Geological characteristics and prospecting direction of porphyry-skarn-epither-mal deposits in Xizang
Focusing on porphyry-skarn-epithermal copper polymetallic deposits in the northern section of the Sanjiang district,in eastern Xizang,the middle and eastern section of Gangdese district,the Bangongco-Nujiang district,regarding metallogenic geology,regional metallogeny,mechanism of plateau uplift and preservation of different deposits,exploration potential copper polymetallic and green exploration technology at the volcanic rock covered district of major Metallogenic Belts in Xizang,from subduction of the New Tethys Ocean to continental collision,this paper systematically summarizes the geology of 26 large-giant porphyry-skarn-epithermal copper polymetal-lic deposits,reveals the regional metallogeny and give new direction for further exploration.The main diagenesis and metallogenic ages of porphyry-skarn-epithermal deposits in Xizang are Early Middle Jurassic(160～174 Ma)in the middle of Gangdese Metallogenic Belt,Early Cretaceous(89～123 Ma)in the West of Bangongco-Nujiang Metallogenic Belt,Paleocene(50～65 Ma),Oligocene and Miocene(14～23 Ma)in the East and West of Gangdese Metallogenic Belt,and Eocene(39～43 Ma)in Yulong Metallogenic Belt.The deposits related to oceanic subduc-tion are mainly Cu(Au and Ag)deposit,such as the island arc type Xiongcun Cu(Au and Ag)(with a total of 2.38 million tons of Cu,202 tons of associated Au,and 1041 tons of associated Ag),and the continental arc type Tiegelongnan,Duobuza,Bolong and other Cu(Au and Ag)deposits(with Cu resources exceeding 24 million tons,associated Au exceeding 500 tons,and associated Ag exceeding 5000 tons).The main deposits related to crustal thickening caused by continental collision are skarn Pb-Zn(Cu-Au-Ag)deposits,such as Mengyaa,Dong-zhongla,Bangbule,Chagele,as well as low sulfidation epithermal Ag-Pb-Zn(Au)deposits.The main deposits re-lated to continental collision and strike slip are porphyry-skarn Cu-Mo-W deposits,such as the Yulong Cu-Mo-Au-W deposit belt and the Nuri-Chengba Cu-Mo-W ore district.The main deposits related to the continental colli-sion and extension are porphyry-skarn Cu polymetallic deposits,including the Julong(Qulong)Cu-Mo polymetal-lic deposit,Jiama Cu polymetallic deposit,Bangpu Mo-Cu polymetallic deposit,Zhunuo Cu-Mo deposit,etc.The future exploration should be focused on the deep and edge of giant deposits,searching for multi-center high-grade thick and large ore bodies of different types in the same mineralization period.The newly found Cu resources at deep of Tiegelongnan,Duolong district,exceed 4 million tons,and the deep edge of Bolong exceed 2 million tons.The next exploration and evaluation should focus on the epithermal-porphyry Cu-Au deposits in volcanic rock covered area.Volcanic rocks from early to middle Jurassic to Miocene are extremely developed in Xizang,which suggested to be great prospecting potential.The Zhule-Mangla area in Bangongco-Nujiang belt is expected to achieve a breakthrough in the exploration of porphyry-epithermal Cu-Au deposits.
copper polymetallic depositsmetallogenic regularitythe direction for further explorationthe porphyry-skarn-epithermal depositXizang
万方数据
维普
