大别山北麓斑岩型钼矿床成矿地质条件及矿床成因

大别山北麓位于华北地块与扬子地块交接部位,属秦岭褶皱带东延部分。区内龟(山)—梅(山)断裂、桐(柏)—商(城)断裂与NE向断裂共同控制着大别山北麓地区岩体的分布,燕山期中酸性小岩体是斑岩型钼矿床的成矿母岩,不同物理化学性质的地层围岩在一定程度上影响矿化强度和矿床产出形式。通过典型矿床地质特征、成矿地质条件的剖析以及矿床成因的分析,认为大别山北麓地区斑岩型矿床具有相同的成因。钼矿床的成矿流体主要为高温、高盐度的流体,成矿物质来源于斑岩体,而成矿斑岩体为中国中东部伸展构造体制下岩石圈减薄、下地壳部分熔融的产物。在相同的构造-岩浆及成矿作用下,在不同的地质部位和空间环境中形成了多种型式的斑岩型铜钼矿床,成为中国东部中生代大规模金属成矿作用的一部分。

Metallogenic conditions and genesis of porphyry molybdenum deposit in the northern piedmont of Dabieshan Mountain

Northern Piedmont of Dabieshan Mountain is held by North China plate and the Yangze plate belonging to the eastward extensional part of the Qinling fold belt. The Guishan-Meishan fault zone, Tongbai-Shangcheng fault zone and NE faults control jointly the distribution of rock masses in the piedmont area. Small intermediate-acid intrusive bodies of Yanshan stage are the hosts of porphyry molybdenum deposit. The host rocks differing in physical and chemical property influence more or less the intensity of mineralization and occurrence of the deposit. Analysis of geological feature, metallogenic condition and genesis of the typical deposits shows that porphyry molybdenum deposits in Northern Piedmont of Dabieshan Mountain are of similar genesis. The ore fluid is generally in high temperature and high salinity. Ore material is from porphyry body. The host porphyry body is product of extensional tectonic regime of the east China of lithosphere thinning and partial melting of the lower crust. Under the same tectonic-magmatic metallogeny porphyry Mo deposits are formed in different geological and spatial enviroments in the piedmont area of the large-scale east China metallic metallogenesis.