History:This collection of geologic, mine, and related maps was compiled and used by S. Warren Hobbs for his research on the Coeur d’alene Mining District, Idaho - Professional Paper 478 (1965).
The Coeur d’Alene Study:General geology of the Coeur d’Alene district, one of the larger lead-, zinc-, and silver-producing areas of the world, is presented. The geology was remapped at a scale of 1:24,000 and compiled on five maps from west to east as follows: Smelterville, Kellogg, Wallace, Mullan, and Pottsville. Bedrock, primarily the Precambrian Belt Series which forms the host rock for the ore, is a thick conformable geosynclinal group of fine-grained clastics. Igneous rocks are principally two groups of small monzonitic intrusives and other dikes. Structurally the district is located at the intersection of a major anticlinal arch in the geosynclinal sediments with a major zone of weakness, the Lewis and Clark line; faults are the dominant structural feature. Mineral deposits formed near satellite intrusions of larger igneous bodies intruded during the Mesozoic within a structural knot of highly fractured rocks.
