摘要
东秦岭北部存在世界最大的钼矿带,并蕴涵著名的小秦岭造山型金矿田,金、钼矿床成矿时代和构造背景一直存在争议。河南小秦岭金矿田大湖金矿床深部新发现了石英脉型钼矿床,查明钼资源储量已达中型。6件辉钼矿样品Re-Os同位素模式年龄介于215.4±5.4～255.6±9.6Ma,等时线年龄为218±41Ma(2σ误差,MSWD=38),加权平均年龄为234±18Ma(2σ误差,MSWD=23),表明钼矿化发生在印支期。结合对已有年龄资料的归纳和分析,认为秦岭造山带曾在印支期发生重要的岩浆-成矿事件,但被燕山期造山作用所改造或破坏,在秦岭造山带北缘尚有明显保留或记录。
The northeastern Qinling Orogen is the largest Mo belt in the world, which hosts the well-known Xiaoqinling orogenictype gold field. The age and tectonic setting of the Mo and Au deposits in the northeast Qinling Orogen have been a long-time debated issue. Recently, Mo orebodies of quartz-vein type, with total Mo reserve being ranked as medium size, have been discovered in the deep extension of the Dahu orogenic-type Au deposit, Xiaoqinling gold field. Six molybdenite samples from the deposit yield Re-Os isotopic model ages ranging from 215.4 ± 5.4 Ma to 255.6 ± 9.6 Ma, an isochron age of 218 ± 41Ma （2σ, MSWD = 38）, and a weighted average age of 234 ± 18 Ma （2σ, MSWD =23）. This shows that the Mo mineralization occurred in Indosinian Orogeny or Triassic period. Based on summarizing and synthesizing the available isotope ages, this paper suggests that in the Qinling Orogen a significant magmatism-mineralization event occurred during Indosinian Orogeny. This event, however, was modified or destroyed during Yanshanian Orogeny, and could still be survived or recorded in the northernmost area of the Qinling Orogen.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第4期810-816,共7页
Acta Petrologica Sinica
基金
国家973计划2006CB403500项目
自然科学基金项目(编号40730421和40425006)
中国科学院百人计划项目的资助。
