 All right, I have 10 a.m. SLT and Chantel and Jess said that I could start anytime I want and Mike Q or ready to roll our recording. Okay, I'm gonna start and then if there's a problem you let me know Okay, great central says we're ready to go So I'm honored to be the first speaker of the new season and about you, but I missed The science circle presentations. It's always a fun way to spend Saturday afternoon. Just didn't seem the same Okay, with without them. All right, but today I want to talk about mass extinctions of the fossil record I'm gonna be sharing some research that I did this summer around Virginia Not only did I do a lot of field work this summer I went to about four or five different locations within Virginia to try and get information on this topic I also did considerable reading. I read a PhD dissertation at Virginia Tech that had a lot of data in it The other thing I would really recommend is Alicia Stigle at Ohio State University is doing some very cool work as well on mass extinctions and environmental science and I want to say by no means am I an environmental scientist I'm more of a geologist paleontologist, but I I see The sole whole field of paleontology is going in that way and it is a new avenue of study for us So this is a presentation. I'm gonna just list The five mass extinctions. Some people think there's a sixth And then I want to focus primarily on the late or division of it as that's where most of my field work has focused the other thing that I want to say from the very from the outset is This summer had the opportunity to go to the Smithsonian Institution in Washington DC You may have heard that there's a brand new exhibit that they opened up all the deep time exhibit And if you are able to get to DC and I know we're all over the planet But if you are able to make your way to DC, it's well worth the time to go through that exhibit I thought they did an excellent job. They talked about the mass extinction events Now I was able to go through the exhibit I also was able to meet the several of the curators After lunch and go into their collections area and I got permission from the Smithsonian Institution just this past week to share some fossils from the collections in this presentation So I appreciate them applying me to do that. I don't have a lot of specimens, but I do have some I'm hoping I've talked to Chantel and Jess about doing Another presentation later in the fall talk more about some of the collections that are some of the specimens that are available in those collections So without further ado Let's get into the talk. The other thing I want to say by the way before I forget Real informal if you have a question if you have a comment We we can't do voice you can't do voice But feel free to put question or comment chat. I have the local chat open I'll be happy to stop at any point and Try and answer your question as best as I can I'm by no means an expert on all the mass extinctions, but I will try and do the best that I can So my interest in the mass extinction of fossil record probably goes back to the 1980s when I was doing my PhD dissertation at the University of Chicago and Back in the 80s Chicago was the hotbed. I think of of paleo paleontology and paleobiology That was going on. There are people like Dave Ralph Tom shop Jackson cast you that were really doing groundbreaking work They were compiling huge amounts of data on on fossil record and then trying to look at patterns of the of the fossil record Jackson Kowski was my evaluator for a while and here's one of the graphs that I got out of a textbook that was shamed Shamelessly ripping him off. It's one of the ones. Unfortunately that I use my earth science class and it shows Jack's data on the number of families versus geologic time and Jack documented five main mass extinction events, which I'm going to list in a minute Some of us are very familiar with the terminal Cretaceous one in which the dinosaurs went out. Maybe the Permian one I was surprised to learn from Dr. Sipkowski that there were actually three other events one at the end of the Ordovish in about 450 million years ago one at the end of the Devonian about 350 million years ago and one at the end of the Triassic When I was at the Smithsonian Institution one of the things that I thought was interesting was that the scientists at the Smithsonian had another mass extinction event one at the end of the Vendian, which is not discussed much about 543 million years ago those of you that came to hear To the panel discussion with Alex Hastings and myself and also we were fortunate to get Shuheis out to come on Second life. He talked a lot about the pre-Cambrian to Cambrian transition The Vendian was at the very end of the pre-Cambrian and if you can sort of zoom in on this it shows Some of this is a fossil from the Smithsonian of actual Vendian animals. They're very enigmatic When you when you get in these late pre-Cambrian for as it's not even clear what the heck you're looking at but you see the fossil on the left and Reconstruction of what the animal may have been like they sort of resemble ferns or plants, but they're actually animals very simple organisms where probably all they did was extract nutrients from the from the water, but at the end of the Vendian at the end of the pre-Cambrian You see this rapid shift from very simple organisms to First invertebrates first more complicated things that are coming into the oceans The Smithsonian Institution has suggested that if there was a terminal Vendian extinction event It may be biotically produced in other words that the things that were coming out Cambrian may have just displaced some of the pre-Cambrian organisms and that's one theme that I see going on in paleontology that People are starting to apply apply environmental science concepts to deep time So paleontologists are starting to look at for example Invasive species and what event they had and now I'm going to say a lot more about that later on period But there seems to be some interesting Interactions that are going on All right, then we have the terminal or division extent event about four and forty four million years ago and One of the things that Jack's of Caskey always used to say is there there are always organisms There are always species that are dying out This he called it a background extinction event So you always have a couple of them going out every couple of million years But there are times in the geologic past where the extinction rates were greatly exaggerated The end of the automation some eighty six percent of the species that were around passed away So we start losing Graph to lights they're shown in the top slide here The picture at the bottom is a is a brachypod from the Smithsonian These sort of flat-shelled strophemy and brachypods they take a major hit at the end of the automation But they don't entirely go out they get replaced later on in the Devonian time period and some of the The reasons for this extinction event may be due to glaciation that occurred in South Africa Like I said, I'm gonna say a lot more about this terminal or division extinction event As we go through here But let's list some of the other parts of the other major extinction events There was one that occurred during the late Devonian about three hundred seventy five million years ago some 75% of the species perished We see some bizarre trilobites going out like the illustration of the slide at the top There are also these wings by rifrids That I love collecting in fact these were some of the first Brachypods I collected in the bottom part of the slide here about 30 gosh It's been 40 years since I started collecting fossils And they don't appear anywhere else in the fossil record These these weird things and question is what may have caused that well again, there's some suggestions that perhaps Nutrients released in the oceans these nutrients allowed algae to bloom that which may have Pleaded oxygen levels suffocating by boiling organisms again. It's sort of hard to tell Yes, you know the sort of chemistry is rarely preserved in the fossil record. Although we do get Some black shells which are typical of of low oxygen conditions in the Devonian All right, then we go on to the terminate terminal Permian extension, which which was about 250 million years ago Almost it almost drained the oceans This is the one that's perhaps one of the most famous marine Extinction events 96% of the species died away some of the animals that that perished Include the horn corals the tabulate corals All the trilobites die out at this point that Brachypods get a major hit. There are these weird Brachypods that have spines to them are called reductants they go out and The the cause of this extinction debate Cause of this extinction event have debate been made heavily when I was in graduate school the predominant Terministic factor behind it was plate tectonics. So we thought that What happened was that Africa and North America came out together in fact all the continents collide to form the supercondent known as Pangea and as that collision event occurred the sea level dropped as mid-ocean ridges collapsed Continental shells were drained so all these marine organisms all of a sudden really had No place to go. I mean well, I mean the options were either they go in deep water Some crinoids were able to do that. Some organisms came on land for example snails and you see that this time period The first amphibians are starting to come out On the land but most organisms just could not adapt and just perished Since the 80s there have been a number of other Theories that have opposed as to why this was such a terrible time for mass extinction events We do know that there is a massive crater In Africa. So it was a collision event at that time That could have had some impact on life that existed back then We also know that there were major volcanic eruptions that were occurring in Siberia those eruption events could have produced Greenhouse gases carbon dioxide very much like today that may have had an effect on the atmosphere In fact, the Smithsonian a deep time exhibit makes a major point of saying that if it could happen 250 million years ago and wipe out and drain that many Drain the ocean of that many organisms that could certainly happen again today. Oh, yeah The earth is full point five six billion years old all right, then we go on to the Triassic event first age of dinosaurs and You have these weird organisms called conodots That are that were very common in the Triassic actually they were also common throughout the belly of Zoic as well but a lot of them die out and Three years valiantologists debated what the heck a conodot was and then finally we found the whole conodot animal it was over in Germany and It was this eel-like organism that existed with all these teeth But again You know the question is why would so many organisms perish? okay at the end of the Triassic and the And not many people know but we think it may be doing to do the volcanoes That released gases like carbon dioxide sulfur trioxide Combined with water that entered in the oceans. It might have made the ocean somewhat more acidic would have made more difficult certainly for Gaussian carbon a producing organisms to survive All right now we get to by far the most famous of the mass extinction events the terminal Cretaceous 66 million years ago about 76 percent of all the species On land in the air in the war of perish So of course this we tend to think that when we think of this Extinction event we think of things like triceratops. That's the last known dinosaur dying out There were a lot of Hadrosaurus or these duck-billed dinosaurs that also perished at the end of the event. We know in the oceans this was a time when Organisms like big or I necessarily clams pass away. There were many organisms and the Micro-organisms and the plankton that passed away You have things squid-like organisms called scaphides They pass away. This was an event that hit every trophic level every sort of ecologic group It spared very few organisms the only things that made it through the terminal Cretaceous Were bees small mammals some birds were able to make it through There are some some organisms in the oceans that survive The most and then there's of course the most likely impact since the 1980s has been an impact of an object space I'm sure you're all familiar with the paper that was published in the 1980s where some rare earth geochemists studied iridium and osmium at the you had the thank you Vic the Alvarez team Some reason that scientists came out of my brain The Alvarez team proved that there were high levels of iridium osmium right at the Cretaceous tertiary boundary and that those iridium osmium osmium levels Were a biochemical fingerprint of some sort of impact event What's interesting is The original model of the Alvarez team was you have this object that comes in and slams into the earth and produces a dust cloud and That would have blocked out the app the sunlight and would have killed off the the plants which would have killed off the The plant eating dinosaurs which in turn would have killed off the carnivores That was the original ecological model that Alvarez's team came up with However, what's interesting is in the 1990s they finally tracked down where the Where the impact event was and this was a very Very clever sort of detective story because for years people were looking for the crater and they just couldn't find it I mean there are plenty of them on the earth But we just we couldn't find the right size couldn't find the right age and then somebody said Why don't we measure the clay layer at the end of the Cretaceous where it's the thickest? That's probably closest to the impact event And they found out that the thickest clay layer was in the Caribbean So they intensified their search around there and they finally found it between the coast of the Honduras and Cuba I believe it was underwater and covered with sediment What's interesting is people start to look at the impact site and what they found recently And this is not even in the Smithsonian deposits only come on the latest publication Is that that object slammed into gypsum? I mean it was the worst possible impact site because it slams into gypsum and Gypsum as I'm waiting for Mike to talk to tell us about this is calcium sulfate so Calcium sulfate becomes vaporized by the impact event So you're producing large amounts of sulfur Into the atmosphere which mixes with water and you're raining down sulfuric acid So it must have been a very dangerous environment high temperatures They actually had a picture of the impact site or the terminal Cretaceous tertiary event in At the Smithsonian and you can see the thin clay layer and then right on top of it They've got a layer of charcoal. So just everything started to burn okay as Results of this event We also know that there were volcanoes that were erupting if you look at India at the Deccan traps Large amounts of sulfur gas have been produced as well from those Temperatures might have actually dropped during this time as a result of accumulation of dust and other materials around the planet and I see a bunch of comments that are coming in from Burgon Okay, again, if you says that you can see where major cities were at any one time on Earth's history All right. So again, if you have any questions, feel free to throw them into local chat All right. So those are the five to six You know depending upon how you want to count them mass extinction events that have been documented in the the fossil record last year last spring towards the end of the of the presentations on science circle Chantel gave me time to give a tour of the museum The geology museum that science circles very generously provided me The location on that I greatly appreciate and in the second floor I talked quite a bit about no-mathetic versus idiot graphic geology and paleontology and science and For those of you that couldn't make it Let me give a a brief summary of what I meant by those terms before we go on because I think it's really important Geology and paleontologists when they first got started a couple hundred years ago And I guess you could even trace it back to times of the Greeks. I mean they studied fossils as well to be sure We're really just trying to go out now Oh, here's a cool fossil and they would describe it and then they would draw a picture of it and they'd try and publish it and That really is a good starting point, you know, what else are you gonna do other than, you know, simple descriptions and over the years We've accumulated thousands of fossils now That are well-described and classified, which is good The latest work though since I would say about the 1970s and 80s There's been an attempt Especially by people like let's pick Steve Gould who I think was first to really coined the term no-mathetic geology And he said that it's not enough to just go out and find a cool-looking fossil and document it describe it and publish it What you need to do is think about what is the bigger implications? How does this fall into our bigger understanding of maybe its evolution or plate tectonics? Okay, or geologic processes In time and thanks Mike for throwing up some more information about the calcium hydroxide spray And I think Steve Gould was absolutely correct in that term and I've I got admit It's it's a transition that I had to make I first started with fossil collecting in 1972 And that's all I did was put together a collection describe and classify it and then after going through Chicago I realized know the better thing to do is try and look at you know What some of the you know, how does it fit in this sort of bigger picture, right? So one of the places I love to go in Roanoke is or in Virginia is Catawba Mountain For those of you not familiar with Virginia Catawba Mountain is just a few miles west of Roanoke, Virginia Here's a picture of the area. It's really a pretty scenic site And I was telling Chantel this summer that I was going to be doing a number of field trips And he goes oh, please put some scenery pictures in it So this is Chantel. Here you go. This is one of the best shots that I've got of Catawba Mountain It is nothing to do with geology. Okay, but it is it is a pretty area to work in and Usually you go into the mountains. It's it's nice and cool except when it rains or the fog comes in and It also is important in terms of our history There were at least one important Civil War bowels that were fought near Catawba Mountain In fact, one of the areas that I wanted to move to Virginia was to learn more about the Civil War I've also been to Tennessee and Learned that often it was the geology that made or break the The outcome of that event I'm not sure exactly what the details of that bow, but I do know that there were some that were worth it All right, so here's a quick overview of the geology of Catawba Mountain So on the south side of the mountain as you get off Route 81 for those of you for the area That's the main interstate through Virginia You run into these rocks. These are carboniferous rocks that formed I would say somewhere in between about 280 to 250 million years ago They represent some of the youngest sediments that are located in the Appalachian Valley They consist of mostly silt stones and sandstones As you go further up into the carboniferous, you can get coals you can get inglomerates This represents the very end of the time of of the marine deposition in Virginia And one of the things that you may notice is you follow the layers that they sort of curve These are these are strongly folded and the reason for that is that this was the site where Africa and North America slammed together forming Panjia So we can we can see it here in terms of the geology. So by the way, there are no fossils in this. These are all It's pretty very shallow sediments non-marine All right, and here is a picture you may need to zoom in on this site Sorry birds being so small, but this is one of the major cliffs again on the south side of Katowah mountain and What's nice here is you could see carboniferous age rocks at the top and then there's some late Devonian rocks that are at the bottom and I put a Red line right between the carboniferous and the Devonian Lake Devonian This is the site of a major mass extinction for years I've collected from the rocks here and there's a very sharp contrast between the Shallow marine sediments at the bottom you get back you get lots of brachypods you get Clams lots of clams in the sequence. In fact, I guess it was about 30 years ago I was collecting fossils with some of my students came across a very rare conularic fossil Which I immediately recognized from Cornell the days I was at Cornell Conularids are these weird jellyfish that had a thin chitinophosphatic shell to them Just enough for some of them to be preserved. They're very rare in the fossil record As far as I know, that's the only one that's ever been found in the state of Virginia It was in my personal collection for many years and then I realized that That it really needs more prominent place. So I donated it to Virginia Tech's Geology program so they could do research on it But the point I'm trying to make here is the sharp contrast in organisms from very Fossiliferous layers in the late Devonian to almost nothing here in the carboniferous so something happened now we do have some fossils in the In the in the carboniferous There are some brachypods. There's something called spherifer That is present but you have to go to other areas to find these things All right So here's what we get to sort of the meat of the of the lecture that the mass extinction event that I've spent the most time studying is the late Ordovician to Solorian one about 444 million years ago Tom a mountain has one of the best exposures where you can go right through the Ordovician into the Into the Solorian And it's marked by a very sharp contrast by rock types The ones on the left are late Ordovician They are dirty sandstones very shallow water sediments and then the ones on the right are these nice clean Solorian sandstones and thick and glomerate beds At the bottom so there's a dramatic change in terms of the geology that we see along Kitabu mountain So here's a little close up a better image of some of these sandstones and conglomerates that are there Very shallow water possibly non marine sediments that we see all right as we move down the the outcrop There the rocks go from these Conglomerates by the way are these sort of pebbly sandy units in the Solorian Below that is the late Ordovician the dirty sandstones then as you go below that you get into sandstone shales of limestones and Further down the sequence you get nice clean limestones in fact, I didn't show it here, but This well this site is is obviously well visited by geologists We have the evidence for that number of beer bottles and containers along the outcrop that people left behind unfortunately But what I was saying is beyond the Martinsburg formation if you keep going down. Yeah. Yeah, what can I say? As you go further down below the Martinsburg formation a late Ordovician You get into these Sort of purple green silt stones and shales which have been interpreted as continental slope deposits below that is the the I think believe it's late or to be yeah late Ordovician Shales so you go from basically These deep basinal deposits very deep tectonic probably produced by a tectonic hinge And then it becomes progressively shallower as you go along All right, this table summarizes some of the work that I've done this summer One of the things that we're able to do is using some very careful measurements of the thickness of these layers We can come up with and do sedimentary rate calculations so we can tie that into the data from the absolute geologic time scale and I'm able to refine some of these zones so we recognize now that there's at least I Think there's at least three bars driver zones that are present on the top of mountain And I've listed them there. There's the glyptoclycella zone, which is mostly a lingulate There's wrapping a screen at which you've seen before and then there's Diplograftus, which is a graft to light. I also showed you a picture of that earlier on I'm going to show it to you again case you forgot I'm showing the thickness of those in meters Notice also the rock. This is important the the geology how that changes going up So at the very bottom, we have these nice clean deep water limestones Then as we go up they get somewhat shallower sandstones and shales and then at the very top of The the Martinsburg you get these dirty sandstone such that are very shallow water And then you go into the Solorian which are nice clean sandstones and plumbers beach sandstones if you will In the last column I've given the age and millions of years So between the sedimentary rate calculations and the radiometric dating We're getting this down to probably a couple of million years, which is pretty cool when you think about it We're going back almost a half a billion years that we can get resolution of deep time on the order of a couple of million years That's not bad. All right for these zones All right, so for those of you that don't remember Here's what here's what the major changes that are going on in the late Ordovish that I see on Katala map and Like I said, there's a there's lots of data One of the things that's nice is the Springer PhD dissertation that was done This guy that did his PhD work in Virginia Tech Is now available online and a lot of the information he collected isn't one but appendix at the back that Just basically needs to be put into a computer somewhere but I'm going to summarize what Springer is said here and also what Elisha Stigl has said and Basically what we see at the late bottom of the late Ordovish is you have all these graphite lights These are things. Oh, if you're not familiar, they look like pencil markings on the rock But they were actually sort of either a planktonic organism sort of like a jellyfish Or they were bentonic and they lived on the bottom So you have these all on the bedding plates you see lots of these graphite lights then as you go up the planktonic Graphite lights and even some of the free swimming squid like organisms. They tend to die out And it's not clear in my mind why that would happen. I mean Certainly these things were able to travel over great distances I've talked to other experts the feeling is that there was some kind of change in the chemistry of the oceans That was going on that may have had the pectonum So in the middle of the lake Davoni the Ordovish and you see these very flat Strophomia brachypods in the middle left-hand side of the slide They're all over the bedding plates. All right, they were extremely abundant. I mean it was a simple way of life You know, you just lived on the bottom of the sea floor and then you open up your shells and you take in water you take in oxygen and You got everything you need to survive. Okay, except for one little problem All right, and that one little problem are clams Okay, towards the middle of the Ordovish during the middle of this it's called cation period Clams start coming in force and I've shown you one in the Sort of lower both the middle right-hand side there That's muddy alopus and it's a pretty good size clam. It's about I would say six to seven centimeters across and these things were informal when they come in These are the invasive species of the Ordovish right and You know, we tend to think I'm going to use some environmental terms here We tend to think of invasive species as carnivores, maybe things like a Lionfish or if that's the right term things that come in they just start attacking the native species Who have no resistance and they just die but back in the middle of the beach and there were carnivores I'm going to talk about them in a minute But I think the bigger problem was these clams they start coming in they just start churning up the Turning up the sediment on the bottom of the sea floor making extremely unstable for things like the like the stropho means specifically raffinus quina that we see right next to it and if you're used to laying on the bottom of the sea floor and Opening up your shell and taking in Oxygen and food That's okay, but once you get in the sediment even a centimeter or two buried now you open up your shell instead of getting food and oxygen you get mud and The loaf of four the main organ is organ and these things that she used to Separate out the food and the oxygen from other stuff just gets clogged and they're dead And so what we see as you go up the stratigraphic reference Stratigraphic record is dramatic change in the fauna at the very top of the Lawrence bird at the very end of the late Ordovish on Catawba Mount Okay, what you have here is These lingula lingula looking brachypods Which they're originally called lingula. I've decided to call them flip the cell of Hellentologists these days are just saying 450 million years is too long for a genius to survive So they're starting to break it down and put different names on them But lifted to sell a right. Thank you tagline lingula Translated out of the lat basically means tongue these are things that sort of have if you look at your pinky Look at the fingernail on your pinky. They sort of have an oval shape like that And that's perfect design for if you want to if you want to dig into the sediment And that's what was essential at the end of the Ordovish for survival Is that you could burrow into the sediment that you didn't have to live on top of the sediment and think of the Advantage is that that that gives you basically what it means is that you can hide from predators It doesn't matter where the sediments being churned around or not because you don't care In many cases these lingulets had a muscle that allowed them to dig into the sediment anchor themselves in so even if you're You know you have waves and currents coming along and digging you out You can still anchor yourself somewhat because one of the big problems in near shore areas is you don't want your shell Picked up bashed against a rock and all your soft marts hanging out for whatever Unfriendly greater happened to be in the environment and And there certainly were some nasty predators around We certainly know that there were Cephalopods squids armored Cephalopods back then that were probably ravenous feeders We know probably there was some snails back then you had your rip grids These sort of sea scorpions that were going around that were hungry. So Definitely had to worry about that predation coming in all right So one of the problems that I ran into is unfortunately there is an Unconformity there is a gap in the geologic record I could top them out Between the very end of the Martsburg and the very beginning of the Solerian and it's a we estimated It's about a six million year gap. It's right at the crucial time Where the late or division is terminating and the Solerian is starting And what do you do? I mean when you run into something? Well, you'll look for more rocks So I got my car and I drove the haters gap which is in the southwest part of virginia and decided to spend a day on haters gap and There's a nice more complete sequence of rocks Right from the top of the martinsburg right to the bottom of the Solerian And I was able to collect from there and what I found was this Um non marine sediments Okay, no fossils in them other than maybe a worm tube or something like that But clearly I would say by about 100 and Let's say 450 million years ago A lot of the oceans in virginia were just cleaned out marine organisms Maybe they were there in other places. Certainly they survived to give rise to to the marine organisms in this Solerian But in virginia, they were mostly gone. Okay, the water was very shallow And finally I have a question good Bergen asked does non marine mean the layer was lifted above water for a spell? um, I would think so these are either um Very shallow water deposits. I would even I wouldn't even say shallow water I would say above above the water level as well to to get these because there's a lot of iron in these Which means that you had to be below the atmosphere to have the oxygen mixing in with the form of the hematite If it's shallow Water, you're going to get things like uh ripple marks and so on what you see in the Solerian So I essentially think that this was was pretty much above water or maybe in intertidal zone All right, so here's my uh conclusions About what was probably the result of the late portavision extinction based upon what I see here in virginia Um, there's a clear classic Regressive sequence in the geology. So there was definitely a drop in sea level There was an influx of plastic sediments towards the towards the end There's clear evidence in of glaciation in Africa And colleagues that have worked in europe and have gone to africa Have documented these tillite deposits or glacial deposits in africa What that meant is that as the glaciers started to form in africa You would have had a a eustatic a global wide drop in sea level Which would have drained any of these connell shells producing the regressive sequence that we see in virginia There was an introduction of informal clams Into virginia and in other parts of basins that would have Fired to be the sediment created instability of the sea floor Killing off epiphenyl organisms that we used to living right on the bottom of the sea floor We know that there were carnivorous organisms such as squids sea scorpions Some fish were coming around back then so it would have been difficult to uh To survive and there's one more thing that we that's very clear that I haven't talked about yet um on Tava mountain vet night deposits All through from the water vision right into the celeriac and they get even thicker in the celeriac. We know that There was north america. We call that actually lorencia And there was a connell shelf around lorencia Then off the coast of north america. There was a volcanic island arc In fact, probably the best way to try and visualize this is think of japan off the coast of asia That's what north america would have looked like about 450 million years ago And the volcanoes in that volcanic island arc were very active shooting off ash layers pyroclastic flows going into the oceans I mean the late automation was just not a good time to live okay for a marine organism Uh, it was very difficult during that time period And that's the end of my presentation. I've left about 15 to 18 more minutes for those of you that have questions Be happy to answer them Uh, yes, that's true, uh, africa was connected to south america and antarctic and india and uh the uh in the in the uh, Automation and you're right. It would have been close to the south pole. So it would have been easier for, um For glaciers to form Adriene, good to see you again. I hope you had a good summer And erica. I'm glad you were able to attend as well Yeah, I'm going to check that out thick Yeah, one of my uh, one of the graduate students, uh, chrisco teased was in chicago when I was going through graduate school and He had a map showing Current latitude latitudes on his paleo geographic reconstructions All right, so we have a question. Are there any theories on the cause of the six billion year gap between those areas just quirks of the gilet? Yeah um absolutely, uh goat the devil, um It's like anything, you know, there's some areas that are underwater Um, or that preserve the rock record and then there is some where you have lots of And and so when you have an uncomformity like this, there's always the question in your mind Is it due to non-deposition of sediment? Okay, where you just don't have enough sediment coming in to preserve the father that serve the geologic record Or the other option is that the sediment was deposited and that was eroded and we just don't know Um, let's see and we have that's what's amazing. These are mountains. They used to be sea vets. Oh, yeah um, you know in virginia uh, typically those cemetery rock layers are a couple of thousand Thousand feet above sea level If you talk about the Himalayas, which are five miles above sea level, uh, that was underwater as well. So Yeah, I mean, I'm in a war at how powerful plate tectonics is and the other thing that we've learned is It doesn't take a long time geologically speaking a couple of million years to make a mountain range and chain and raise Uh, sea floor sediments to the top of mountains Nature season euclidean space I'm not sure what tagline is getting at there I wonder how many uh, how much is slowing or shut down of ocean currents played in previous extinctions Did you have any findings on that? um Adrienne there have been a lot of attempts to reconstruct ocean currents in the past and I think I think you're absolutely right. If Elisha Steigl was here She would absolutely say that ocean currents were extremely important certainly introducing um invasive species like Maudiolopus into different basins would be important because if you think about it adult clams Are Cecil they they just settle down from the war column and they're there They don't move around the only way that the currents can drift an invasive species like clam is as the larval state So that would certainly be important um And I can also think of certainly other ways ocean currents would impact for example Controlling the temperature distributions within the oceans distribution of nutrients I think you're absolutely right that understanding ocean currents and there are a number of reconstructions of them in the past Would be important Uh, let's see given Yeah, um Mike says you know how much we know of the geologic record. It's not surprising that there are gaps There's lots of gaps if you look at the Grand Canyon There's a class example where you see lots of these unconformities Almost all the Ordovician salurian is cut out of the Grand Canyon because that just was no deposition that was going on there and Really the way geologists work is it's like it's literally like a big jigsaw puzzle You go around to different places and you try and figure out which pieces of the puzzle you're looking at And you try and tie them together to make a a one large Geologic column or timescale from all these little pieces Let's see big saying really isn't the tectonic plates and mountains We'll see a little and that all has been really accepted in my lifetime. That's the other thing Yeah, uh within my lifetime there's been a dramatic shift from oh the continents don't move That was when I was born the 1950s too. Well, of course the continents move they're part of these larger plates that have been sliding around All right, bergon asked glaciers scrape away a few million years of layers. Certainly. That's true Um, don't have any evidence The the only evidence for glaciers in virginia. You got to go back a billion years Certainly not the Ordovician. Um Because we we were just at the wrong location Uh, you've got to go back a billion years to snowball earth time when the planet froze over and that hasn't happened since then So certainly glaciers and higher latitudes or higher elevations could scrape away a lot of the rock record there extremely powerful bulldozers Uh, in my mind one of the I'm more worried about the role that humans are playing uh, and I've been working in a quarry with uh, susan libel from the uh From the smithsonian and one of the things i'm worried about is how humans are destroying our our rock record. Um, my My way of looking at geology is strange. It used to be when I first started Oh, let's go out have students collect fossils and it's fun and so on And now what I'm worried about is that a lot of the classic Um localities geological locations In the united states are just being destroyed through either the department of transportation going in And removing these these slopes because they're afraid the rocks are going to come down Or commercial collectors going in and scraping every last brachiopato off the rock You know take your pick or weathering an erosion And so now my priority is to go around and try and document I would say a kataba mountain is is probably the last Of the good exposures of the uh, the Paleozoic and virginia What used to be present I would say, you know in the 70s and 80s like painter's gap They're gone. I mean when I went there. I couldn't find any fossils at all at one time. They were very fossil efforts So what I'm trying to do for the virginia museum of natural history is go through collect key beds I look at what we don't have collections of go out into the into the field collect them document them Identify them and put them in museums so that future generations will still be able to slowly this stuff And tagline says we need to let mining and petroleum companies develop national parks vacant federal lands in the u.s. Of course That's important personal. I I detect a sense of skepticism from tagline here Music effort Former transportation locals. Yeah, one of the things I'd really like to see how have happened Is the department of transportation's work more with geologists? And I think there's some interest there. I was up at uh in pennsylvania and talked to Some of the the people up there and I think there is interest because there are some spots that are really rich in fossils And the problem is that a lot of governments are just saying we don't want you working along the side of Of some of these interstates because it's just downright dangerous. The traffic is going by at 55 60 miles an hour It's not like in the 40s and 50s when cars, you know, you pull up you pull your Model t4 to the side of the road and People slowly and carefully went around you when you're doing field geology Now there is a there is a Danger of you getting hit and that's it. You're dead. Okay. If it's on some of these interstates And that's sort of in the back of my mind is is always a problem or always a danger Uh, do you have any more questions about the presentation? And I presume the video is going to be posted on online, right? Uh, jess or shantel Yeah, um, adrian, you are absolutely right. I never used to wear a flak vest anymore But more and more they're saying you have to these day and ages And like in the quarry that is a great idea shantel. That's something that I wanted to do is sort of global geology Um, if people would go into their backyard or you know, if you pass by an interesting rock outcrop And you can safely take a picture and tell me where it is. I think that would be real interesting to discuss that So what major and what After all right, so vicks asking so what replaced, you know in the order of issue we have um Mostly they're dominated by this brachypod raffinus quina. We have Diplografted which are Uh, graft delights that have two openings on both sides Um in the salorian what we see is new brachypods coming on the scene There are these things called pentamerates which have a very different shape And guess what they're designed for living in the sediment. No surprise. Okay based on what I've said Um, you also get what a different type of graft delight coming back called the monografted Um, you get lots of eruptures or sea scorpions. They seem to be doing quite well, but they're they're swimmers Um, you basically get a change in the in the in the biota biota in the oceans Oh, the juror mount is right. Cass. I remember we've talked about that Uh, lovely. Cass. I'd love to see more pictures from you about that And I've even talked to her about doing a joint presentation On the juror mounts, which are very famous geologically speaking Yeah, I figured tagline is going to say that um Well Yeah, one of the things I forgot to put in here is my email address. So let's do that There you go. Feel free to email me And maybe we need to put together some kind of pending. I don't know how we do it But I think that would be a lot of fun Would be to look at pictures from different plants and tie part of the plant and show it sort of tie that into the geology And before we all run off because I know we're getting close to we try and keep these to an hour what I I want to make a quick Verb I'm giving another lecture not On the science circle, but september 23rd I'm part of visti the virginia society of technology and education I'm going to be talking about virtual reality and education. So And I know time zones are a problem. Uh, that presentation is going to be at 5 p.m SLT time. So I know People in australia and asia and europe that's going to be a problem for jess, but um, if you If you are able to come that would be great on the visti sim And uh, I know vik already said he has an interest in that So if you're interested in virtual reality and how it could be used in schools, please come that is september 23rd by pmsl t 8 p.m. Eastern time at 7 central for vik I'll be on the visti sim And feel free to uh to say if you're interested coming to that you happen to give you the lm It's on the mainland visti Just moved from their own island To a smaller sim mainly to save some money, but we're trying to get more people showing up for those And I thank you all for coming Yes tagline. It's uh 5 p.m. Pacific daily time or second life time And again, if you need a uh, if you need a landmark, let me know. I'll be happy to drop you one Or when you know, just come on that time, you know, I'll TP you to it Yeah, that the september 23rd presentation is um, not here at science circle. It's going to be at the visti sim Again, if you're interested, let me know. I'll I'll drop you the location Okay, I sent one to an lm to tagline is anybody else that want it wants it for september 23rd. All right, well Um, hope all of you have a good day or a good night depending where you are And again, thanks for coming