Esther K. Stewart

Research interests

My research interests are focused on understanding Wisconsin’s oldest rocks—those that formed during Precambrian time, generally more than 800 million years ago. These rocks underlie all of Wisconsin and may be exposed at the land’s surface or buried by several hundred to over a thousand feet of younger rocks and glacial sediments. Though Wisconsin’s Precambrian rocks are hard to directly observe across much of the state, they control or have a significant impact on many of the state’s natural resources, including metallic and non-metallic mineral deposits, groundwater quantity and quality, geothermal energy potential, and potential carbon sequestration. My primary goal as a scientist at the Wisconsin Geological and Natural History Survey is to develop research programs that improve our understanding of the distribution and variability of different kinds of Precambrian rocks—what Precambrian rocks underlie Wisconsin and how did they get there? Through constraining our understanding of Precambrian rocks and structures we can better understand their impact on the state’s natural resources.

My current research areas include:

1. The stratigraphy and deformation of ca. <1.7 billion-year-old Baraboo-interval metasedimentary rocks in south-central Wisconsin
2. The stratigraphy and deformation of volcanic and sedimentary rocks of the ~1 billion-year-old Midcontinent Rift underneath Lake Superior

Current projects

See my projects on this interactive map

Research area 1: Stratigraphy and deformation of Baraboo-interval metasedimentary rocks

• Dodge County, WI bedrock geologic map (USGS STATEMAP program)
• Precambrian bedrock geologic map of the Baraboo Hills
• 1:24000-scale geologic mapping, Baraboo Hills area
• Mapping the base of the Cambrian aquifer through geophysical modeling of Precambrian topography, southern Wisconsin (State of Wisconsin Groundwater Research & Monitoring Program for State FY 2018)

Research area 2: Stratigraphy and deformation of volcanic and sedimentary rocks of the Midcontinent Rift underneath Lake Superior

• Sedimentology, sequence-stratigraphy, and geochemical variations of the Nonesuch Formation
• Seismic interpretation of the volcanic and sedimentary rocks beneath Lake Superior

Collaborations

Collaborations with researchers and students from outside of the Wisconsin Geological and Natural History Survey are an important component of my research. Recent collaborators include:

• Faculty, researchers, and students from UW-Parkside, UW-Baraboo, and UW-Madison
• Faculty and students from the University of Minnesota-Duluth Earth & Environmental Sciences Department
• Researchers from the US Geological Survey Minerals Resources Program
• I also mentor students from UW-Madison and other UW campuses on directed study projects

Publications

Publications available to download

Papers in refereed journals and proceedings

These are refereed technical publications in national or international scientific journals.

• Stewart E.K., Bauer, A.M., Prave, A.R., 2024, End-Mesoproterozoic (ca. 1.08 Ga) epeiric seaway of the Nonesuch Formation, Wisconsin and Michigan, USA: GSA Bulletin, v. 136, p. 2940–2960. doi: https://doi.org/10.1130/B37060.1
• Stewart E.K., Brengman, L.A., Stewart, E.D., 2021, Revised Provenance, Depositional Environment, and Maximum Depositional Age for the Baraboo (<​ca. 1714 Ma) and Dake (<​ca. 1630 Ma) Quartzites, Baraboo Hills, Wisconsin: v. 129, n. 1. https://doi.org/10.1086/713687
• Stewart, E.D., Stewart E.K., Bradbury, K.R., Fitzpatrick, W., 2021, Correlating Bedrock Folds to Higher Rates of Arsenic Detection in Groundwater, Southeast Wisconsin, USA: Groundwater, v. 59, p. 829-838. https://doi.org/10.1111/gwat.13102
• Stewart, E.D., Stewart E.K., Walker, A., and Zambito IV, J. J., 2018, Revisiting the Paleoproterozoic Baraboo interval in southern Wisconsin: Evidence for syn-depositional tectonism along the south-central margin of Laurentia, Precambrian Research, v, 314, 221-239.
• Medaris, G.L., Driese, S.G., Stinchcomb, G.E., Fournelle, J.H., Lee, S., Xu, H., DiPietro, L., Gopon, P., Stewart, E.K., 2018, Anatomy of a sub-Cambrian paleosol in Wisconsin: Mass fluxes of chemical weathering and climatic conditions in North America during formation of the Cambrian Great Unconformity, The Journal of Geology, v 126, 261-283.
• Wellner, R..W., Varban, B.L. Roca, X., Flaum, J.A., Stewart, E.K., and Blum, M.D. 2018, Simple is better when it comes to sequence stratigraphy—the Clearwater Formation of the Mannville Group reinterpreted using a genetic body approach, AAPG Bulletin, v 12, 447-482.
• Stewart, E. and Mauk, J.L., 2017, Sedimentology, sequence stratigraphy, and geochemical variations in the Mesoproterozoic Nonesuch Formation, northern Wisconsin, USA, Precambrian Research, 294, 111-132.
• Kingsbury-Stewart, E.M., Osterhout, S.L., Link, P.K., and Dehler, C.M., 2013, Sequence stratigraphy and formalization of the Middle Uinta Mountain Group (Neoproterozoic), central Uinta Mountains, Utah: A closer look at the western Laurentian Seaway at ca. 750 Ma, Precambrian Research, 236, 65-84.
• Dehler, C.M., Fanning, C.M., Link, P.K., Kingsbury, E.M., and Rybczynski, D., 2010, Incipient Rodinia breakup, marine transgression, and peri-Gondwanan sediment source in western Laurentia at <766-742 Ma:  New SHRIMP data from the Uinta Mountain Group and Big Cottonwood Formation, northern Utah:  Geological Society of America Bulletin; v. 122; no. 9/10; p. 1686–1699.

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