REGIONAL POLYPHASE DEFORMATION ON THE NASHVILLE AND JESSAMINE DOMES, TENNESSEE AND KENTUCKY II: EXTENSIVE DATABASE FOR RESOLUTION OF FAR-FIELD EFFECTS OF THE ACADIAN AND ALLEGHANIAN OROGENIES

The Nashville and Jessamine domes in Tennessee and Kentucky are major regional structures located west of the Appalachian basin, flanking the Appalachian orogen farther east. They contain a variety of more subtle second-and third-order structures. This research attempts to unravel the pre-Devonian tectonic history of the two domes truncated by the 360 Ma unconformity by generating detailed structure contour maps of the formations to resolve the smaller-scale structures on the two domes. This was accomplished by using the abundant available surface and subsurface data in TN and KY from the USGS, TN Geological Survey, KY Geological Survey, mineral prospect holes, oil and gas well logs, mineral resource summary reports, and the TN oil and gas database. Surface data were acquired using a digital database of the 7.5-minute quadrangle geologic maps in TN and KY. The rock units of primary interest make up the Middle Ordovician Trenton and Black River Groups, all formations of interest for oil and gas exploration.

Detailed geologic maps were digitized where needed and converted to geodatabases for analysis in ArcMap™, and particular horizons were contoured (base of Devonian-Mississippian; top of Middle Ordovician; and top of Black River). Subsurface data for the same horizons were also compiled into geodatabases for contouring where well control is close enough to resolve the pre-Devonian and deeper structure. An automated process was implemented in ArcMap™, which permitted rapid data collection across both the Nashville and Jessamine domes. A cross-check of the surface and subsurface data was made easier by use of available LiDAR data. This large dataset permits resolution of second-and third-order structures on both domes to better understand the tectonics of the far-field effects of the Neoacadian and Alleghanian orogenies into the craton.