Copper Sandstones and Shales

beds of sedimentary rocks, primarily sandstone and shale, containing copper minerals and classified as copper ore. Beds of copper sandstones and shales are distributed over significant areas, have a uniform thickness, and are limited strictly to definite stratigraphic horizons usually consisting of sediments deposited in lagoons and bay-lagoons of ancient seas. The chief copper minerals in copper sandstones and shales are bornite, chalcocite, and chalcopyrite; in association with the rarer sulfides of iron, zinc, lead, nickel, cobalt, molybdenum, rhenium, bismuth, antimony, arsenic, and other minerals they form disseminated ore. In the area of the deposits, zones of changing mineral composition, from iron sulfides through copper sulfides to iron oxides, gradually give way to one another. The genesis of the deposits has not been settled. Some investigators, including V. M. Popov and D. G. Sapozhnikov, believe they are sediments of ancient seas, which are synchronous with the beds of ore-bearing rocks, while others, including K. I. Satpaev, think that they formed hydrothermally when ore minerals were deposited from hot mineral waters circulating at depth.

Copper sandstones and shales form large deposits. Some of the best known are in the USSR, including Udokan in Chita Oblast (Proterozoic) and Dzhezkazgan in Kazakhstan (Carboniferous). Among major foreign deposits are deposits of the copper belt in Central Africa (Proterozoic), Lower Silesia in the Polish People’s Republic, and Mansfeld in the German Democratic Republic (Permian).