My primary research interests lie in the intersection between geomorphology, tectonics/structural geology, sedimentology and paleoanthropology. Specifically, I am interested in understanding the tectonic and climatic influences on hominin landscanscapes by reconstructing paleoerosion rates (as a part of HSPDP). I also have a secondary volcanology research project at the Pinacate volcanic field in Sonora, Mexico, and have previously completed research at the Brussels Hill (Wis.) meteorite impact structure during undergrad.
Hominin Sites and Paleolakes Drilling Project (HSPDP)
The East African Rift Valley serves as host to fossil assemblages fundamental to our understanding of hominin evolution. From the numerous specimens of Australopithecus afarensis, like “Lucy,” found in Afar, Ethiopia, to specimens of Homo ergaster, like “Turkana Boy/Nariokotome Boy,” found near Lake Turkana in Kenya, the Rift Valley provides a record of nearly six million years of hominin evolution. One long-enduring pursuit of scientific and public interest is understanding the relationship between Earth system history and human evolution.
The Hominin Sites and Paleolakes Drilling Project (HSPDP) has recently collected drill cores from lacustrine depocenters near key Plio-Pleistocene paleoanthropological sites in Ethiopia and Kenya to establish a highly resolved paleoenvironmental record which surface outcrops may otherwise be unable to preserve. I will utilize core sections collected from the Baringo Basin/Tugen Hills, Kenya (3.3–2.5 Ma), Chew Bahir, Ethiopia (500 ka–present), Northern Awash, Ethiopia (3.3–2.9 Ma) and West Turkana, Kenya (1.9–1.4 Ma) drill sites to reconstruct paleoerosion rates and characterize the watershed-scale response to tectonic and climatic forcings.
I will reconstruct both millennial-scale (10^3-4 yrs) and million-year-scale (10^5-6 yrs) erosion rates utilizing cosmogenic radionuclides (CRNs) and (U-Th)/He detrital low-temperature thermochronology, respectively. With my research, I will work to answer the following questions: (1) What do the paleoerosion rates indicate about the spatiotemporal variability in tectonic activity and climatic fluctuations? (2) What associations can be found between the erosion rates and other paleoenvironmental proxies? (i.e. lake depth, paleoprecipitation/evaporation, lacustrine-subaerial transitions). (3) Is there a clear correlation between patterns of erosion rates and patterns of early hominin evolution? (i.e. hypothesized stasis in A. afarensis prior to ~3.1 Ma and morphological change at 3.1 Ma).
Pinacate Volcanic Field (Sonora, Mexico)
The Pinacate volcanic field (PVF), located in the El Pinacate y Gran Desierto de Altar Biosphere Reserve of Sonora, Mexico, comprises a 1,500 km2 area of Pleistocene lava flows and contains nearly 400 cinder cones and eight maars. My work studies the tephra deposit produced by one of the youngest eruptions in the PVF to reconstruct the characteristics of the source eruption. I dug pits across the tephra deposit to describe its stratigraphy, measure unit thickness and collect samples for grain size analyses. I created isopach and isopleth maps to determine the volume of the eruption, estimate the column height and calculate the mass eruption rate. The source vent had two tephra-producing episodes; the first explosive eruption was Subplinian and the second was a violent Strombolian.
Brussels Hill (Wisconsin) meteorite impact structure
Brussels Hill is an anomalous area of intensely fractured, faulted, and folded bedrock in a region of otherwise undeformed lower Silurian dolostone in Door County, WI. The area of disturbed rock coincides with a distinctive, nearly circular, flat-topped topographic high ~2 km in diameter, standing 40 m above the surrounding landscape and ringed by rugged tree-covered slopes. Bedding orientations vary dramatically over distances of meters. Both mono- and polymict breccias occur, commonly as wedges that seem to have been intruded between bedding planes. Silurian dolostone is the only bedrock normally exposed in this area, but fault-bounded blocks of sandstone occur at Brussels Hill. This atypical rock likely comes from Cambrian strata that lie up to 300-400 meters below the surface.I conducted a focused microscopic study of the dolostones, breccias and sandstones found at Brussels Hill to look for shock-metamorphic features that could be diagnostic of an impact origin. By examining thin sections made from samples collected in the field and running an XRD analysis of the breccias, my goals were to (1) determine the stratigraphic origin of the in situ sandstones, (2) examine deformational characteristics of the breccias on the micro-level, (3) classify and describe any shock-metamorphic features found in the samples, and (4) determine if an impact origin is the best fit for explaining the disturbance at Brussels Hill.