David Dominic (Committee Member), Ernest Hauser (Advisor), Doyle Watts (Committee Member)
Master of Science (MS)
In August 2017, a dynamite-sourced 2D seismic reflection survey was conducted along a gravel road northwest of Portland, Indiana. The main focus of the survey was to determine the orientation of a lithologic unit previously identified by Welder (2014) on a similar 2D seismic reflection survey in the same area. Drillers logs of two wells within this area identified a limestone layer below the Mt. Simon Sandstone, and a similar limestone layer was identified in a well drilled in Clark County, Ohio. As the focus of this study, this limestone layer will be informally named the `Votaw limestone'. The seismic line studied by Welder (2014) was oriented west-east; the seismic line utilized in this study is oriented north-south and crosses the previous one. Together, these seismic lines allow the true orientation of the Votaw limestone to be determined. Geophysical logs from nearby wells and two distant ones (north central Indiana and western Ohio) were used to produce synthetic seismograms which together with drillers logs were used identify the top of Eden, Trenton, Knox, Eau Claire, Mt. Simon, and Middle Run formations. The top of the Votaw limestone was associated with a reflection in the seismic data using the synthetics and the driller's logs for the nearby wells. Importantly, where the Middle Run Formation exists, the Votaw limestone occurs below the top of the Middle Run. The Votaw limestone is horizontal in both north-south and west-east seismic lines, confirming that it is truly horizontal in this area. This limestone could be present beneath the Middle Run in Warren County, Ohio, based on similar seismic characteristics of reflectors. The pre-stack CDP's were used to analyze the Amplitude Variation with Offset (AVO) response of the limestone layer. The limestone reflector primarily exhibited a negative gradient with some variations suggesting an impurity of the limestone. The limestone reflector in the area is parallel to the overlying Paleozoic reflectors suggesting the lack of any Grenville deformation. For all these reasons, the site could be a prime candidate for drilling and coring of the entire lithologic sequence beneath the Mt. Simon Sandstone.
Department or Program
Department of Earth and Environmental Sciences
Year Degree Awarded
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