The Study Of Mengyaa Ore-controlling Structure In Lead Zinc Polymetallic Ore Deposits In Maizhokunggar,Tibet

Mengyaa lead-zinc deposit located in Gangdise-Nyainqentanglha plate, which with the same continental crust and continental surface formation as Himalayan plate which is between Bangong Lake-Nujiang suture zone and The Yarlung Zangbo. Consequently, it may be a part of the northern margin of early Gondwana.Mengyaa lead-zinc deposit was affected by another extension of Bangong-Nujiang which produced large-scale subduction and napping effect toward south in Indosinian northern Gangdise metallogenic belt, orefield mainly form a series large-scale M type inclined-congruous reversed fold with axis toward south in Serirong-Baga rift basin, because of napping effect. In early Himalayan Brahmaputra dive to north、till its extinction and collision orogenesis combination. Mengya-a lead-zinc deposit tectonic framework and ore-controlling mainly yield mesh-vein structure and lenticular ore body which bearing in axial plane cleavage of inclined overturned fold with occurrence is160°～175°∠40°～70°.locally yield by mesh-vein structure and stripped structure.In this area,the hosting strata is Luobadui formation which is comprised by limestone、marmarization limestone carbonaceous slate and Laigu formation limestone. Affected by invasion of early stage magma, the major of Laigu formation carbonatite was eroded. While the first section of Luobadui formation generated a very intense marbleization, the second section of Luobadui formation mudstone was baked by magma and turn to carbonaceous slate,this special lithology difference, offering a good condition for ore-forming hydrothermal solution rising. The first section of Luobadui formation marbleization limestone occur very intense skarns mineralization, between The first section of Luobadui formation and the second section of Luobadui formation contact zone generated bedded mineralization because of the lithology difference. As well as the second section of Luobadui formation carbonaceous slate offer a good screening effect for contact metasomatism, making metasomatism have sufficient time react.Chasagang formation in Songduo terrain generated intense deformation in outside of orefield. Forming a up-right and closeness fold, it indicates that Mengyaa lead-zinc deposits ore-controlling tectonic framework msut have respond on structure.Offering reference for ore-controlling structure and ore-controlling model.Through my detailed field work, combed with the previous research data,this paper make a new understanding on ore-controlling structure and factor of deposit in Mengyaa lead-zinc deposit area.Overturned the previous researchers have but a hazy understanding on metallogenic scale, making a very important contribution for making clear the factor of this type^metallogenic forecasting and potential evaluation.