浙西北寒武系碳酸盐岩内找萤石矿地质因素与前景

GEOLOGICAL FACTORS AND ITS PROSPECT FOR PROSPECTING FLOURITE DEPOSITS IN CARBONATE ROCKS OF CAMBRIAN SYSTEM IN NORTHWEST ZHEJIANG PROVINCE

近几年来在浙西北一带寒武系碳酸盐岩内断续发现新类型萤石矿,矿床严格受围岩的岩性、构造、岩浆岩、矿化蚀变等地质因素所制约;其中寒武系上、中统大理岩化灰岩、泥质灰岩为主要含矿围岩。层间滑动破碎带、岩体接触面和断裂构造是主要的含矿构造,它控制了矿体的形态和产状。燕山期超酸性、富碱性、富含氟元素的花岗岩"杂岩体"是区内萤石矿床的库源和热源。矿床规模以中、小型为主,少数达到大型,矿体形态以似层状、透镜状为主,部分为陡倾斜脉状矿体。矿床成因具有多期次、多成因、多类型的特点,以中、低温热液成矿期为主,其次矽卡岩期亦是伴生萤石矿成矿期之一,成矿作用具有明显的交代和伴有充填作用的特点。对今后浙西北乃至国内其它地区具备和上述地质背景相似的区域,开展同类型萤石矿普查找矿和寻找深部隐伏萤石矿体具有启发性意义。

The flourite depsotits has been found from carbonate rocks of Cambrain in the northwest of Zhejiang province over the years, the flourite deposits controlled strictly by lithology of surrounding rocks, structure, magma and alteration-mineralization ; The main ore-bearing country rocks are aregillaceous limestone and marmarization limestone of upper-middle Cambrian. The main ore-bearing structure are the interlayer-gliding fracture zone, contact area of rock mass and fracture structure, which controlled the shape and the occurrence of orebody. Granite complexes of Yanshanian with properties of ultra acid, rich-alkaline and rich in Fluorin is the heat source and the material origin of flourite deposits,Most of which are medium and small scale size, only few of.them achieve large size, The morphology of ore body mainly appears in near bedded and lenticular shapes, part of them appears as steep inclined veined orebody. With properties of polyphyletic,polyphase and polygenetic, the hydrothermal mineralization period of intermidate and .low temperature mainly the dominant, then secondly skarn duration associated with the main minerlazation period of flourite deposits, the mineralizations reveal obvious metasomatic accompanied by infilling mineralization. This study on this paper gives the signeficance of prospecting same type of flourite deposits and deep concealed location prediction deposits in northwest of Zhejiang or even other areas with similar geologic background.