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Cornell College 2014-2017 Newsletter

Bahamas Trip 2016

Featuring: Class Trips, Department Honors, Student Research, Notes from Faculty, and a Call to Alumni.

DEPARTMENT OF GEOLOGY

ASSEMBLED AND EDITED BY NINA MORRIS ’17 Page 2 2014-2017

FROM THE CHAIR Dear Geology Alumni,

Greetings from a gorgeous fall day in Mount Vernon, IA! The maple trees around Norton are stunning in red and orange, and the sky is a true October blue. I am happy to report that we have two newly planted maple trees right in front of Norton, on either side of the main campus entrance—these replace two older trees that were removed within the last three years. We have also had some work done around the side, handicap-accessible entrance to improve visibility and access to that entrance as well as to increase the aesthetic appeal of the landscaping.

Since our last newsletter, we have also made some changes inside Norton. In the main upper- level classroom (108), microscope cases were removed from the desks to enable additional student seating. While some students were sad to see the change, it made the room much more comfortable for our larger classes—it once seated 12 comfortably but now can seat up to 18 quite easily. This was helpful over the last three years, as many of our 200- and 300-level courses were larger than the earlier cap of 12 students. Facilities continued to replace the dark, old carpet with brighter, faux-wood flooring—this time in the front of our large classroom (208), where they also cut down the huge front desk that once fully separated the professor at the chalkboard from the class in their seats. We hope to have the risers and old chairs removed and replaced with moveable tables and chairs—not only will that increase the comfort of the students in the room, but it will also increase the possibilities for classroom use (by geology or other departments). In our thin section lab, we have moved to an epoxy curable by ultraviolet light. This is exciting, because this will cut down on the time needed to make thin sections, as well as improve the hold of rock to glass slide.

We continue to have personnel changes within the department! In May 2015, John Orcutt completed his second year with us as a Post-Doctoral Fellow in paleontology. He has since moved back to the Pacific Northwest and currently holds a Lecturer position at Gonzaga University. We particularly appreciated the research mentoring that he provided for a number of our students, one of whom has almost finished his Master’s in paleontology. Also in 2015, Ben Greenstein agreed to continue in the Associate Dean position for an additional two years (for a total of 5 years). We were thrilled for Ben, who is doing fantastic things for the college in his current role, but again it left the department without a paleontologist. Fortunately, we were able to hire alumna Kelsey Feser ‘10 for a 2-year Visiting Assistant Professorship in Paleontology and Sedimentology. The faculty and students are extremely pleased to welcome Kelsey, who has proved to be a phenomenal, energetic, and creative member of the department. Last year (2015- 16), Rhawn Denniston was on full-year sabbatical, so we also hired Jonathan Baker (ABD in paleoclimatology at the University of Nevada, Las Vegas) to teach three paleoclimate classes (two introductory and one advanced). Jonathan was also a fantastic colleague, and we wish we could have kept him for more than just one semester. I must say that I count myself as very, very fortunate to have had these two, high quality colleagues to step into the absences left by both Ben and Rhawn.

Our major numbers, which had been quite high, are beginning to feel the effects of this lack of a permanent third member to the department (along with other factors, including overall lower enrollment in the college, and the change from 2 required Science courses in the General

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Education requirements down to just 1 required Science course). The quality and dedication of our majors, however, remains high. We have had 7 students complete honors theses over the last three years. Over the last three summers, 12 of our majors pursued research on campus with a geology faculty member (for the past two summers they participated officially in the Cornell Summer Research Institute, designed and implemented by our very own Ben Greenstein in his role of Associate Dean). We also placed students in a variety of fantastic off-campus summer experiences, including a competitive NSF-REU, work with the Iowa Geological Survey, and research in several R-1 universities around the country.

We are always looking for more research and internship opportunities for students, so if you have the potential for having a Cornell geology student at your work place, please let us know! Alternatively, if you have particular career advice for future geologists, we’d love to hear it. Come, give us a talk about what you do, or send us a video clip telling us about your career, how you got there, and how your Cornell Geology major prepared you. Of course, any time you plan to be in the Mount Vernon area, please let us know—otherwise, keep in touch.

Cheers, Emily ------Call to Alumni, We Need You!

We are putting together an alumni spotlight video series to show to our students, particularly the intro students, what it is that geology majors do after they leave Cornell. We hope you will participate!

Nationally, college students are more and more concerned about the jobs they will have after they graduate from college. For many of them, college is just the pathway to get to a career, rather than a time to explore and learn for the sake of learning. As most college students don't know what geology entails, they also have no idea what geology majors can do after they graduate. By highlighting the careers of our alumni and the different paths they took to get there, we hope to answer this question for our students: What amazing things can you do with a geology major?

For these videos, we plan to ask questions about: your job (current or former) and job search, your day-to-day duties, where your job has taken you, what you enjoy(ed) most about your job, how your geology major at Cornell prepared you for your position, and what recommendations you have for current students. The final videos will be edited down to ~2-3 minutes.

If you are willing to participate, we'd love to hear from you. If you would like to make your own video and send it to us, that would also be fantastic!!

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Geology Class Field Trips

Paleoecology: 2015 Devonian Fossil Gorge Field Work

Tectonics: 2016 Physical Geology: 2016 Baraboo Park Wildcat Den State Park

Historical Geology: 2016 Kayaking Trip down the Upper Iowa River

Igneous Petrology: 2014 St. Francois, Southeastern Missouri

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Geology Field Work and Field Courses

Bahamas Trip 2014, 2015, and 2016

Making Cross-Sections in 2015.

Scuba Diving in 2016.

Cave Exploring in 2014.

Student James Garrett ’17 and Dr. Rhawn Denniston conducting research in an Australian cave during the summer of 2015.

New Zealand Trip 2014-2015

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NOTE FROM JONATHAN BAKER Last year (2015-16), Rhawn Denniston was on full-year sabbatical, so Jonathan Baker (ABD in paleoclimatology at the University of Nevada, Las Vegas) was hired to teach three paleoclimate classes (two introductory and one advanced).

Having grown up in Colorado and Utah, I have long been interested in reading Earth's story. Currently, I am a Ph.D. candidate in Geoscience at the University of Nevada, Las Vegas, where I completed my M.S. degree in 2010. Over the past 4 years, I have attempted to reconstruct Holocene climate trends in western continental Eurasia, where there is currently a paucity of high-resolution proxy data. To this end, I have focused on the chemistry of secondary cave formations (stalagmites) and carbonate lake sediments in western Russia. I was fortunate to spend a year and a half living in St. Petersburg, Russia with my wife— who is from Samara, Russia—through the Fulbright program. During this time, I developed lasting professional and personal relationships with students and researchers alike, while learning the language and culture. Coincidentally, the first American I met in St. Petersburg was a student from Cornell College (J.R. Byers), and our friendship ultimately led me to apply for my current teaching position. This Fall, I had the pleasure of teaching three courses on paleoclimatology while Dr. Denniston enjoyed his sabbatical retreat. The experience was incredibly rewarding, albeit exhausting, and I am happy to report that I survived the dreaded block system! During my block "break", I worked with two students on independent research topics, which yielded fantastic results. We coordinated with Dr. Cindy Strong to analyze major cations in my cave and lake sediments, using the ICP-OES on campus, and interpret hydroclimate variability during the Holocene epoch. ------NOTE FROM BEN GREENSTEIN Greetings geology alumni,

All of you know that we geologists have a unique relationship with the notion of time. Perhaps better than most, we wrap our minds around seemingly incomprehensible time spans in our work. I have often thought that geologists are able to keep their life experiences in a healthy (and often much different) perspective than those who never have had the privilege to learn about earth’s immense history. That said, my current perspective is that the last few years since we assembled our alumni newsletter elapsed in an alarmingly rapid fashion. I don’t honestly know whether this is because I have been so busy, or because a three-year interval represents a proportionally smaller and smaller chunk of my life as I age.

In any event, I have spent most of my time these last three years engaged in academic administration as Associate Dean of the College. My ongoing course in the Bahamas allows me to keep rewarding contact with geology students, and of course I am frequently “haunting” the corridors and offices in Norton Hall to stay up to date with Rhawn and Emily. We welcomed Kelsey Feser ’10, having recently completed her Ph.D at the U. of Cincinnati, to a full time two-year position in the department to keep the strong tradition in sedimentary geology alive; she is doing so with aplomb.

We were very pleased to hear from Chelsea Korpanty ’11 last fall via a video call from the IODP drill ship JOIDES Resolution. Chelsea was one of the sedimentologists on board the two-month cruise to the NW Australian shelf and arranged a call to a couple of geology classes in order to discuss the expedition’s investigation of the history of the Leeuwin Current. Chelsea took a two-month hiatus from her Ph.D work at U. Queensland to participate on the cruise. I was also glad to hear from Elizabeth Erickson ’11 who now has hiked over the Andes Mountains and the length of the Pacific Crest Trail, seemingly on a quest to find the perfect graduate program. And, even though Elizabeth defected from paleontology to

Page 7 2014-2017 paleoclimatology, I am very proud to report she achieved her quest and enrolled in a Ph.D. program at UC Santa Barbara last year.

The literature database I reported on in my last newsletter contribution has been combined with a database compiled by Jeremy Jackson and a gaggle of post-docs that orbit around him. We composed a paper that demonstrates clearly that the decline of acroporids in the Caribbean region pre-dates the sea urchin mass mortality and white band disease of the early ‘80’s and instead occurred a few decades earlier, perhaps in response to increased nutrient loading from run-off derived from agricultural regions. This result reinforces the importance (and efficacy) of local marine management strategies, even in the wake of global climate change and increasing ocean acidification. I am hoping the final paper hits the newsstands (in Science) in the next few months.

I was very proud to write a successful proposal to the Andrew W. Mellon Foundation for $500,000 to support the Cornell Summer Research Institute over a three-year interval. Our inaugural season occurred in the summer of 2015, when 26 faculty members and 36 undergraduate students – the latter housed in a living-learning community – began a 10-week session devoted to collaborative faculty-student research. Current projects in liberal arts disciplines across divisions of the college ranged from Art History (3D imaging and reconstruction of pre-Columbian tombs and their artifacts in Oaxaca, Mexico) to Zoology (distribution, migration, and nesting success of ornate box turtles in Iowa). Of course, geology was well represented – with Rhawn and Emily each supporting two student researchers. I also arranged a variety of programming for students participating in the institute; examples include panels on applying to graduate school, research ethics, and leveraging research experiences in job and graduate school interviews. Faculty mentors also presented their scholarly interests to institute participants in a series of “Ted Talks” during the 10-week interval. The Mellon grant also supported initiatives in the digital liberal arts – including the purchase of a 3D printer that has seen wide use across the college, including in our invertebrate paleontology course, where Professor Feser had students design and print an organism. The Institute expanded this past summer to accommodate 39 students and now has a dedicated web page complete with short videos that summarize each project. Check it out at http://www.cornellcollege.edu/research/.

I think that is enough reporting on my administrative activities – all of which keep me sufficiently occupied.

Our boys continue to thrive far away from Iowa. Elijah spent last year in Tokyo while on a Fulbright that supported his dissertation research. He now is married and living in Taipei as his wife completes her Fulbright. Jonah lives in NYC and most recently worked with Laura Poitras, academy award winning director of Citizen Four, on a new film about Julian Assange. The film premiered at the Cannes Film Festival’s Fortnight of Directors this summer, for which Jonah had to purchase a tuxedo.

Best to all of you and don’t hesitate to stop by should you be in town (you’ll find me in Old Sem).

Dr. Ben Greenstein remaining active in sharing his expertise with students in his yearly Bahamas field course.

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NOTE FROM EMILY WALSH Hi! Happy Halloween to everyone. Halloween is on my mind a lot this month, as my 6-year old, Franklin, has been talking about it nonstop since October 1st. Our house is fully decorated with bats, ghosts, spiders, and pumpkins, and the word “candy” is heard constantly. It has been a fun month! Edwin, my 2-year old, isn’t quite as aware of Halloween, of course, but he has certainly learned that ghosts say “Boo”!

Halloween is also the first day of Block 3, and so it has been on my mind for other reasons—that’s the day I’ll start teaching a brand new course, a W (first-year writing) course about Natural Hazards. I am planning the course now, and I think it will be a lot of fun. We are going to start by exploring a local natural hazard—flooding—with lots of input from professionals at the Iowa Flood Center, the Army Corps of Engineers (Rock Island District), and the City of Cedar Rapids. I want students to learn about the geology of natural hazards, of course, but I also want them to begin to explore the social, economic, and geographic factors that make a natural hazard a natural disaster. This course seems particularly timely in light of all the hazard events that have been in the news over the past several months.

This year was the second year I team-taught a first-year seminar with Sociology professor Erin Davis. The course is an interdisciplinary examination of environmental and social sustainability, as viewed through the lens of consumption (or our consumer culture). Students work in groups throughout the course to research the life-cycle of a particular consumer object (like coffee, video game consoles, or hybrid cars) from the acquisition of raw materials, through production and use, to the dump or recycling center. Course highlights include our three fieldtrips: to a coal-fired powerplant in Cedar Rapids, to the Linn County Landfill, and to a local Consumer-Supported-Agriculture (CSA) farm. Most students are not excited about those particular fieldtrips to begin with, but they all reflect favorably upon them after the fieldtrips—they are completely eye-opening for the students, most of whom have never really thought about where/how we get our electricity, or what happens at the dump. Erin and I have submitted two pedagogy manuscripts related to this team-taught course, and one has recently been accepted for publication in the Journal of Geoscience Education.

During first block, I also went to the Geological Society of America meeting in Denver, to present a poster about a new research area—the Harcuvar core complex, western Arizona. We have pretty exciting new data that suggest the footwall rocks underwent significant uplift (from greater depths) much earlier (Cretaceous rather than Miocene) than previously thought. It was a terrific meeting—as always, so much fun to reconnect with colleagues and to work on ongoing projects, such as my projects involving the ophiolite and (U)HP rocks of the North Qaidam, China. While I did not have any research students this past summer (a first!), I was able to spend quite a bit of time gathering geochemical data from the year- old electron microprobe at the University of Iowa. I have enjoyed working with the new technician at Iowa, and I am planning to take my 4th block Metamorphic Petrology class down to work on the microprobe—I am envisioning a project-based course where students are given rocks to research, learning the fundamentals of metamorphic petrology along the way. Again, more things to plan, but again, something that I think would be really fun for the students (more fun that typical lecture and lab).

We really like to hear from alumni, and we’d love to have more consistent contact with you! Please let us know if you are going to be in the area—drop in and say hi.

Cheers, Emily

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History of The Norton Geology Center and Anderson Museum (Special thanks to Ryan Shanks ’16 for the curator work of the collection.)

The Norton Geology Center originally served as the campus library, built back in 1905. The library was built with the intent to serve as both a community and collegiate library.

Second floor of the Cambridge Building (Now the Norton Geology Center)

Ichthyosaurus intermedius plaster cast in Room #303 -The original fossil was found by Thomas Hawkins some 200 years ago and is now in the British Museum. -This replica was made for the Henry A. Ward (Ward's Science) catalog of fossil replicas in 1866. -The fossil cast was only made for one year and then the model was put in storage for 140 years.

Ichthyosaurus Fossil

Pliosaurus Paddle

Pliosaurus paddle fossil cast Room #308

-Another of the original plaster casts of Henry Ward's catalog of fossil casts from 1866 (also only made for one year and then the mold was put in storage Fossil can be seen displayed in top center of for 140 years). above picture taken in the museum.

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NOTE FROM RHAWN DENNISTON Dear Geology Alumni,

It’s a beautiful fall here in Iowa. I am back to work after a sabbatical last year (which took us to Britain for a while, a country of marvelous geology) which allowed me to time to concentrate on writing papers about a couple of projects. One study involved using stalagmites from Portugal to examine how ocean temperature has impacted rainfall over Iberia for the last 230,000 years. Another study involved evaluating extreme rainfall events from the Australian tropics, research that took James Garrett (’17) and me to Western Australia for three weeks last September. We installed monitoring equipment into and above a series of caves in order to determine how the caves respond to the heavy rains that come from hurricanes and monsoons. When we went back this July, we found very dry caves, a result of that strong El Niño. Hopefully there will be more rain there over the next 12 months. Stalagmites from these caves contain evidence of flooding events going back thousands of years and it is my hope to link these flood layers to ancient climates. Each trip involves 36 hours of flying in each direction and 2200 miles of driving clockwise from Perth along the coast almost to Darwin. We did some rappelling into one cave (absolutely terrifying), saw large expanses of the remarkable Australian countryside (beautiful), and had a couple of unexpected and wonderful experiences including bottle-feeding orphaned baby kangaroos (delightful).

Last year I had two students doing honors theses with me on quite different projects. Chris Felt worked in the stable isotope lab at the University of Nevada during the summer of 2015 with Dr. Matt Lachniet on stalagmites dating from past ice ages. Chris was focused on understanding how short-term interruptions in growth in a Nevada stalagmite might have impacted how we reconstruct past rainfall changes from that region. And Tom Weiss worked in the stable isotope lab at Iowa State University with Dr. Al Wanamaker on 5 million-year-old fossil corals from the Dominican Republic. Tom found evidence of ancient El Niño in these corals which was growing in the Caribbean when it was connected to the Pacific because Central America didn’t exist yet. Chris is now working in the private sector and Tom is a PhD candidate at Columbia University. This year I am working on Australian stalagmite projects with James Garrett and Elena Skosey-LaLonde. We just returned from a week at the University of New Mexico where we dated the stalagmites, and then James and Elena spent a couple of days at a different lab at Iowa State.

All’s well with Jen and the girls. Anna (11th grade) and Harper (8th grade) are, to my great sadness, growing up, although they are wonderful people who show only the rarest hints of succumbing to the Dark Side. Both are running on their cross country teams, throwing themselves into their classes, and enjoying their friends. Anna has turned into a huge baseball fan, spending many a weekend afternoon watching high school games, listening to the Cubs on the radio, and rehashing plays, stats, and strategy with her dad. Harper is designing dresses, making fashion accessories, and studying styles from past decades. Jen continues to enjoy writing the Orlando and Grand Canyon travel guides for Lonely Planet, work that took us all to Flagstaff, Las Vegas, and the South Rim last summer. If you are planning a trip to Grand Canyon, let me put in a plug for the more remote North Rim, a cool and serene alternative to the heat and crowds of the South Rim; it’s more than worth the drive.

Best wishes to you all and know that we DELIGHT in hearing your news, so please stay in touch.

Best, Picture taken on the island of Staffa which is just off the western Rhawn Scottish coast. I visited them on my sabbatical last spring.

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New Zealand Trip 2014-2015

“The whole world is, to me, very much ‘alive’ - all the little growing things, even the rocks...The same goes for a mountain, or a bit of the ocean, or a magnificent piece of old wood.” -Ansel Adams

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NOTE FROM KELSEY FESER Greetings from the basement of Norton! First, I would like to introduce myself as the newest full-time member of the Geology Department here at Cornell. I also happen to be an alumna (class of ’10), so I am thrilled to be reconnecting with all of you who share my affection for our department!

After graduating from Cornell, I attended graduate school in paleontology at the University of Cincinnati, home of the incredible Ordovician “Cincinnati Arch” deposits and an amazing place for field paleontology. While there, I built upon an interest that I developed at Cornell in conservation paleobiology. My research at UC was focused on tracking compositional changes in marine communities through time and space. This line of research is interesting both because it utilizes paleontological tools to address modern ecological tools and because it has taken me to some incredible Caribbean field localities (one of the best parts of my job!).

As I am now in the second year of my appointment, I am finally settling back into the pace of the block plan and am really enjoying my time here. I’ve gotten to know some wonderful students – both majors and non-majors – who have been bright, engaged, and inquisitive in the classroom. In invertebrate paleontology, my majors have been creating and 3D printing hypothetical invertebrate organisms that are displayed on campus. In marine science, students spend time discussing and debating major global issues associated with marine environments (e.g. sea level rise, El Niño, etc.). Taking students on field trips is another highlight of my job. Recently I took my historical geology class on a kayak trip down the Upper Iowa River, and it was an amazing moment when they realized that all that limestone formed during the Devonian because Iowa was underwater!

I’ve also had the opportunity to engage in research with a number of our students. Last year, one of our senior geology majors, Ryan Shanks ’16, worked with me to investigate the paleoecology of a genus of trilobite called Cerarus. Working in our collections and travelling to the Field Museum in Chicago, Ryan put together an interesting project that he presented at the Student Symposium this spring. This summer, I also participated in the Cornell Summer Research Institute with another major, John Lewis ’17 on a project aimed at learning and employing a shell dating technique called amino acid racemization. To do this, we travelled to Cornell University (and I of course reminded them that we are, in fact, the first Cornell) to process samples at the Paleontological Research Institute there. John, along with two additional majors, Nina Morris ’17 and Jeannie Kort ’17, will be working with me this fall to conduct their capstone research on related conservation paleobiological questions.

Aside from that, I’m just enjoying being back in Mt. Vernon and am especially loving the beautiful fall colors, which are reaching their peak as I write this. I want to invite you all to come back and visit campus any time and feel free to stop by Norton 102 and say hello!

Best, Kelsey

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3D Printing in Paleontology Ben Greenstein’s successful proposal for the Mellon grant supported purchase of a 3D printer that has seen wide use across the college including in the invertebrate paleontology course, where Professor Feser had students design and print hypothetical invertebrate organisms.

3D Organism Display Case for 2016 Year Below: Organisms made by students over the past two years.

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Geology Days 2015-2016 Cornell celebrated its first Geology Days March 31st to April 5th. Events included the explosive power of Earth’s volcanos with the University of Iowa’s Dr. Ingrid Peate demonstrating a volcano in a trash can. Other activities included the Igneous Petrology class and Physical Geology class giving hands-on and poster presentations showing the destructive power of volcanos and other natural geological hazards.

Students Jeannie Kort ‘17 (right) demonstrating rising magma plutons and Michael Sanders ’17 (above) demonstrating an erupting volcano.

Students James James Garrett ’17 and Students presenting on the Orange Carpet. Kendra Christensen ’17 present viscosities of different lavas.

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Geology Days 2015-2016 Volcano in a Trash Can

Students gathering to watch the demonstration. Dr. Ingrid Peate from the University of Iowa (right), with Dr. Emily Walsh(left) and Dr. Kelsey Feser, preparing to demonstrate the volcano in a trash can.

The Eruption

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Bahamas 2014 From February 12th– 26th, 2014, I took part in the GEO 255 Modern and Ancient Carbonate Systems class which went on a two-week trip to San Salvador Island in the Bahamas. It has been a lifelong passion of mine to become a field marine invertebrate paleontologist. This experience allowed me to work with other students and Professor Ben Greenstein on his ongoing research on San Salvador Island. I was able to go scuba diving and snorkeling while studying marine environments, the carbonate system, rock outcrops, caves, sinkholes, and more while at the Gerace Research Center. This was a once in a lifetime opportunity I will never forget. Ryan Shanks ’16

Beach across from the Gerace Research Center. Bahamas 2015 Being in the Bahamas was absolutely breathtaking. As much as I love Cornell, it was just wonderful to get a chance to see another part of the world, and any chance to get up and work outside was more than welcome in the dead of winter. Every day we were in the field we were seeing a different facet of the Bahamas, from the muddy hyper saline lakes to the inside of flooded caves. We got to hold living stromatolites in our hands before we climbed a fossil sand dune and ate lunch on a sandy beach under a palm tree. If there's one thing this course taught me, it was exactly how valuable field research is, because no amount of preparation in a classroom can quite compare with the kind of hands on experience that a field course offers. Anne Zegers ’16

“A road cut is to a geologist as a $20 bill is to a starving man”

-John McPhee Bahamas 2015

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Student Research

Dating clams to study pollution history on St. Croix, US Virgin Islands The Paleontological Research Institution (PRI) in Ithaca, New York, USA is currently running a campaign to support its new dating laboratory. This is a lab for gauging the ages of biominerals such as seashells and bones using a technique known as amino acid racemization (AAR) geochronology (for info on how this works see PRI’s project page). The dating of biominerals and seashells has many applications in research. Fields such as paleontology, tectonics and marine conservation all benefit from accurate dating methods that can help scientists put their samples in temporal context and form a clearer understanding of what has been going on over a period of time.

We spoke with Dr. Kelsey Feser, a paleontologist from Cornell College in Iowa, USA, who is visiting PRI’s AAR lab to date seashells from St Croix, U.S. Virgin Islands. Dr. Feser collected the shells from sediment cores and is using them to investigate the history of seagrass meadows that are threatened by pollution. During her visit to Ithaca, we took the opportunity to ask her a few questions about her research and why AAR dating is an important tool for her project…

What can seashells tell us about human impacts on the spectacular marine environments of St. Croix? Clams and snails are very sensitive to environmental changes, particularly those imparted by human activity, so through this research we hope to determine whether the population changes we found were caused by nearby sources of pollution.

The sorts of pollution sources that we think could be impacting marine clams and snails in St. Croix include runoff during heavy rains and Dr. Feser and her undergraduate student, John Lewis contamination from a power plant and a large, ’17, at work in the AAR lab. unregulated dump.

Why is AAR dating important for your research on St. Croix? What do you hope to learn from the data you are collecting at PRI?

I’ve been working in St. Croix for six years, and the question that keeps popping up is “how old are these shells?” And it’s not a trivial question. I am interested in the effects of human impacts on populations of marine clams and snails through time, so it is incredibly important to know how recently these population changes took place. If they happened 5,000 years ago, humans were likely not the cause! By sampling in seagrass beds, where a thick root mat anchors the sand and prevents it from getting mixed up by waves, we are hoping to find that the deeper the shells are buried, the older they are.

Text and interview done by Stephen Durham, “Paleontological Research Institution”

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Survey of Stone Age Archaeology and Quaternary Landscapes in Mozambique, and Recording Artifact and Feature Distribution in Lapa do Picareiro, Portugal.

Over the Summer of 2016, I participated in a month long geo-archaeological survey in Mozambique. The primary target of the trip was to return to the southwestern region of Massingir, and survey Quaternary deposits, including eolian sands and fluvial gravel terraces, along the Elephant River. During the survey we came across many artifacts, composed of quartz, quartzite, chert, and rhyolite--all local, and easily accessible raw materials in the Massingir, Massingir Velho area. We were able to identify one site, Txina Txina, a Late-Middle Stone Age through Iron Age open-air site, located along a smaller tributary of the Elephant River. Digital models of the site’s elevation and artefact distribution across the landscape were created using photogrammetry methods of images taken with a DJI Phantom 3 Pro UAV, and processed using Agisoft. We will return in the summer of 2017 to excavate the site further. We completed our survey along the coast, in the Vilankulos area, where the dominant composition was Quaternary deposits. This made the area have high potential area for Stone Age archaeology. We use a stratified survey strategy to specifically target extant Quaternary landscapes including landforms such as Quaternary coastal bluffs, dune-fields, fluvial terraces, and Tertiary limestone uplands with caves, rockshelters, and lithic raw-material sources. The project was supported by grants from the Fundação para Ciência e para Tecnologia, the National Geographic Society, and the Wenner-Gren Foundation for Anthropological Research.

After my survey in Mozambique, I returned to Portugal for my second consecutive season working at the Paleolithic site, Lapa do Picareiro, under the direction of Dr. Jonathan Haws, of the University of Louisville. The site is located in the limestone mountain range of Serra d’Aire, in the Estremadura region of Portugal, and sits approximately 570 meters above sea level. Excavations at Lapa do Picareiro began in 1994, and shows episodic habitation periods from the modern through the Pleistocene. The interior of the sheltered site consists of a large room, with its lowest point reaching 10.5 meters below datum. My primary purpose at the site was operating the total station and data collection system, digitizing, and recording the spatial relations of excavated artifacts, and assisting in setting permanent site data, gridding new units, recording placement of prominent features of the cave, and logging targets used in photogrammetry of larger profiles. I will return to Lapa Do Picareiro in the summer of 2017.

Elena Skosey-LaLonde ‘17 Chicago, IL

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Harcuvar Metamorphic Core Complex

During fourth block of the 2015-2016 school year, I worked with Professor Walsh on metamorphic rocks from the Harcuvar Mountains in western Arizona for my GEO 485 class. From previous work with thermobarometry, it was known that these rocks were found along a fault where different ages were given based on the history of the slip along the fault. I was specifically looking at the pressures and temperatures from which the rocks were exhumed. This information is displayed graphically in a pseudosection, which is a representation of stable mineral assemblages within a bulk rock sample over a range of pressure and temperatures. These are created by a program called Perple_X. Within the program, there are subprograms that set up the pseudosection to output a graph. After several runs through the program, and analyzing the textures of the minerals within thin sections, it was concluded that the Harcuvar rocks experienced up to ~10 kb at greater than 750°C, suggesting that these rocks were exhumed from lower crustal depths. Because these conditions correlate with older monazite ages, we propose that the Harcuvar rocks were exhuming over a longer period of time than previously thought.

Kendra Christensen ’17 Lakewood, CO

Olivine Inclusions from Basaltic Lavas

Over the summer I had the pleasure of working with Brennan Alderwerlet, a PhD student at the University of Iowa campus. My project involved looking at melt inclusions within olivine crystals taken from basaltic lavas in Arizona. Melt inclusions in olivine represent accidentally trapped silicate melt that provides us snapshots into the evolution of a magma system. These inclusions are the result of any number of irregular crystal growth of the olivine. By exposing these melt inclusions at the surface, we are able to use the electron microbe at the University of Iowa in order to get a chemical signature from each inclusion in the crystal. My work involved creating the mounts for the single olivine crystals and polishing them until the inclusions were exposed at the surface. Unfortunately, my time for the summer was up before the first samples where run through the electron microprobe.

Nina Morris ’17 Maxwell, IA

Page 20 2014-2017

Geology Majors of Phi Beta Kappa

The Cornell College Geology Department recognizes the recent graduates inducted into Phi Beta Kappa, the nation's oldest and most prestigious undergraduate honors organization.

2013-2014: Ni An (Annie), Angelique Gonzales, and Amanda Houts

2015-2016: Christopher Felt, Thomas Weiss, and Anne Zegers

Special Note: In the 2013-2014 academic year, 3 of the 12 students inducted into Phi Beta Kappa were majors within the geology department!

2013-2014 Phi Kappa Beta Inductees

From left to right: Ni An (Annie), Angelique Gonzales, Amanda Houts, and Dr. Emily Walsh.

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Graduating Majors 2013-2014 Graduating Majors: Angelique Gonzales, Ni An (Annie), Amanda Houts, Aaron Campbell, Stephanie Wheeler, JB McElroy, Max Bertsos, KJ Passaro, Maggie Savage, Laurel Perper

2014-2015 Graduating Majors: Nicole Werling, Jake Butts, Scott Kottkamp, Emmett Wilder, Stefanee Lucker, Nikki Ahline, Natalie Nish, Setsen Altan-Ochir, CJ Frazer

2015-2016 Graduating Majors: Stephano Garcia-Riefkohl, Thomas Weiss, Ryan Shanks, Sean Quick, Vreni Riedel, Erin Newman, Christopher Felt

Student Awards and Honors Herbert Hendriks Award Paul Garvin Award (Outstanding Senior Geology Major) (Outstanding Sophomore Geology Major) 2014-Amanda Houts, Angelique Gonzales, 2014- Thomas Weiss Ni An 2015-John Lewis 2015-Scott Kottkamp 2016-Thomas Weiss Gene Hinman Geology Award (Outstanding Geology Fieldwork) William H. Norton Geology Award 2014-Nikki Ahline (Outstanding Junior Geology Major) 2015-Christopher Felt 2014-Scott Kottkamp 2016-Elena Skosey-LaLonde 2015-Thomas Weiss 2016-John Lewis Departmental Honors in Geology 2014- Amanda Houts, Angelique Gonzales, Ni An (Annie) 2015-Scott Kottkamp 2016-Thomas Weiss, Christopher Felt

Sigma Gamma Epsilon (Geology Honorary Society Graduating Seniors)

2014- Kristian James Passaro, Angelique Gonzales, Ni An (Annie), Amanda Houts, Aaron Campbell, Max Bertsos, Maggie Savage, and Stephanie Wheeler (at UNI chapter)

2015-Setsen Altan-Ochir, Scott Kottkamp, Stephanie Lucker, and Nicole Werling 2016-Anne Zegers, Ryan Shanks, and Thomas Weiss

Student Symposium A full list of Symposium contributions and abstracts can be found on the college website at this address: http://symposium.cornellcollege.edu/?s=geology Following is a selection of abstracts of the varied topics that have been featured at recent symposiums.

Page 22 2014-2017

Honors Thesis A stalagmite record of millennial-scale continental climate variability during the last glacial cycle from western Iberia

While ocean conditions along the Iberian margin have been tied to millennial-scale climate variability during the last glacial cycle, continental climates in Iberia from this time period are much less well understood. Here we present a stalagmite record from cave Buraca Gloriosa, western Portugal, which shows a direct link between Iberian paleoceanographic changes and continental climate variability. This record reveals millennial-scale variability in both carbon and oxygen isotopic values similar in timing and structure to D/O events observed in Greenland ice cores. Stalagmite chronologies are anchored using 47 high precision 230Th dates and reveal intermittent stalagmite growth from 82.1 ± 0.4 to 1.2 ± 0.1 ka with growth hiatuses spanning most Heinrich stadials.

Oxygen isotopic values shift by 1.0-1.5‰ during MIS 3-4 with lower values defining D/O interstadials and showing the same characteristic asymmetry of these structures in the Greenland ice records. Although temperature effects on oxygen isotopic ratios of meteoric precipitation as recorded at the GNIP station of Porto, 179 km north of Buraca Gloriosa, are statistically significant, the slope is shallow; hence the stalagmite record from this region likely reflects precipitation dynamics rather than temperature changes. At this location, amount effects impart a prominent influence on modern isotopic ratios of precipitation. Thus, amount effects, as well as the strong seasonality of precipitation in this Mediterranean climate, are thought to be the primary drivers of oxygen isotopic variability in Buraca Gloriosa stalagmites.

Carbon isotopic values shift by 3.5-4‰ between D/O events, with lower values defining D/O interstadials. These changes likely reflect increased vegetation density and reduced prior calcite precipitation during the warmer, wetter climates of D/O interstadials. Hiatuses during Heinrich stadials likely also reflect these cold and dry conditions. Future measurements of temperature, humidity and barometric pressure in Buraca Gloriosa will provide additional insight into seasonal changes in cave conditions that could influence these isotopic fluctuations.

Amanda Houts ’14 Jefferson City, MO

From right to left: Setsen Altan-Ochir, Dr. Rhawn Denniston, KJ Passaro, and Amanda Houts.

Page 23 2014-2017

Honors Thesis A MONTHLY-RESOLVED OXYGEN ISOTOPIC TIME SERIES FROM A PRISTINE FOSSIL CARIBBEAN CORAL SUPPORTS MODERN ENSO CONDITIONS AT THE MIOCENE/PLIOCENE BOUNDARY The Pliocene warm period (PWP) (5.3-2.6 Ma) is a common analog for a future, warmer world. The nature of El Niño Sothern Oscillation (ENSO) during the PWP is the subject of debate, with conflicting models and centennial-scale marine core proxy data suggesting either a (1) persistent El Niño-like state (Wara et al., 2005, Science v.309, p.758) or (2) persistent La Niña-like state (Rickaby and Halloran, 2005, Science v.307, p.1948). Alternatively, a sub-annually-resolved oxygen isotopic time series of a pristine fossil coral from the western Pacific identified PWP sea surface temperature variability consistent with modern ENSO conditions (Watanabe et al., 2011, Nature v.471, p.209). No similar analysis has been performed on pristine PWP corals from the eastern Pacific. Because prior to ~2.7 Ma the Central American Seaway (CAS) allowed Pacific waters to flow into the Caribbean Sea, ENSO signals could have been propagated directly into the Caribbean. Pristine corals from the latest Miocene now found in the Dominican Republic have been previously dated using U-Pb techniques (5.5±0.1 Ma) and analyzed for oxygen and carbon isotope values (Denniston et al., 2008, Geology v.36, p.151). We have micromilled at ~15 samples/year adjacent sections of the previously analyzed corallite, thereby extending this stable isotope record to 27 years in length. Following the methods used by Watanabe et al. (2011), the seasonal cycle in these oxygen isotopes was deconvolved and positive and negative departures were identified. This record suggests that anomalous winter sea surface temperatures occurred at intervals consistent with modern ENSO behavior. These findings should be integrated into paleoceanographic models of the CAS at 5.5 Ma to better understand their connection to ENSO. Future research will lengthen this record, further clarifying the state of PWP ENSO. Thomas Weiss ’16 Fairfield, IA

American Geophysical Union meeting in San Francisco in December 2015.

Page 24 2014-2017

Honors Thesis Characterization of Layer-Bounding Surfaces in a Great Basin Stalagmite Utilizing both Petrographic and High-Resolution Stable Isotope Analyses

Layer-bounding surfaces in stalagmites represent hiatuses in growth due to either erosion during wet climate periods (type E layer-bounding surfaces) or a period of lesser deposition when climate is relatively arid (type L layer-bounding surfaces; Railsback et al., 2013, Int. J. Spel., 42, 167). Accounting for layer-bounding surfaces not only offers an additional method of tracking past climate change, but can also be useful when constructing stalagmite chronologies.

We conducted a petrographic and high-resolution stable isotopic analysis of the layer-bounding surfaces in stalagmite LMC-1 from Lehman Caves, Nevada. Fourteen 234U-230Th ages show that deposition occurred discontinuously between ~659 – 243 ka, with two hiatuses at ~243 ka and ~387 ka, within error of interglacial periods (MIS 7 and 11, respectively). A third, less well- defined hiatus at ~308 ka may also be the result of arid climate during MIS 9. One additional hiatus with a poorly constrained age (U-series ages show only that it occurred between ~659 – 423 ka) may have occurred during interglacial period MIS 13. Petrographic observations of these hiatuses reveal they are type L layer-bounding surfaces, suggesting arid Great Basin climates similar to the Holocene.

High-resolution (100 ìm) stable isotope analyses drilled up to and across each hiatus reveal that ä18O values become progressively more negative towards the termination of each layer- bounding surface. If increases in evaporation or prior calcite precipitation had dominated at these hiatuses, an opposite trend would be expected, with ä18O values becoming progressively more positive. The isotopically light trend is thus interpreted to be the result of a consistent change in the processes that control the ä18O value of drip water in Lehman Caves, such as a shift in the dominant sources of precipitation. ä13C values exhibit less consistency at the L surfaces, however, and may reflect multiple effects, such as variations in vegetation density, soil water residence times, or variations in the pCO2 of the cave atmosphere. Overall, petrographic and high-resolution stable isotope data of LMC-1 may offer an additional method of deciphering climate change that was not possible using coarse-resolution stable isotope data.

Christopher Felt ’16 Provo, UT

Page 25 2014-2017

Reconstructing the Caledonian Orogeny Through Zircon U-Pb Geochronology and Geochemistry, Western Gneiss Region, Norway The Western Gneiss Region (WGR), Norway, is an ultrahigh-pressure (UHP) terrane containing coesite. Coesite forms at >29 kbar and >700oC indicating the WGR, which consists of Baltica basement and the overlying Lower, Middle, Upper, and Uppermost allochthons, was subducted to depths of ~125 km or greater (Smith, 1984). Zircon U–Pb ages from the different units record multiple orogenic events, with all but the Uppermost Allochthon recording the Scandian (~415– 395 Ma) ultrahigh-pressure event (Roberts, 2003). We analyzed zircon geochronology and trace element geochemistry from the Moldefjord area to better understand the pre-Caledonian events and reconstruct the units involved in the Caledonian orogeny and UHP metamorphism.

Our zircon ages ranged from 2697 ± 73 Ma to 394 ± 8 Ma, but generally clustered around dates that correspond to known events. Of the main age clusters, the oldest corresponds to the Transcandinavian Igneous Belt (1832 ± 11 Ma), the next to the Sveconorwegian orogeny (1060 ± 5 Ma), the northeast Høybakken extensional detachment (463 ± 5 Ma), and lastly the Caledonian orogeny (436 ± 9 Ma). One sample from the Middle Allochthon, E4721G, contains Sveconorwegian ages but is located at the northeastern edge of the WGR. The Sveconorwegian orogeny was thought to have affected only the southwestern WGR. Our data suggest the Middle Allochthon was affected by the Sveconorwegian orogeny in its original position as the westernmost portion of the Baltica basement. These rocks were then thrust to the SE, indicating that the Sveconorwegian orogeny affected a larger area than previously recognized.

Maggie Savage ’14 Appleton, WI

From left to right: Maggie Savage, Dr. Emily Walsh, and Stephanie Wheeler

Page 26 2014-2017

The understanding of ultrahigh-pressure (UHP) eclogites in Tso Morari through the study of major and trace elements When the Indian and Asian plates collided to form the Himalayas starting 45 million years ago (mya), sheets of rock were thrust up and exposed at the surface. These sheets, known as nappes, provide windows into the formation of the mountain building event. In the northern Indian Himalayas lies the Tso Morrari nappe. This area has linear intrusions of magma from the Ordovician Period (~450 Mya) that were metamorphosed into eclogites, rocks formed at extremely high pressures and temperatures. In this study, we used an electron microprobe and a scanning electron microscope to analyze the trace element chemistry of the eclogites. These chemical data were used to reconstruct the pressure and temperature paths of formation of the Tso Morrari eclogites. These data support the idea that the eclogites form at anomalously high pressure (called ultra-high pressure) areas within the mountain belt, suggesting that these rocks were exhumed from deep within the Himalayas.

Nicole Ahline ’15 Lemont, IL

What Can Isotopes Reveal to Us About Iberian Climate in the Past?

Marking the southwestern coast of Europe, the Iberian Peninsula (IP) is a hotspot for studying transitions of climatic signals from high-to-mid latitudes, because it is a sensitive region to abrupt climatic variations. There are numerous paleoclimate studies on marine cores from the Iberian Margin that reveal synchronous changes in SST inferred from isotopic ratios (O18/O16) of foraminifer shells and terrestrial plant species from pollen records deposited from land. However, lack of data from terrestrial proxies is necessitates investigation of local responses to climate forcing, which may show different patterns.

In this study, we analyzed stalagmites from Rabbit Farm cave in the western coast of Portugal to extend previous study conducted on stalagmites from the nearby Glory Hole and Almanda caves that dated back to 132000 years ago, and to get a more complete picture of climatic changes in this area. We determined the ratios of oxygen (O18/O16) and carbon (C13/C12) isotopes in the stalagmite calcite (CaCO3), because they reflect local or regional climatic changes. With the dates obtained by U-Th dating to get the chronologies of the stalagmites, we developed age models to construct isotopic profiles of the stalagmites through time. The stalagmites from Rabbit Farm cave were found to respond to regional and local variables. While they stopped growing during major Heinrich events, there is no sign of deglaciation around 178,000 years ago that are present in Greenland records, alluding to dominance of local factors.

Setsen Altan-Ochir ’15 Ulaanbaatar, Mongolia “Show me a person who throws money into a shifting crack in the ground, and I’ll show you someone who is generous to a fault.” -Unknown

Page 27 2014-2017

Testing Bergmann’s Rule on North American Hyaenodon Throughout the Eocene and Oligiocene

In this study, I conducted research on the cause and effect relationship between Hyaenodon’s body size and the fluctuating climate throughout the Eocene and Oligocene. Hyaenodon is an extinct genus of mammals that belonged to a group of carnivorous creodonts called Hyaenodontidae. My focus will be the study of Hyaenodon’s teeth, a proxy for body size in mammals. Hyaenodon was a fierce predator due to its extremely powerful jaws. Furthermore, Hyaenodon’s teeth were specially adapted for slicing through meat, making food digestion more efficient. All of the Hyaenodon fossil collections material I measured was stored in the Field Museum of Natural History in Chicago.

I will be testing the theory of Bergmann’s Rule on Hyaenodon dental data. Bergmann’s Rule states that during periods of changing temperatures, the result of that change will be an alteration in the size of an animal, reflecting the warmer or cooler temperatures. What his theory illustrates is that during warmer periods, we expect to see smaller-bodied animals because they have an easier time releasing heat in hot temperatures. For cooler temperatures, we expect to find larger- bodied animals because it is easier for them to store heat to adapt for colder temperatures. Approaching the Eocene and Oligocene boundary, we saw a sharp rise in temperature called the Eocene Thermal Maximum, about 50 million years ago. Across the boundary, there was a fast drop in temperature. This provides a perfect change in climate for Bergmann’s Rule to be tested. I expect to find that Hyaenodon increased in body size over the Eocene and Oligocene boundary, due to the decreasing temperature.

I tested the relationship of body size in Hyaenodon and changing climates across the Eocene and Oligocene boundary, and found positive results supporting Bergmann’s Rule. In the warmer climates of the Eocene, I found there were smaller-bodied Hyaenodon than during the cooler climate of the Oligocene.

Jake Butts ’15 Watertown, WI

Page 28 2014-2017

Evolution Towards Larger Body Size and Hypercarnivory in Hesperocyon of the White River Group Over the Eocene-Oligocene Boundary There have been three major groups of dogs: the hesperocyonines, the borophagines, and the canines. The former two groups both diversified, dominated a niche as hunters of large prey, and then declined to extinction in turn. This radiation and subsequent decline of dog clades mirrors a wider pattern in faunal succession of large predators throughout the Tertiary. Each predatory ecomorphological role seems to be filled by a given family for 10 million years or so before that group declines and is replaced by another. Since this pattern of extinction repeats predictably in major taxa of mammalian predators, its possible causes are worth investigating. Furthermore, results may inform conservation methods for modern analogues.

The purpose of this research project was to test the hypothesis made by previous researchers that larger body size and hypercarnivory evolved together in hesperocyonines. This was done by seeing if their predictions were supported in specimens from the White River Group, a region with an excellent fossil record from a time when hesperocyonines were dominant. This would help determine whether changes in size and diet were universal or varied by region in hesperocyonines. Since the White River covers the Eocene-Oligocene boundary, this study also aimed to discern if the climate shift that occurred across that boundary had any influence on hesperocyonine evolution.

Data collection methods involved taking measurements of craniodental features strongly correlated with body size and carnivory, primarily the length of the first lower molar (m1) and the length of its trigonid. The sample tested at the Field Museum totaled 93 specimens, all Hesperocyon (some identified to species as Hesperocyon gregarius). Data analysis was performed by averaging measurements for all specimens from the same period or North American land mammal age, and then graphing the average lengths versus times.

The resulting data display an increase in both m1 length and relative blade length over the Eocene-Oligocene boundary. The increase in relative blade length is proportionally larger than the increase in m1 length: average m1 length increased by about 2.7% from the Eocene to the Oligocene, while relative blade length increased by 5.86%. Furthermore, the change in relative blade length is significant within a 90% confidence interval, while the change in m1 length is not. This suggests that changes in hesperocyonine diet over the Eocene-Oligocene boundary were more significant than changes in body size, and thus may have been the greater driving force in hesperocyonine evolution at that time.

Scott Kottkamp ’15 Aurora, IL “(In geology) we find no vestige of a beginning – no prospect of an end…”

-James Hutton

Page 29 2014-2017

Paleomonsoon Implications of Carbon Isotopic Variability in Late Holocene Aragonite Stalagmites from the Central Australian Tropics Summer monsoons provide the majority of annual precipitation in much of the global tropics. In northern Australia, the hydroclimate is dominated by the Indo-Australian Summer Monsoon (IASM). This monsoon provides 70-90% of yearly rainfall, all within the austral summer, supporting agriculture and regional ecosystems. Historical records of the IASM began in the late nineteenth century and reveal limited monsoon variability. In order to better understand how the IASM may respond to anthropogenic warming of the oceans and atmosphere, previous studies utilized oxygen isotopic ratios of stalagmites from the Kimberley region of easternmost tropical Western Australia. As a complement to that work, I analyzed the carbon isotopic ratios of the same stalagmites. The addition of carbon isotopic data provides a more complete picture of hydroclimate variability. Stephanie Lucker ’15 Bozeman, MT

Rediscovery and Lithic analysis of Rummells-Maske Site 13CD15 The Rummells-Maske site, 13CD15, lost within the memories of those who originally excavated it back in 1968, may be seen once again. With the archeology field classes’ efforts in 2012 and 2014 and the guidance of professionals from the department of the state archeologist of Iowa, this site may once again be observed and studied. John Doershuk and Mark Anderson, among others, have studied a site near Cornell College that exhibits evidence of Paleo-Indians. This site, 13CD15, was thought to be the home of an excavation that took place in 1968-1969. It was labeled a “find-spot” due to the bundle of fully fluted Clovis points found in 1968 and a scattering of flakes and points found throughout the site. However, by re-evaluating the maps, journals, and photographs, we believe that this is not a find-spot or a Clovis cache, but instead a hunter-butcher site. After years of search, we have come across enough evidence to definitively outline the boundaries of 13CD15. Through the lithic analysis of artifacts found at the Rummells-Maske site, we can confirm that the lost “find-spot” has not only been found, but actually is more than a “find-spot”. We will discuss why we believe it is actually a hunter butcher site left behind from Clovis people. As one of only three known Clovis sites in Iowa, this is an exceptional chance to continue our studies of the original paleopeoples of America.

Natalie Nish ’15 College Station, TX

Page 30 2014-2017

Grazers vs. Browsers: A Study of Diet Amount the Horses at Ashfall Fossil Beds, Nebraska The evolution of equids (horses) has been extensively studied and is often used as an example of how evolution occurs, and has many times been used to prove that evolution does in fact occur. Horses appear in North America early in the Eocene at about 55-50 Ma. The story of horse evolution in North America focuses mainly on how horses have adapted to changes in the environment. Before grasslands emerged horses are thought to have been browsers, meaning that their diet consisted mostly of soft leafy vegetation or fruits. As grasslands started to replace forests during the Miocene (23-5.3 Ma), it is believed that the main food source for horses became the abrasive grasses found in the grasslands. This meant that horses would benefit from higher crowned teeth that would not wear down as easily while eating these abrasive grasses. Recently, multiple studies have questioned this simple evolutionary story as evidence has been found that horses were still browsers long after they evolved hypsodont teeth. In this study, mesowear analysis was performed on the teeth of 22 specimens from the Ashfall Fossil Bed site in Antelope County, Nebraska. These specimens represent 4 different genera that were alive and living together in this area around 11.8 Ma. Even though there were multiple species of horses competing for the same food source, and, in contrast to other recent studies, the results support the traditional horse evolution story. The horses at Ashfall were mainly grazers, and there was little variation between the different genera. More data from other sites in Nebraska would provide validation to this study. Also, mesowear analysis data from a site in Oregon that is similar in age to Ashfall would give a good set of comparison data and show if a different environment with a different variety of food sources would yield different results, results in which the hypsodont horses were actually browsers. Nicole Werling ’15 Cedar Rapids, IA

Coral mortality recorded in Bahamian reef sediments Coral populations have declined significantly over the past few decades in a phase shift towards macroalgae. Until the advent of white-band disease in the early 1980’s, Acropora cervicornis was a dominant coral in reefs throughout the Caribbean. In an effort to determine precedence for such a die-off, scientists tested for a signature in the Pleistocene fossil record. The current mass- mortality of A. cervicornis is found to be unprecedented in the fossil record. Yet, preservational bias of soft macroalgae could allow for this event to pass unseen in the fossil record. An increase in coral mortality leads to a higher ratio of coral skeletons to other constituent particles. If recent mortalities are recorded in the sediment, then a particle analysis of several reefs surrounding San Salvador Island, Bahamas should reflect their different histories and mortalities. I tested this hypothesis by doing a constituent particle analysis on the aforementioned reefs and comparing the results to coral mortality history. Preliminary results suggest that reef sediments are indeed influenced by coral mortality. Emmet Wilder ’15 Oak Park, IL

Page 31 2014-2017

The Distribution, Identification and Rock-Ice Dynamics of Permafrost Melting on Alpine Mountains

A review of existing literature was done to understand how ice interacts with rock, specifically in Alpine mountains when permafrost is present. Due to recent global climate change, permafrost has been melting at an increasing rate. This melting is causing talus slopes and various types of landslides to occur. It is through studying the rock-ice dynamics that we will be better able to prepare ourselves for the damage that is to come.

CJ Frazer ’15 Des Moines, IA

Some of the 2015 Graduating Geology Majors.

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Hydrological Response to an Increasingly Warm Volga Region Western Russia has warmed at nearly twice the global rate over the past century; however, despite it being a major center of agricultural production, the hydrological response to such warming has not been well constrained. This investigation analyzes Mg and Sr variations in a U- Th dated stalagmite from the Volga Basin of the Southern Ural Mountains, which were interpreted to reflect local precipitation and water residence time from roughly 11,700 to 1,800 years BP. Pollen data indicate that the modern and forested landscape has been in place for roughly 10,000 years, and this vegetation has been the major source of carbon for the underground caves. Previously reported ä13C values of our cave were interpreted to reflect changes in warm-season precipitation. Such changes support the Mg data, and suggest a drying trend during the last four centuries of stalagmite growth. Previous isotope data reveal that ä18O tends to slowly increase, which suggests the region has gradually warmed since the beginning of the Holocene. Precipitation changes have not been as continuous; moreover, the chemical ratio data suggest that the Volga climate became increasingly humid following the Younger Dryas, stayed relatively wet throughout the Holocene climatic optimum, and has progressively become drier ever since. Unprecedented warmth and dryness in the future climate threatens agricultural sustainability in otherwise fertile lands, which majorly affects populations that depend on Russian food production.

Stefano Garcia Riefkohl ’16 Acapulco, Mexico

Sefano Riefkohl (right) with Dr. Jonathan Baker (left), from the University of Nevada, Las Vegas, presenting at GSA 2016.

Page 33 2014-2017

Types of Pathology in Megalodon Shark Teeth and the Implications for Feeding Habits and Health Deformities such as pathologies and pseudopathologies found within fossil specimens can be informative about an ancient species. One species in particular about which we still know far too little is Carcharodon megalodon (the largest shark species in history). In this study I examined the types of pathologies and pseudopathologies and their frequency in C. megalodon teeth in order to determine their patterns of occurrence and what they meant for the species. From this research and future research, I hope to be able to draw insight into factors of C. megalodon life, such as its hunting style and be able to compare the patterns of pathology and pseudopathlogy in C. megalodon to other shark species in an attempt to determine whether C. megalodon belongs to the genus Carhcarodon or the genus Carcharocles. The research I conducted consisted of recording data on C. megalodon teeth from the Field Museum. I recorded general information including the size of the teeth, their positions in the mouth, and whether there were any pathologies or pseudopathologies and if so, what types. I then determined the rates of pathology and pseudopathology in the teeth sorted by different variables in order to understand how each variable effects the pathology rate.

I found that as size increases, the rate of both pathology and pseudopathology increases and that more often than not, pathologies and pseudopathologies occur towards the front of the mouth. In addition to physical reasons, there may also be behavioral reasons for why large teeth seem to be more susceptible to pathology and pseudopathology such as the larger, adult C. megalodon sharks hunted larger prey such as whales and other marine mammals (as apposed to the fish that juveniles hunted), and the bone of marine mammals enable the teeth to be knocked out and bitten more easily. A possible explanation for the pattern of pathology relating to teeth from the front area of the mouth of C. megalodon is that this area had a greater chance for injury from feeding and thus, a greater chance for the formation of pathologies and pseudopathologies.

Ryan Shanks ’16 Des Moines, IA

Page 34 2014-2017

Elemental Zoning Analyses in Eclogitic Garnets from the North Qaidam UHP Metamorphic Belt: Testing Trace Element Zoning Models and P/T Path

Trace elements, including the rare earth elements (REEs) and Y, constitute low concentrations (<0.1%)of bulk rock compositions. These elements do not control growth, but instead record metamorphic events through zonation patterns in garnets. For example, heavy rare earth elements (HREEs) tend to be concentrated in the core of the garnet because they are preferentially incorporated by garnet early in its growth. This is known as a bell-shaped distribution pattern. Light rare earth elements (LREEs) are larger and cannot be as easily incorporated into the garnet structure. This study also examined major mineral zoning for Ca, Fe, Mg, and Mn in garnets, as well as analyzed accessory-phase minerals apatite, monazite, xenotime, allanite, zircon, titanite, and rutile to predict REE patterns and help refine the trace element analysis. Major element maps were created using the JEOL JXA-8230 Superprobe at the University of Iowa using an accelerating voltage of 15 kV and a 100-nA beam current, with a dwell time of five seconds. Accessory mineral data for the current study were gathered using a variable-pressure 5-3400 Scanning Electron Microscope (SEM) with a beam voltage set to 15 kV and a vacuum setting of 6. Analysis of major element maps and accessory mineral data revealed the North Qaidam ultrahigh-pressure terrane was heated during exhumation, underwent prograde metamorphism, and experienced mineral growth during decompression. Based on the accessory minerals, it is expected for future studies that the garnets will display a bell-shaped distribution pattern for Y and M-HREEs while LREE concentrations will be high.

Sean Quick ’16 San Rafael, CA

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Corrected Trace Element Data from UHP Garnets of the Tso Morari Complex, Ladakh Province, NW India: Evidence for Diffusion-Limited Uptake

This project compares trends in the abundance of trace elements from the lanthanide series of rare earth elements (REE) from five garnets from the ultrahigh-pressure metamorphic Tso Morari Complex (TMC), Ladakh Province, NW India. Raw trace element abundance data were obtained by McElroy in 2013, using laser ablated-inductively coupled plasma mass spectrometry, and plotted in counts per second against length of laser ablation. These data were corrected using the known abundance of the isotope 29silicon in garnet as an internal standard, following the procedure of Lin (2006). Changing trends of trace element abundance indicate changes in the rate at which trace elements are transported between garnet grains, commonly influenced by changes in metamorphic conditions. By correlating the sections of the element abundance profiles from the five garnets that represent periods of simultaneous growth, this study observed trends in the shape of the profiles that indicate changes in the rate at which trace elements were incorporated into the growing garnets as the trace elements diffuse through the parent rock. In the TMC garnets, the light REE form bell-shaped profiles, associated with rapid diffusion of trace elements in an unchanging assemblage of matrix minerals, or oscillating profiles, associated with rapid diffusion during the breakdown of matrix minerals (Moore et al., 2013). M-shaped profiles in the medium and heavy REE is interpreted to mean that the limiting factor in the rate of trace element uptake by the garnets was the rate at which the trace elements were transported through the intergranular medium (Moore et al., 2013).

Anne Zegers ’16 Machias, ME

Facts are simple and facts are straight Facts are early and facts are late Facts all come with points of view Facts don’t do what I want them to

-Talking Heads, “Crosseyed and Painless,” 1980

Dr. Emily Walsh with student Anne Zegers ’16

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17 Years on a Beach: A Comparative Study of Beach Dynamics over Time

This research compiles beach profiling data obtained yearly between 1999 and 2016 and indicates annual changes in the beach morphology of three beaches on San Salvador Island, Bahamas. The profiles provide a visualization of the effect of different hydrodynamic regimes present on each beach. The beaches surveyed are each affected differently by wind- and wave- energy regimes, resulting from their associated offshore environments and geographical location on the island. Rocky Point Beach is located on the northwestern side of San Salvador and is sheltered from the northwesterly winds and waves associated with cold fronts during the winter season, thus allowing the beach to remain in a relatively stable state since 1999. East Beach, located on the eastern side of San Salvador, is a moderately-low-energy beach, resulting from the presence of an algal ridge 200 meters offshore that acts as a wave breaker. East Beach is predominantly affected by waves associated with the NE trade winds as well as hurricanes. These alter the beach’s morphology and allow it to build out into the shallow environments offshore. The third and final beach examined in this study is Sandy Point Beach. Located on the southwestern side of the island, this highly-exposed beach is affected by both the trade winds during the summer months and northwesterly winds and longshore currents that flow down the western side of the island during the winter. The research presented here shows 1) the influence of beach location on geomorphology; 2) yearly “normal” variation in beach morphology; and 3) the effect of major hurricane events, specifically Hurricanes Frances (2004) and Joaquin (2015), on the beach systems.

Elena Skosey-LaLonde ’17 Chicago, IL

…I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect; of this history, we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. -Charles Darwin

Elena Skosey-LaLonde ’17 with Dr. Ben Greenstein

Page 37 2014-2017

Stalagmite Records of Climate Change Spanning the Last 500,000 Years from Cape Range, Western Australia

Paleoclimatology is the study of past climates through the use of climate proxies, geologic or biologic records that preserve evidence of temperature or precipitation prior to those periods recorded by humans. Stalagmites, mineral deposits formed from dripwater on the floor of caves, are useful as paleoclimate proxies for two reasons. First, they can be precisely dated to ~500,000 years ago, and second, carbon and oxygen isotopes in stalagmites track a variety of climate signals. Oxygen values change due to where the precipitation comes from, how much it rains, air temperature, and the distance the atmospheric moisture traveled, while carbon reflects moisture and plant activity above the cave system.

This project involves a stalagmite reconstruction of climate change from Cape Range, Western Australia over portions of the past 500,000 years. A prominent source of uncertainty in Australian paleoclimate is the influence of the Northern Hemisphere (NH), particularly heating of the Asian landmass, on Australian monsoon rainfall. Stalagmites from China have shown that the Eastern Asian Summer Monsoon (EASM) reflects NH insolation, the amount of solar radiation that reaches earth’s surface, which allows for heating of landmasses. However, the role of NH insolation on Australian paleoclimate has remained poorly constrained because Australia has few high-resolution continental records spanning hundreds of thousands of years. Cape Range is well-situated for recording changes in Australian hydroclimate. This region marks the boundary between monsoon rainfall coming from the tropics and middle-latitude rainfall from the south. We find similarities between monsoon trends recorded by stalagmites from China and stable isotopic trends in stalagmites from Cape Range. Both oxygen and carbon isotopes in Cape Range stalagmites suggest that elevated rainfall occurred during times with a stronger EASM. These times of stronger EASM are marked with more positive oxygen values and more negative carbon values. The dates of these observed peaks are roughly 470,000; 270,000; 100,000; and 10,000 years ago. There are still unanswered questions as to why we see these peaks.

James Garrett ’17 Fountain, CO