This summer I traveled to Southern Mongolia through funding from the Keck Geology Consortium.
I worked with several American as well as Mongolian students and advisers for two and half
weeks in the Shine Jinst region of the Gobi-Altai Terrane. Our research was aimed at
paleobiogeographic reconstruction of the area which included carbonates, shales, conglomerates,
and sandstones of Late Ordovician to Devonian age. My research was focused on a Late Ordovician
145 meter sequence of carbonates, sandstones, and shales. My work this semester will involve
isotope geochemistry as well as magnetic susceptibility analysis on the samples I collected while
in the field. I will be writing a research summary for the Keck Geology Symposium 2010 Volume
and preparing a poster to be presented at the Keck Symposium in April.
This summer, I did a research project on the organic geochemistry of sediment cores from Indonesia. Working at Woods Hole Oceanographic Institution with paleoceanographer Dr. Delia W. Oppo, I analyzed marine sediments for concentrations of the bio-marker cholesterol, an indicator of integrated marine primary productivity. From sediment multi-cores I created the first core-top calibration of cholesterol and showed that concentrations are strongly correlated with upwelling. Additionally, I generated a down-core record of cholesterol concentrations over the last 12,000 years which can be interpreted to represent a mid Holocene transition to a more El Niño-like mean Pacific state. This Fall, I will be presenting my work at a meeting of the American Geophysical Union and am currently working on a paper for Nature Geoscience. For more detailed information about my work check out the project's website.
Maria Princen Southeast Alaska
This summer, I spent three weeks scrambling across the Kootznahoo, a Tertiary sedimentary formation found in Southeast Alaska. Our projects focused on exposed section in and around the small town of Kake, about 100 miles southeast of Juneau. As a group, our main goal was to investigate the depositional history of the Kootznahoo Formation with a specific focus on the exhumation history of the Coast Mountains batholith. My project was aimed at the sedimentary rocks of the Kootznahoo of which we drilled approximately 100 cores in the field. My individual research includes analysis of magnetic susceptibility, poles, and reversals of these samples with the goal of determining relative ages and correlating sections across the formation.
Karanina Scheel Ashfall Fossil Beds, Nebraska
For my summer research project, I spent part of June traveling with Professor Ray Rogers to study the ash bed that covers the fossils of perfectly preserved Miocene rhinos, camels, horses, deer and birds at Ashfall Fossil Beds State Historical Park near Royal, Nebraska. The fossils are the result of a volcanic catastrophe that occurred approximately 12 million years ago, blanketing the animals that had congregated around a water hole on the ancient plains of Nebraska. The ash killed and entombed the animals, and preserved them all in exquisite quality. My senior thesis includes a detailed description of the ash bed, which consists of perfectly preserved tiny glass shards, and an interpretation of the various processes that led to the accumulation of over 2 meters of ash in this particular locale.
Alex Nereson Svalbard
Part of my summer was spent working with a team of faculty and student researchers
in the high-arctic archipelago of Svalbard. Organized and funded by the Keck Geology
Consortium, our continuing work is focused on utilizing sedimentation patterns (varves)
in proglacial lake Linné as a proxy for past environmental changes. Currently, Linné’s
varves are a text written in an unfamiliar language—we may be able to sound out the
syllables, but we are largely unsure of their significance. By studying modern processes
at work in Linné Valley side-by-side their depositional products, we hope to gain the
power to confidently infer past environmental change. My efforts in this project are
centered on recognizing variations in the mineralogy of sediment cored from Linné’s
deep, distal basin. Ideally, it will be possible to link such variations to patterns
observed in the instrumental climate record.
Jeff Dobbins Ashfall Fossil Beds, Nebraska
I examined the geochemistry of volcanic ash from Ashfall Fossil Beds
in northeastern Nebraska. The site is a deathbed of large mammals
preserved in two meters of volcanic ash about 12 million years ago.
Using the SEM-EDS and XRF at Macalester, I am analyzing the
geochemistry of several samples in order to correlate the ash to a
specific eruption. The most probable source is a volcanic center in
southwestern Nevada from the Yellowstone hotspot track. I also plan
to date the ash using 40Ar/39Ar radiometric dating.
Macalester College · 1600 Grand Avenue, St. Paul, MN 55105 USA ·
651-696-6000
Comments and questions to Thole@macalester.edu
