Geology of the Fort Hill quadrangle, Lincoln County, Wyoming

TLDR: The Fort Hill quadrangle lies along the boundary between the Idaho-Wyoming thrust belt and the Green River Basin and has been extensively studied in the last few decades as discussed by the authors.

Abstract: The Fort Hill quadrangle lies along the boundary between the Idaho-Wyoming thrust belt and the Green River Basin. A sequence of Paleozoic and Mesozoic sedimentary rocks about 24,000 ft thick has been intensely deformed along the front of the thrust-belt mountain system. Only Cambrian to Ordovician and Triassic to Cretaceous rock units are exposed now within the quadrangle. Middle and upper Paleozoic rocks are covered by partly deformed, but well-exposed, Tertiary strata that help date some of the tectonic events. Drilling within the quandrangle has provided data which help outline the third dimension of structures mapped. Westerly dipping lower Paleozoic to Mesozoic units overrode gently folded Cretaceous rocks eastward along the Hogsback fault. Above the Hogsback fault are 3 other thrust faults, interpreted as slices of the Hogsback fault that cut across the section moderately abruptly. Billions of cubic feet of natural gas and millions of barrels of oil have been produced from stratigraphic traps, in part controlled by structure in the NE. part of the quadrangle. Other natural resources of the area include helium, oil shale, coal, and phosphate. (140 refs.)