Geological characteristics of the Chenjiazhangzi cryptoexplosive breccia-type gold deposit, Inner Mongolia and direction in mineral prospecting

Abstract： The Chenjiazhangzhi gold deposit is an epithermal cryptoexplosive breccia-type gold deposit discovered newly at the north margin of the Northern China plate and in the eastern segment of the Inner Mongolia axis. The deposit is hosted in a near-surface intruded into Archean metamorphic series of the Jianping Group and early Yanshanian granite. From the center outward the cryptoexplosive breccia pipe shows apparent zoning of rock types： the central part is cryptoexplosive clast-bearing crystal and lithic tuff, and outward clasts increase in size and the rock gradually grades into shatter breccia. The breccia has been intensely altered and shows pronounced alteration zoning. The alteration includes mainly sericite-quartz alteration and carbonation and subordinately silicification, adularization, argillization and propylitization. The gold bodies occur as veins in the west-central part of the breccia pipe. gold minerals are mainly present in fissure gold and intercrystalline gold. Yanshanian acid cryptoexplosive breccia pipe, silicification, adularization and sericitization, and Au, Ag, Cu, Pb, Zn, Bi and As anomalies are main indicators of gold prospecting.