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Dr. Julie M. Bloxson


Far–field Tectonic Controls on Deposition of the Ordovician Utica/Point Pleasant Play, Ohio using Core Logging, Well Logging, and Multi-variate Analysis

11:30 AM Wednesday, May 15, 2019
at the Cascades
4511 Briarwood Road
Tyler, TX 75709

Cost: $25


Far–field Tectonic Controls on Deposition of the Ordovician Utica/Point Pleasant Play, Ohio using Core Logging, Well Logging, and Multi-variate Analysis
Dr. Julie M. Bloxson
Stephen F. Austin State University, Department of Geology

The Ordovician Utica shale is an extensive and important part of the Appalachian Basin subsurface, providing a source for hydrocarbon reservoirs, acting as an unconventional hydrocarbon reservoir, and of interest as an impermeable cap rock for carbon dioxide sequestration in Cambrian formations. The Utica shale and adjacent formations (Point Pleasant Formation, Trenton/Lexington Limestones) are a mixed siliciclastic-carbonate system that is mostly in the subsurface in areas of interest within the Appalachian Basin. Most outcrops are located to the east, in the Appalachian fold and thrust belt, and few public cores are available for study from key areas in the basin. Using a combination of core/well logging and multi-variate analysis with GAMLS software, lithofacies based upon mineralogical variations and sedimentology were extrapolated to electrofacies across the state of Ohio. These electrofacies were then mapped to identify controls on deposition during the Upper Ordovician time in Ohio. It typically is assumed that the primary control on regional deposition during this time period was the Taconic tectophase of the Taconian Orogeny; however, Precambrian basement structures appear to have localized influence on deposition also, such as the Waverly Arch, Utica Mountain Fault, and Harlem Fault. Also, the Sebree Trough has previously been reported to end in southwest Ohio, yet electrofacies mapping shows that the dark, calcite-poor shales that infilled the Sebree Trough continue towards northeast Ohio in a possible trough-like feature. These shales may have later timing compared to the Sebree Trough proper. Overall, lithofacies mapping combined with electrofacies mapping indicates that these Upper Ordovician formations are not homogenous rock types deposited across the state (such as layer-cake stratigraphy), but rather vary in mineralogy and thickness both horizontally and vertically across the region due to multiple controls on deposition.



Julie Bloxson
Assistant Professor
Stephen F. Austin State University

Julie received her B.S. in geology from The University of Akron, where she focused her undergraduate research on core analysis of tidal rythmite deposits associated with Pennsylvanian coal seams within the Appalachian Basin. She received her M.S. in geology from Kent State University, studying the Grimbsy Sandstone/”Clinton Sands” in Eastern Ohio. This project focused on using a combination of core and well log analysis to extrapolate porosity and permeability across a county, and determined the controlling factors of porosity/permeability in tight gas sands in the Appalachian Basin. She received her Ph.D. from Case Western Reserve University, focusing on the Utica Shale and controls on deposition. Julie continued this work at the Ohio Geological Survey, working within the Energy Group on various subsurface mapping projects that focused on salt deposits, carbon sequestration, and unconventional resources. She is currently an assistant professor at Stephen F. Austin State University, and heads the East Texas Core Repository at the Science Research Center, where she is creating the Black Shale Research Facility. This facility will help to expand non-destructive core analysis, and continue to correlate core data to well log data for better subsurface analysis for natural resources and energy related issues. Her goal for the facility is to allow students to gain necessary skills for industry and research, and to facilitate a connection between local industry and academia for future research.

Earlier Event: May 14
Private Screening: The Iron Orchard
Later Event: May 19