Full Title: Geologic Map and Measured Stratigraphic Section for the Rockerville Quadrangle, Pennington County, South Dakota
Compiler: Perry H. Rahn
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Two sheets, 20" x 30". From text: The Rockerville 7½ minute quadrangle, on the eastern edge of the Black Hills, contains rocks of Precambrian through Cenozoic age. The Precambrian rocks are mostly steeply dipping schist, metagraywacke, and quartzite; some pegmatite intrudes the southern part of the quadrangle. Paleozoic sedimentary rocks unconformably overlie the Precambrian rocks; the Paleozoic section is about 1,350 ft thick and is well exposed in Spring Creek Canyon. Paleozoic and Mesozoic rocks generally dip gently to the east, but the dip is locally affected by small Laramide faults and folds. Nearly flat-Iying Oligocene limestone and shale overlie the older rocks in the central part of the quadrangle. Placer gold was discovered in Rockerville in 1876 in the basal Cambrian Deadwood Formation and in terrace gravel, colluvium, and alluvium derived therefrom. The Precambrian source of this placer is not known but may lie several miles to the east of Rockerville beneath the Paleozoic cover.
Published: 4/01/1987
Pages: 16 plus 2 sheets
Product Category: Maps and Charts