Research on Au-Ag characteristics and occurrence state of Ga'erqiong copper deposit,Tibet,China

The Ga'erqiong copper deposit is an important and representative skarn type copper deposit.It is located on the west side of the Bangong lake-Nujiang river metallogenic belt.Because the research degree of the ore is low,the deep study of the mineralization and ore genesis as well as the further comprehensive development and utilization of the deposit are limited.The authors make a detailed and systematic study of the ore composition,gold-silver occurrence state and gold-bearing minerals by means of field geological survey and sampling,microscopic observation,scanning electron microscopy,X-ray energy spectrum analysis,electron probe composition analysis,and mineral crystal chemical formula calculation.The results show that the ore-forming process experienced the magmatic hydrothermal period and supergene weathering period while the gold formed in the former.The gold and silver occur mainly as intercrystalline gold and inclusion gold in the form of intermetallic compounds,then fissure gold and film gold.The gold-bearing minerals are iron oxides,metal sulfides,quartz,and so on.The genesis type of the Ga'erqiong copper-gold deposit belongs to the skarn type caused by post-magmatic hydrothermal contact metasomatism.