Jose Luis Antinao,
Don Tripp Peter M. Jacobs (University of Wisconsin-Whitewater)
U.S. Geological Survey (USGS) - Great Lakes Geologic Mapping Coalition
||The geomorphic history, deep stratigraphy, and chronology of events in the Flatwoods area is needed to understand the history of Illinois Episode glaciation. This is important in south-central Indiana, because ice-marginal sediments host aquifers in areas otherwise dominated by bedrock where aquifer potential is low. This project also improves our understanding of the dynamics of the Illinoian Epsiode ice sheet and the paleoclimate associated with an ice sheet advance which reached further south than the most recent Wisconsin Episode glaciation.
||The objectives of this study are to compile existing stratigraphic, mineralogic, and geophysical data and couple this with new data collection (passive seismic, deep coring, and geochronology) in order to reconstruct the Quaternary geologic history of the Flatwoods area.
||For stratigraphic control, shallow (<15 meters depth) coring was completed as part of a Ph.D. project of Peter Jacobs in the early 1990s. One new deep core (53.5 m wireline core) was completed in the thickest unconsolidated fill in the study area. Legacy IGWS seismic refraction data, along with new passive seismic (HVSR) data, help in building detailed bedrock surface and unconsolidated thickness maps. Optically stimulated luminescence (OSL) is being used to determine the age of deposition.
||A manuscript will be completed, to be submitted to the Indiana Journal of Earth Sciences, on the geologic history of the Flatwoods area. It will include cross sections, a bedrock surface map, mineralogic data (XRD and pXRF), and chronologic data (luminescence ages).
||Demonstrating the spatial and vertical variability of the type and origin of glacial sediments in the glaciated region of the state is one of the main goals of Quaternary geologic mapping. The Flatwoods area has one of the greatest density of cores (stratigraphic control) in the state and this allows for an improved understanding of the processes associated with deposition in glacial environments. This geologic framework is critical for evaluating water resources.