A palinspastic reconstruction of the Coeur d'Alene mining district based on ore deposits and structural data

Abstract

Two palinspastic reconstructions of the Coeur d9Alene mining district have generated similar geologic maps. One of the reconstructions is based on the types of ore deposits and movement along the Osburn and Dobson Pass faults. The other is based on a detailed analysis of structural deformation in the district. The studies show that all of the deposits in the district with the exception of the mines located on Pine Creek are localized within a large structure named the Silver synclinorium. Anomalies reported from a previous regional geochemical survey are confined to this structure and numerous fold axes and regional faults parallel the axis of the synclinorium.The different styles of deformation north and south of the Osburn fault are related to movement along the Osburn fault and structural buttressing by the Gem stocks and the Atlas pluton. Complex rotations in the Osburn fault, Placer Creek fault, and Polaris fault system may be responsible for reorienting fold trends south of the Osburn fault.