Research Projects
Plow vs Ice Age: Human and climatic impacts on erosion rates in the Whitewater River Basin
Euro-American settlement irrevocably altered the landscapes of the Upper Midwest and dramatically increased erosion and sedimentation within river valleys. In this project I use a paired geochronology (cosmogenic 10Be and optically stimulated luminescence) approach to construct a pre-settlement, late Pleistocene paleoerosion chronology to better contextualize the impacts of Euro-American agriculture on this landscape. I additionally relate paleoerosion rate variability to paleoenvironmental shifts prior to settlement.
Identifying Provenance of Glacially-Derived Outwash Sediments (Undergraduate Advisee)
In this project, I am working with UMN Undergraduate Abigail Wilwerding, to understand the source of glacially-derived slackwater sediments collected near the mouth of our field area in southeastern Minnesota. We are using a combination of core description, optically stimulated luminescence (OSL) and X-ray fluorescence (XRF) to identify these sediments and relate their deposition to past glacial meltwater routing down the Mississippi River. This project aids our understanding glacial sedimentation and sediment sourcing of the Mississippi River during the most recent glacial period.
Glacially modulated base level change impacts on channel long profile
As the Laurentide Ice Sheet retreated after the Last Glacial Maximum, pulses of glacial sediment and meltwater dramatically altered base level for tributaries connected to the then proglacial Mississippi River. By pairing glacial chronology with river channel long profile evolution and bedrock morphology during this period, we are able to build a field-based dataset that demonstrates how rivers respond to changing base level without additional tectonic signals. This, in turn, allows us to test models of how transport-limited river systems respond to perturbations using real world, physically-based data.
Collaborator-Driven Projects
Kettle Lake Morphology
This project (currently led by Jillian Prescott, University of Wisconsin Madison), explores the relationship between ice sphere volume and burial depth to kettle depression morphology. I will be expanding upon this initial study (Prescott et al., Accepted) to build a larger dataset for kettle lake formation morphologies using new testing parameters and applying these laboratory findings to field settings.
Last Glacial Maximum retreat of the Lago Argentino Outlet Lobe
In this collaborative project (led by Matias Romero, University of Wisconsin Madison), we are working to constrain the ice lobe retreat and paraglacial landscape response of the Lago Argentino outlet lobe of the Southern Patagonian Ice Sheet. The project uses remotely sensed data and field-based geochronology (10Be and infrared stimulated luminescence (IRSL)) to map and date glacial features in the Rio Santa Cruz Valley, on the edge of Lago Argentino in southern Patagonia, Argentina. For this project, I collected processed IRSL samples of landforms in the valley to further develop the paraglacial evolution of the valley.
Publications
| In Press |
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| Romero, M., Penprase, S., Van Wyk De Vries, M., Jones, A., Strelin, J., Wickert, A., Marcott, S., Martini, M., Brignone, G., MacGregor, K., Shapley, M., Ito, E., Rittenour, T., Caffee, M., 2024, Late Pleistocene glacial history of the Lago Argentino outlet lobe. Climate of the Past. doi:10.5194/cp-20-1861-2024. |
| Van Wyk De Vries, M., Romero, M., Penprase, S., Ng, G.-H.C., and Wickert, A.D., 2023, Increasing rate of 21st century volume loss of the Patagonian Icefields measured from proglacial river discharge: Journal of Glaciology, p. 1–16. doi:10.1017/jog.2023.9. |
| Accepted |
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| Prescott, J., Zoet, L., Hansen, D., Elmo, J., Penprase, S., Controls on Glacial Kettle Morphology. Earth Surface Processes and Landforms. |
| Wickert, A., Barnhart, K., Armstrong, W., Romero, M., Schulz, B., Ng, C., Sandell, C., La Frenierre, J., Penprase, S., Van Wyk de Vries, M., MacGregor, K. Open-source automated ablation stakes to constrain temperature-index melt models. Annals of Glaciology. |
| In Review |
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| Penprase, S., Wickert, A., Larson, P., Wood. J., Larsen, I., Rittenour, T., Signals of environmental vs agriculturally-driven change in catchment-averaged erosion rate in the Trout Creek River Basin, southeastern Minnesota. Geology. |
| In Prep |
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| *Denotes Undergraduate Advisee |
| Penprase, S.B., *Wilwerding, A.C., McKenzie, M., Wickert, A.D., Larson, H., and Rittenour, T. Slackwater sediments reveal time-variable glacial meltwater routing down the Upper Mississippi River at the Younger Dryas–Holocene transition. Climate of the Past. |
| Penprase, S., Wickert, A., Larson, P. H., Rittenour, T., Riedesel, S., Running, G., Faulkner, D., Dunn, C., Mitchell, P., Iscen, N., Hassenruk-Gudipati H., Kwang, J., Jones, J., Barefoot, E., Schewe, J., Romero, M., and Van Wyk de Vries, M., A natural experiment for base level change in alluvial river systems: post-glacial evolution of the Whitewater River, southeastern Minnesota . Earth Surface Dynamics. |
Research Themes
Fluvial geomorphology, optically stimulated luminescence, cosmogenic nuclide dating, geochronology, remote sensing, sedimentology, computational modeling, environmental geophysics