Mineralization Of Antimony Metallogenic Zone In Northern Tibet And A Simple Comparison Of Antimony Metallogenic Zones In Northern Tibet And Southern Tibet

Northern Tibet antimony metallogenic zone, located in the north ofBangong Co-Nujiang suture zone, lies in southern Qiangtang depression.The host rock, ore-controlling structure, material sources, genesis andore-forming epoch of Meiduo antimony in northern Tibet antimonymetallogenic zone are studied in the dissertation. On the basis ofmineralization, geophysics and Himalayan volcanic rocks in Qiangtangmassif, relationship between mineralization, delamination and diapirismis discussed in northern Tibet antimony metallogenic zoneAccording to the study, the host rock in northern Tibet antimonymetallogenic zone, which was thought to dacitic and rhyolitic volcanicrocks belongs to chert. This is based on three facts as follows:â‘ stratified structure chert and framboidal pyrite in cherts arediscovered;â‘¡the chert is mainly composed of microscopically small andmean quartz;â‘¢SiO₂ in cherts varies from 88.61 to 96.76 %. Thegeochemistry, origin and forming environment of the cherts is studiedin the dissertation.According to the host rocks and mineralization, three types of thedeposits in northern Tibet antimony metallogenic zone are classified asfollows:â‘ chert-hosted disseminated or stringer-disseminated antimonydeposits;â‘¡vein antimony deposits in feldspathic litharenite;â‘¢vein anddisseminated antimony deposits in chert. Northern Tibet antimonymetallogenic zone is controlled by regional NW-trending SouthXiaotanggula fault, but antimony ores fill in NE-NNE trending extensionfractures. Sulfur, lead and helium isotope indicate that material sourcescame from mantle with ore-forming solution from meteoric water. Thedeposits and Himalayan volcanic rocks, whose age is about 20Ma, arerelated to delamination and mantle diapirism.Finally, a simple comparison of antimony metallogenic zones innorthern Tibet and southern Tibet is carried out in the dissertation. Thefeatures of antimony mineralization in northern Tibet and southern Tibetare summarized as follows:â‘ the mineralization was related not only tointra-continental orogeny along with thrust nappe, strike slip andextension but also to Himalayan volcanism.â‘¡material sources came frommantle or mantle-crust hybrid, indicating that material and energyinterchange occur between mantle and crust.