Geological characteristics of the veinlet-disseminated type ore in Shimensi Tungsten Deposit, Jiangxi Provence

摘要

Shimensi tungsten deposit was discovered in 2010 at Dahutang area, where the world's largest tungsten deposit was found. The deposit is genetically associated with the Late Mesozoic granitoids. The intersection of Shimensi fracture and Xianguoshan-Dahutang-Shiweidong basemental fractures controls emplacement of the ore-bearing granite and distribution of W-polymetallic deposits. The mineralization types of the deposit are divided into veinlet-disseminated type, cryptoexplosion breccia type and quartz thick vein type. The veinlet-disseminated type deposit accounts for about 90 % of total reserves. The host rock of the veinlet-disseminated type deposit is the Late Jinningian biotite granodiorite and the mineralization mother rocks is a Late Mesozoic porphyraceous biotite granite. The veinlet-disseminated orebdies are stratiform-like with gentle occurrence and are appromately parallel to the contact surface of biotite granodiorite and the top of porphyraceous biotite granite stock. The metallicminerals in the orebdies, accounting for about 1% to 2%, are mostly scheelite, wolframite, chalcopyrite, molybdenite and pyrite. The gangue minerals are mainly quartz, feldspar, biotite and clay minerals. The textures of ores are mostly xenomorphic, idiomorphic-hypidiomorphic granular textures and structures of ores are sparsely disseminated or dense disseminated and veinlet. The major ore bodies are labelled as I 1 and Ⅱ1. The I-1 Orebody accounts for 57% of the total amount and 11-1 Orebody accounts for 32.7%.