Metallic Mineral Districts And Mines Of The Northern Black Hills, South Dakota And Wyoming
Ed DeWitt, Anna Burack Wilson, 1990. "Metallic Mineral Districts And Mines Of The Northern Black Hills, South Dakota And Wyoming", Metallogeny of Gold in the Black Hills, South Dakota, Colin J. Paterson, Alvis L. Lisenbee, Tommy B. Thompson
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The northern Black Hills of South Dakota and Wyoming contain a large number of mineral deposits that range in age and type from Quaternary placers to Early Proterozoic or Late Archean pegmatites. Classification of the different deposits according to age, metals present, and structure of the deposits (DeWitt et. al., 1986) allows the delineation of twenty-two metallic mineral districts, which contain 303 mines or mineral deposits. These districts and mines are shown on four maps across the northern Black Hills. The mines or mineral deposits are listed numerically and alphabetically in Tables 1 and 2. These metallic mineral districts differ significantly from conventional mining districts, which generally had geographic or political boundaries and could contain mineral deposits of differing age and genesis. In contrast, metallic mineral districts are defined by geologic criteria and are classified by age of mineralization, metals present, and structure of the deposit. Therefore, one district contains only one age and type of mineral deposit.
Metallic mineral districts across the northern Black Hills are present in four major clusters: in the Bear Lodge Mountains of Wyoming (Fig. 1); at Tinton on the South Dakota-Wyoming border (Fig. 2); in the Lead area of South Dakota (Fig. 3); and in the Galena area of South Dakota (Fig. 4). Mines and mineral deposits on all figures are given a letter designation (C, T, etc.) and a plotting symbol (filled circle, filled square, etc.) that indicates the deposit type. Plotting symbols are consistent from one figure to the next.
Figures & Tables
Since the discovery of gold in 1874, the Black Hills has been well-known as a gold metallogenic province. In fact it is one of the richest areas in the world, having produced approximately 354 kg/km2 (31,750 oz/mile2). The premier mine in this province, theHomestake mine, is one of the oldest and longest -operating in the world, having been in production since 1876. Furthermore, the variety of gold deposit types in such a small area is unique. These include Au-U quartz pebble conglomerate deposits of early Proterozoic age, iron-formation-hosted and quartz vein gold deposits of middle Proterozoic age, paleoplacer Au in basal conglomerates of Cambrian age, epithermal igneous-hosted and sediment-hosted Au-Ag deposits of early Tertiary age, and recent gold placer deposits (see summary of gold deposits in Paterson et al., 1988; reprinted in this volume).
Although the history of mining here is a long one, the origins of the Homestake and other gold deposits in the Black Hills are yet to be fully explained. This is not a result of lack of interest or investigation. Significant studies regarding these deposits were conducted as long ago as 1904 by Irving, and subsequently by Connolly (1927) and Connolly and O'Harra (1929), and by Noble (1950) and Noble and Harder (1948). Then as now, there were opposing schools of thought regarding the origins of the various deposit types. For example, for the Tertiary sediment-hosted replacement deposits, Irving (1904) favored ore deposition from meteoric waters heated by the Tertiary igneous intrusions, whereas Connolly (1927) was a proponent of the magmatic-hydrothermal origin for the sediment-hosted replacement gold-silver deposits. Simultaneously, it was recognized that there were important structural and stratigraphic controls on ore localization, and that the mechanics of the sill and laccolith emplacement influenced the continuity and distribution of ores.
There remain many important questions to be answered regarding the origin and distribution of the gold deposits in the Black Hills. We summarize here some of the more important ones for your consideration during this field conference.
Is the Homestake deposit epigenetic (Noble, 1950; Slaughter, 1968; Bachman and Caddey*; Kath and Redden) or syngenetic but later remobilized (Rye and Rye, 1974; Rogers)? There is no consensus here, even among geologists working directly or indirectly with the Homestake Mining Company. There is general agreement however, that the mineralization is Proterozoic in age (Bachman and Caddey), and not Tertiary as reported inadvertently in the introduction to the