A widespread dolomite layer, less than 15 feet thick, in the stratigraphic interval separating the quartzites of two of the ore bodies of the Mufulira mine area (Zambia) is interpreted as an algal biostrome formed in a nearshore environment. Its fringe was formed by algal binding of sediment. The feldspar content decreases, and dolomite and algal bedding increase toward the center. Appreciable feldspar content inhibited growth or preservation of algal structure. The mineralization is confined to fine-grained, algal-bedded, sandy sediments. The aerated, high-energy environment represented by the biostrome is not compatible with biologic fixation of sulfides, so copper is believed to have been introduced as detritus from an adjoining basin of precipitation.