Presentations by Keck Geology Consortium at the 2019 Annual Meeting of the Geological Society of America
22-25 September 2019, Phoenix, Arizona
Sunday, 22 September 2019; 09:00 AM – 05:30 PM Phoenix Convention Center – Hall AB, North Building
Booth 223: TAPHONOMIC COMPARISON OF VERTEBRATE MICROFOSSIL BONEBEDS FROM THE UPPER CRETACEOUS JUDITH RIVER AND HELL CREEK FORMATIONS OF MONTANA Peter Zimmermann (Oberlin College), Asha Lang (Smith College), Gabriela Roat (Colorado College), Kaylee Velasquez (Union College), Sun Tun (Macalester College), Katherine Irving (Macalester College), Sedalia Gomez (Amherst College), Nolan Clark (Pomona College), Kristina Curry Rogers (Macalester College), Raymond Rogers (Macalester College)
Wednesday, 25 September 2019; 09:00 AM – 06:30 PM Phoenix Convention Center – Hall AB, North Building
Booth 210: CAPTURING A LATE CRETACEOUS PALEOFAUNA: A NEW VERTEBRATE MICROFOSSIL BONEBED IN THE UPPER CRETACEOUS (CAMPANIAN) JUDITH RIVER FORMATION, MONTANA Gabriela Roat (Colorado College), Sedalia Gomez (Amherst College), Sun Tun (Macalester College), Katherine Irving (Macalester College), Asha Lang (Smith College), Nolan Clark (Pomona College), Peter Zimmermann (Oberlin College), Kaylee Velasquez (Union College), Raymond Rogers (Macalester College), Kristina Curry Rogers (Macalester College)
Team Belize after SCUBA certification and ready to begin work on the local reefs.
The Belize project was an overwhelming success thanks to our 9-student team of rising sophomores and our dedicated peer mentor, a rising senior. We spent the first week at Washington and Lee learning about coral reefs, exploring analytical equipment and techniques, and in the pool learning how to SCUBA dive. We spent the next two weeks in the field where each student passed the check-out dives (with the reef sharks) with grace and enthusiasm. In Belize and back at Washington and Lee for another two weeks, we developed three areas of focus for research. Catie Caterham (Franklin and Marshall), Nick An (Oxford College of Emory), Sydney Walters (Colgate), and AJ Mabaka (Washington and Lee) assessed whether declining coral cover over the last few years has resulted in the kind of phase shift to algal dominance that has been so widely recorded across the Caribbean. This group assessed the percent live coral and algae, as well as urchin and farmer fish densities in comparison with previous years. Petra Zuñiga (Amherst), Will Riley (Vassar), and Riley Waters (Macalester) characterized the impacts of massive Sargassum blooms washing across the Caribbean and accumulating on shorelines. This group measured dissolved oxygen and pH levels and mapped the extent of the ‘brown tides’ associated with decaying Sargassum, with an eye towards thinking about what kind of mitigation efforts should be considered. Matti Horne (Pomona), Jolie Villegas (Wesleyan), and Sydney Walters (Colgate) assessed whether the ‘new’ hybrid coral species Acropora prolifera that is increasingly recognized on Caribbean reefs is a ‘true’ replacement for its declining parent species. This group paired urchin, fish, and non-acroporid coral abundance with 3D photogrammetry techniques to quantify surface area to volume and morphology of ‘spaces’ to compare the kind of habitats these different species might provide for the reef. Our outstanding peer mentor, Ginny Johnson (Washington and Lee) collaborated on all three projects. By the end our 5 weeks together (and some very late nights) we had 3 abstracts submitted to the Fall AGU meeting. We look forward to seeing all of our outstanding students present their work in San Francisco in December!
Keck Montana measuring section along the Missouri River.
Keck Montana conquered the muddy Cretaceous in exquisite fashion. The Macalester crew consisted of Ray Rogers, Kristi Curry Rogers, Jeff Thole, and sophomore Chloe Kahn (peer mentor), along with first-year students Sun Tun and Katherine Irving. Student crew members from other institutions included Asha Lang (Smith College), Abby Roat (Colorado College), Peter Zimmermann (Oberlin College), Sadie Gomez (Amherst College), Nolan Clark (Pomona College), and Kaylee Velasquez (Union College). The work began in the labs at Macalester, where this diligent Keck crew learned how to recover (via wet sieving), sort, and identify the tiny fossilized bones and teeth of animals that lived in the Late Cretaceous of Montana (the faunal lists they compiled include dinosaurs, mammals, turtles, amphibians, and lots of fish). After tuning up on the scopes, identifying thousands of fossils, working through image analysis protocols and data analysis, and writing two GSA abstracts, we flew to Montana to begin the field adventure. Our first stop was the famous Hell Creek Formation near Jordan Montana (T. rex country), where we focused on two of the sites that we first encountered in the lab. The Hell Creek camp along the shores of Fort Peck Reservoir proved to be the perfect setting to hone field skills and learn how to prospect for fossils and measure section. Our hosts, University of Washington grad students Luke Weaver and Brody Hovatter, gave us the grand tour of classic Hell Creek sites – we even collected samples of the K-Pg boundary! After a few days in the Hell Creek we moved on to the small town of Malta, Montana, where the crew attended the “Judith River Formation Symposium,” which was hosted by the Great Plains Dinosaur Museum. Attendees included famous dinosaur paleontologists Jack Horner and Phil Currie (both of whom joined us for dinner), among others. After a few focused days of talks on Judith River rocks and dinosaurs, we continued on to the Upper Missouri River Breaks National Monument, and the heart of Judith River country. After provisioning up, we hit the rocks and got to work on our final fossil site, which was located in badlands along the Missouri River. In addition to collecting vertebrate microfossils on the surface, we also excavated the site and discovered several cool dinosaur bones, including vertebrae, toe bones, and one large chunk of a limb bone – all of which came from hadrosaur (duckbill) dinosaurs. After a few days in camp, and after surviving a few particularly memorable thunderstorms, we launched our canoes down river to explore a few more localities. After a few glorious days floating the river, we wrapped up our Montana adventure with a visit to the Museum of the Rockies, where we were treated to a behind the scenes tour from curator John Scanella. Two posters featuring the results of our work will be presented in September in Phoenix at GSA.
Team Yellowstone at “The Narrows” of the Yellowstone River.
Team Yellowstone had a successful and productive field season. We focused on the Gallatin River and Blacktail Deer Creek. The team managed frigid mornings, sweltering afternoons, hail, freezing rivers, driving rain, lightning, elk, grizzly bears, and temperamental survey equipment with aplomb. Using a GPS and a Total Station we surveyed more than 150 channel/valley cross sections and over 10 km of long profiles, accumulating over 13,000 points in the process. The team characterized the channel bed material by pebble counts, measuring over 25,000 pebble diameters! In addition to surveying, the team described stratigraphic sections and collected charcoal and wood samples for radiocarbon analyses. The team also collected over 50 soil probes for short-lived radionuclide analyses. The team met with the Park Archeologist to learn about cultural resources in Yellowstone. This included instructions on how to identify cultural materials in stratigraphic sections. The team also explored some of the thermal features of Yellowstone, did some wildlife viewing in the Lamar Valley, and learned about landslide hazards at Earthquake Lake. Back at Whitman, the team went to work on digitizing all of the field data and preparing samples for lab analyses. Currently, everyone is back at their home institutions and excited to dig into the data!
The Keck Wyoming team made up of Michael D’Emic (Adelphi University), Simone Hoffmann (New York Institute of Technology) and Brady Foreman (Western Washington University), as well as six students, Grant Bowers, Michael Ford, Richard Gonzalez, Danika Mayback, Emily Randall, and Isaac Sageman spent four weeks in the northern Bighorn Basin, Wyoming collecting 56 million-year-old fossils and placing them into geological context. We also had the pleasure to join Amy Chew and Ken Rose for a few days at their field site in the southern Bighorn Basin, visit the Illinois State University’s Geology Field Camp lead by David Malone, and get a behind the scenes tour at the Draper Natural History Museum in Cody by their Assistant Curator Corey Anco. Our field effort included collecting more than 100 crocodiles, turtles, and mammal fossils, including the early mammal Coryphodon, the first mega-herbivore after the Cretaceous-Paleogene extinction and the focus of our study. We already prepared 10 Coryphodon specimens in our field laboratory for histological thin sections. Grant Bowers and Danika Mayback will be using these and other histological samples to study changes in growth in Coryphodon through a major global warming event, the Paleocene-Eocene Thermal Maximum (PETM). Together with Richard Gonzalez’s project on finding relevant proxies for body mass estimates, these studies will help understand the growth mechanisms underlying body size evolution of Coryphodon in relation to environmental change. We also measured 15 stratigraphic sections and collected more than 90 sediment samples for isotope and pollen analysis from our new Coryphodon sites. Isotopes analyses conducted by Isaac Sageman will help place our localities in relation to the PETM and provide proxies for temperature and precipitation. Pollen analyzed by Michael Ford will help evaluate changes in plant distribution (and potential food resources of Coryphodon) throughout the PETM. Emily Randall will be investigating soil morphology in our stratigraphic sections. We plan to present this work at the spring GSA Rocky Mountain Section meeting in Utah in 2020.
Team Wyoming measured 600+ meters of stratigraphic section comprising early Paleogene lakes, rivers, swamps, and deltas, including >70 measurements of paleodrainage conditions. The group constrained paleo-vegetation structure spanning global warming event (PETM) from about 100 measurements of fossil plant material. Their findings also included a new plant macrofossil site in Hanna Basin. In the laboratory, the group complete 400+ stable isotope measurements constraining carbon cycle variability from ~60 Ma through ~54 Ma, and identified the PETM global warming event using stable carbon isotopes. Students collaborated with researchers at Chicago Field Museum and USGS. They also presented 5 abstracts as posters at the GSA Regional meeting in Manhattan Kansas and one lucky student presented at EGU in Vienna Austria.
