaccination.
Laura Bilenker: On the right, you can see a few well non traditional stable isotopes but, including metal stable isotopes so at the top we've got molybdenum we've got selenium zinc copper iron chromium.
Laura Bilenker: On the left of this plot it mentions the oxidation states, so a lot of them have more than one which makes metal stable isotopes a great tracer redux processes.
Laura Bilenker: And what I want you to note, just to kind of.
Laura Bilenker: get a relative scale on the magnitude of fraction nation is down here we've got if we're thinking about delta notation for any of these elements, we have a total scale of about 20 per mil.
Laura Bilenker: And many of these elements are only spanning five to 10 per mil so in order to robustly measure the fraction ation that we see unnatural samples, we need really reliable.
Laura Bilenker: instrumentation and sample preparation methods, which is why I want to go into them in a little bit of detail before we talk about some of the applications.
Laura Bilenker: So there's two ways that we have measured recently metal stable isotopes originally.
Laura Bilenker: thermal ionization mass spectrometry your tim's which you've heard already, where you have thermal ionization of an analyzer on a model filament like this.
Laura Bilenker: So that was the main instrumentation that was used, but now within the last sort of decade and a half, maybe 15 years multi collector and actively couple of the plasma mass spectrometry.
Laura Bilenker: has become the go to analytical tool for metal stable isotopes, so this is where you have a plasma source and argon plasma.
Laura Bilenker: Which.
Laura Bilenker: Ionized is the analyzer so here's your your plasma there's your eye on beam and then this Cone there's a tiny, tiny hole on the left side, where my pointer is where that I on beam of all of your Ionized sample goes into the mass spectrometer.
Laura Bilenker: A couple of times we've mentioned ICP Ms just on its own and.
Laura Bilenker: Also, other mass specs and essentially the concept is the same so i'll show you sort of what the insides look like in a second, but we have our ICP our inductive couple of plasma for the front end of the instrument so on the left side, this is where our sample introduction happens.
Laura Bilenker: And then on the end we have multiple collectors.
Laura Bilenker: sample introduction can happen as a solution or you can use laser ablation to introduce really tiny particles of a solid sample.
Laura Bilenker: laser ablation whether or not you can do it robustly and reliably will depend on what isotope system you're using what samples you're using the reference materials and standards that are available.
Laura Bilenker: Also, the environments and instrumentation it's a lot more difficult, and if, at the end anyone wants to talk more about the challenges of laser ablation I would be happy to do so, but.
Laura Bilenker: Moving on, will focus on solution multi collector ICP Ms because that's the way that most of our metal stabilizes whole systems will be analyzed.
Laura Bilenker: Generally, you really don't need much so it used to be with the channels that for something like.
Laura Bilenker: iron, you need about four micrograms which is really not a lot now was the Multi collector we're down in the nanogram level so point one micrograms is what you can get by with on a multi collector there's a caveat, though, because you have to keep in mind that using teeny tiny samples.
Laura Bilenker: may not be getting you the most representative data from what you're working with, and so you may prepare a bulk solution and then take our clients out.
Laura Bilenker: In order to.
Laura Bilenker: not overload the instrumentation.
Laura Bilenker: So here on the on the right here's our ICP source.
Laura Bilenker: So maybe i'll just flip back real quick to show you again, so this is what it looks like from the outside, on the left and again the collectors are here, this is our magnet.
Laura Bilenker: This is what it looks like looking down so plasma over here we have a series of lenses and this ESA isn't electrostatic array and once you have your sample Ionized after that plasma, you can use basically.
Laura Bilenker: You can use that charge to focus the eye on beam around through the flight to.
Laura Bilenker: The isotopes are separated, as they pass through this magnet.
Laura Bilenker: there's additional focusing message mechanisms beyond that magnet and then there's a collector right of multiple collectors fair day cups.
Laura Bilenker: At the end which what you'll then see on your computer screen is a wiggly signal which will show you in a bit so you can collect different masses on each one of those cups.
Laura Bilenker: There are some challenges to be aware of when it comes with.
Laura Bilenker: When it comes to using multi collector ICP Ms to study things like metal stable isotopes and what I want you to get out of the next few slides is just thinking about what does it take to get good.
Laura Bilenker: metal stable isotope data and it's going to be different for different research questions different geologic materials and even.
Laura Bilenker: Your different isotope systems, but generally, these are the common threads.
Laura Bilenker: So there's four that i'm going to go through and i'll go through them each individually we'll talk about ice if Eric interferences matrix effects.
Laura Bilenker: Meeting to separate your family or your element of interest from the sample matrix and then fraction nation that might happen during sample prep and analysis.
Laura Bilenker: server isometric interferences what we're talking about our interferences of equal mass so I so or I saw being equal, Barrett being weight.
Laura Bilenker: And i'll use iron as an example and if I haven't disclosed this already I iron is my.
Laura Bilenker: What I have the most experience and it's my favorite metal stable isotopes but it's also a little tricky to work with so irons mass what we do is we look at masters 5654 and 57 generally.
Laura Bilenker: And, as I mentioned earlier, the plasma in the ICP is an argon plasma, you have a lot of argon gas in the environment.
Laura Bilenker: You also have a little bit of the atmosphere things like oxygen hydrogen nitrogen because of that sample introduction.
Laura Bilenker: And so, are gone combine can bond with nitrogen oxygen and also oxygen and hydrogen, to make the masses that equal iron.
Laura Bilenker: So here on the right, what you can see, is basically if you were running an IMC ICP Ms your screen would show wiggles like this, the higher the peak, the higher the signal intensity is usually volts and the higher the concentration of what you're measuring.
Laura Bilenker: So what you can see, I can we can focus on this top line.
Laura Bilenker: Is that this highest plateau is iron 56 plus are gone outside.
Laura Bilenker: The iron 56 alone is just this little bump to the left and the same thing happens on this lower Gray line for iron 54 where the art on nitride and the iron 54 combine.
Laura Bilenker: And you can't figure out which one is which.
Laura Bilenker: And so what you do is you analyze your iron 56 year iron 54 and ultimately also you're earning 57 on the shoulder just on the edge of the signal that's incoming from the instrument.
Laura Bilenker: Another thing you have to keep in mind is that other elements and in the case for iron nickel and chromium or provide interferences.
Laura Bilenker: Their masses, they have they may have masses that overlap with your system as well, so what we do if we're going to analyze iron 58 is we monitor for nickel 60.
Laura Bilenker: And then we're able to estimate how much nickel 58 there might be in the system during analysis and subtract that and same for chromium 54 interferes with iron 54 so we monitor for chromium.
Laura Bilenker: And do a correction after we get our data.
Laura Bilenker: The reason why nickel and chromium matter, in particular, is because there are parts of the mass spec sometimes that are made from chromium and nickel, and so they could even in small amounts be within the system, and you want to make sure that you take that out.
there's.
Laura Bilenker: Another thing to mention is that there are actually multi collectors that fully resolve these peaks so instead of having that shoulder your iron.
Laura Bilenker: peeps in your Oregon interference peeps for your iron and your chromium and nickel can be completely separated in terms of their signals.
Laura Bilenker: And so what this requires, though, is a larger geometry so here, you can see a multi collector called the 1700 made my new instruments understandably that magnet is much, much bigger the introduction side is the Left same as before, whereas the collector side is on the right.
Laura Bilenker: And because of the large geometry and also some shields and movable features of the collectors you can get very.
Laura Bilenker: Detailed in the way that you set up the instrument and avoid those interferences so it's really important to know what kind of instrumentation you're working with what kinds of interferences might exist, and what you can do to mitigate.
Laura Bilenker: mitigate that.
Laura Bilenker: Another thing that comes into play kind of in different amounts for different isotopic systems is matrix effects.
Laura Bilenker: So this could be from the element itself or other elements, but basically as your sample is going through the system.
Laura Bilenker: different outcomes that are present will interact with each other and as they interact, they will change the behavior of each other within the the plasma and potentially the flight tube.
Laura Bilenker: So those interactions.
Laura Bilenker: Again, maybe present or not for different isotope systems for iron, if you have zinc in high enough concentrations zinc behaves very similarly to iron and it can actually.
Laura Bilenker: mess up its behavior in the place.
Laura Bilenker: In the mass spec or in the plasma and give you data that is not accurate.
Laura Bilenker: So, to combat these first few challenges we need to separate our element of choice, from the sample matrix the matrix might be a stream water, it might be a mineral or it might be a rock.
Laura Bilenker: So if you have sample solid samples, but you want to do first is crusher samples.
Laura Bilenker: So in this case.
Laura Bilenker: i'm doing this for iron isotope analysis and so another thing to always keep in mind, is whether contamination is going to be an issue So here we have tungsten carbide plates in a very protected crushing box, so that when I crush this sample which actually comes from the.
Laura Bilenker: floor of the Atlantic Ocean, when I crush the sample I know that i'm not adding additional iron or nickel or chromium which provide interferences into my sample unintentionally.
Laura Bilenker: So after it's crushed you crush it some more so, you want it to be a nice fine powder here, this is an aggie.
Laura Bilenker: an aggregate container with a gate small balls and what happens is that gets put into this mill and it gets kind of catapulted around for a while and when you're done, you have a lovely powder.
Laura Bilenker: That powder will then be dissolved in acid, so I told you that you could analyze solid samples by laser ablation with an MC ICP Ms but we're going to focus on the solution analysis.
Laura Bilenker: And again just a reminder that, especially with metal stable isotopes because we have metal everywhere it's really important to use the proper equipment.
Laura Bilenker: To avoid contamination and even when you're thinking about a project and your research questions before you go to sample collection.
Laura Bilenker: If you think hammering out a sample with a steel hammer is going to be a problem for your iron isotopes it's important to keep that in mind, from the beginning.
Laura Bilenker: And so, once you have your sample dissolved it's going to be a mix of lots of different elements plus what you actually want to analyze.
Laura Bilenker: And so we do a method called column chromatography and there's different procedures for different isotopes essentially different recipes.
Laura Bilenker: What you do is you pack so here's kind of a closer version you pack a stem of a column with resin, so this is kind of what it looks like when it's in there.
Laura Bilenker: And you condition the resin with a series of different acids and what you're telling the resin to do is to hold on or release different elements at different times, and so, by doing that we can isolate in this case the iron So you see that Nice yellow.
Laura Bilenker: That nice yellow solution, and when you drive this down on a hot plate.
Laura Bilenker: This is what you get so this is pure iron in the bottom left and we've isolated our iron from the rest of the elements in the.
Laura Bilenker: In the Rock in this case.
Laura Bilenker: Again, if contamination is going to be a challenge for you, you want to work in a clean environment, so in this case the university British Columbia you take your shoes off go in you put on a head to toe suit, which is very.
Laura Bilenker: marshmallow like and then here, you can see, looking into the lab.
Laura Bilenker: So pass the second door.
Laura Bilenker: it's all plastic it's all very clean there's filters in the air source.
Laura Bilenker: And there's basically no metal anywhere, except these doorbells.
Laura Bilenker: Okay, and then the last thing to worry about with mass spectrometry multi collector or not.
Laura Bilenker: Is that fraction each and can happen during during sample preparation and analysis, so in nature, vaccination happens due to geologic processes.
Laura Bilenker: And in within the instruments or within your column when you're doing column chromatography it's no different so heavier and lighter masses may respond differently or at different.
Laura Bilenker: yeah in different ways to the processes that you are putting them through.
Laura Bilenker: here's an example so for tim's here are filaments the light blue small circles represent lighter isotopes, whereas the red circles represent heavy and you can actually have preferential ionization of the light masses over the heavy ones.
Laura Bilenker: In a plasma it's the same thing so here is our torch so moving toward the right these would be our cones.
Laura Bilenker: And you can have one mass that's preferentially.
Laura Bilenker: transmitted over the other.
Laura Bilenker: And I will say that, overall, on a on the general scale this difference can be small.
Laura Bilenker: But remember back to the beginning when we're thinking about heavy stable isotopes the fraction nations in nature that we're wanting to analyze and interpret are so small that we need to make sure we do everything in our power to minimize fraction ation.
Laura Bilenker: incrementally and then, also in terms of sample prep.
Laura Bilenker: Then there's a couple of things you might have to do to correct sometimes or run takes hours days with multi collector the plasma can change over time it'll warm up it'll become more stable than it might become less stable, you know, three or four days into your run.
Laura Bilenker: So just to start with the most straightforward, we have something called standard sample bracketing where you alternate your analyses of standards and samples.
Laura Bilenker: And what this looks like is you set up a run you have your standard, which in this case for iron is going to be something synthetic that we really we know the composition of.
Laura Bilenker: And for a really long run, we might do a standard before and after every sample.
Laura Bilenker: For some really stable instruments or other isotopic systems, potentially, you could run 234 samples between each standard.
Laura Bilenker: But each one of these is called a bracket and what you want to do between your sample and your standard is matched the concentration and the matrix to make sure that there's nothing affecting the standard that's not affecting the sample and vice versa.
Laura Bilenker: And then, when we think about the delta notation we average the standard that have that was analyzed before and after our sample, and so this increases our precision, it helps us to correct for.
Laura Bilenker: instrumental drift.
Laura Bilenker: And just to show you the way how helpful, this can be so if we have our delta value of iron on the y axis so coming down to about half a per mil and then time, so this is just 200 minutes moving toward the right.
Laura Bilenker: The black squares are and bracketed sample so single measurements.
Laura Bilenker: The gas coming into the system.
Laura Bilenker: could be a regular and so in this case they're calling us an interference burst.
Laura Bilenker: And so you have this really big jump of half a per mil.
Laura Bilenker: In your single measurement samples, the ones that were able to be corrected during the same time with a bracketing measurement of a standard.
Laura Bilenker: are unaffected, essentially, and so this is the value in the power of standard sample bracketing.
Laura Bilenker: there's two other ways that we can correct the first is internal normalization where we add other elements of similar mass to the one you're interested in also correct for.
Laura Bilenker: instrumental drift, but more non systematic compared to standard sample bracketing and then we have something called a double spike technique, where you add two.
Laura Bilenker: Additional isotopes of the analytics so in the case of iron, we would add 5758.
Laura Bilenker: Very well, characterized solution and then what we can do is correct, for any mass bias or fraction nation within the instrument later, and this is a really precise approach double Spikes are used an iron chromium molybdenum lots of metal stable isotopes.
Laura Bilenker: And then we also just want to do a quality check.
Laura Bilenker: So.
Laura Bilenker: Sorry.
Laura Bilenker: What you'll end up doing if you have metal stabilizer to up data is comparing.
Laura Bilenker: Over time, all of your measurements, so in this case it's up to 57 vs delta 56.
Laura Bilenker: To make sure that they all fall along this mass dependent vaccination line and make sure that nothing is.
Laura Bilenker: Getting fraction aided within the instrument.
Laura Bilenker: Okay, so took a little longer than I had wanted it to you, but I think it's really important to know how to get good data if you're inspired to use metal stable isotopes and also what really goes into even one data point it's a lot of time.
Laura Bilenker: it's a lot of resources and it's also a really great experience.
Laura Bilenker: Okay, so i'm going to just highlight a few examples relatively quickly.
Laura Bilenker: I wanted to cover a wide range of geologic systems, and if we want to have additional discussion, I want to make sure they leave time for questions.
Laura Bilenker: So i'm just going to start and igneous systems, because this was most influenced by the improvements in the Multi collector instrumentation and also the methods like.
Laura Bilenker: Double spike so initially, so this is a paper from 1999 you can see terrestrial igneous rocks on this scale of plus 1.5 to minus 1.5 are all essentially homewood genius.
Laura Bilenker: On the right you've got some samples that are biologically affected but generally so vcr to is assault.
Laura Bilenker: The standard is essentially an igneous rock the assumption was that the the mass difference of heavy stable isotopes was too small for any significant fraction nation to happen in high temperature systems, and this makes sense somewhat.
Laura Bilenker: As Dr Vito mentioned earlier, a.
Laura Bilenker: fraction nation scales inversely, with temperature so as you get toward higher temperatures your fraction nation is going to get really, really small.
Laura Bilenker: And so.
Laura Bilenker: In 1999 and those data that I just showed were were analyzed on a tim's.
Laura Bilenker: It was a pretty safe assumption that igneous rocks showed no fraction Asian and here you can see just in the schematic how igneous rocks cover really narrow range, as you meteorites whereas sedimentary rocks carry cover a much wider range in terms of iron isotope compositions.
Laura Bilenker: This is because stabilized to do it for action nation is a product of processes and conditions, and so what we're seeing here is the preservation of geologic processes in these rocks.
Laura Bilenker: But then what happened was in about 2004 2005 people started analyzing igneous rocks with the Multi collector.
Laura Bilenker: And here i'm going to build out this plot a bit, but we've got increasing silica going to the right so essentially basalt to Riley and igneous rocks formed from temperatures that are you know.
Laura Bilenker: 750 800 degrees 1000 degrees so upward.
Laura Bilenker: and
Laura Bilenker: What they saw was not homogeneous at all so there's this really nice.
Laura Bilenker: increase toward heavy.
Laura Bilenker: isotopic Lee heavy iron over increase in silica.
Laura Bilenker: So more people analyze more rocks.
Laura Bilenker: And they found again that, generally, as you increase silica or a differentiation within a magnetic system you increase the delta 56 value.
Laura Bilenker: And there were a couple of proposed.
Laura Bilenker: hypotheses for why this would happen on the first is that there was a loss of fluid from the magnetic system, and so this is assuming that fluid sequesters isotopic light iron.
Laura Bilenker: And in this schematic so we have these chlorine bearing light blue fluid bubbles, where the light is going into that fluid random magnetic Chamber deep underground we're also forming crystals which i'll get to in a second, but the assumption was that this heavy.
Laura Bilenker: residual.
Laura Bilenker: magma or rock now.
Laura Bilenker: was just reflecting loss of fluid.
Laura Bilenker: So again, more people analyze more rocks and propose then that may be fractional crystallization so here with these green circles, maybe fractional crystallization is actually.
Laura Bilenker: A control on iron isotope vaccination and igneous rocks.
Laura Bilenker: And as you would crystallize magnetite the heavier iron would go into the magnetite.
Laura Bilenker: So an iron bearing rock or mineral sorry and as that magnetite formed the melt will become progressively ice topically later.
Laura Bilenker: And then, what that also highlighted is that may be redux processes are actually also being preserved in the igneous rocks.
Laura Bilenker: So iron two plus and a lighter isotope.
Laura Bilenker: correlating versus iron three plus and heavier isotopes.
Laura Bilenker: So what multi collector ICP Ms allowed us to do was really elucidate what processes might be at planning new systems and note this scale it's really only about Point six per mil just over half of promote.
Laura Bilenker: And the conclusion was basically several processes are likely a play.
Laura Bilenker: The key and also for any geochemical data is that we need to consider the context the geologic context in order to pin down what process is that play.
Laura Bilenker: Okay.
Laura Bilenker: we'll skip to this.
Laura Bilenker: Okay, so that's high temperature systems here on earth, but let's look beyond earth for a second.
Laura Bilenker: So chromium isotopes have actually been analyzed in moon rocks, and so this is an example of analyzing.
Laura Bilenker: The metal stable isotope composition of a national sample and then what these authors did was they compared those values to pre existing theoretical data and experimental data to interpret their results and from their modeling what they found.
Laura Bilenker: So what their question initially was.
Laura Bilenker: Did of these moon rocks.
Laura Bilenker: Did That was the geo chemical signature.
Laura Bilenker: Something that was preserved before or after impact.
Laura Bilenker: chromium isotopes are really temperature sensitive, and so the idea was that the chromium isotopes can provide insight as to whether the.
Laura Bilenker: The GEO chemical signature was from the high temperature conditions of impact or during cooling later and what they found so here you'll see compared to the earth mantle.
Laura Bilenker: And these moon rocks what they found when they they incorporated their chromium isotope data with their elemental data is that.
Laura Bilenker: They the moon rock separated from the mantle rocks, and so what their conclusion was is that the geo chemical signature was reflecting processes post impact, rather than during impact.
Laura Bilenker: I haven't talked much about biological cycling, but I wanted to mention this here in terms of planetary considerations so experiments have been done to show that there's large fraction ation for iron, specifically by.
Laura Bilenker: Biology that we could in theory track, so if we can quantify it here and experiments if we get rocks from SAVE Mars or meteorites and we look at the iron isotope composition potentially that could offer insight into whether life existed or not there are not.
Laura Bilenker: This is actually a currently a pretty interesting field but you'll note that the citations here 2002 2003 and so not much it's really challenging question and not much.
Laura Bilenker: there's still a long way to go, is what I should say.
Laura Bilenker: Okay, so the last or there's two more and then basically over time, so the last thing I want to touch on is or deposits.
Laura Bilenker: So something that we've seen in copper isotopes is that primary minerals from magnetic systems that form.
Laura Bilenker: or deposits like copper poor freeze will have different isotopic signatures, then those that are further away from the the or and heavily leached by the the fluids that carry that copper there, and so what we can do is compare primary minerals to secondary leached minerals.
Laura Bilenker: And if we can characterize that fraction nation.
Laura Bilenker: And spatially analyze the copper isotopic composition of an order deposit we can vector and predict where the order is actually going to be.
Laura Bilenker: Okay, and then the last thing I wanted to touch on was environmental tracers.
Laura Bilenker: And there is a case study by alyssa she'll from 2013 that use cadmium and zinc isotopes to understand why there was such high concentrations of cadmium.
Laura Bilenker: In French bivalves so things like muscles and oysters so here, you can see, on the left, that the cadmium is really, really high relative to other sources of muscles oysters so in France it's very high.
Laura Bilenker: And what they saw so specifically for two sites.
Laura Bilenker: Here, and the Western.
Laura Bilenker: French coast.
Laura Bilenker: Is that, based on the cadmium and zinc isotopic composition so here we've got our cadmium French oysters and our zinc isotopes for our French oysters.
Laura Bilenker: That the signatures they saw compared to natural waters.
Laura Bilenker: Were.
Laura Bilenker: The signatures they saw were not reflective of the natural waters, but actually reflective of pollution in the area.
Laura Bilenker: smelting and metal processing had ended in 1986 but what they showed in 2013 is that, even though there had been remediation these past mining practices are not mining but or processing processes practices actually still provided the main source of cadmium in these oysters.
Laura Bilenker: So.
Laura Bilenker: I think.
Laura Bilenker: I will stop there, and I may I think i'm over my time anyway, but if anybody has any questions I will also share my slides and I had a couple of other.
Laura Bilenker: Case studies that would probably be interesting.
Ann Ojeda: Thanks Laura that was great I especially love the environmental tracers that's my that's my jam I didn't know you could use.
Laura Bilenker: I said yeah there's actually a lot.
Laura Bilenker: yeah so that paper goes through a lot of examples and yeah as I was talking, I was, I was it was my pleasure to give some of my time to radio genetics, but I think I missed it.
Ann Ojeda: Okay well we'll open the floor to questions that the closing remarks are, thank you for coming, this has been a long afternoon, but I think we've touched on so many different great topics in.
Ann Ojeda: earth processes and tracing earth prophecy processes using isotopes and so, if you have questions for Laura or any of our hosts or want to bring up a topic, or you find any threads down any threads that.
Ann Ojeda: encourage your own research we'd love to hear that as well.
Ann Ojeda: brennan did you raise your hand.
Brennan van Alderwerelt: yeah I have a question if nobody else is jumping at the bit or whatever that phrase is.
Brennan van Alderwerelt: I have an analytical question actually so aspects right it's the mass to charge ratio so i'm wondering how you deal with I might have missed this, but how you deal with multi Vaillant metals, do you just measure what you think is the dominant Valence or.
Laura Bilenker: So there um it's not actually an issue in the mass.
Laura Bilenker: So they're all when you Ionized them.
Laura Bilenker: yeah it'd be that's not something that you need to deal with yeah.
Brennan van Alderwerelt: Oh Oh, I get it yeah I mean, I think I want to just then emphasize laura's statement that to do isotopes you really got to understand the machines it's really important.
Laura Bilenker: yeah because if you didn't if that was the thing and then instrumentation, then it would be, it would cause additional vaccination that's a good question.
Ann Ojeda: And Laura i'll jump on that too I don't see any raise hands so i'll continue on this analytical trajectory because it's one of my favorite.
Ann Ojeda: Is that we actually see a lot of instrument fraction nation in our carbon isotope and even in the EA and we do a very similar bracketing standard bracketing.
Ann Ojeda: And then some processes you can't correct for and you understand that your instrument in somebody else's instrument just have a little different feel a little different prophecies and a little different magnitude of that instrument bias.
Ann Ojeda: And that's been a really interesting challenge for our comparing in our in our laboratory studies right understanding your machine is quite important.
Laura Bilenker: Which is why reference materials are so important, so something that.
Laura Bilenker: I don't think I mentioned a meant to you is that.
Laura Bilenker: You want to between sessions in between laboratories analyze the same material, so that you know you're still on track you're still getting accurate data.
Laura Bilenker: I focus a lot on precision, because in metal stable isotopes that something that you know, the better the precision, the more we can illuminate and that's that was.
Laura Bilenker: being very clear igneous metrology.
Laura Bilenker: But yeah that's a really important thing.
Ann Ojeda: I think one of the most highly cited publications in our environmental forensic stuff is a guy who came up with a whole bunch of standards.
Ann Ojeda: and sent them around and said okay guys you guys use this stuff because you know the environmental world we can't use.
Ann Ojeda: PTV right we don't use carbonate rocks, we have to use organic standards that are then tied to ptb.
Ann Ojeda: In a very specific way so i'm essentially the usgs came up with a whole bunch of leaf waxes and like polystyrene stuff that you have to analyze to tie back to that rock record rock standard, but we don't analyze the rocks we analyze you know one step beyond that or more organic.
Ann Ojeda: Any other questions any questions about.
Ann Ojeda: Any threads perhaps that emerged in the isotope world that you were.
Ann Ojeda: You notice or I didn't expect or expected and i'll open that up to our panelists as well or course leaders any threads that emerged for you.
Ann Ojeda: In all of these isotope talks.
Willis Hames: October Colin has a question.
Beth McClellan: Thank you will.
Beth McClellan: This was actually following up on some stuff Laura was doing so I haven't quite made this connection.
Beth McClellan: But I found I found this.
Beth McClellan: metal isotope stuff really interesting and I know almost nothing about it.
Beth McClellan: But i've been reading lately about um Banda darn formations, which of course were.
Beth McClellan: around in the hierarchy and and put it, a result, but then kind of disappeared, for a long time and then during the Sturdy and snowball earth episode and then the operators elec.
Beth McClellan: they reappear and I was just wondering if you were familiar with any of the litter tour or even tell me anything about banded on formations.
Laura Bilenker: yeah absolutely um because the fraction nation is so large and lower temperature environments and then, especially when biology's involved.
Laura Bilenker: Most of the earlier samples that were analyzed were best actually so Johnson and buried at Wisconsin and the late 90s and early 2000s, and probably since then i'm sure have done a lot of analyses on bender bender dire Informations about it so.
Laura Bilenker: i'm not nearly as familiar with that side of things, as I am with the higher temperature stuff but I know that you can disentangle formation processes from them temperature.
Laura Bilenker: Biological contributions that sort of thing so they're yeah they're really interesting and especially from an iron isotope perspective, so I highly recommend checking out the reviews of mineralogy and geochemistry volumes that I mentioned there's a bunch of stuff in there too.
Beth McClellan: Oh good Thank you.
Haibo Zou: Another factor in terms of.
Haibo Zou: hiring isotope where Asia units rocks might be the simulation, especially with a realize they stay in the magma Chamber for a long time, sometimes you get a simulation for all the controls that's my.
Haibo Zou: Just a one possibility yeah.
yeah.
Laura Bilenker: yeah.
Laura Bilenker: yeah sorry were you gonna say.
Haibo Zou: I say problem for this and I probably combined with other I suppose you can draw out the assimilation at literally evaluate you know yeah.
Laura Bilenker: yeah that's exactly what I was gonna say so, for isotopes really helpful for that initially when you, you can look at it igneous rock as a bulk rock or.
Laura Bilenker: As the minerals, and so in minerals like pure tight, for example, you can actually see signatures of assimilation, in both the iron and the silver isotopes.
Laura Bilenker: So yeah I kind of sped through that right, I mean it's what I said several processes are likely at play situation can definitely be one of them.
Thank you.
Haibo Zou: Actually earlier, I read a paper I think that's a real and borrow from universal Rochester originally.
Haibo Zou: He also mentioned the colon cancer can change our ISO.
Haibo Zou: Composition I don't know if data is still true or not.
Laura Bilenker: yeah so you have to be really careful and there's several different procedures out there, and you know, like you have to pay attention I showed the columns that are long and skinny, but if you have a different.
Laura Bilenker: Size columns stem that's wider versus longer you know it, it actually affects it can affect the.
Laura Bilenker: It can affect your results and.
Laura Bilenker: there's nothing else I was gonna say about that yeah so what you do to check is number one you check that you're getting what you expect to be 100% yield.
Laura Bilenker: So make sure all of that is coming off that column compared to what you put in, and then the other thing is, we run reference materials through so.
Laura Bilenker: If we're not seeing fraction ation in the reference materials and we're putting about the same amount of iron onto those columns and we analyze them and their isotopic compositions are what we.
Laura Bilenker: hope they are then we're pretty confident that that we're Okay, but yeah if you have low yields if you're not getting all the iron off your columns your data is give me bad yeah.
Haibo Zou: Thank you.
Brennan van Alderwerelt: yeah one thing i've seen this using a spike blank and calm chromatography, which is where you put the unknown.
Brennan van Alderwerelt: it's yeah it's a non zero blank and you monitor that isotope ratio that comes out in that blank and you check it against other standards, but I do think it's a really good point to point to.
Brennan van Alderwerelt: Note that column column chemistry is something you'll see that phrase a lot and just kind of the assumption, you know what that means it's a phrase to be really wary of.
Brennan van Alderwerelt: Because like lori mentioned there's a lot of stuff that falls under the category and column chemistry.
Brennan van Alderwerelt: there's even such stuff as dry calm chemistry, which involves like powders i'm not sure if it's used much and in the geology world and then there's the high aspects and the low aspect.
Brennan van Alderwerelt: and also an interesting that I see thing that i've seen in working with strontium his lifetime kind of classic cat I an exchange resin calm.
Brennan van Alderwerelt: Calm chemistry, and I also use something called strontium spec resin which is.
Brennan van Alderwerelt: specifically designed for cleaning up like nuclear waste, but it has this other issue where along with strontium, we can also pick up organic molecules that their combined.
Brennan van Alderwerelt: weight is about the same as strontium I think that's how it works i'm not quite sure.
Brennan van Alderwerelt: Its proprietary so I have no idea what's in that resin, but there are like a lot of considerations about which little.
Brennan van Alderwerelt: brand of weird resin you stick in your columns and everything so it's again it's it's.
Brennan van Alderwerelt: it's you got to know yourself and like Laura I learned, most of all, I know from.
Brennan van Alderwerelt: Getting actively involved with labs, especially in Grad school sometimes sending an email that was like can I come watch you do this and most people will yes.
Brennan van Alderwerelt: I would encourage all the students out there to to keep that in mind when you're.
doing your homework.
Ann Ojeda: Now pick up on that sample reference material procedure we call it the it person up procedure which is identical treatment so for everything that you do.
Ann Ojeda: you treat your reference.
Ann Ojeda: or your standard and your sample the exact same way, so that you can track any fraction nation and correct for any fraction ation during these prep steps.
Ann Ojeda: Because they're very can be very intensive yeah we do chromatography all the time and sometimes we just accept that me doing the chromatography is going to give us a three per mil offset but if I can consistently get a 3.0 per mil offset, then I can correct for that.
Ann Ojeda: that's part of me that's part of the limitations right you work with with what you can.
Brennan van Alderwerelt: I do think it's also part of the value of isotopes is so often the reported in reference to something else instead of absolute numbers, which I think makes them very.
Brennan van Alderwerelt: useful and consider things like internal references for a lab or you can readjust your numbers, perhaps if the standards are hard work of the Community changes.
Ann Ojeda: And typically we have.
Ann Ojeda: internal working standards.
Ann Ojeda: So the reference materials are so expensive, I mean you can't run those every day you just can't you can't afford to run them with every sample.
Ann Ojeda: So what you do is get something that is cheaper that you can really count on one of the things that we run every day is a CO2 tank of gas.
Ann Ojeda: So you have a hydrogen tank of gas and a CO2 tank of gas, and you spend a lot of money characterizing that tank.
Ann Ojeda: And then, once you know the tank you can do internal referencing to your tank and then make sure your tank is calibrated to the reference standard, but I think that's another point, this all these things cost a lot of money and.
Ann Ojeda: You know, especially standards man.
Ann Ojeda: they're quite expensive, and so we try to do our best working within those those frameworks.
Ann Ojeda: And then, and then beg your friends to give them their standards right, so one of the things we would do.
Ann Ojeda: In our isotope lab was asked for CO2 gas from other people, so what are your internal reference standards that you're working gas standard.
Ann Ojeda: And we send them around we would send them in bottles over ups and we would get a whole bunch of standards from our friends and say is this what you got Is this what I got Is this what you get is this that I got to make sure that all of our.
Ann Ojeda: All of our data was comparable.
Ann Ojeda: So we just have a couple more minutes and I do want to end on time.
Ann Ojeda: Are there any like.
Ann Ojeda: outstanding questions from our audience, I want to give students a chance to speak up or anybody that's had a burning question in their heart.
Ann Ojeda: And it's been crickets when I asked that question before, but maybe somebody will just bite the bullet.
Ann Ojeda: No okay so again, thank you so much for spending, this time with us it's been great i've learned a lot I hope you've been able to take something away and we will.
Ann Ojeda: do our best to send slides and reference materials to the email list so you are on that email list by having this link no need to send us anything.
Ann Ojeda: And you'll receive that hopefully within a week i'm putting that pressure on our our leaders, give them a deep breath after GSA and then we'll turn that back around to you, hopefully, within a week or.
Ann Ojeda: 14 days.
Ann Ojeda: Okay, oh can.
Ann Ojeda: you hear can people turn their cameras on and let's take a GSA zoom.
Ann Ojeda: um.
Ann Ojeda: I think okay so i'll Count of 312 there.
Ann Ojeda: All right, good job team.
Ann Ojeda: And I think that's like the official end of all zoom meetings right as when you take the picture.
RISE- Audrey Heun GSA: I just want to step in, on behalf of GSA and just thank you to all of you i'm gonna so and Laura.
RISE- Audrey Heun GSA: bill Brendan.
RISE- Audrey Heun GSA: hair bow harbor Thank you so much for putting this, all together, you guys did a great job.
RISE- Audrey Heun GSA: I think it was really informational and just you know testing the sorry, I have a little zoom photo bomber here, but just you know testing the waters with.
RISE- Audrey Heun GSA: Online i'm sorry guys, thank you for sorry i'm trying to be professional here testing.
RISE- Audrey Heun GSA: How these online short courses are going to happen and you guys did a great job, so I really appreciate it, and thank you to everybody for sticking around all day and.
RISE- Audrey Heun GSA: don't forget that here in a little bit, we have the opening spatial chat reception that bill and katie have really spent a long time so hopefully we can.
RISE- Audrey Heun GSA: have fun there, but thank you again i'm gonna mute.
Okay.
Willis Hames: Thank you all.
Brennan van Alderwerelt: Thank you everyone for coming.
Laura Bilenker: And thank you.
Laura Bilenker: Do we need to talk about anything.
Ann Ojeda: No, I didn't say thank you.
Laura Bilenker: it's got it went well I.
Laura Bilenker: got a little flustered during the time was like I looked down and i'd been in for 30 minutes.
Laura Bilenker: Talking about mess bags so far, David.
Brennan van Alderwerelt: I that I had that same feeling when I hit six minutes and I was still on the intro I thought.
Brennan van Alderwerelt: So i've uploaded my final slides to box and you can see them there there's about twice as many as I got through including some and that I think you will be interested in environmental uses and.
Ann Ojeda: I guess it's the challenge of doing a broad eyes to workshop alright well i'm going to jump off object Thank you so much.
RISE- Audrey Heun GSA: yeah Thank you sorry.
RISE- Audrey Heun GSA: I could not like push her way but.
RISE- Audrey Heun GSA: You guys did awesome Thank you so much.
RISE- Audrey Heun GSA: really big round of applause you guys very professional stayed on track made it fun and engaging so really great job, so I really appreciate it, I know GSA appreciates it so.
RISE- Audrey Heun GSA: good job on all this hard work so i'll see you guys at other sessions i'm sure.
RISE- Audrey Heun GSA: You don't buy. 1334