摘要
东戈壁Mo矿是新疆地区近年发现的超大型斑岩型矿床,Mo金属储量50.8万吨,它与矿体下伏的花岗质岩体(包括斑状花岗岩体和花岗斑岩岩脉)有密切的成因联系,矿区地表没有花岗质岩体出露,但在多个钻孔中可见。矿体石英脉辉钼矿Re-Os同位素等时线拟合年龄为233.2±2.2 Ma,加权平均年龄为235.4±2.5 Ma,斑状花岗岩锆石206Pb/238U加权平均年龄为237.0±4.7 Ma,花岗斑岩锆石206Pb/238U加权平均年龄为233.2±4.1 Ma。这些年龄测定表明东戈壁斑岩型Mo矿成岩成矿时代为晚三叠世,为印支期岩浆活动和成矿作用的产物。矿床的形成与花岗质岩浆的演化密切相关,花岗质岩体为东戈壁Mo矿床的成矿母岩。东戈壁斑岩型Mo矿的发现进一步说明了东天山印支期成矿事件的存在,结合区域上的岩浆活动,我们认为矿床形成于拉张伸展的构造背景,花岗质岩浆的形成可能与地幔物质的内侵有关。
The Donggebi Mo deposit, located in Eastern Tianshan, Xinjiang, is a supper-large porphyry type deposit with a reserve of over 0.5 million tons of molybdenum. The porphyritic granite and the granitic porphyry underlying the ore bodies are believed to have played important roles in the Mo mineralization. The Re-Os isotope results for the molybdenites from the ores yield an isochron age of 233.2＋2.2 Ma and the weighted average age of 235.4~2.5 Ma. Zircon U-Pb ages of the porphyritic granite and the porphyry are 237.0~4.7 Ma and 237.0~4.7 Ma, respectively. These dating results indicate that the Donggebi porphyry Mo deposit and the related granites were formed in the late Triassic epoch. The granitic intrusion probably provided the ore-forming metals which led to the formation of the Donggebi deposit. The occurrence of the Donggebi porphyry Mo deposit demonstrates that the Indosinian orogeny is an important metallogenic period in East Tianshan. Based on the regional magmatism, we suggest that the Donggebi Mo deposit was related to a regional extension and the granitic magmas were produced by intrusion of mantle material into the continental crust.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2013年第4期743-753,共11页
Geotectonica et Metallogenia
基金
国家973项目(编号:2014CB440802)资助
作者简介
吴云辉（1987-），男，硕士研究生，矿物学岩石学矿床学专业。Email：253003002@qq．com
