衡阳盆地及其周缘成矿特征与成矿规律

    Metallogenic characteristics and regularities of Hengyang Basin and its surrounding areas

    • 摘要: 衡阳盆地位于华南褶皱系赣湘桂粤褶皱带与江南台隆的交接部位,发育多期、多类型的金属、非金属矿产。当前研究工作还缺乏对区域成矿规律的系统性总结,阻碍了成矿理论的构建和找矿预测。总结分析了衡阳盆地及其周缘的成岩成矿作用、时空展布等特征,结果表明: 衡阳盆地自古生代以来发育有多期次岩浆活动及成矿作用,其中以印支期和燕山期为主; 盆地内的矿产大多与岩浆作用关系密切,且矿化类型从高温到低温均存在; 岩体和矿床的空间分布与深大断裂紧密相关,各矿床均发育不同类型的垂向分带; 盆地自北西向南东方向发育有3个不同类型的矿化组合带,表现出成矿温度逐渐升高的趋势; “衡阳式”盆岭构造格架可能受制于华南地区多期次岩石圈伸展背景下的地幔柱活动; 成岩成矿作用经历了岩石圈不同位置的部分熔融、分离结晶、深部富矿流体上涌及围岩萃取等多种作用的叠加。研究成果可为华南地区中生代—新生代盆地成矿规律研究和找矿预测工作提供思路。

       

      Abstract: Hengyang Basin is located at the junction between Jiangxi- Hunan-Guangxi-Guangdong fold belt of South China fold system and Jiangnan platform uplift, with the development of multi-stages and multi-types metallic and non-metallic deposits. The systematic summarization of regional metallogenic regularities is deficient in current research, which hinders the establishment of metallogenic theory and ore prospecting. The authors in this paper summarized and analyzed the characteristics of magmatism and metallogenesis, temporal and spatial distribution of Hengyang Basin. The results show that multi-stage magmatism and mineralization were developed since Paleozoic, mainly in Indosinian and Yanshanian Period. Most of the main metal deposits in the basin are closely related to magmatism, and the mineralization types developed from high temperature to low temperature exist. The spatial distribution of rock mass and deposits in the basin is closely related with the deep-seated fractures, and various types of vertical zoning are developed in each deposit. Three different types of mineralized assemblage zones are developed in the basin from northwest to southeast, with mineralization temperature rising gradually. The Hengyang type basin and range structural belt are mainly controlled by the effect of lower mantle plume activities under the tectonic setting of multi-stage lithospheric extension in South China. The diagenesis and metallogenic activities are triggered by the superposition of multiple process, including partial melting and fractional crystallization in different locations of the lithosphere, upwelling of deep fertile ore fluid and the extraction of metals from surrounding rocks. The research results could provide some references for the study of metallogenic regularity and further prospecting in Meso-Cenozoic basins in South China.

       

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