Geology of the copper deposits in the Eminence region, Shannon County, Missouri

Copper has been known to occur in Shannon County, Missouri since the early 1830\u27s. A number of small deposits in an area around Eminence has been worked intermittently up to the present day. Little detailed geologic information is available on these deposits. The geology of the Eminence region consists of Precambrian rhyolite porphyry knobs projecting through dolomites and sandstones of Upper Cambrian and Ordovician age. A conglomerate of limited horizontal extent overlying the Precambrian is found at certain localities within the region. The only structures noted are the structural highs formed where the Paleozoic sediments lap upon the knobs. The copper deposits occur as irregular replacement type bodies within the conglomerate overlying the Precambrian basement. The copper minerals present are chalcopyrite, chalcocite, covellite, malachite, azurite, and chrysocolla with hematite, limonite, calcite, and dolomite occurring as gangue material. The deposits appear to be structurally controlled as all but two of the seven known deposits occur at the head of buried Precambrian valleys --Abstract, page ii