M.A. Norton, 1983. "Kemmerer Area, Lincoln County Wyoming", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The Kemmerer area seismic line is in T22N, R114 and 115W, Lincoln County, Wyoming. The line is an east to west traverse across the Hogsback Thrust plate which is the youngest and most eastern major thrust fault of the Idaho-Wyoming-Utah thrust belt salient. The Hogsback thrust carries an imbricated sequence of sediments ranging from the Upper Cretaceous through the Mississippian Madison Limestone in the upper plate. The footwall of the Hogsback thrust is the western margin of the Green River basin. The Green River block consists of a complete stratigraphic sequence ranging in age from Cretaceous to Cambrian. Drilling has confirmed the imbricate structure of the upper plate. Repeat sections of the Permian Phosphoria through Mississippian Madison were encountered in the upper plate in Well Nos. 1 and 2. Well No. 2 penetrated the Hogsback thrust and drilled a normal sequence of Lower Cretaceous through Jurassic Nugget in the Green River block. Surface geologic features consist of several north to south trending folds and a north to south normal fault. The upper plate folding is related to the ramping of the overthrust plate and subsequent imbricate faulting which results in a stacked section in the core of the fold.
The depth conversion of the seismic section illustrates one of the classic problems in overthrust exploration. The apparent seismic time structural rollover in the subthrust Green River block is a velocity anomaly produced by the higher velocity Paleozoic rocks thrust over the lower velocity Mesozoic strata. The overthrust belt of Western Wyoming has been the scene of numerous discouraging attempts to interpret and drill subthrust structure. This example points up the need for good quality seismic data and meticulous velocity studies to make more reliable structural interpretations of subthrust structures in the overthrust belt.