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Page 1 2014-2017
ASSEMBLED AND EDITED BY NINA MORRIS ’17
Cornell College
2014-2017
Newsletter
DEPARTMENT OF GEOLOGY
Featuring:
Class Trips, Department Honors,
Student Research, Notes from
Faculty, and a Call to Alumni.
Bahamas Trip 2016
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
Page 3 2014-2017
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!!
Page 4 2014-2017
Paleoecology: 2015
Devonian Fossil Gorge Field Work
Tectonics: 2016
Baraboo Park Physical Geology: 2016
Wildcat Den State Park
Historical Geology: 2016
Kayaking Trip down the Upper Iowa River
Igneous Petrology: 2014
St. Francois, Southeastern Missouri
Geology Class Field Trips
Page 5 2014-2017
Geology Field Work and Field Courses
New Zealand Trip 2014-2015
Student James Garrett ’17 and Dr. Rhawn
Denniston conducting research in an
Australian cave during the summer of 2015.
Scuba Diving in 2016.
Cave Exploring in 2014.
Making Cross-Sections in 2015.
Bahamas Trip 2014, 2015, and 2016
Page 6 2014-2017
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.
Page 8 2014-2017
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
Page 9 2014-2017
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.
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.
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
for 140 years).
Second floor of the Cambridge Building (Now the Norton Geology Center)
Fossil can be seen displayed in top center of
above picture taken in the museum.
Pliosaurus Paddle
Ichthyosaurus Fossil
Page 10 2014-2017
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,
Rhawn Picture taken on the island of Staffa which is just off the western
Scottish coast. I visited them on my sabbatical last spring.
Page 11 2014-2017
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
Page 12 2014-2017
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
Page 13 2014-2017
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.
Page 14 2014-2017
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 James James Garrett ’17 and
Kendra Christensen ’17 present viscosities
of different lavas.
Students presenting on the Orange Carpet.
Students Jeannie Kort ‘17 (right)
demonstrating rising magma plutons and
Michael Sanders ’17 (above) demonstrating
an erupting volcano.
Page 15 2014-2017
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
Page 16 2014-2017
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
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
Beach across from the Gerace Research Center.
Bahamas 2015
“A road cut is to a geologist as a
$20 bill is to a starving man”
-John McPhee
Page 17 2014-2017
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
contamination from a power plant and a large,
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.
Dr. Feser and her undergraduate student, John Lewis
’17, at work in the AAR lab.
Text and interview done by Stephen Durham, “Paleontological Research Institution”
Page 18 2014-2017
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
Page 19 2014-2017
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.
Page 21 2014-2017
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
(Outstanding Senior Geology Major)
2014-Amanda Houts, Angelique Gonzales,
Ni An
2015-Scott Kottkamp
2016-Thomas Weiss
William H. Norton Geology Award
(Outstanding Junior Geology Major)
2014-Scott Kottkamp
2015-Thomas Weiss
2016-John Lewis
Paul Garvin Award
(Outstanding Sophomore Geology Major)
2014- Thomas Weiss
2015-John Lewis
Gene Hinman Geology Award
(Outstanding Geology Fieldwork)
2014-Nikki Ahline
2015-Christopher Felt
2016-Elena Skosey-LaLonde
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.
Page 32 2014-2017
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
Page 35 2014-2017
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
Dr. Emily Walsh with student Anne Zegers ’16
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
Page 36 2014-2017
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
Elena Skosey-LaLonde ’17 with Dr. Ben Greenstein
…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
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
