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地球学报 2010
The Discovery of the Bismuth Mineralization Belt in the Bangong Co-Nujiang Metallogenic Belt of Tibet and its Adjacent Areas and Its Geological Significance
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Abstract:
Bismuth is one of the rare metals, and its distribution is very uneven in the world, with the vast majority of the bismuth resources distributed in China. China's bismuth resources are mainly concentrated in Shizhuyuan, Hunan Province. Through systematic field survey, sample collection, indoor ICP-MS analysis and SEM energy spectrum analysis, the authors have reached the conclusion that along the Bangong Co-Nujiang metallogenic belt bismuth content of single samples in 12 ore deposits or ore spots can meet the requirement of the cut-off grade, and that in 9 ore deposits or ore spots can meet the requirement of the industrial grade. The geological body with high content of bismuth (up to 9575×10?6) is in zonal distribution. Four bismuth prospective areas were delineated, namely the Caima skarn iron ore deposit, the Gaerqiong skarn copper ore deposit, the Shesuo skarn copper-lezd-zinc polymetallic ore deposit-Shexiang polymetallic ore deposit-Genai skarn type copper iron ore deposit,and the Lawu skarn type copper ore deposit-Youkalang vein type lead ore deposit. There are four species of bis-muth minerals, i.e., sulfur-bismuth-copper ore, natural bismuth, copper-bismuth-lead-sulfur ore, and sul-fur-bismuth-silver ore. Bismuth samples of high grade is mainly seen in skarn deposits, whereas porphyry type deposits have relatively poor bismuth. The mineralization of bismuth in the Bangong Co-Nujiang metallogenic belt should have occurred at the collision stage after the southward subduction and closure of the Yanshanian Bangong Co-Nujiang. The Lawu polymetallic deposit which has a relatively high bismuth content is now being mined. Be-cause the unit value of Bi is by far higher than that of copper, lead, zinc and some other resources, the evaluation of bismuth resources should be further emphasized in the exploration of the ore deposit so as to improve the com-prehensive utilization of resources.
