中国超大型钼矿床

Super scale molybdenum deposits in China

中国目前共发现并探明10超大型钼矿床,其成因类型全部属于斑岩型矿床。超大型钼矿床特点是:①全部位于古板块对接带的仰冲带一侧,属于被动的冒地槽单元外侧;②成矿母岩:a.岩石学名称绝大多数是花岗斑岩类;b.岩石化学:三高一低,即高酸、高碱、高钾、低钙镁的正常太平洋型钙碱性系列的超浅成侵入岩;c.岩石地球化学:Mo,W均为特富集元素,Cu,Pb,Zn则为中等富集,从而说明成矿物质主要来源于上地幔与下地壳的混熔体;从成矿母岩的成岩和成矿年代学方面可知,中国超大型钼矿床主要形成于中生代燕山白垩纪中、晚期。

There have been discovered for ten super scale molybdenum deposits,the porphyry type,in China. The mineralization featurs of the super scale molybdenum deposit are as follows.All the deposits are located on the obduction sides of ancient plates connections that belong to the inner side of passive miogeosyncline u-nit.Secondly,their maj ority mother rocks are granite porphyry,with a small amount of granodiorite-por-phyry,with the lower deposit grade for the latter.The intrusive feature is that three highs and one low,they are peracid,high in alkaline and potassium,low in calcium and magnesium,normal Pacific typed calcium al-kaline hypabyssal intrusive rocks.The petro-geochemistry feature is as that Mo and W are both enriched ele-ments,while Cu,Pb,zinc are medium intensive.It is further proved that the ore-forming materials mainly are mixed magma from the upper mantle and lower crust.The diagenesis and mineralization chronology of the mother rock indicate that large molybdenum deposits in China were mainly formed in the middle to late Cretaceous within mid-late Mesozoic Yanshan period.