| Director: |
Henry Loope |
| Other Researchers: |
Jose Luis Antinao,
Henry Gray,
Drew Packman,
Robin Rupp,
Don Tripp Peter M. Jacobs (University of Wisconsin-Whitewater and IGWS Research Affiliate)
Russell Boulding (retired, USDA-NRCS)
|
| Issue: |
The sediments and geomorphology of the Beanblossom valley provide insight into pre-Wisconsin glacial processes and landscape evolution. The history of the Beanblossom Valley has been of interest for well over 70 years (e.g, Thornbury, 1950), but new techniques (e.g., optically stimulated luminescence) and data (e.g., high-resolution topography from LiDAR) allow for a more detailed investigation of the age as well as stratigraphic and geomorphic relationships of pre-Wisconsin sediments in the Beanblossom valley. The age and distribution of possible pre-Illinoian ('Kansan') tills in the Beanblossom Creek basin is also of interest as it may represent the oldest glacial advance into Indiana. |
| Objective: |
The objective of this project is to determine the timing of glacial advances into the Beanblossom Creek basin by using optically stimulated luminescence (OSL) and paleopedology. Research going back over 100 years suggest that Illinoian (Isotope Stage 6) ice blocked the westward-flowing ancestral Beanblossom Creek and created a large glacial lake. We seek to quantify the Illinoian age assignment using both OSL and detailed analysis (pedologic description, particle size analysis, silt and clay mineraology and silt geochemistry) of the Sangamon Geosol. The two techniques will complement each other, as OSL will provide absolute chronology and analysis of the Sangamon Geosol will supplement the OSL age with weathering ratios, depth of carbonate leaching, and amount of clay accumulation (among others). |
| Approach: |
We plan to collect GeoProbe and Giddings cores associated with several distinct geomorphic features in the valley (e.g., modern Beanblossom Creek floodplain, fluvial/lacustrine terraces, and a possible moraine/head-of-outwash). Cores will be photographed and sampled at the IGWS. OSL samples will be collected from shielded coring tubes or from outcrops where possible and be processed through the IGWS Luminescence Geochronology Lab. Detailed pedologic descriptions of the Sangamon Geosol and lab work for clay and silt mineralogy (XRD) and silt geochemistry (pXRF) will be completed by Peter Jacobs (University of Wisconsin-Whitewater and IGWS Affiliate). We also plan to collect passive seismic (HVSR) data to delineate the bedrock surface (and hence thickness of fill) in the valley.
Sediments associated with this glacial lake (e.g., offshore silt, deltaic/fluvial sand) will be mapped with the aid of LiDAR-derived topographic maps. USDA-NRCS SSURGO soils data will also be used to delineate map units and help in identification of coring locations.
Several historic infrastructure projects (construction of the Lake Lemon dam, construction of State Highway 37, and siting of the Anderson Road landfill) provide stratigraphic data which provide an important base for reconstructing the Quaternary history of the valley. Other archive IGWS data (seismic refraction, hollow stem augering, description of historic road cuts) from Henry Gray, Al Schneider, and Bill Wayne, along with a MS thesis from Indiana University by Alan Pratt in 1960, provide a rich dataset from which this project can build off of. |
| Products: |
The goal of this project is to produce a manuscript for submission to the Indiana Journal of Earth Sciences regarding the history of the Beanblossom Valley. Data will include mapped surfaces/terraces, core locations (legacy cores and new cores), core data (from legacy cores, described sections and from new cores including particle size, geochemistry, and detailed pedologic description), OSL ages, and geophysical data (legacy refraction seismic and new passive seismic). This manuscript and data will feed into a larger paper (likely an external international journal) associated with the broader story of Illinoian glacial lakes in south-central and southwestern Indiana, which includes the Flatwoods and glacial Lake Patoka. |
| Benefits: |
Provides additional stratigraphic information within the valley to inform land use and water resource potential. Provides a model for the stratigraphic architecture of bedrock valley fills in the state, many of which are deeply buried by glacial sediments in the northern two-thirds of Indiana. Expands the capabilities of the Luminescence Geochronology Lab at the IGWS, and demonstrates the applicability of using OSL on pre-Wisconsin age sediments. |
