| 湘西层控白钨矿床地质特征及其成矿作用 |
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| 引用本文：.1987.Geological Features And Mineralization Of Stratabound Scheelite Deposits In Western Hunan[J].Mineral Deposits,6(4):33~42 |
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| 中文摘要:湖南西部层控白钨矿床，主要分布于江南地轴西缘雪峰弧形构造带的东段和中段，赋存于元古界板溪群浅变质的硅铝质碎屑岩内。矿床的空间分布总是与特定的地层层位联系在一起，其下常有不整合面或假整合面存在，地层控矿的专属性是类矿床的重要地质特征。区内东西向、北东向构造的转折或复合部位，以及主干断裂旁侧的羽状断裂带，是矿床的主要控矿构造；而矿化强度则受到岩石物理性质和化学成分的制约。矿体具有多层性，多数为盲矿体。成矿作用是在区域地层具有较高的初始钨丰度基础上发生的。区域变质作用或花岗岩浆侵入是成矿物质活化转移的主要热源。成矿流体为低盐度、中低温度，以变质水为主并有大气循环水加入的混合热液。硫同位素组成具变质硫特点。属于变质热液成因的层控白钨矿床。 |
| 中文关键词:层控白钨矿床 地质特征 成矿作用 湖南西部 |
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| Geological Features And Mineralization Of Stratabound Scheelite Deposits In Western Hunan |
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| Abstract:Located along the western margin of the Jiangnan Geoaxis, the stratabound scheelite deposits in western Hunan are distributed mainly in eastern and middle parts of the Xuefengian arcuate structural belt, lying mostly in the thick slightly-metamorphosed aluminosilicate clastic rocks of Proterozoic Banxi Group, with very few ones seen in Sinian and Cambrian. The spatial deposits is invariably related to specific stratigraphic horizon, underlain frequently by unconformity or pseudoconformity surface. lt is evident that being controlled by specific strata seems to be the main feature of this Sort of deposits. Ores are largely confined to such structural positons of this area as turning points or compounding points of EW-trending and NE-trending structures and feather-like faulted zone flanking the trunk structure. The intensity of mineralization is conditioned by physical proparties and chemical composition of the rocks, while granitic intrusion makes up a prerequisite for the formation of skarn-like deposits. ln addition, mineralization is characterized by multiple layers, forming mostly blind orebodies. Mineralization took place obviously ort the basis of comparativey high initial tungsten abundance of the regional strata. The thermal energy resulting from regional metamorphism- or granitic intrusion caused the activation and transferring of tungsten material which was then to be concentrated in the favourable interstratal structures. The ore-forming fluids were mixed hydrothermal solutions dominated by low salinity and medium-low temperature fluids as well as metamorphosed water with some atmospheric water added in. Sulfur isotope composition shows characteristics of metmorphic sulfur, suggesting stratabound scheelite deposits of metamorphic-hydrothermal origin. |
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