构造演化与叠加改造成矿问题探讨——以豫西矿集区为例

豫西矿集区地处华北板块南缘,是我国重要的金、钼多金属矿产地之一。在收集和分析大量矿床同位素年龄数据的基础上,结合典型矿床实例研究,总结了叠加改造型矿床的基本特征,探讨了构造演化及体制转换与叠加改造成矿的关系。认为叠加改造是豫西矿集区重要的成矿作用,主要发生在印支期和燕山期,且以燕山期为主。印支期成矿作用与陆—陆碰撞后的拉张环境有关;燕山期成矿作用对应于构造体制大转变和岩石圈拉伸减薄,除形成斑岩型钼矿、热液型银铅矿、爆破角砾岩型金矿外,对印支期预富集的金矿化(体)进行了叠加和(或)改造,形成了成矿元素和矿石矿物复杂的叠加改造型矿床。原定的构造蚀变岩型金矿和部分石英脉型金矿应归为叠加改造型矿床。

Discussion on tectonic evolution and superimposed mineralization: A case study on mineralization concentration area in western Henan

The mineralization concentration area in western Henan Province is located in southern margin of the north China plate, and is one of important gold, molybdenum & polymetallic resources producing areas. Based on integrated analysis of a large number of isotope age data of the deposits, this paper summarizes basic characteristics of the superimposed and transformed deposit, and the relationship between the superimposed reworking mineralization and tectonic evolution and regime transformation was discussed. It is suggested that the superposition and transformation is an important mineralization in the ore concentration area in western Henan, and took place in Indo-Chinese epoch and phase of Yanshan, with phase of Yanshan as its main forming time. The mineralization in Indo-Chinese epoch may be concerned with tension environment after the land-land collision. In Yanshan epoch, the ore-forming processes may be associated with transition of tectonic and dynamic regime and lithosphere stretching thinning. In addition to the formation of porphyry molybdenum deposit, hydrothermal silver, lead deposits and explosive breccia-type gold deposit, the pre-enrichment of gold mineralization (body) were superimposed and/or transformed, and superimposed and transformed deposits were formed with the complex mineral composition and metallogenic elements. The original structural altered-rock type gold deposit and some quartz-vein type gold deposit should be classified as superimposed and transformed deposits.