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地球学报 2012
Geochemical Characteristics and Genesis of the Bolong Porphyry Copper-Gold Deposit in Gerze County, Tibet
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Abstract:
The Bolong Cu-Au deposit with great prospecting potential is a large ore deposit in the western part of the Bangong Co-Nujiang River Metallogenic Belt of the Himalayan Tethyan metallogenic domain,and also an important part of the Duolong ore concentration area.The ore-bearing porphyries of the Bolong ore field were basically mineralized.The ore body in the irregular pipe columnar form was in early Cretaceous granodiorite porphyry and the contact zone with Lower Jurassic Quse Formation sandstone.The ore body is 1200 m in length and greater than 1000 m in downward extension(dipping 200°),and its maximum continuous thickness is 473.47 m.The ore body hasn’t been penetrated by drilling.The planar projection of the ore body is oval-shaped and its area is approximately 1.2km 2.The authors studied geological and geochemical characteristics of the Bolong Cu-Au deposit and found that the formation of this deposit was related to porphyry emplacement and magmatic evolution of the ore-forming fluids.This deposit is a copper-gold porphyry deposit.Ore structure is typical porphyry copper veinlets-disseminated structure.Metallic minerals are mainly chalcopyrite and secondarily pyrite,bornite,molybdenite,magnetite,and specularite,whereas non-metallic minerals are quartz,feldspar,sericite,biotite,anhydrite,etc.The Bolong porphyry copper-gold deposit was formed in an island arc environment and its granodiorite porphyry was calc-alkaline series,as evidenced by silicate analysis and Rietmann combination index-Gotti graphic table.REE geochemical characteristics suggest that the mineralization was mainly magmatic hydrothermal mineralization.
