Geological data on genessis of secondary quartzites in the Hercynides Central Kazakhstan

A critical coordination of the often contradictory ideas on the relation of secondary quartzites to volcanism, granitoid intrusions, and deposition of endogenic ores, represents them essentially as products of postvolcanic hydrothermalism, as metasomatites, and as predecessors of the ores. Physicomechanical and chemical properties of secondary quartzites, and also their morphology and structural positions are particularly conducive to their functioning as barriers or screens in the deposition of ores. The very same properties, genetically inherent, usually disqualify secondary quartzites as potential host rocks of the imposed ores.