WEBVTT 1 00:00:07.200 --> 00:00:18.780 Virginia Butler: Okay um, it is time to get started, I want to welcome you to tonight's presentation, my name is Virginia Butler i'm a professor in the department of anthropology at portland state. 2 00:00:19.440 --> 00:00:29.550 Virginia Butler: Before we get started with our formal presentation, I want to have a few introductory things and and one is is that I want us to take a moment of silence to. 3 00:00:29.940 --> 00:00:41.970 Virginia Butler: acknowledge the horrific tragedy that has unfolded in Texas with yet another school massacre and I just feel like we have to. 4 00:00:42.540 --> 00:00:56.550 Virginia Butler: close our eyes and send some thoughts to the families of the of the children and adults that have have been lost today through some horrible business so let's just take a moment to reflect on that. 5 00:01:48.810 --> 00:01:49.890 Virginia Butler: Okay, so. 6 00:01:50.910 --> 00:01:51.570 Virginia Butler: again. 7 00:01:56.040 --> 00:02:09.600 Virginia Butler: we'll move to tonight's proceedings, and I welcome you, one of the things that the archaeology roadshow has has developed and it's a work in progress is a land acknowledgement that. 8 00:02:10.740 --> 00:02:28.020 Virginia Butler: That we're again we're working through, but we think it's important to share some of these words that are also hard, but I think they point to future directions in the ways that archaeologists and can work with tribes, so let me share our statement. 9 00:02:29.340 --> 00:02:34.650 Virginia Butler: We know in this digital space, you are coming to us from many places, but our host institution. 10 00:02:35.040 --> 00:02:47.340 Virginia Butler: portland State University is located in the place we now call portland and the traditional homelands of many indigenous nations who made and make their homes along the Columbia and laminate rivers. 11 00:02:47.670 --> 00:02:54.540 Virginia Butler: This land was stolen through genocide and the destruction of culture, language in life ways by Earl American settlers. 12 00:02:55.950 --> 00:03:04.380 Virginia Butler: We acknowledge this terrible history but recognize the resilience of past and present digits communities and their deep connections to the land. 13 00:03:05.070 --> 00:03:11.400 Virginia Butler: Many of the presentations and this year's roadshow lecture series are a testament to the strength and resilience. 14 00:03:12.180 --> 00:03:19.110 Virginia Butler: We challenge ourselves to support indigenous communities by taking action in our work and in our personal lives. 15 00:03:19.680 --> 00:03:28.350 Virginia Butler: Actually, can take a variety of forms, such as challenging stereotypes of indigenous peoples demanding and providing accurate history education. 16 00:03:28.890 --> 00:03:40.050 Virginia Butler: Educating ourselves about tribal issues are pressuring government officials to support programs that provide some measure of redress for previous systematic harmful policies. 17 00:03:41.430 --> 00:03:53.670 Virginia Butler: we're popping a website in the chat that you can go to if you want to learn more about the indigenous communities in your area where you live, and this is a great resource. 18 00:03:53.910 --> 00:04:07.440 Virginia Butler: If you're just learning about it now fantastic and share it with other people that you want to communicate your own how you feel about this and how much you think this is a story that we need to keep sharing and pushing out there. 19 00:04:08.970 --> 00:04:13.410 Virginia Butler: So tonight's presentation was part of a month long celebration. 20 00:04:14.910 --> 00:04:27.510 Virginia Butler: Of archaeology heritage and indigenous knowledge on the theme, the archaeology of water over the month of May we've been having formal zoom sessions or zoom presentations like the one tonight. 21 00:04:28.080 --> 00:04:38.700 Virginia Butler: And so we're glad you're here to be part of the celebration, even though it's digital we come together we are humans, we are interacting and we revel in that. 22 00:04:39.900 --> 00:04:49.560 Virginia Butler: Besides these presentations we have dozens of exhibits that include blogs videos story maps and other kinds of of. 23 00:04:50.010 --> 00:05:02.310 Virginia Butler: Virtual activities on the webpage archaeology roadshow.org check out the exhibits there that have been created by all kinds of organizations agencies tribes. 24 00:05:02.760 --> 00:05:20.640 Virginia Butler: Individuals students nonprofit organizations again that that support this celebration, and our desire to share with the public, some of the things that give us joy and we want others to be in on that and and and not to hold it for ourselves. 25 00:05:22.290 --> 00:05:28.830 Virginia Butler: What I want to do, and I also want to make a call out to the financial donors that are. 26 00:05:29.850 --> 00:05:41.010 Virginia Butler: indicated on this this the slide we could not do this event, without the financial support of these agencies these companies, these individuals so. 27 00:05:41.790 --> 00:05:54.030 Virginia Butler: gaze upon those names and logos and let's give them applause, we would be, we would be clapping if we were in a public space where we could all be together. 28 00:05:55.200 --> 00:06:00.450 Virginia Butler: So I want to share the next slide let's see if I can do that okay. 29 00:06:02.340 --> 00:06:04.560 Virginia Butler: I know all this time and i'm still struggling. 30 00:06:07.170 --> 00:06:20.910 Virginia Butler: I wanted to suggest to after I introduce our speaker, he will present for about 40 minutes and then we'll have time for questions and answers I request or we request that you remain muted throughout. 31 00:06:21.720 --> 00:06:28.080 Virginia Butler: You can be typing thoughts and questions into the chat feel free to do that, but we'll hold the questions to the end. 32 00:06:28.350 --> 00:06:38.850 Virginia Butler: And we'll have you can raise your hand physically, you can use the reaction button to raise your hand all kinds of ways to get your questions out there, but I really want you to have some questions because. 33 00:06:39.630 --> 00:06:54.300 Virginia Butler: Speakers love questions they feel they haven't penetrated anything they don't get themselves feel compelled to to ask those questions so i'm going to start sharing so that I can pull it over. 34 00:06:56.520 --> 00:07:04.230 Virginia Butler: To Adam because I want to introduce our next speaker so Adam if you'd be transitioning to this share. 35 00:07:05.760 --> 00:07:17.670 Virginia Butler: So tonight's speaker is Adam Hudson, who was a geochemist at the US geological survey and Denver Colorado where he currently leads the Denver radiogenic isotope laboratory. 36 00:07:18.150 --> 00:07:25.440 Virginia Butler: He received his PhD from the University of Arizona and geosciences with a minor in anthropology archaeology. 37 00:07:26.070 --> 00:07:33.360 Virginia Butler: His research specializes in lakes wetlands and soils, with a focus on carbon materials that form in the settings. 38 00:07:33.690 --> 00:07:41.730 Virginia Butler: He is particularly interested in what the chemical composition of carbonates say about the environmental history of these types of environments. 39 00:07:42.090 --> 00:07:53.250 Virginia Butler: His main research goal is to understand what affects water availability and Eric regions he's done work in in Tibet, the Andes and the Western United States. 40 00:07:53.580 --> 00:08:09.300 Virginia Butler: His current research is focused in the US and the US and the great basin Alaska and the southern rocky mountains so i'm so delighted to introduce Adam Hudson we've been having this celebration of. 41 00:08:10.500 --> 00:08:24.510 Virginia Butler: humans and water and Adams work, looking at the geoscience side of this is critical to our really putting people in there, in the context and so i'm so excited that Adam is going to presenting be presenting. 42 00:08:24.750 --> 00:08:34.710 Virginia Butler: there's something fishy in the great basin a 15,000 year long environmental record from the Paisley case so take it away am. 43 00:08:36.240 --> 00:08:39.150 Adam Hudson: Thank you Virginia, I hope that everybody can hear me. 44 00:08:39.480 --> 00:08:40.710 Virginia Butler: And i'm. 45 00:08:41.070 --> 00:08:51.810 Adam Hudson: Really excited to be here tonight I can't Thank you enough Virginia for inviting me to be here and I can't Thank you enough for teaching me so much about fish and are, along with all my other. 46 00:08:52.860 --> 00:09:01.590 Adam Hudson: So archaeological and archaeological and paleontological colleagues that are listed down here that were co authors on the study that i'm talking about tonight. 47 00:09:02.220 --> 00:09:13.890 Adam Hudson: That I you know I wouldn't have been able to pull off a piece of the case study that i'm going to talk about tonight, if it weren't for all of you, so thank you so much for giving me the opportunity to enter into the Paisley caves well. 48 00:09:15.210 --> 00:09:16.530 Adam Hudson: And with that. 49 00:09:17.670 --> 00:09:18.690 Adam Hudson: Virginia already. 50 00:09:20.070 --> 00:09:29.310 Adam Hudson: gave away the title, but this kind of tongue in cheek title there's something fishy in the great basin alludes to the fact that the talk that i'm going to give tonight is a. 51 00:09:30.390 --> 00:09:41.490 Adam Hudson: see if I can get my slides to advance there we go okay sorry sorry for the delay is really about a fish out of water in quite a literal sense and it's this fish here. 52 00:09:42.000 --> 00:09:50.490 Adam Hudson: And a fish that's out of water or its remains really that somehow ended up in the sentiments of the Paisley caves. 53 00:09:51.210 --> 00:10:00.090 Adam Hudson: And, in particular, this talk is going to be about what the remains the bones of this fish their chemical compositions specifically can tell us. 54 00:10:00.420 --> 00:10:12.060 Adam Hudson: about the greatest natural climate change that has happened in the recent geologic past and probably within the human history of occupation of North America and that's the transition from the. 55 00:10:12.720 --> 00:10:23.970 Adam Hudson: peak of the last ice age, all the way up to the present and, at the peak of the last Ice Age North America looked quite a bit different than it does today, with the main different feature being that. 56 00:10:24.390 --> 00:10:28.860 Adam Hudson: Canada was completely covered by a giant ice sheet called the laurentide ice sheet. 57 00:10:29.310 --> 00:10:38.220 Adam Hudson: That was, you know 3000 meters thick connected to the fennel scandium in Greenland ice sheets here by continuous ice in the northern hemisphere. 58 00:10:39.060 --> 00:10:45.360 Adam Hudson: And if we zoom into the area that we're going to be focusing on today here's the state of Oregon roughly in this cartoon image. 59 00:10:45.750 --> 00:10:53.730 Adam Hudson: Things weren't under ice and ice sheet per se but man mountain ranges like the cascades and Sierra Nevada and the rocky mountains all had. 60 00:10:54.060 --> 00:11:03.270 Adam Hudson: Extensive mountain glaciers that extended much down Valley, from where they are, today, in fact, in most of that area, no glaciers exist anymore at all. 61 00:11:03.900 --> 00:11:14.460 Adam Hudson: And, even in the arid intermountain basins of the great base in here, where there are very arid conditions and only applies left behind, today, there were. 62 00:11:14.880 --> 00:11:24.060 Adam Hudson: A great lakes, called the Pluto lakes that occupied nearly every one of these valleys and they're shown kind of cartoonishly the two biggest legs lake Lon. 63 00:11:25.320 --> 00:11:28.860 Adam Hudson: Excuse me wake lahontan and like bonneville here in this. 64 00:11:30.150 --> 00:11:30.960 Adam Hudson: In this image. 65 00:11:32.820 --> 00:11:46.020 Adam Hudson: So with that i'll return to my title slide and i'll tell you a little bit about myself, I am not an archaeologist I have a little bit of archaeological training on call myself archaeologically adjacent best. 66 00:11:47.160 --> 00:11:49.950 Adam Hudson: i'm a researcher geologists at the US geological survey. 67 00:11:50.520 --> 00:12:04.380 Adam Hudson: And I do have a long standing interest in trying to understand the Paleo environment of the great basin of the western us through the lens of looking at study of these Pluto lakes, that I have talked about in the last slide. 68 00:12:05.340 --> 00:12:10.680 Adam Hudson: And in fact the picture that i'm showing here that's part of my title slide shows. 69 00:12:11.310 --> 00:12:21.900 Adam Hudson: landscape photo of one of the remnants left behind one of these Pluto lakes that existed in the drainage basin that contains the Paisley caves and that lake. 70 00:12:22.350 --> 00:12:29.400 Adam Hudson: flat and pancake he, as it is in the front of this image off of this Ridge looking South where it is called, like a bird. 71 00:12:29.910 --> 00:12:38.520 Adam Hudson: And like a word today is a pretty uh sorry excuse for approval lake it's about 20 feet deep at its deepest on a good year. 72 00:12:38.940 --> 00:12:49.620 Adam Hudson: And it's extremely salty it's a you know about a salty as the ocean, if not even saltier than the ocean, depending upon how much water has evaporated further on a given year. 73 00:12:50.280 --> 00:12:59.850 Adam Hudson: And, as a consequence of that there's a giant salt flat Playa that surrounds it and the water that's in it today is not fit for human or livestock consumption. 74 00:13:00.360 --> 00:13:10.860 Adam Hudson: No fish live in it for the most part and pretty much the only thing that can survive in there today is brine shrimp and algae and things specially adapted to the extremely. 75 00:13:12.030 --> 00:13:21.030 Adam Hudson: sailing conditions to characterize this lake and it's a partner summer lake, which is in the adjoining base and that actually contains the Paisley caves. 76 00:13:22.230 --> 00:13:35.670 Adam Hudson: And just to give you a little more context on where we are, if we look along the base of this hill slope here this up throne basin and range fault block of up throwing basalt called the event room, which is one of my. 77 00:13:36.150 --> 00:13:44.970 Adam Hudson: favorite features of this field area if i'm being honest us highway 395 runs along the base of this Hill and hugs the edge of the lake. 78 00:13:45.300 --> 00:13:52.590 Adam Hudson: And exits out to the Center of the photo over the drainage divide through lakeview Oregon and pretty quickly on passed the California boerner. 79 00:13:53.310 --> 00:14:00.150 Adam Hudson: And if we look over off of this direction, towards the headwaters of the watershed of a bird lake. 80 00:14:00.660 --> 00:14:09.150 Adam Hudson: Of the yukon river and over these hills and down on the other side into the basement of summer like that's where the Paisley caves lie and so there's a. 81 00:14:09.750 --> 00:14:19.200 Adam Hudson: Pretty close location or geographic relationship, I guess, between this Pluto lake that used to exist in this space and and the Paisley caves. 82 00:14:19.920 --> 00:14:27.180 Adam Hudson: And, in fact, although this is a salt lake today there is some evidence that we can see on the landscape that this was not always the case. 83 00:14:27.450 --> 00:14:37.140 Adam Hudson: And, in particular in this image in front of me if you look at this rounded hill slope that kind of comes down in front of this rocky promontory there are some feet horizontal lines. 84 00:14:37.650 --> 00:14:56.880 Adam Hudson: That can be seen on the edge of this hillside that are actually old shorelines of the Pluto lake that are a testament to the fact that, at some time in the past conditions were a lot wetter in this drainage basin, so that there could be a very deep Long live lake within it. 85 00:14:58.710 --> 00:15:07.710 Adam Hudson: And since my I was working on the end of my PhD dissertation i've been interested in lakes in the great basin and this lake in particular and so. 86 00:15:08.010 --> 00:15:25.860 Adam Hudson: That you might not find me in an archaeological excavation, but you will find me in an excavation into one of these shorelines and here's me in a soil pit in one of the shorelines north of like a bird pretty much behind the photo that I just showed looking for. 87 00:15:27.060 --> 00:15:41.790 Adam Hudson: materials made of the mineral calcium carbonate and the shorelines that we can use for radio carbon dating take them back to the lab subsample them and measured their chemical and isotopic composition on a mass spectrometer like this one. 88 00:15:42.810 --> 00:16:01.710 Adam Hudson: And i've been working on this for close to a decade now trying to develop a record of the ups and downs of this lake throughout the last 20,000 years or so, since the peak of the last glacial period, based on the shoreline deposits of like chicken. 89 00:16:03.660 --> 00:16:14.040 Adam Hudson: And the reason why i've been so interested in this is because, as a Virginia advertised at the beginning i'm very interested in how climate change affects water availability in Arab lands. 90 00:16:14.490 --> 00:16:36.600 Adam Hudson: and lakes like this are extremely sensitive to changes in the watersheds in that they are drained from so that they are internally drained, which means that they have no outlet to the ocean, which is part of the big reason why they are salty and what this means this internally drained. 91 00:16:38.490 --> 00:16:50.700 Adam Hudson: aspect of them is that they receive water as runoff comes in, mostly a snow and the headwaters but then runs into the lakes and the only way that you can escape by the process of evaporation and. 92 00:16:51.540 --> 00:17:02.490 Adam Hudson: Today, this is a very arid environment, even though it's located in in Oregon and so that almost a meter of water evaporates bottom of the lake surface of any one of these lakes in a given here. 93 00:17:03.120 --> 00:17:10.920 Adam Hudson: And they're sensitive enough that if you remove a couple of meters in a couple of drought years like is what happened between when I took this photo. 94 00:17:11.280 --> 00:17:21.720 Adam Hudson: In May of 2013 when I took this photo and September of 2015 that a couple of drought years can make a big difference from a beautiful blue lake. 95 00:17:22.200 --> 00:17:28.740 Adam Hudson: To a lake it's dried all the way down to the Playa in the course of just a couple of years, and this was the first time. 96 00:17:29.400 --> 00:17:37.830 Adam Hudson: That, I think that this happened since the dust bowl drought of the 1930s there's a pretty good historical record of the variations of like a bird. 97 00:17:38.400 --> 00:17:47.640 Adam Hudson: And so, this really illustrates that if you can have a handle on what the age of shorelines were in the past and track the ups and downs of the lake like this, you have a pretty good idea. 98 00:17:48.030 --> 00:17:51.300 Adam Hudson: Of what periods of the past represented drought conditions. 99 00:17:51.780 --> 00:18:01.500 Adam Hudson: Periods of the past represented wet conditions and in comparison with other global records of climate change, get some inferences about what's really controlling. 100 00:18:01.890 --> 00:18:12.630 Adam Hudson: Beyond aridity and wet conditions in the northern great basin so that's been my perspective, as far as an area of study in the northern great Lisa and. 101 00:18:13.020 --> 00:18:19.230 Adam Hudson: I have to stick this in here, because you know I feel a little bit of a kinship as part of this agency of the usgs. 102 00:18:19.680 --> 00:18:29.370 Adam Hudson: Because this is i'm certainly not the first person to think about these lakes and, in fact, the very first usgs monograph the very first publication of the usgs. 103 00:18:29.700 --> 00:18:41.490 Adam Hudson: was on the shorelines of Lake bonneville which, if we look at the sunset map here is this big lake here in Western utah the modern great salt lake your salt lake city is the modern gram negative of. 104 00:18:42.270 --> 00:19:01.410 Adam Hudson: lake bonneville and gk Gilbert the geomorphologist that one of the most famous usgs geologist is very first publication was on the shorelines of Lake bonneville even at that time, he was pretty sure that these shorelines represented a. 105 00:19:02.730 --> 00:19:06.540 Adam Hudson: Ice Age period in which things are a lot wider in the face of it, they are today. 106 00:19:07.830 --> 00:19:15.810 Adam Hudson: And so my my lake based on that i've been working on is a lot more humble than that it's this one right here shown in the map like Chihuahua con. 107 00:19:16.380 --> 00:19:28.320 Adam Hudson: But in this part of the northern great basin in over the Oregon border kind of in this area where there's the triple junction between Nevada California and Oregon there's a number of. 108 00:19:28.830 --> 00:19:44.400 Adam Hudson: Pluto links that filled all of the basement rage basins during winter climate conditions, so the last question period and, as a kind of fortuitous at least fortuitous for that this research project fortuitous. 109 00:19:46.650 --> 00:19:59.010 Adam Hudson: Accident of geography, the PC caves are located roughly about here at this red star right on high shoreline of Paleo late chicken and so it's a little foreshadowing here that. 110 00:20:00.030 --> 00:20:05.520 Adam Hudson: Maybe something in the Paisley case could give us some insight into variations in the lake through time. 111 00:20:08.250 --> 00:20:18.510 Adam Hudson: So before we dive into the piece of the caves record, I will just orient everyone a little bit to what we do know about the variations in like chima con. 112 00:20:18.960 --> 00:20:27.360 Adam Hudson: and by extension of wet and dry periods over the last 20,000 years the northern great base so i'm going to show a lot of. 113 00:20:27.900 --> 00:20:43.140 Adam Hudson: Time series plots like this over the course of this talk where we've got zero years back to 20,000 years before present and calendar years or calibrated years for present on this X axis and some other. 114 00:20:44.370 --> 00:20:50.760 Adam Hudson: indicator of wetness or otherwise on the y axis here, and so what i'm showing here in this top. 115 00:20:52.110 --> 00:21:01.110 Adam Hudson: Top time series is the Greenland ice core record which is dominant lead a proxy for high latitude temperature in the northern hemisphere. 116 00:21:01.620 --> 00:21:15.750 Adam Hudson: and showing percent glaciated area of North America, which is a proxy for the extent of the ice sheets throughout the last glacial maximum up to the present and here i'm showing the elevation of shorelines with intellectual kind of base. 117 00:21:16.530 --> 00:21:32.250 Adam Hudson: And the basic takeaway of looking at this, this figure is that during the peak cold peak ice sheet period of the last question period the lake was pretty deep quite a bit above where it is today It actually seems to reach its most deep. 118 00:21:33.420 --> 00:21:43.170 Adam Hudson: Phase somewhere after that, after which the rent is sheet and started to melt and temperatures have begun to warm across the last place will transition. 119 00:21:43.710 --> 00:21:50.460 Adam Hudson: And then it kind of makes its way down, overall, as he continues to melt in temperatures continue to warm. 120 00:21:51.090 --> 00:21:56.130 Adam Hudson: But the thing I want to note here is that this quite a bit of gaps actually in this record. 121 00:21:56.460 --> 00:22:06.480 Adam Hudson: it's based on radio carbon dating of the individual shorelines and when you're dating individual shorelines here and there and everywhere around the base and you end up with a very bad fragmentary record. 122 00:22:06.840 --> 00:22:15.210 Adam Hudson: You have very good fidelity about where the leaks stood at those particular times, but they tend to be a lot of gaps and sometimes those gaps fall and important periods of time. 123 00:22:15.600 --> 00:22:24.270 Adam Hudson: places like the younger dryas krona zone, which is a kind of an important time interval and our understanding of the archaeological record of West. 124 00:22:24.690 --> 00:22:29.160 Adam Hudson: And so, one of the main things that I was very interested in when looking at. 125 00:22:29.610 --> 00:22:41.130 Adam Hudson: The settlement record from the Paisley caves is getting an opportunity to look at a more continuous record of hydrological variation through time since the Paisley cave span of time spans. 126 00:22:41.550 --> 00:22:48.780 Adam Hudson: More or less continuously between present and 15,000 years ago, so I was excited to take advantage of this fact. 127 00:22:50.460 --> 00:22:57.810 Adam Hudson: And so let's return back to the fish at this point and the fish that are distributed throughout the sediments of the Paisley case. 128 00:22:58.560 --> 00:23:07.140 Adam Hudson: And i'll you know, give a short primer to the Paisley caves but it's the archaeological site of some notoriety that probably needs no introduction. 129 00:23:07.800 --> 00:23:18.360 Adam Hudson: But it's in a West facing we've cut notch of hi Stan of Pluto HQ icon at the base of assault flow and a series of rock shelters. 130 00:23:18.840 --> 00:23:29.850 Adam Hudson: We studied in specifically caves to and cave five for the samples that we took from the Paisley caves they contain in total, a stratified. 131 00:23:30.390 --> 00:23:36.660 Adam Hudson: sediment sequence that spans approximately the last 15,000 years up to present more or less continuously. 132 00:23:36.990 --> 00:23:53.310 Adam Hudson: constrained very well and age by over 250 radiocarbon dates on a variety of different organic materials so a constraint on age that's completely independent of anything that i've been able to place on the shorelines themselves by dating. 133 00:23:54.330 --> 00:24:02.250 Adam Hudson: And the settlements of the people, the caves are probably most famous for their exceptionally good preservation organic material. 134 00:24:02.580 --> 00:24:17.730 Adam Hudson: And, including copper light fossils in the lower most layers that are most famous for containing human DNA and being dated by radiocarbon to more than 14,000 years in age and further up in this particular fee there, of course. 135 00:24:19.050 --> 00:24:32.040 Adam Hudson: Project how points of the western stemmed tradition, as well as sporadic but continuous evidence throughout the sediment sequence of human occupation throughout the late pleistocene and Holocene period. 136 00:24:33.180 --> 00:24:38.370 Adam Hudson: And, along with artifacts of a human origin they're also a lot of funnel remains. 137 00:24:38.580 --> 00:24:52.230 Adam Hudson: Within the caves including something that I didn't appreciate before being involved in this project, thousands literally thousands of fish bones fish for some fossil fish that were in the in the excavations. 138 00:24:52.770 --> 00:25:03.240 Adam Hudson: And there are two taxa that are represented in the caves at a very low level there's some from the family sound manatee which are most likely rainbow red band trout. 139 00:25:03.840 --> 00:25:11.700 Adam Hudson: But the overwhelming majority or this fish here that i've been showing you a photo of which is the to each other from the family support entity. 140 00:25:12.990 --> 00:25:24.090 Adam Hudson: And the actual fossils themselves are a variety of different skeletal elements, this is what we targeted for the so archaeological and isotopic analysis. 141 00:25:24.510 --> 00:25:36.840 Adam Hudson: The things like teeth and bones of various kinds, all of these types, including vertebra and some others as well that are distributed throughout the sessions and. 142 00:25:38.490 --> 00:25:47.100 Adam Hudson: To each other, in particular, are they make sense that they're there but they also make sense as a particular we. 143 00:25:49.080 --> 00:26:00.090 Adam Hudson: suitable vehicle for trying to reconstruct past variation in hydrology and a basin like Pluto HQ icon because they have a are endemic, to the great basin. 144 00:26:00.570 --> 00:26:13.620 Adam Hudson: showing this reported distribution from my colleague, Pat Flynn minsky's of recent paper, there are endemic, to the great basin and today they mostly inhabit the clothes watersheds that in Nevada and Eastern California and. 145 00:26:14.760 --> 00:26:29.580 Adam Hudson: Southern Oregon that are enclosed based watersheds these days, and they probably been in there, for you know at least a million years they've been long adapted to the kind of ups and downs rapid ups and downs in lakes that occur in these kinds of watersheds. 146 00:26:30.060 --> 00:26:34.980 Adam Hudson: And, as a result of that they're highly adaptable to a variety of environments, they can live. 147 00:26:35.370 --> 00:26:46.320 Adam Hudson: Firstly, an extremely high salinity still up to a point that can occupy these very sailing lakes, but when the lakes get even too salty for them to live in, they can also. 148 00:26:46.710 --> 00:27:02.400 Adam Hudson: School into freshwater environments like spring pools and streams and to escape the saltiness of the lake and take refuge in these freshwater environments until climate conditions become wet enough in order to support. 149 00:27:03.120 --> 00:27:15.360 Adam Hudson: More dilute lake they also eat a wide range of pelagic inventing food sources so that they can take advantage of different food sources in these different environments and from a. 150 00:27:16.500 --> 00:27:28.860 Adam Hudson: Human perspective there's lots of ethnographic and archaeological evidence that they've been used as a long standing food source by peoples in a in the great basin in a variety of archaeological contexts. 151 00:27:32.010 --> 00:27:42.960 Adam Hudson: And so, when we embarked upon our journey to try to better understand the to each other within the Paisley caves, the first thing that. 152 00:27:43.500 --> 00:27:52.980 Adam Hudson: Immediately jumps out is that the fish remains are not uniformly distributed within the time depth of the settlement record. 153 00:27:53.670 --> 00:28:03.720 Adam Hudson: And i'm showing them relative to time again between zero and 16,000 years before present, but this is really an exchange for depth and probably. 154 00:28:04.710 --> 00:28:13.110 Adam Hudson: A big shout out that I have to give that I I probably can't can't do or can't think enough, is the development of an age model. 155 00:28:13.440 --> 00:28:19.530 Adam Hudson: For all of the excavation layers in caves two and five that we worked on by my colleague megan emery Weatherill. 156 00:28:20.160 --> 00:28:30.630 Adam Hudson: She put a lot of work into along with Dennis Jenkins into developing this age model in order to take all the 200 plus radiocarbon dates to constrain. 157 00:28:31.080 --> 00:28:42.870 Adam Hudson: The sentiments of the Paisley caves and give every excavation level statistical age and uncertainty on that age, so that we, or anyone who studies these excavation levels in the future. 158 00:28:43.260 --> 00:28:54.660 Adam Hudson: can place undated specimens like all of these fish into a secure age context, and so this is kind of the basis of placing everything in an age context going forward. 159 00:28:55.140 --> 00:29:01.290 Adam Hudson: and want you'll note that in the lowest oldest Asia age sediments within the excavation there's. 160 00:29:02.130 --> 00:29:09.810 Adam Hudson: Much much greater density of fish remains than there are, as you go higher up into the younger layers of the site. 161 00:29:10.620 --> 00:29:19.680 Adam Hudson: And if we just look at these bars, which represent the median of all of the excavation levels that were averaged together to make each one of these data points. 162 00:29:19.980 --> 00:29:33.930 Adam Hudson: That it gets particularly high around this kind of 15,000 year period and then more or less exponentially decays through the late pleistocene to extremely low levels, once you. 163 00:29:34.470 --> 00:29:42.540 Adam Hudson: complete the last glacial transition and end up in the Holocene and in fact it got so low that to see the kind of low level variability we had to multiply. 164 00:29:42.960 --> 00:29:59.730 Adam Hudson: The density times 10 which is what's shown in dark blue here, so there is some variability once you get into the Holocene where the fish abundance declines is very low, and this middle Holocene period between about 4008 thousand years ago, and then comes back in again towards the present. 165 00:30:01.200 --> 00:30:11.700 Adam Hudson: So this distribution is kind of a first clue that there may be some sort of Paleo environmental control on the fish record that's showing up in the Paisley caves. 166 00:30:14.040 --> 00:30:34.530 Adam Hudson: And so, based on this, the question that I came in, to answer in some respects, is where did all these fish come from, why does their abundance changed through time and is it linked to environmental and habitat change in the telecom Basin and the northern great basin at large. 167 00:30:37.680 --> 00:30:50.670 Adam Hudson: And so, for that i'm going to turn to your chemistry lesson for the night and, hopefully, hopefully, everyone is aware of the fact that water in the lake is in fact a molecule. 168 00:30:51.240 --> 00:31:02.880 Adam Hudson: it's the molecule h2o and in salt lake's, in particular, there are also solids that are being brought in from the watershed things like sodium and calcium, and the trace elements strontium. 169 00:31:03.300 --> 00:31:12.990 Adam Hudson: and add ons like chloride and carbonate and sulfate and, once these legs get concentrated enough by evaporation they can start to precipitate minerals. 170 00:31:13.290 --> 00:31:23.250 Adam Hudson: Like calcium carbonate similar to the way that you would be able to precipitate things like salt crystals from drying your middle school science experiment. 171 00:31:24.210 --> 00:31:36.930 Adam Hudson: And I spent a lot of time thinking about calcium carbonate within the chicken basin surrounding the Paisley caves, particularly because there's carbon that substitutes in it that can be used for radio carbon dating. 172 00:31:38.070 --> 00:31:46.710 Adam Hudson: So I spent a lot of time digging in shorelines and driving around in the CIO con base and looking for calcium carbonate materials that were formed in the lake. 173 00:31:47.280 --> 00:31:55.560 Adam Hudson: Things like aquatic mollusks are shown here that we're living in the high lake deposits at the time the lake was much deeper. 174 00:31:56.160 --> 00:32:07.950 Adam Hudson: ostracods which are micro crustaceans that live in the bottom of the lake under the right conditions spring mound to fuzz places where spring mountain so forum where. 175 00:32:08.940 --> 00:32:19.830 Adam Hudson: spring water coming up along faults was discharging into the bottom of the lake when it was salty as well as to first formed on the rocky shorelines in response to algal photosynthesis. 176 00:32:20.370 --> 00:32:30.570 Adam Hudson: And every one of these materials is composed of the mineral calcium carbonate and at the because of that it records something about the chemistry of the water at the time of its formation. 177 00:32:31.680 --> 00:32:40.110 Adam Hudson: And that can be applied to fish bones too because, like our bones the bones of all animals fish bones are also mineral. 178 00:32:40.620 --> 00:32:48.420 Adam Hudson: they're mainly composed of the mineral appetite which is calcium phosphate but about 10% of of. 179 00:32:48.990 --> 00:32:58.290 Adam Hudson: Most bones is also substituted for this carbonate and I and so there's quite a bit of calcium carbonate in bone as well, which has the same. 180 00:32:58.710 --> 00:33:08.880 Adam Hudson: ability to substitute things like strontium carbon and oxygen into its chemical structure as the calcium carbonate that are forming from the lake itself. 181 00:33:10.050 --> 00:33:22.860 Adam Hudson: And, like the calcium carbonate in the lake water they they record something about the habitat, in which the bone was forming in which the fish was living and eating things at the time that it was living. 182 00:33:24.180 --> 00:33:34.650 Adam Hudson: And the way that this is being recorded is by an isotope composition and I know i'm getting a little deep in the weeds here, but I promise, this is the this is your nuclear chemistry lesson for the night. 183 00:33:35.700 --> 00:33:40.950 Adam Hudson: isotopes, if you remember from chemistry our atoms have a particular element that have the same atomic number. 184 00:33:41.430 --> 00:33:47.040 Adam Hudson: But they have different atomic weights and the example that i'm showing here is that have an oxygen atom. 185 00:33:47.490 --> 00:33:51.870 Adam Hudson: Where where oxygen has eight protons, which is what makes it oxygen. 186 00:33:52.200 --> 00:34:04.530 Adam Hudson: Eight protons and electrons, but it also has a balancing number of eight neutrons for its most dominant isotope and if you add those two together, it has an atomic weight of 16 so that's 16 oh isotope. 187 00:34:05.130 --> 00:34:21.150 Adam Hudson: they're also rare isotopes of this and nearly all of the other elements that have extra or less neutrons than would be expected, so they have the same number of protons which means it's still an oxygen but with two extra neutrons it becomes an oxygen with a wheat of 18. 188 00:34:22.230 --> 00:34:31.590 Adam Hudson: And the the consequence of having different isotopes of the same element is that they behave largely the same in chemical and physical reactions. 189 00:34:31.980 --> 00:34:38.820 Adam Hudson: The oxygen in h2o is composed of a mix of both oxygen 16 and oxygen a team. 190 00:34:39.180 --> 00:34:52.230 Adam Hudson: But because they have slightly different mass they behave a little bit differently in some chemical reactions and physical reactions and that can be used in a natural context to tell us something about differing habitat through time. 191 00:34:53.070 --> 00:35:10.110 Adam Hudson: So we're going to look at variations and oxygen isotopes in bones and carbonates variations in carbon 13 carbon 12 ratios those isotopes in the bones, as well as take a little bit of a look at strontium isotope strontium 8786. 192 00:35:11.160 --> 00:35:20.760 Adam Hudson: All of which are pretty straightforward indicators of the source of fish bones, and the peace, the caves and the habitat in which they were living. 193 00:35:24.630 --> 00:35:39.120 Adam Hudson: So let's think about the the carbon and the oxygen in the fish bones of the carbonates first as a stable isotopes system, just to give a little primer on how things work, just so we know how we're interpreting the plots and i'm going to show going forward. 194 00:35:40.740 --> 00:35:48.750 Adam Hudson: So, in a lake system like the closed lake in this cartoon that i'm showing that is not at all meant to look like like a brute. 195 00:35:50.730 --> 00:36:07.650 Adam Hudson: The there is water it freely exchanging with the salt in organic carbon and freely being sequestered in calcium carbonate in the lake water and the calcium carbonate derives its carbon largely from this gic pool and its oxygen largely from the water itself. 196 00:36:08.670 --> 00:36:09.300 Adam Hudson: and 197 00:36:11.130 --> 00:36:23.670 Adam Hudson: In a in a, this is a sailing environment or in a freshwater environment, but if we start in the fresh water runoff coming into the lake it tends to be in oxygen space quite enriched in 16 know. 198 00:36:24.330 --> 00:36:34.530 Adam Hudson: And i'll tell you the reason why, in just a second, and it also tends to be quite enriched in 12 see so the lighter isotope of carbon as opposed to 13 see in this is because. 199 00:36:35.640 --> 00:36:36.390 Adam Hudson: Plant. 200 00:36:38.100 --> 00:36:49.620 Adam Hudson: Plants tend to like to incorporate 12 see into their into their tissue a lot over 13 C and must most of the carbon that ends up in freshwater's. 201 00:36:50.100 --> 00:37:01.020 Adam Hudson: That is percolating through the soil is and is derived from plant carbon sources, and so the thing that you need to take away from this is if you're in a freshwater environment, you have. 202 00:37:01.590 --> 00:37:07.980 Adam Hudson: Low weight isotope oxygen low weight isotope carbon dominating once you. 203 00:37:08.550 --> 00:37:19.230 Adam Hudson: run off and end up in the lake as a water molecule filled with solids evaporation tends to select for this light isotope also. 204 00:37:19.590 --> 00:37:27.720 Adam Hudson: And that's because, as all of the molecules of water sit at the surface from evaporation the ones that have 16 Oh, and then we're just. 205 00:37:28.260 --> 00:37:35.070 Adam Hudson: Just that much lighter and just that much more likely to enter water vapor and be blown away into the atmosphere. 206 00:37:35.520 --> 00:37:45.930 Adam Hudson: And since water is evaporated from the ocean that eventually becomes precipitation that's the reason why precipitation derived run off and groundwater tend to be isotopic light. 207 00:37:47.820 --> 00:37:53.550 Adam Hudson: But the consequence of this foreclosed lake basin is, as this is a topically like oxygen is. 208 00:37:54.300 --> 00:38:07.290 Adam Hudson: being taken away from a lake like this over time what's left behind in the lake tends to get enriched in oxygen etc, and so we have a lot more heavy oxygen in the water that's left behind in a closed basin sailing lake. 209 00:38:09.000 --> 00:38:20.340 Adam Hudson: When it comes to the gic that's in the lake it also gets a lot heavier higher in 13 see content and that's because it's continuously exchanging with the atmosphere, which also has a higher 13 see content. 210 00:38:21.180 --> 00:38:26.580 Adam Hudson: And all of this is a very complicated way of telling you that as we're going forward in this. 211 00:38:28.560 --> 00:38:42.210 Adam Hudson: Talk about trying to assign habitats to different fish bones if they're coming from a freshwater environment they tend to have low oxygen 18 and oxygen and carbon 13 and if they're coming from a sailing lake environment they have the opposite. 212 00:38:45.390 --> 00:38:47.430 Adam Hudson: And I also ends up in the bones of fish. 213 00:38:50.070 --> 00:38:59.940 Adam Hudson: And so the way that that's generally expressed on a plot is a by plot of the oxygen 18 content and the carbon 13 content by plot here. 214 00:39:00.420 --> 00:39:09.030 Adam Hudson: And in this particular example i'm showing a whole bunch of data that i've generated from carbonates that have been collected from the CIO con basin. 215 00:39:09.420 --> 00:39:16.320 Adam Hudson: And we have on this higher end where we have high oxygen 18 high carbon 13 a lake and member that consists of. 216 00:39:16.980 --> 00:39:22.260 Adam Hudson: The lake to fuzz and aquatic mollusks shells and things that I showed you photos of before. 217 00:39:22.830 --> 00:39:32.610 Adam Hudson: And on this end, we have a stream freshwater spring and member, which consists of spring travel teams and a few other things that are formed in a more of a fresh water environment. 218 00:39:33.330 --> 00:39:43.260 Adam Hudson: And so, this lake in Member represents a sailing like environment like this, this stream and spring and Member represents. 219 00:39:43.710 --> 00:39:53.940 Adam Hudson: If we're looking on this photo here, probably here's the on a reservoir where the on a river issues, out of a spring something that's very close to the outlet of the spraying where it breaks ground. 220 00:39:54.540 --> 00:40:04.290 Adam Hudson: But then there's this kind of mixing zone in between where we're in sort of an intermediate space of covariance trend between these two end members that represents. 221 00:40:05.010 --> 00:40:17.130 Adam Hudson: The kind of habitats that are ponds or areas that are undergoing evaporation exchange with the atmosphere between where they are ultimately freshwater and where they end up jumping into the lake. 222 00:40:17.850 --> 00:40:24.900 Adam Hudson: And so what we're seeing, at least in the carbonates that are being plotted here is the entire span of kind of. 223 00:40:25.680 --> 00:40:34.200 Adam Hudson: inferred habitats that might exist in Libya lake based on like this, stretching all the way from fresh water environments, all the way to the same mix. 224 00:40:34.680 --> 00:40:42.300 Adam Hudson: And an important thing to note here is that all of these carbonates come even from the highest shorelines of. 225 00:40:42.660 --> 00:40:51.510 Adam Hudson: The Pluto lake so even when you're at a very deep lake and when actually the salinity of the lake is probably pretty low it still has a very high oxygen and carbon. 226 00:40:51.840 --> 00:41:02.100 Adam Hudson: Composition because it's still being concentrated by evaporation so deep lake doesn't necessarily mean fresh lake when it comes to these oxygen carbon isotope. 227 00:41:04.590 --> 00:41:15.300 Adam Hudson: So let's just talk about strontium briefly here this one we're going to look at much more simplistically and it's the ratio of 87 strontium to 86 strontium and. 228 00:41:16.740 --> 00:41:27.900 Adam Hudson: The main control on this is just the age of the bedrock in the basin, and so in places where we've got like the Canadian shield rocks that are 4 billion years old this value is very high. 229 00:41:28.320 --> 00:41:37.680 Adam Hudson: In places like the Pacific Northwest like in Oregon where there's lots and lots of young volcanic it tends to be very low that's these blues here, and so this is really just a basic check. 230 00:41:38.070 --> 00:41:44.250 Adam Hudson: To measure these a fish bones to check in are they coming from the to work on base and are they coming from somewhere else. 231 00:41:46.260 --> 00:41:52.020 Adam Hudson: And so, as part of this, we measured the water composition of all the waters that are flowing through the base and because the bedrock. 232 00:41:52.860 --> 00:41:57.420 Adam Hudson: Composition of strontium is inherited in the waters that flow through it and we found. 233 00:41:58.320 --> 00:42:04.890 Adam Hudson: pretty much what we expected that there's a narrow range variability with low values consistent with young volcanic bedrock. 234 00:42:05.280 --> 00:42:19.980 Adam Hudson: In both all of the rivers and creeks and the modern leaks that are low, and so the expectation is that the fish that are forming in a lake or river in that she was on base and should reflect the same strontium isotope composition. 235 00:42:21.420 --> 00:42:28.980 Adam Hudson: With that let's go to comparing fish we're going to compare, in particular in the kind of high stand phase of the lake that I showed in the first plot. 236 00:42:29.280 --> 00:42:41.220 Adam Hudson: Between around 13,000 15,000 years ago and i'm comparing the carbonates from that lake phase to the fish bones and fish tooth enamel from the exact same time period in the pace in caves. 237 00:42:41.640 --> 00:42:55.740 Adam Hudson: And Lo and behold there a near perfect match and all three isotope measures so strontium compositions that are consistent with the formation from the waters that were forming and late to a con during this time period. 238 00:42:56.520 --> 00:43:01.860 Adam Hudson: Highly evaporated oxygen isotope compositions and highly evaporate or like. 239 00:43:02.580 --> 00:43:14.550 Adam Hudson: atmospherically exchanged compositions of carbon so a pretty much a dead ringer the fish that the vast majority of the to each of that appear in the base of the page the caves were coming out of Pluto HQ upon the time that it was deep. 240 00:43:15.330 --> 00:43:22.590 Adam Hudson: This makes pretty much perfect sense, because at this time that the shoreline would have been you know basically lapping up to the cave within 100 years. 241 00:43:24.540 --> 00:43:36.330 Adam Hudson: If we look at this on this by plot, however, if we look outside these kind of Green dots shown here which are that same time period and plot clearly within this lake and Member if we look towards. 242 00:43:37.560 --> 00:43:43.320 Adam Hudson: Fish specimens that are coming from younger parts of the strategic fee and the Paisley caves. 243 00:43:43.830 --> 00:43:50.160 Adam Hudson: They start to move off towards this mixing zone, even in some of them towards this stream spring and member. 244 00:43:50.730 --> 00:44:04.470 Adam Hudson: Which is a indication that maybe we have some more habitats being represented by the to each other through time, so the interesting comparison, the most interesting comparison to me as then, to look at this in terms of time. 245 00:44:05.610 --> 00:44:15.240 Adam Hudson: And so i'm showing a whole bunch of plots here with the shoreline record that, as we know it plotted on top, the fish abundance record and the oxygen. 246 00:44:15.690 --> 00:44:25.950 Adam Hudson: Carbon and strontium isotope composition through time and Lo and behold, we have very good agreement with the dated shoreline record with the most abundant fish. 247 00:44:27.210 --> 00:44:38.190 Adam Hudson: In the Paisley caves occurring during this high stand during times, where we have of isotope compositions consistent with a highly evaporated lake and. 248 00:44:39.090 --> 00:44:49.530 Adam Hudson: But through time as the lake declines, based on the shoreline record all of these other things declined to towards lower fish abundance more freshwater habitats. 249 00:44:50.010 --> 00:45:03.150 Adam Hudson: A lower 13 see diet and and read they reach a low point during the middle Holocene and then actually come back in and the last 4000 years consistent with evidence that the late came back in as well. 250 00:45:03.690 --> 00:45:10.650 Adam Hudson: And so, this is pretty clear evidence that the fish in the PC caves are more or less tracking the availability of. 251 00:45:11.130 --> 00:45:18.600 Adam Hudson: Closed lake versus freshwater habitats within the team ICAN basin across the past 15,000 years she's extremely excited. 252 00:45:19.590 --> 00:45:28.260 Adam Hudson: And so, with that for the last part of my talk, I want to go back to thinking about the last ice age in the last transition and try to think in detail about what would. 253 00:45:28.680 --> 00:45:39.150 Adam Hudson: be the extent of lakes and other environments in the chicken basin have looked like to inhabitants of the Paisley caves over the course of the last 15,000 years. 254 00:45:41.310 --> 00:45:48.540 Adam Hudson: So i'm just going to step through time here, starting with that same high standard lake which i've already pretty much detailed to you that. 255 00:45:49.440 --> 00:45:57.240 Adam Hudson: What I think was going on and be the most interesting thing about this when you look at it on the map is that the Paisley caves are located here on the shoreline. 256 00:45:57.570 --> 00:46:04.980 Adam Hudson: And it's pretty hard to ignore the fact that there's a pretty giant lake between them and the CIO river and. 257 00:46:05.610 --> 00:46:12.660 Adam Hudson: and any of the kind of like forest in upland parts of the base and it's mostly desert out this way, and so this kind of begs the question. 258 00:46:13.050 --> 00:46:24.600 Adam Hudson: That was such a giant lake in the way what we're doing in the Paisley caves, and I mean maybe they were fishing, which is why there's so many fish in there, because that was would have been an abundant resource at the time. 259 00:46:25.770 --> 00:46:38.340 Adam Hudson: Another interesting aspect of the shoreline record and the fish record is that, as we move into the period of the younger dryas, which is a somewhat associated, I understand, with the. 260 00:46:38.730 --> 00:46:48.210 Adam Hudson: period of the western stem tradition, with throughout the great basin, this is seems to be a time that is somewhat thought to be cold and wet but actually this. 261 00:46:48.840 --> 00:46:57.960 Adam Hudson: Time based upon the shoreline record in the fish record in the yukon base and seems to be a time of transition towards the lakes falling a time of crying. 262 00:46:58.590 --> 00:47:10.380 Adam Hudson: And what this would have done is opened up more wetland habitat in the upper and lower chiba con marshes as well as along on a river and as these links drive down at the end of the last glacial period. 263 00:47:12.840 --> 00:47:20.070 Adam Hudson: Once we move into the early Holocene However, it seems like there is at least some evidence that the lakes either rebounded or we're still quite high. 264 00:47:21.000 --> 00:47:31.470 Adam Hudson: But there were still maybe they were maybe too salty at that point to support fish, because all of the isotope compositions of the fish at this time, indicate the fresh water sources so. 265 00:47:32.010 --> 00:47:40.800 Adam Hudson: they're very low abundance in terms of total abundance efficient the caves at this time, but there still was some opportunity at places where the. 266 00:47:41.280 --> 00:47:48.300 Adam Hudson: Chicago river, for instance, was dumping into the upper part of this lake where there would have been wetlands habitat and for fish to be living. 267 00:47:49.530 --> 00:48:01.920 Adam Hudson: During the middle Holocene However it the lake level Evidence seems to suggest that, during this Holocene out the thermal period the lakes were probably dry at least some of the time, all the way down to the Playa and both. 268 00:48:02.520 --> 00:48:14.010 Adam Hudson: pieces, and this is consistent with basically no fish in the caves during this period and very, very low isotope compositions consistent with the fact that the only habitat available for to each other, probably would have been. 269 00:48:14.460 --> 00:48:24.390 Adam Hudson: Very close to the outlets of springs, like the on a river or the opportunity on marsh where she was on river was breaking into the upper chillin on Mars area. 270 00:48:25.590 --> 00:48:33.450 Adam Hudson: And it's also consistent at the end of the Holocene with re expansion of the lakes as a wet climate wetter climate conditions were. 271 00:48:34.320 --> 00:48:50.520 Adam Hudson: reestablished in the last 4000 years or so, and the fish isotopes also come back up indicating that we're moving back towards a more intermediate habitat preference and fish increase a lot as well coming up to the present. 272 00:48:52.020 --> 00:49:00.360 Adam Hudson: And so, with that I hope that i've been able to convince you that something like a humble fish can in fact tell us something about. 273 00:49:01.050 --> 00:49:08.310 Adam Hudson: One of the greatest climate changes of the recent geologic past, and I will go ahead and move on to. 274 00:49:08.670 --> 00:49:18.510 Adam Hudson: Acknowledging all of the people who made this possible, which include funding for this study, which came from the Bureau of land management and my support by the usgs. 275 00:49:18.840 --> 00:49:22.740 Adam Hudson: Everyone who supported me during my dissertation work in the early parts of this. 276 00:49:23.370 --> 00:49:30.840 Adam Hudson: Some people who are integral in this, including Perry chalk, to have the climate tribes who continues to support the Paisley caves project. 277 00:49:31.380 --> 00:49:43.440 Adam Hudson: And many of my other Co authors and co conspirators in laboratories that have been so instrumental in producing the data that i've shown you that compose the great record tonight with that i'd be happy to take questions. 278 00:49:50.520 --> 00:49:55.560 Virginia Butler: Thank you so much, Adam whoo hoo the humble to each other. 279 00:49:59.970 --> 00:50:07.500 Virginia Butler: So we do have a question already, and it has to do with the chub and how large they get. 280 00:50:09.660 --> 00:50:10.770 Adam Hudson: You might have to answer that one. 281 00:50:12.360 --> 00:50:32.430 Virginia Butler: So it really varies depending on where they live in some of the larger like systems, they can get to be you know, a big but in lots of cases they're very small living sometimes just two to three years, but in more stable large lakes, they can get to be sizable. 282 00:50:33.900 --> 00:50:37.710 Virginia Butler: The ones from the Paisley caves tend to be pretty small. 283 00:50:38.580 --> 00:50:46.830 Adam Hudson: yeah I mean I think probably the if you went to the cross section of one of their vertebra they're probably dime size or smaller it's pretty small fish that's probably the biggest one. 284 00:50:47.400 --> 00:51:01.920 Virginia Butler: Right, but in, and I want to just add that they are in the minnows family in Parliament, you know and in popular culture minnows we tend to think of our small but don't think that, because a lot of minerals are actually really big. 285 00:51:03.690 --> 00:51:05.760 Virginia Butler: Okay, so other questions out there. 286 00:51:09.750 --> 00:51:19.230 Virginia Butler: So i'll go with Bob timmer Another question is what would be the change in average temperature from 15,000 years ago to now. 287 00:51:19.800 --> 00:51:23.430 Adam Hudson: I mean, I think that that's really 15,000 years. 288 00:51:23.430 --> 00:51:36.450 Adam Hudson: To now so temperature start really starts to change a lot so let's preface this by saying, on the global average the change between the last glacial maximum and today is something like six degrees Celsius so something like. 289 00:51:36.990 --> 00:51:49.620 Adam Hudson: You know 10 degrees Fahrenheit or something like that, I mean annual average temperature, I think the change that happened between 15,000 years and today is probably. 290 00:51:51.390 --> 00:51:56.370 Adam Hudson: I don't know, maybe four see something half that quite a lot of warming is already happened by that time. 291 00:51:57.000 --> 00:52:13.200 Adam Hudson: And so, so I think that the best evidence for how cold things remained and how late they remained as the extent of mountain glaciers in the western us which tend to stay near their last glacial maximum positions as late as about 16,000 but they're in very rapid retreat after that. 292 00:52:16.980 --> 00:52:19.290 Virginia Butler: Okay, others out there. 293 00:52:23.910 --> 00:52:33.240 Virginia Butler: Well, Bob just keeps coming here to the change in Lake level in the image middle Holocene be tied to Amazon Thomas rather than climate. 294 00:52:34.230 --> 00:52:36.270 Adam Hudson: um you know, I think. 295 00:52:36.330 --> 00:52:42.840 Adam Hudson: I think the answer to that i'm going to have to go with my hypothesis is no there's a lot of other evidence within the. 296 00:52:43.470 --> 00:52:54.750 Adam Hudson: Elsewhere in the great basin and within the Western us in general, the shows that this kind of out of thermal period of the middle Holocene was exceptionally dry across the board and it's probably a combination of the fact that. 297 00:52:55.980 --> 00:53:03.150 Adam Hudson: That the ice sheets and more or less completely melted away and so there's no effect on the winter westerly storm crack at that time anymore, and also that. 298 00:53:03.480 --> 00:53:10.260 Adam Hudson: Summer insulation in northern hemisphere, is very high, at that time and so it's kind of the the the worst case scenario in terms of. 299 00:53:11.520 --> 00:53:22.440 Adam Hudson: dry conditions and when it comes to the Madonna tougher in the summer league base in at least my understanding is that they it's actually you know, been reworked into dunes, and it was a. 300 00:53:22.800 --> 00:53:30.510 Adam Hudson: erupted onto a international surface at the base, and so the interpretation is that the lake was already dry at the time that it was interrupted. 301 00:53:32.190 --> 00:53:36.810 Virginia Butler: This some questions in the chat, but I want to call him on richie richie rosencrantz. 302 00:53:38.190 --> 00:53:45.780 Richie Rosencrance: hi Adam great talk, something I had been wanting to ask you about and i'll will probably talk about this more this summer. 303 00:53:46.140 --> 00:53:52.320 Richie Rosencrance: But exact is like understanding exactly where the water is in the two we can base and during the younger dryas. 304 00:53:52.950 --> 00:54:07.170 Richie Rosencrance: I know if it's if it's drying and the waters receding we wouldn't necessarily expect like well developed shorelines but i'm just kind of picking your brain about where we might like target areas where the marshes are during that time. 305 00:54:08.310 --> 00:54:10.980 Adam Hudson: yeah I mean, I think that there's so there's kind of a. 306 00:54:11.790 --> 00:54:13.440 Adam Hudson: In terms of where the lake might. 307 00:54:13.470 --> 00:54:16.350 Adam Hudson: Be your during the younger dryas I think that there. 308 00:54:17.790 --> 00:54:23.880 Adam Hudson: there's a couple of things at play there, I think the the lake is drying overall during that time, but there's also a. 309 00:54:24.630 --> 00:54:35.070 Adam Hudson: kind of drainage reconfiguration and that, as the lake drives down after that high standard the chewbacca Han river gets sucked out of the summer league basin and into the a really basin. 310 00:54:35.430 --> 00:54:38.070 Adam Hudson: And so the summer league base and dries out a lot faster. 311 00:54:38.550 --> 00:54:50.040 Adam Hudson: And so I think that there's a you know a little bit of radiocarbon evidence that's unpublished, that I know about that would seem to indicate that, basically, as soon as you're starting the younger dryas summer lake is basically gone. 312 00:54:50.580 --> 00:55:03.360 Adam Hudson: And so I think that one potential scenario for the reason why we don't see any carbonates in the abrahamic base and even though there should have been a lake in there of some kind, is that it was overflowing. 313 00:55:03.780 --> 00:55:13.500 Adam Hudson: At the drainage divide and so that we know that there's at least a channel that's overflowing, at least for a little while across that drainage divide right, you can see it on satellite imagery. 314 00:55:14.370 --> 00:55:27.360 Adam Hudson: But the question is how long that that persistent and so I think you know I don't really know because you know I have not those would be my guess is it's dry in summer lake so there's a lot of spring. 315 00:55:28.770 --> 00:55:40.080 Adam Hudson: marsh area available on that that valley floor in the abrahamic based on I don't know because it was either high or it was low and so either one of those marshes could either be exposed or not and. 316 00:55:41.040 --> 00:55:46.920 Adam Hudson: I you know I don't really know without coring The virtue economy, Lord Shiva con marsh how he would try to figure that out. 317 00:55:48.660 --> 00:55:57.810 Richie Rosencrance: Great thanks I actually didn't realize there was that draining free configuration so that that actually tells me a lot and stay tuned maybe we will core. 318 00:55:58.530 --> 00:56:09.270 Virginia Butler: know so Steve has a question has there been a similar studies using other species of food, and I think he means from Paisley. 319 00:56:10.290 --> 00:56:13.140 Virginia Butler: Paleo environmental reconstructions. 320 00:56:14.130 --> 00:56:27.060 Adam Hudson: I mean, I think you know from an isotopic perspective I would I don't think so i'm not aware of anything like that i'd be interested to do more isotopic work on other final remains but I mean there's certainly been work on. 321 00:56:27.780 --> 00:56:36.240 Adam Hudson: The kind of food sources that are showing up in coprolites and you know the floral remains the floral history of changes throughout time and the pace of case then. 322 00:56:37.350 --> 00:56:39.510 Adam Hudson: Tell something about people's diet. 323 00:56:40.200 --> 00:56:56.220 Virginia Butler: You know I just to follow up on that there's certainly been so many brilliant people working on the Paisley cave deposits for different reasons and they've looked at the Paleo botanicals and other animals, but they haven't. 324 00:56:57.270 --> 00:57:11.370 Virginia Butler: put it in like a systematic timeframe that allows you to really closely look at at the change at the level that that Adams leadership brought us to so. 325 00:57:12.270 --> 00:57:21.780 Virginia Butler: You know a lot of the folks it's like big chunks of time, you know 1500 years and other 1500 years we've got a lot of high rez here and. 326 00:57:22.530 --> 00:57:38.820 Virginia Butler: There would be an opportunity to take some of the other animal remains and plant tissues from the same unit levels that we put into this brilliant time series and and see how those cross compare that is definitely something that needs to happen. 327 00:57:39.900 --> 00:57:52.110 Adam Hudson: yeah I mean like I said megan's work was you know completely pivotal to being able to do this and you know we're forever in debt to all of the Read iterations of the agent model that we made her go through before we published this paper. 328 00:57:52.830 --> 00:58:02.130 Virginia Butler: And you know that's something that is it's I have not been a part of a project that took advantage of the statistical modeling of radiocarbon dates. 329 00:58:02.130 --> 00:58:08.730 Virginia Butler: But that was really critical and i'm having trouble with my mouse moving this chat down. 330 00:58:09.450 --> 00:58:23.700 Virginia Butler: So someone asked about contemporary to each other populations in that area to into existence bring habitats, is there any indication that the to each of remains in the Paisley were harvested in these versus the sailing lake so. 331 00:58:25.200 --> 00:58:32.580 Adam Hudson: Absolutely yeah I think that all of the freshwater habitats that are being represented by the stuff that's coming you know to each other that are coming in at least a. 332 00:58:33.330 --> 00:58:38.040 Adam Hudson: Low abundance and all the same levels are probably coming out of environments like these uh. 333 00:58:38.550 --> 00:58:51.960 Adam Hudson: These spring habitats, and I mean, I think that the to each of exist, to my knowledge in that she would come basin today and they live in these types of environments and they probably persisted in there from glacial to interglacial for. 334 00:58:52.620 --> 00:59:04.470 Adam Hudson: You know the last million years or so, in fact, I know that there's to each of bones and exposed lake sentiments that have been uplifted along faults that are probably an excess of half a million years old. 335 00:59:07.980 --> 00:59:15.810 Virginia Butler: Post fish knew how to take advantage of those refugees, you know and like resilience just the epitome of it. 336 00:59:17.550 --> 00:59:28.170 Virginia Butler: So a question here is is the legs continue to receive is there evidence that people move closer to move closer to locations near the lake. 337 00:59:31.140 --> 00:59:39.420 Adam Hudson: I mean i'm not much of an archaeologist so I don't know if i'm the right person to answer that question, but I know I mean I was reading back through the Oregon archaeology book that a. 338 00:59:39.510 --> 00:59:49.110 Adam Hudson: dentist put me on to, and it does seem one thing that I had to remember, it is once you get into the late policy and that there's actually during that kind of boulder village period that's called out in there there. 339 00:59:49.380 --> 00:59:55.110 Adam Hudson: It turns out that there's quite a significant settlement that borders, the western edge of like a bird. 340 00:59:55.560 --> 01:00:04.350 Adam Hudson: And, at a time when it seems like the the to each of I still compositions are trending more towards a one customer and end Member and so. 341 01:00:04.650 --> 01:00:13.620 Adam Hudson: I wondered, you know that same kind of thing is where people living along the lake being able to explain the customer resources again as climate got wetter during the late policy. 342 01:00:15.000 --> 01:00:34.590 Virginia Butler: And just to follow up on that with Greenspan has looked at fish remains from some of the sites all along, like a bird that are kind of late Holocene and again emphasizing that the water went into like a bird and it wasn't really that available and summer late for for fish populations. 343 01:00:36.510 --> 01:00:40.500 Virginia Butler: Any any other thoughts and questions out there, great questions. 344 01:00:46.080 --> 01:01:00.750 Virginia Butler: i'm so glad you've taught me this is a great talk i'm so excited about having this take this recording that we're going to have on our on our web page and we can share it with all the people that didn't get here tonight, so. 345 01:01:01.500 --> 01:01:02.340 Virginia Butler: Thankfully. 346 01:01:02.370 --> 01:01:10.050 Virginia Butler: We have technology to record these great talks you're a great teacher, I wish i'd had you as my chemistry Professor. 347 01:01:10.350 --> 01:01:26.490 Adam Hudson: yeah well, I mean I probably will get slapped for way over simplifying things but I too am really happy to be here i'm glad to talk to everyone tonight, and I really appreciate the opportunity to spread the word about isotopes to the broader community. 348 01:01:27.120 --> 01:01:37.230 Virginia Butler: Well i'm so excited you're coming up to work with the folks that kindly caves and hope to see you and hear about all the projects you're doing in. 349 01:01:37.680 --> 01:01:53.190 Virginia Butler: Oregon and the northern great basis, so if you want to turn your your camera on if you're not embarrassed about that and let's just give them a round of applause you whoo Thank you so much here's caitlin to. 350 01:01:54.900 --> 01:01:56.130 Virginia Butler: Excellent really. 351 01:01:56.400 --> 01:01:57.930 Adam Hudson: Everyone Thank you. 352 01:01:58.620 --> 01:02:00.480 Virginia Butler: stay well everybody and. 353 01:02:02.100 --> 01:02:04.770 Virginia Butler: I don't know I never know how to end days but. 354 01:02:06.240 --> 01:02:06.690 Virginia Butler: bye bye. 355 01:02:06.720 --> 01:02:07.800 Adam Hudson: Thank you and good night. 356 01:02:07.980 --> 01:02:08.430 Virginia Butler: good night.