Revisiting the Horseshoe Canyon Formation

Revisiting the Horseshoe Canyon Formation



okay good morning everyone and welcome to the 2013 Royal Tyrrell Museum speaker series today the Royal Tyrrell Museum in its cooperating Society are proud to present another regular of the speaker series our very own dr. David E berth dave is a research scientist here at the Royal Tyrrell Museum where he has worked for the past 28 years they've obtained his undergraduate degree in zoology from the University of Massachusetts he then moved to California to pursue his master's degree in paleontology at the University of California Berkeley where he studied permeance pineco daunted a group of animals that include the famous sail back Dimetrodon subsequently they've moved back to Canada to pursue his PhD in geology at the University of Toronto where he studied the Permian red beds of the American Southwest fresh out of his ph.d they've joined the ranks of the scientists at the Terra Museum in 1985 and has been here ever since Dave's primary research interests include the city of dinosaur patio environments and vertebrate F&O me over the years he has conducted field research in Canada Argentina Germany China Mexico the u.s. Mongolia and even the Canadian High Arctic today they will explain how the rocks exposed in the Drumheller area provide a unique glimpse at the environmental changes that took place 70 million years ago and how dinosaur faunas responded to those changes so without further delay I present you dr. David E berth all right can everybody everybody hear me yes very good so you've had time to digest the title of the talk why Drumheller rocks and indeed rather than just going through the fact that Drumheller is kind of a cool place in its own right I thought I'd try to dig in in this talk into some of the some of the new research that we're doing both geologically and bio stratigraphically to get at questions of why things are the way they are so it's going to be a little bit of a talk about your backyard and what I've done is I've committed a cardinal sin I've got basically data from two research papers both of which are I don't know 40 50 pages thick and I'm going to put it all in this one talk so you guys can start clawing your way to the exits now if you if you want to these are the two manuscripts that I'm talking about so just wanted to let you know that what I'm going to tell you right now is in or about to be in the scientific literature also I have to put this in the title why Drumheller rocks this is not to be confused with Brent Nolan's webpage Drumheller rocks his Geotourism page and brent is here today put your hand up Brent there he is I was looking he gave me a call yesterday was fo upset about the fact that I was using his trademarked term and asked if I would be so kind therefore to make up for this this sin if I wouldn't put his webpage in the talk and I looked at his web page last night I don't know about 10 o'clock while I was putting the talk together and I saw this little paragraph I thought wait a minute that's actually you know pretty true to the what I'm gonna do today let me be your guide listen to the beautiful story the rocks can tell and I have over thirty years of geological experience and a passion for the earth well true so well done Brent for bringing that to my attention a royal tyrrell museum check what all right so the Horseshoe Canyon formation absolutely gorgeous we're all familiar with these kinds of scenes going right from the East Coulee area where we have the the hoodoos up into the Drumheller and Horsethief Canyon area and even farther north up into the Tollman bridge dry island of buffalo jump area just gorgeous scenery and in a very very attractive natural landscape we all know that we also know that the Horseshoe Canyon formation can be truly inspirational give us insights into things that go far beyond matters of science the horse you can information attracts many geologists and technical people and has done so as long as I've been here and I'm and I'm sure before then we find lots of geologists coming in to look at academic matters because the rocks are so well exposed because they have such a fine beautiful story to tell this is an opportunity for people to come down and look at things like the Willow Creek inclined heterolytic strata which represent ancient meander a meandering estuary channels lots and lots of evidence for tidal high-resolution tidal deposits and I just threw in a couple of old photographs that I had of geologists following in a duct like manner up up the rock to hear the hear the word from on high the Horseshoe Canyon formation of course is also famous because of its hydrocarbon resources most notably the coals and of course we're all familiar to varying degrees with the coal mining history of the valley the fact that the the town is largely here because of that history or at least got its start because of that more recently although not at the present time coal bed methane is a major component coal bed methane and the Horseshoe Canyon formation can be retrieved from these coal bearing layers in this little arc that you see outlined in black and indicated by blue and through here and of course many of you are familiar with the strip mining that goes on for power generation all focused on the coal so of course you can information is really important for for resources but we're also very very aware just given the the fact that the museum is here that the Horseshoe Canyon formation is also a major source for dinosaur fossils and although I'm not going to be going through in any detail individual fossils and discoveries I just thought I'd indicate some notable dinosaurs and recent discoveries from the formation just to kick things off here you know Triceratops a a relatively primitive form of the Triceratops clade one that we found from the horse in the Horseshoe Canyon formation in predates Triceratops by close to a million years pakhi rhinosaurus this ceratopsian dinosaur that has large wart like growth on its nose instead of the big horns very very famous here in the lower beds around Drumheller and of course it Montes horas one of the larger dinosaurs a duck-billed dinosaur one of the larger dinosaurs in the world our display right out in the galleries here when you walk into the galleries the so called Cretaceous Alberta is based on research that was done on the albertasaurus bone bed which is in the Horseshoe Canyon formation up in the dry island Buffalo Jump area and of course I think most of you are familiar with this paper that just came out in October the end of October last year involving many of us here at the Museum and driven largely by Francois and his wife Darla is Ellen in ski at the University of Calgary and this is a discovery of the first feathered dinosaurs non-avian non bird dinosaurs in North America many of us are of course familiar with all the huge array of feathered dinosaurs known from China well this represents this discovery here in the horseshoe canyon formation of a ornithomimus and ornithomimus with feathers indicates the first discovery of feathered dinosaurs in north america fairly important also important because there's a lot of insight that we can glean from these fossils about how feathers evolved and what their original purpose was and where they show up in the evolutionary hierarchy of dinosaurs and if you want to know more about that corral Francois it's not a talk about that today so let's get into what we're going to do today we're gonna look at the new geological and bio stratigraphic research and particularly we want to know this because it helps to explain the origins of the horseshoe canyon formation in these wonderful dinosaurs that's always that's always good and as well it also helps to understand why these resources these coal resources are here it also allows the dinosaurs and other fossils to be better appreciated in a global bio stratigraphic and evolutionary perspective so it's very very important stuff and it's in our backyard so we might as well just enjoy it before we get into the details though we're going to do a little bit of geological background just to bring everybody up to speed I'm sure most of you are already aware of what I have to say in terms of the background but we'll go over it anyway the horseshoe canyon formations package of rocks here in Drumheller in the Drumheller region that is named after this quarter section patch of badlands out on highway 9 coming out just west of Drumheller and if here's a photograph of photo mosaic of that area of beautiful badlands typical Horseshoe Canyon formation strata with the coals and these multicolored drab browns and grays and greens but it's important to note that the Horseshoe Canyon formation as part of the Edmonton group a much larger package of rocks that includes the Horseshoe Canyon battle and scholars that horseshoe canyon formation can be traced all the way from nantan in outcrops of south of Calgary all the way through the Drumheller area right up north of Edmonton now this area that I've highlighted in gray indicates the surface outcrop of the Edmonton group including the horse you can information north of there because the rocks take on some different care mystics those rocks are given a different name and are assigned to the what is called the Wapiti formation and there we also have the battle and thus Collard above that but the horseshoe canyon equivalent strata are referred to as Wapiti and likewise south of this nantan area the horseshoe canyon formation strata are referred to as Saint Mary River so my point is very large area of outcrop for the horseshoe canyon formation and it's laterally equivalent rocks the age of the rocks of the horseshoe canyon formation should be considered in the context of the Mesozoic we can think of the Mesozoic as including the age of dinosaurs from the basically from the end of the Triassic right up to the end of the Cretaceous so a large swath representing about 150 million years now Berta's dinosaurs as I like to say only represents about ten million years what we have in Alberta only represents the last ten pursue a 10% of that hundred and fifty million years for the last 15 million years running from 80 to 65 million years ago so a very important slice of the dinosaur record an important slice because it tells us about the end of the age of dinosaurs when we look at the Horseshoe Canyon formation just concentrate on the numbers here the top of the formation is 67 million years old and the bottom of the formation is 74 million years old so in that swath of 15 million years in Alberta we've got seven million years wrapped up just in the Horseshoe Canyon formation which represents 4.5 percent of the total age of dinosaurs pretty significant little package of rock on the global in a global context if you want to understand what's going on with dinosaurs over the years we've been able to correlate the horse you can information with other formations and we've learned that the Horseshoe Canyon formation being a terrestrial unit that is a land-based unit that has these dinosaurs running around in it correlates at least in its lower half with marine strata in other places in North America so for example in Saskatchewan Montana Colorado rocks of the same age as the lower half of the horseshoe canyon formation are made up by marine shales and thus they don't have dinosaurs in them they've got other fossils but they don't have dinosaurs so the horseshoe canyon formation becomes very important because it tells us about land environments and we can't get that information from other very famous places like Montana Colorado and Saskatchewan the overall setting for the horseshoe canyon formation in terms of the paleo geography of North America is that it was deposited during the overall withdrawal of this intercontinental Seaway so we have going from 75 million years ago to 65 million years ago at the end of the Cretaceous gradual withdrawal of that sea drying up if you will of the interior of the continent and 70 million years if we just use that as the average age for the horseshoe canyon formation although I just got finished saying it stretches across 77 million years but if we use that as the average age basically we're looking at an intermediate phase in this withdrawal of the see where we're getting these very large land environments Pro grading and building out into that interior sea as the sea withdraws so there its context and as we're all familiar with the horseshoe canyon formation was deposited in a in a wet warm temperate to subtropical climate and there were shorelines and there were meandering channels and straight channels and wetlands everywhere now if we consider the structure this is kind of cool actually if we consider the structure of the horseshoe can information in the context of all the other strata beneath our feet in this area we actually find if we were to take a cross-section a west to east cross section around Edmonton but you can do this anywhere from Edmonton right down through the international border we'll find that the strata and particularly the horse you can information strut a dip toward the west the dip is extremely slight it's less than one degree so you don't when you're standing in the outcrop you don't actually see the rocks tipping down but the is there if you measure it over a large area and as a result of that if you walk along the landscapes different geographic areas will have rocks of different age what do I mean by that well if you come down to the Drumheller area and when you look at this swath of edmonton group most of it made up by course you can information it simply means that at the points here labeled 1 2 3 4 5 and so on and so forth but out towards the east Dorothee the rocks are older and they get younger as you move towards the west and it's an important point to keep in mind because it means at different places that we go if we go to east Coulee Drumheller or moron bridge or up the Tollman bridge and I'm going to make the assumption and many of you are familiar with these Geographic names but if we go to these different areas the portions of the Horseshoe Canyon that we're looking at have a different age the different part so for example down on East Coulee if we consider the white in this diagram in this cross-section is basically the horse you can information we can see that we're in the lower portions of the Horseshoe Canyon formation in our measured sections what we have available to look at indicated by these rectangular boxes and as we move to more and bridge and Tolman bridge we're eventually going higher and higher in section so what we have to do is geologists and paleontologists as we tend to think of the Horseshoe Canyon formation in terms of composite information so we measure our sections all over this place and then we put them together into this type of composite measured section so this is just a measured section from the outcrop all the width and all the symbols that you can't read from your chairs back there are simply indicating the different lithology x' and this indicates that in the Drumheller area the horseshoe canyon formation is about 250 meters thick the same formation is you move over to the west is about 400 meters thick it gets thicker as you move towards the west towards the source area towards the mountains where the sediments were plowing in so we've got new research I keep promising I'm going to talk about the new research and then I give you something else to consider so we have new research on the geologic history of the Horseshoe Canyon formation and basically this falls into four categories we've got new information on the stratigraphy that is how the formation is put together it's a different strata we have new information on physical environments what the ancient environments were we've got new information on tectonics and tectonics is a term you may or may not be familiar with it simply refers to the history of the crustal or the crustal part of the earth and in particular we tend to think of it as the relationship between mountain building and sedimentation so big-picture aspects of the crust being modified over time through plate collisions or plate separations and so on and so forth and then we also have in new information on the climate and I need to point out at this point but this isn't research that I've done all by myself this is a project that's been going on for almost 15 years and involves significant contributions from Dennis Bremen Don Brinkman Francois therian and Quinny bill Strait and a host of other people who I'm sure will yell at me for not having your names up there all right so this is part one of the talk and we'll talk about the dinosaur biostratigraphy towards the end of the talk now the geologic information the way we've gathered the data falls into two categories we've got outcrop data that is information that we just pull out of the rocks that we can get our hands on and we've done that by measuring 16 measured sections through the Drumheller area and you can see all the little dots that are numbered represent the measured sections and I showed you a measured composite measured section in a couple of slides ago and we have submillimetre scale of sorry sub meter scale resolution in these sections so pretty high high resolution information and the information that we are looking at an outcrop involves pollen ology this is basically Dennis Brahmins area which allows us to look at Paley ancient environments and consider climatic information and stratigraphic information we have information from ancient soils Cretaceous age soils this is the work that's been contributed by and Quinny and Francois therian and this allows us to look again at ancient environments and consider information about climates we have information about the overall sedimentology that's my contribution to the geology and that gives us insights again into the ancient environments climates the stratigraphy and tectonics and we have of course information from the paleontology contributed by hosts the paleontologists here at the Museum as well as some other colleagues and this allows us also to look at environment and climates so we have all of these categories of information drawn from the outcrop and allowing us to consider these different aspects of the story so for an example we've get up to an outcrop this is the Morin bridge just east of the of the bridge on the hill some of you may actually be familiar with this outcrop and you can D see the different strata the different colors and tones indicating different horizons and there's a person for scale truck for scale you get out we measure the section and then we build these little logs and we record all of that information that I just reviewed with you and then we do that over and over again and put assemble the data and process the data and interpret the data pretty simple stuff in some ways very tedious in others we also have data from subsurface and this is again basically work that I've contributed in this case we've used 226 subsurface wells that's wells geophysical data that are available from the oil companies that are held in on file by the Alberta government and we've used those wells to link together what we call cross-sections and we've hung those cross sections on a datum we have to be able to correlate each well with each adjacent well and so we use a datum in this case the Drumheller bentonite zone which is well exposed down by Denny's gas and splash there or what used to be Denny's gas and splash and this allows us to extend what we learn about the crop over much larger areas so consider there's Drumheller and we're basically our outcrop data are just coming in through here but now we can tie into the outcrop and then by using these subsurface cross-sections we get a handle on what's going on in a much larger scale it also gives us the opportunity to look at the geometry of the individual subdivisions now the colors have gone wonky I guess on this projector that should be blue but it's green so this is the Bearpaw marine formation and this is simply one of the cross-sections one of the subsurface cross-sections that can be built this one runs from cochrane out to dorothy through this area and this is a simple gamma well log that we use to recognize different units and we can subdivide the package the Horseshoe Canyon formation on the basis of this so this is simply just to show you how we use the subsurface data now tectonics before I get into the results of this kind of work I just want to dive a little deeper into the notion of tectonics and our Paleo climate our tectonic interests derive from the fact that during the Late Cretaceous Alberta was an active Basin this portion of Western Canada was an active Basin with sediment pouring in from the mountain belt and filling up that Basin now that Basin is a four land basin which by definition means that it's strongly asymmetric so from the west to the east adjacent to the mountain belt the basin is quite thick and you're getting lots and lots of sediment piling in and building up these sedimentary layers and as you move off to the east you have less and less sediment being deposited giving rise to this asymmetric fill of sedimentation all right but the the for land basin forms as a result of collisions of in this particular case collisions of the Pacific plate and a loch thinnest terrains a little micro continents being blue assembled on to the western margin of North America over time and as a result of those forces pushing the crust toward the east you end up with what are called over thrusts where the crust breaks up and actually climbs up on top of itself often like what you would see if you're shoveling snow out in the yard you'll see the snow actually piling up on top of itself you can see a remnant of this kind of event in places like mount rundle in Banff where you've got these layers of sediment that are very deeply lithified that have been thrusted up into the air and the strata are actually oriented this way if we look at the original layers so we know that that strata has been pushed up toward the east east is over here West is there in this particular photograph so this is just the reverse east west of what we would see over here and that mount rundle would represent one thrust sheet in many stack thrush sheets that are formed during this tectonic collisions this is really kind of cool stuff because there's a we understand a lot today we understand a lot about how this process works and we see this process going on today all over the world wherever you have con wherever you have crustal sheets that are colliding and as a result of that we've been able to develop overtime models that explain what to look for in the sedimentary package and what that sedimentary package can tell us about the history of Mount uplift the history of uplift is really really important in any Basin because it controls climate it controls resource distribution it controls rates of sedimentation it controls areas where animals can evolve it's just amazingly important to really understand the tectonic context of your sedimentary fill one of the most simple bottles that I find extremely powerful to use is that during the multi million year cycles of uplift and and non uplift we can actually the patterns developing in the distant in the distal part of the basin that are quite discrete so we have times of app active uplift where the sheets are actually being lifted up and the sediment there's because those sheets are being lifted up they down warp the crust right next to the mountain belt and most of the sediment that gets eroded off gets trapped very close to the mountain belt and we see sediment starvation in the distal part of the basin it's important to realize that Drumheller represents a more distal location than adjacent to the mountain belt so Drumheller in this diagram would be out here during non active Tecton ism so when when there's no colliding going on basically what happens is that crust rebounds lifts itself back up again and starts eroding all that sediment that had originally been captured and trapped next to the mountain belt and that ends up being transported out into the basin this really really kind of cool so we have a what we call a loading phase when the when the clutter when the plates are colliding and sediment gets trapped close to the uplift and sediment is basically starved from the distal part and we have an unloading phase sediment is reworked into the basin very very neat now since those models were developed back in the 70s and 80s we've gotten a lot more sophisticated I'm not going to go through all of the information in this slide but this slide is basically what it's attempting to do is reverse that information we basically take the information that we see out in the distal part of the basin and based on the patterns that we get here in the sediment pile we can infer what was going on tectonic Li and that's what we've done in the Horseshoe Canyon formation so for example if we see reduce sediment supply if we see small sinuous paleo channels poorly drain landscapes lots of vertical stacking of the channels we know that there was tectonic loading going on and sediments were being trapped very close to the mountain belt and then the distal portion out in Drumheller was being starved conversely if we see Rosson loss lots and lots of coarse sediment and stacking of channels and larger straighter paleo channels and better drain landscapes we know that it's a time of tectonic quiescence there's no active thrusting going on and the crust is rebounding and it's pushing all that sediment into the deeper part of the Basin that's really important because we can link that information into the evolution of dinosaurs the development all sorts of resources and we can make predictions about where we're gonna find those resources what horizons they're gonna be abundant in and what horizons they shouldn't be climate I also need to just just very very quickly say that climate our information about climates is comes in from a huge variety of sources so we get it from the fossil plants that are provided here and that's obvious if you've got plants that are have close living relatives that live in certain environments you can make inferences about what the climate was like the pal analogical information that Dennis Bremen has contributed allows us to really dig into what climatic conditions were like through time and the horse you can information the sedimentology allows us to understand climate if you see lots of evidence for flowing water as opposed to lots of evidence for mud cracks and dry conditions you can infer what the climate is like but we also have these areas that you're probably a little less familiar with paleo Sol's ancient soils and their geochemistry can be used to infer climate we also have isotope geochemistry stable isotope geochemistry that we can use from the fossils themselves to infer climate and paleo temperatures and we have also patterns of vertebrate diversity things like crocodiles and turtles which are temperature sensitive animals and when we have periods of time when the climate is very very favorable to those kinds of animals we see greater diversity of those taxa when it becomes cooler and less favourable less wet we'll see less diversity so this is a simple diagram to show the application of many of those concepts we consider when we're doing our Paleo climatic we're we consider what's called the general mean annual temperature curve for the world and this is a curve that's been put together from from sources all around the world and it shows that in general we should be expecting if to find a cooling in the middle of the Horseshoe Canyon formation followed by a warming trend based on all the information that's been gathered elsewhere in the world the stable isotope geochemistry is telling us that we should also expect to see a sharp cooling event in the middle of the horseshoe canyon formation this is these are our data from the horseshoe canyon formation but they are quite scant as you can see from this diagram so they're just sort of a hint of what we might expect and then up here I've included some data from compliments of Don Brinkman looking at turtle and crocodile diversity and aquatic vertebrate diversity and again both of these patterns show that there is indeed a drop-off in the in the diversity in this middle part of the horseshoe canyon formation likewise with the Paleo Sol's this is work contributed by Annie Quinny and Francois therian again a fairly complicated diagram but the point is this if you look at the top based on the different types of paleo cells that we find through the horseshoe canyon formation we can see that there are these basic subtle trends with a cooling event occurring in the middle of the formation right here I'm sorry mean annual precipitation declining and a cooling event occurring so the last little bit that I've been talking about it's just my way of saying that we have all of these multiple approaches to getting a handle on climate we have these multiple approaches to getting a handle on the tectonics when multiple approaches to getting a handle on how the environments have changed now if I were to go through all of the steps and all the arguments that we've used you'd have to come back for about a week's worth of seminars on all the data so what I'm going to do now basically what I've done is I've told you what we're after I've told you some of the tools we've used and what all I'm gonna do now is just jump into the results and try to hurry this along a little bit this is a historical diagram that shows attempts to divide the horseshoe canyon formation into subunits and basically what we've done as of 2012 the paper that we just published Dennis and myself we've been able to formalize formalize the subdivisions of the horseshoe canyon formation so this is work that's now published it's now in the literature and what we've done is we've recognized seven different litho members in the horseshoe canyon formation so we have a Strathmore member this is strictly related to the subsurface you can't see it an outcrop it's below your feet even when you get down at the dorothy area it's still you're just getting nicking the very very top of it there but it's much lower in the in the the rock column in the subsurface the next member we have is what's called the Drumheller lift emember and that extends from the dorothy area right up to here at the Tarot Museum this is the 6th and 7th Cole's own material museum is literally built on the 7 coal so all the rocks through Drumheller now belong to what we call the Drumheller little member it's very cool we've got a name that makes sense there the rocks that extend from Drumheller up to basically up to Horsethief canyon and a little bit beyond that are now placed in what's called the Horsethief Litha member we have more on with the member that I named because my wife wanted something named for the town of Warren so really no because the rocks are very very well exposed at that more and more in bridge alright so we have the more on with a member and then the Tollman with a member named because of the rocks up around Tolman bridge and then the carbon member which refers to the packages of rock at the very top of the Horseshoe Canyon formation and the white mud lifts the member as well so these are all formalized terms now so that's one result that's cool we've got official names this is really I hope you can see these these red terms here but this is really the whole result of that geological study we've come through all of these little members and we've recognized these patterns so for example in the Strathmore member we have the the landscapes moving out and then coming back in again shorelines stepping out shorelines stepping back in the Drumheller litho member we see the shorelines really not going anywhere just kind of building up vertically and the channels being nicely separated from one another and lots of coals indicated by these black lines the Horsethief member we have channels that are starting to stack up and become very very dominated at the top of the section and wouldn't you know where we get lots of payload channels gee that's where we get lots of dinosaur fossils very very important then we have these two with the members the mourn in the Tollman where we see the channels become quite small we actually get very very poor coal development even though we even have the marine environments poking their nose in in the so-called Drumheller marine tongue very very poor or coal development associated with that and that's really odd that's we're a very peculiar geologically then we got this zone of stacked channels at the base and then the channels separate out now in the carbon member we see much larger channels lots lots and lots of stacking of those paleo channels returned to kohli conditions and then all heck breaks out in the white mud Litha member lots and lots of paleo cell development and the battle which basically just represents stacked volcanic deposits and landscapes that are starved of sediment this diagram also includes information from the scholar that I'm just going to ignore for the time being so when we take all of that information and we look at all of the sort of the analytical tools and we apply all the analytical tools what we end up seeing is that we can parse the Horseshoe Canyon formation out into these subunits with different kinds of parents different kinds of tectonic settings and different climates so what I've done is I group these together just to make this a little less tedious so the Drumheller member and the Strathmore member together represent the remains of a large Delta and a proximal distal coastal plane and this is an early phase of unloading remember when I said that became tectonic ly quiet you get the rocks rebounding this is an early phase of that unloading so we're basically balancing our sediment supply with our sea-level and we just see this inter fingering of Myr of non marine and marine rocks up through that portion of the path of the package and of all of all of our Paleo climate data tell us that it's warm temperate and wet cool we go up into the Horsethief member so basically right where the tier a museum is built the rocks that are right here and then higher going right up to the rocks that are exposed at the very very base of the Morin bridge area that package of rocks what we see is that there's a shift the sediments have really jumped out into the basin and we've shifted from a delta to a coastal plain setting this is late phase unloading there's just an incredible amount of sediment pouring into the basin at this point indicating that it's tectonic ly quiet but that the crust is rebounding bouncing back up and reworking all that sediment out here this is also a phenomenally rich dinosaur rich interval because we're getting so many paleo channels because paleo channels are a great place to trap and preserve dinosaurs more paleo channels more dinosaurs and it's still warm temperate and wet this is where things go haywire though between the horse thief and the moron member we're seeing a transition back to coastal plain and shore shoreline environments a huge amount of tectonic loading it became incredibly tectonic ly active there was lots of collision happening at that point in time and sediments were being derived from that uplift but they were being trapped right next to the mountain belt instead was being this area was being starved basically of sediment we also find using all of those various tools that we have a shift towards cooler and seasonally wet dry climates at that time and of course the fact that it's tectonic ly active and that there's climate change immediately makes us you know suspicious that there's a link between the Tecton ISM and the climate change because that's what we see all around the world wherever you have major uplift events you can create rain shadow effects you really upset the climatic patterns of a region or an area if you have lots of uplift of the mountains at the very top of this mornin Tolman with emember combo we get into more riverine environments and we start seeing a little bit of unloading happening more sediment starting to pour into this part of the basin but it's still cooler and seasonally wet dry to the carbon member we still have River plain environments we've left that we've left the shorelines behind they're out in the in in the Dakotas at that point and we've got very late unloading so it's we're starting to go into a tectonic lee active phase at that point and we had a return in our climate to warm temperate and wet lastly in the white mud rivers and wetlands it's basically just a sediment starved area intense loading at that point and that sediment being trapped and this area being starved of sediment and a return as continue to return to those warm temperate and wet I put this slide the next slide in on purpose just to reiterate what you've heard it's complicated all right I just spent I don't know I just burned five ten minutes just going through that geologic history and I could have just put this slide up it's complicated it's way more complicated than we ever knew and that is really neat that's really really cool there's us some other information that we've gleaned from this study we've actually been able to map out in one case the size of these deltas that were that were present here at the bottom of the Horseshoe Canyon from so if we go down to the Strathmore member because this is such a prominent tongue of sediment interbedded with non marine and marine we can map those marine non-marine contacts out and actually see the size of the Delta lobe in that case and that Delta lobe is about a hundred to one hundred fifty kilometers wide which which interestingly is on a scale not unlike the Mississippi Delta which surprised the heck out of me we also have some much more complicated ideas going running you know basically going on now about how this this interval of seasonally wet dry and climatically cooler environments came to be and I really don't have time to go through this in any sort of detail to do it justice but one of the things I said at the beginning of the talk was I I pointed out that the horseshoe canyon formation is laterally equivalent with what's called the Saint Mary River Formation to the south and the Saint Mary River information we've O known for a long time is a much drier setting than the horseshoe canyon formation and so what we're proposing is that that that wore that wet and dry that seasonally wet dry climate that takes over in the Morin and Tolman interval sort of in the middle of the horse you can information simply represents a northward expansion of the st. Mary River facies Saint Mary River environment into this area and that's kind of cool because that's one way you can do that on it so this is a regional climate change one way you can do that is with mountain building and I said all our tectonics is pointing towards major mountain building event in this area of the chordal era so it may be that we're just simply looking at a rain shadow effect conversely the glow the cooling that we see we can't explain that simply by this mountain building and we think that that's actually a global cooling event and it fits in with the mean annual temperature curve for the for the world so our climate change seems to be a combination of global processes and regional processes and that is some complexity that is really neat lastly if we stand way back and we consider these patterns of unloading and loading that I've been talking about we can actually see that the duration of these events in terms of millions of years become shorter and shorter as we go through time so the basin is getting noisier there's a lot of things have starting to happen more frequently as we go up through the horse you can information and that gets the that basically gets all of us pretty excited about considering what made the effect of of those of that busyness of that tectonic shifting back and forth what are the potential opportunities for that to affect evolution and evolutionary patterns in in animals and evolution of ecosystems through time and we're just grabbing the surface of this kind of stuff now but because we have this study under our belt we can start asking these questions Wow all right Francois here's here's the second talk alright so I'm gonna basically going to take that information now and I'm going to overlay the dinosaur biostratigraphy on top of it and I'm just going to throw out some morsels for you to consider some stuff that we're that we're that we're working with this isn't this is really quite new and we haven't worked our way through all the implications so again we're concentrated on the Drumheller area we're using 287 identifiable specimens identified the genus 43 different taxa to identify two species or consider to be separate species even if they don't have names yet we're using 138 bone beds and we've for this analysis we've thrown the skull information in and all of the images I'll show you we're all time calibrated that is you're not going to see sections measured in meters you're going to see sections measured in geologic time evenly spaced units yikes here's the final list the dinosaurian finalists for the horseshoe canyon formation and the skull information the oranges the theropods and the greenish is the plant-eating ornithiscians enough said about that we have dinosaurs alright so what we've done is we've taken this stratigraphy here's our time calibrated y-axis so here are the different units that we have that I've just got finished talking about and there you'll see that their relative thicknesses are quite different than what I showed you in the previous diagrams because their time calibrated not thickness calibrated here are the climatic implications from that last study and all we've done is dumped all the fossil remains we've we've retrieved the information over past ten years as to where all of these animals were collected stratigraphically and now we've just laid them out just to see a simple abundance histogram these are the individual skeletons these are the macro fossil bone beds and the micro fossil bone beds you can see that they're not evenly represented there's lots of animals showing up in the Horsethief member and remember I told you be the horse thief's member has lots of channels in it's no surprise that we're gonna get lots and lots of dinosaurs there likewise we're getting lots of animals in the Tollman member which doesn't make a lot of sense relative to what i've just said about the horse thieves so there's something there to study well one of the first things we had to consider is you know are those patterns those non-random distribution patterns an artifact of just there being a lot of rock in some horizons and not a lot of rock in other horizons in other words in the horse thief Canyon the Tollman is it simply because there's huge amount of rock to study that we can find lots of fossils or is there something intrinsically different about the relative abundance between those units so we had to do a correlation analysis and basically this first diagram is what I want you to concentrate on is simply if we plot the number of skeletons against the areal extent of each of the different little members we find that there's relatively poor correlation correlation coefficient of 0.45 and this is telling us that there's something real going on it's not just an artifact of paleontologists being able to collect lots and lots of dinosaurs out of a rocky unit that goes on for four miles it's telling us that some rock units are actually quite extensive and have lots of dinosaurs and others are you know not extensive or are extensive and have fewer dinosaurs so there's something intrinsically valid about the difference in dinosaur abundances we've also been able to go back and look at the geochemistry of the units so for example the white mud in the battle just have poor preservation of any organic material so the fact that we don't have dinosaurs popping out of there is not telling us that there were no dinosaurs they're living at that time it just means that they probably just didn't get preserved likewise if you go down towards Dorothy there's a lot more Moline Rock there and you're just not going to get a lot of dinosaurs there likewise in the Strathmore it's in the subsurface so who knows there may be tons of dinosaurs there we just don't know about it because we haven't been able to look at the rock so we've got these patterns worked out we see that there they are reflecting different aspects of perhaps climate perhaps paleo biology and preservation 'el aspects and lots more work to come on that but the really interesting thing I think from all of our perspectives is what happens when we start laying out the individual taxa in their stratigraphic positions relative to this these interpret these environmental interpretations and climatic interpretations through the horseshoe canyon formation so here all the taxa these the rectangular boxes indicate their ranges through time and within those different litho members and then the numbers simply represent the number of individuals we have representing that taxon so for example for euoplocephalus we've got 11 individuals admin tonyia to pachyrhinosaurs for Anki serotypes 25 so on and so forth you get the idea by doing an analysis of looking at where we get the maximum number of discrete stratigraphic occurrences we've been able to recognize in the horseshoe canyon formation 3 stratigraphic zones defined by differ kinds of dinosaurs this is me this means that when you'd see the Horseshoe Canyon formation fauna being discussed now you know that not all those animals lived at the same time in this lower by ozone defined by Edmund tonyia strictly limited to that zone pakhi rhinosaurus strictly limited to that zone and Edmontosaurus strictly limited to the zone we consider that to be a very discrete biological entity compared to the next zone which is defined by these taxa montana sarah tops or louis hypocrite horas Sparrow theosis and parks a source o albertonykus is in there as well so these are non-overlapping taxa in Drumheller likewise at the very top we have a very weakly defined by ozone defined only by one taxon yo Triceratops but because he Oh Triceratops is such a unique animal we're really really convinced that that's a discrete bio zone so our analysis has identified these bio zones and lo and behold what we see is that the bio zones match up beautifully with changes in climate so this is just the summary of that last diagram here are our three bio zones I've also included dinosaur park information and scholar information up here but we're just going to concentrate on the three bio zones so what is it transitions to these bio zones mean are these evolutionary changes or do they simply represent animals migrating in and out of the area well this is kind of a cool diagram because it tells us here are the taxa again that define the bio zones but this time what I've done is included the ranges of these animals whether they're known in Drumheller or not so for example Paki rhinosaurus and in mono source have much greater ranges than they show in Drumheller and they're known from Alaska Montana Saskatchewan as well as Alberta and the fact that these animals have much larger ranges is telling us that it's more likely that these are our migration and environmental preferences rather than just evolutionary changes the transitions between these two zones then we want to look at in terms of environment and it's very interesting things let the animals that define the lower zone Edmontosaurus and packy rhinosaurus they're found in warm and cool settings in Alberta and Alaska but they're always found in wet settings never in seasonally dry settings so these animals are always found where it's wet if they don't care if it's warm or it's cold but they do care if it's wet or dry likewise conversely in the next bio zone dominated by hypocrisy or since or low ffice these animals are also found in cool and warm settings in other places Alberta Montana and Mongolia but they're never found in saturated landscapes always in seasonally dry landscapes so this information is telling us that these animals these by ozone changes are simply reflecting environmental preferences of the animals and that is extremely extremely cool now our next step is to basically compare these bio zones with similar bio zones to similarly define bio zones in places like dinosaur Park and higher in the section and ask questions about rates of evolution and rates of change why the bio zones so lengthy here in the Horseshoe Canyon formation why are the bio zones such short duration down in the Dinosaur Park formation got lots and lots of questions yet to ask and I came in under an hour [Applause]

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