The Lithospheric Architecture And Nature Of Lhasa Terrane Control On Mineral Systems And A Case Study Of Gandese Porphyry Deposit Belt

Lhasa terrane,which is the most important mineral resources in southern Qinghai-Tibet plateau,attracts the worldwide attention.It grows multiple metallogenic belts among which the porphyry deposit and skarn deposit are great scale potential and the most important metallogenic types.As an ancient micro-continent,it has been suffered from the interaction with Tethys and the successive collision with the Asian continent and India continent from the Triassic or the mid-to-late Jurassic to Cenozoic.The unique tectono-magmatic evolution of the Lhasa terrane created the particular characteristics of lithosphere structure.Various tectonic magmatic activities cause a lot of metal elements transfer and enrichment inevitably.It suggests that there exists coupling effect between the lithosphere architecture and nature of Lhasa terrane and the metallogenic system.Based on the "petrological probe" and the theory of isotopic tracer,we collect the mass previous felsic rocks's data of Zircon Hf isotope within the entire Lhasa terrane.We also add our new data in order to analyse systematically and fully the isotope data.It is best way to reveal the inevitable relationship between the lithospheric architecture and localization of major mineral systems in the Lhasa Terrane by applying to Hf isotopic mapping by Arcgis Microsoft.The Hf mapping results suggest that the Lhasa block has the signature that the Hf crustal modle ages decrease from the center(CL)to margins(NL&SL),and it conforms that the development of an ancient microcontinental.It has also drawn up out of the spatial distribution pattern of the center subterrane of the old lower crust under Lhasa terrane.In general,the center subterrane distributes between the Shiquan River-Nam Tso Melange Zone(SNMZ)and the Luobadui-Milashan Fault Zone(LMFZ),but not is strictly controlled by two faults.The southern Lhasa terrane and the northern Lhasa terrane are given priority to the newly-formed crust.They have the features of east-west subsection and local anomaly.In the Lhasa Terrane,the mineralization types and mineralization elements with the crustal architecture of the Lhasa Terrane has a coupling relationship.Porphyry Cu-Au deposits and porphyry Cu-Mo ore deposits are mainly located in the southern and northern subterrane with juvenile crust.Nevertheless,skam Fe?Fe-Cu deposits and the granite-related skarn Pb-Zn deposits,and a small amount of porphyry Mo deposits,are associated with ancient crust,which is located in the interior,or distributed at the margin of the block.The Gangdese porphyry deposit belt is a typical test of the coupling relationship between the crustal architecture and ore-forming.The paper give a initial understanding that the reason of Gangdese adakite porphyry,whether which has ore-bearing potential,lies in the ratio of the newly-formed crustal material and the old lower crust material.The more ancient crustal material proportion,the difficult to mineralize,but the more contribution of mantle source material,the easy to form porphyry Cu deposit,and the porphyry Mo(Cu)deposit is between the two above.