Cenozoic tectonic evolution of the Tethyan Himalayan foreland fault-fold belt in Southern Tibet, and its constraint on antimony-gold polymetallic minerogenesis

The Tethyan Himalayan foreland fault-fold belt in southern Tibet is made up of the southern Tibet detachment system, Luoza and Rongbu - Zhegu faults, and a series of inverted complex folds. This fault-fold belt was formed by the continent-continent collsion between India and Eurasia plates which resulted in crust shorting, sedimentary cover thrusting from north to south and folding in the Tethyan Himalayan foreland basin during Eohimalayanian. The hanging walls of the southern Tibet detachment system, Luoza and Rongbu - Zhegu faults detached along the thrusting zones formed in Eohimalayanian from south to north, which resulted from the extrusion of the Great Himalayan Crystallines during Neohimalayanian. The antimony and gold polymetallic deposits in the Tethyan Himalayan foreland fault-fold belt in southern Tibet distributed in zoning. They are Shalagang - Chalapu antimony and gold metallogenic belt, Cuomei - Longzi antimony and lead-zinc metallogenic belt, and Lakang - Cuona metallogenic belt in order from north to south, which are divided by Rongbu - Zhegu fault and Luoza fault, respectively. The orebodies are mainly controlled by E-W direction interformational faults within limbs of folds and S-N direction faults. The metallogenic type is epithermal deposit. The metallization occurred in the Neohimalayanian, and is related with Cenozoic tectonic evolution and magmatism. During the extrusion of the Great Himalayan Crystallines in Eohimalayanian, the Tethyan Himalayan foreland fault-fold belt detached from south to north, and resulted in partial melting. The magma formed by partial melting intruded along faults, and provoked groundwater which penetrated along tectonic zone to circulate and converte. When this groundwater met postmagmatic ore-bearing fluid that moved up along fault, the physicochemical condition of the ore-bearing fluid was changed, which resulted in the ore-forming elements precipitated from the ore-bearing fluid, and formed layed, vain and lenticular orebodies in E-W direction interformational faults within limbs of folds and S-N direction faults.