Gangdese Metallogenic Belt Collisional Magmatism And Metallogenic Series

There is large mineral resource potential such as Cu Fe Pb Zn Au in Gangdese metallogenic belt,Tibet,which is a world-class scale polymetallic metallogenic belt in western China.Gangdese metallogenic belt goes through the entire process from plate subduction-collision to plateau uplift.The large-scale porphyry copper deposit such as Qulong Jiama(21-13Ma) is related to magmatism of India-Eurasian post-collision extensional period. The mineralization during India-Eurasian plate collision period(65-41Ma) has been ignored for a long time.Some researchers believe that during India-Eurasian plate collision period, because of sharp structural compressive,the transfer of ore-forming fluid and the sediment of ore-forming element are restricted badly,so the ore-forming activity is not obvious.Some researchers think that because of superimposed change affected by post-collision extensional mineralization and the uplift and erosion of the plateau since Miocene Epoch,the ore-forming record during collision period is not remained though existed ever.This paper summarized the granite-like magmatism during collision period,the linzizong volcatism and the tectonic activity based on ductile shear zone in southern Gangdese,reached several conclusions as follows:1,The Gangdese tectonic-magmatism belt goes through 3 important periods:pre-collision Tethys arc-basin system,India-Eurasian collision,post-collision extension,there are different mineralization during each period.2,According to the evidence based on plate-movement,paleomagnetic,stratigraphical palaeontology and regional-petrology,the collision period is 65-41Ma.3,The magma during the collision period is calc-alkalic acid-intermediate magma,with "I"+"S" granite characteristics.The magma has a obvious negative anomaly in Eu,rich in incompatible elements such as Rb,Th,U,poor in Nb,Ta,Ti,Sr,P,so it is island-arc-collision magma,which is important to the formation of magma polymetallic deposits and porphyry copper deposits.4,There are 3 metallogenic series during collision period:①Fe Cu series of granite-like magmatism②Cu Au series of volcanism③Cu Au series of tectonic-fluid activity.5,The metallogenic geologic condition is good so we can find large-scale polymetallic deposits in Gangdese metellogenic belt.