摘要
文章通过对大量前人构造地质学、同位素年代学等多元信息资料的分析,认为胶东中生代花岗岩和大型_超大型金矿床形成于华南_华北克拉通后碰撞挤压和伊泽奈崎板块快速斜冲剪切的双重构造环境及其后的拉张构造环境。胶东大型_超大型金矿床受控于经历了韧_脆性剪切、挤压_拉张复杂变形叠加的大型构造岩带,同时也受控于被断裂叠加的花岗岩接触带。根据铅、硫等同位素组成特征及地质构造环境的综合分析,认为成矿物质主要来自以太古宙胶东岩群绿岩和深成岩组成的结晶基底,不排除煌斑岩浆带来部分深源物质;根据流体包裹体的氢、氧、碳同位素组成,判断成矿流体为大气水和岩浆水的混合流体;成矿条件为中低温(380～100℃),低压(86～5.4MPa);成矿时代为燕山晚期(125～100Ma),成矿与燕山晚期拉张环境下的岩浆活动有成因联系,属环太平洋成矿带中温热液金矿床。
Based on tectonic and geochronologic analyses, the authors hold that large-superlarge gold deposits and Mesozoic granites in Jiaodong area are generated in both the compressional setting of post-collision between South China craton and North China craton and the shear setting of Izanaqi plate high-speed and oblique subduction as well as in late extension setting. Gold deposits are controlled by a large-size tectonic rock zone which has experienced superimposition of complex ductile-brittle shear and compression-extension deformation, and also by a fractural overlapping-compounding contact zone. Sulfur and lead isotopic compositions and geotectonic setting for gold mineralization suggest that gold ore-forming materials are derived mainly from the crystalline basement consisting of Jiaodong Archaean greenstone belt and plutonic rocks, and possibly partly from deep-seated lamprophyre magma. Hydrogen, oxygen and carbon isotopic components show that gold-bearing fluids are mixture of meteoric water and magmatic water. P-T conditions for gold mineralization are 380-100℃ and 86-5.4 MPa. The gold ore-forming epoch should be Late Yanshanian stage （125- 100 Ma）. The ore-forming process in Jiaodong area is related to Late Yanshanian magmatic activity in an extension setting. The gold deposits are of memthermal type in Circum-Pacific region.
出处
《矿床地质》
CAS
CSCD
北大核心
2005年第4期361-372,共12页
Mineral Deposits
基金
中国地质调查局地质大调查项目(编号:19991020218003和200110200038)
科技部专项资金项目(编号:2001DIB10056)资助
