Research Projects

Axe 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.

Left: Processing cosmogenic samples, Right: Buried pre-settlement soil

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.

Left: Vibracoring frozen sediments, Right: Seismic refraction of buried bedrock

Upper Mississippi River Valley evolution since the Last Glacial Maximum

In this project we are building a regional understanding of how the Upper Mississippi River evolved in response to the changing Laurentide Ice Sheet margin since the Last Glacial Maximum. We are combining regional studies of fluvial response with terrace mapping and previously published works to build a coherent chronology of Upper Mississippi River Valley evolution during this time.

Left: Describing sediments in the Zumbro River Valley, Right: OSL lab sample processing

Collaborator-Driven Projects

Undergraduate Advisee:
Identifying Provenance of Glacially-Derived Outwash Sediments

In this project, I am supervising 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 advances. This project aids our understanding glacial sedimentation and sediment sourcing of the Mississippi River during the most recent glacial period.

Collecting optically stimulated luminescence samples near the mouth of the Whitewater River.

Research Collaboration:
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.

Fitz Roy crew (Kelly MacGregor, Macalester College; Shanti Penprase, University of Minnesota; Matias Romero, University of Wisconsin; Max Van Wyk De Vries, University of Oxford), Argentina 2020

Publications

In Press
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.
In Revision
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 Prep
*Denotes Undergraduate Advisee
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.
Penprase, S., Wickert, A., Larson, P. Geomorphic response of an upper Mississippi tributary to changing climate and base level during the last deglaciation.
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., Late Pleistocene glacial history of the Lago Argentino outlet lobe. Climate of the Past.
*Wilwerding, A., Penprase, S., Wickert, A. Understanding the Provenance of Slackwater Sediment in Southeastern Minnesota’s Whitewater River. Quaternary Research.

Research Themes

Fluvial geomorphology, optically stimulated luminescence, cosmogenic nuclide dating, geochronology, remote sensing, sedimentology, computational modeling, environmental geophysics