摘要
夜长坪钼矿床位于东秦岭-大别造山带,其赋矿围岩为中元古界官道口群龙家园组白云岩,辉钼矿化的主要类型为细脉状、网脉状、浸染状和条带状,围岩蚀变有透辉石化、金云母化、滑石化、绿泥石化、蛇纹石化、硅化和碳酸盐化,为斑岩-矽卡岩型钼矿床。选取5件辉钼矿样品进行了Re-Os同位素定年,获得模式年龄(145.4±2.1)Ma^(143.6±2.4)Ma,等时线年龄(145.3±4.4)Ma(2σ,MSWD=0.80),表明钼成矿作用发生于晚侏罗世—早白垩世。结合前人对东秦岭-大别造山带不同时期地球动力学背景的研究,笔者认为,夜长坪钼矿床形成于古太平洋板块向欧亚大陆板块俯冲的弧后岩浆带。
The Yechangping Mo deposit is a porphyry-skam Mo deposit in the East Qinling-Dabie orogenic belt. Its ore-hosting wall rock is chert banded dolomite belonging to Longjiayuan Formation of Middle Proterozoie Guan- daokou Group, its main ore types are veinlets, stockworks, disseminations and banding, and its major wall rock alterations include diopsidization, phlogopitization, talcization, chloritization, serpentinization, silicification, potassic alteration and carbonation. Five molybdenum-bearing samples were selected for precise Re-Os dating, which yielded model ages ranging from （145.4 ＋ 2.1） Ma to （143.6 ＋ 2.4） Ma and an isochron age of （145.3 ＋ 4.4） Ma （20, MSWD= O. 80）, indicating that the molybdenum deposit was formed in the Late Jurassic-Ear- ly Cretaceous period. Based on a study of geodynamic settings of molybdenum deposits of different ages in the East Qinling-Dabie molybdenum belt, the authors hold that the geodynamic setting of the Yechangping Mo deposit is widespread magrnatism and back-arc extension caused by subduction of the palm-Pacific plate beneath the Eurasian continent.
出处
《矿床地质》
CAS
CSCD
北大核心
2011年第6期1069-1074,共6页
Mineral Deposits
基金
全国危机矿山接替资源找矿项目(项目编号:20089949和200841019)资助
