Abstract

Renewed exploration of an old zinc prospect in Jefferson County, West Virginia, in 1953 by the United States Bureau of Mines and Tri-State Zinc, Inc., led to a field study, sampling, and a petrographic study of thin sections and polished sections of the samples. Resulting descriptions of the deposit show that it constitutes an additional member locality of the "Appalachian low temperature zinc province," a convenient designation proposed for a series of analagous deposits containing sphalerite in the Valley and Ridge sections of Alabama, Tennessee, Virginia, and Pennsylvania.The prospect is developed in the Cambrian Tomstown dolomitic limestone near its contact with the underlying Antietam sandstone on the east side of the Great Valley at the base of the Blue Ridge. There is stratigraphic and structural control of the mineralization as it is in steep westward-dipping breccia zones that roughly follow the bedding. Both cavity filling and replacement were methods of deposition from solutions probably rising from magmas during upper Paleozoic time.Fine fracture cleavage and persistent feldspar typical in the prospect samples have not been recorded as characteristic of the other deposits of the province. However, rosette or halo zoning of the minerals in several patterns and the assemblage of dolomite, quartz, pyrite, sphalerite, and galena, which are characteristic of the other deposits of the province, are also common at the Howell prospect. The paragenic sequence is (1) pyrite, (2) early white dolomite, (3) feldspar, (4) quartz contemporaneous with a second stage of white dolomite and, in some places, followed by still later white dolomite, (5) sphalerite, (6) galena. The prospect is not large enough or of high enough tenor to be of much commercial promise but its description is merited as it bears on definition of the metallogenic province and also represents the richest hydrothermal base metal deposit recorded in West Virginia.

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