Report of Investigations--KGS


Elongate, low-amplitude flexures in strata of Pennsylvanian age have been delineated in recent mapping by the U. S. Geological Survey in co­operation with the Kentucky Geological Survey in a 600-square-mile (l ,536- square-kilometer) area between Pine and Cumberland Mountains in south­eastern Kentucky. Cresta! culminations on gentle anticlinal folds may indicate loci of subsurface closures for entrapment of oil and gas. The area studied is underlain by more than 15,000 feet (4,500 meters) of Paleozoic strata containing potential source-beds, reservoirs, and cap rocks. Faults, unconformities, abrupt facies changes, and regional thickness variations en­hance the geologic setting for possible oil and gas accumulations. Although the area is not producing oil and gas, shows were reported from each of seven exploratory test holes. Drilling depths to potential reservoirs ore mod­erate, and markets are relatively close and accessible.

The area between Pine and Cumberland Mountains is a composite structural basin, as the flat-lying Pine Mountain overthrust fault separates a deep sequence of lower Paleozoic marine strata from the overlying upper Paleozoic marine and nonmarine rocks. The gentle flexures in surface strata of Pennsylvanian age trend east-northeasterly, but the attitude, size, and shape of structures below the thrust fault are unknown. A possible north­northwest interference pattern suggested by a series of axial culminations and depressions may reflect subthrust structural or paleogeomorphic align­ments. Geophysical surveys or additional deep well control are necessary to provide data on the deep subsurface configuration.

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Prepared by the United States Geological Survey (USGS) in cooperation with the Kentucky Geological Survey

KGS10RI141973plates 1.pdf (2855 kB)
Generalized geologic section through the Cumberland overthrust rock

KGS10RI141973plates 2.pdf (640 kB)
Status of geologic mapping at a scale of 1:24,000 in southeastern Kentucky as of October 1971

KGS10RI141973plates 3.pdf (4828 kB)
Map of geologic structure showing locations of test holes and outcrop sections in the Middlesboro basin

KGS10RI141973plates 4.pdf (2553 kB)
Map showing structure on base of the Harlan coal bed and locations of gravity stations, Harlan County, Kentucky

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