Deformation Lamellae Parallel to (10macr13) and (0001) in Quartz of the Coeur d'Alene District, Idaho

Abstract

Deformation lamellae oriented parallel to the (10¯13) and (0001) crystallographic planes in quartz have been considered to be deformation structures unique to shock metamorphism induced by meteorite impact. Rocks of the Belt Supergroup of the Coeur d'Alene district, Idaho, contain quartz with deformation lamellae parallel to both (10¯13) and (0001). All available evidence indicates a geotectonic rather than an astrotectonic origin for the deformation lamellae of the district. Therefore, the uniqueness of these orientations to astrotectonic deformation is doubtful.