摘要
东昆仑是我国地质矿产研究相对薄弱而又具有重要意义的区域成矿带。初步研究结果 ,东昆仑中带金矿主要表现蚀变构造岩和隐爆角砾岩型两种矿化 ,局部有夕卡岩型和石英脉型矿化出现。成矿具深源、浅成特征 ,金的矿化主要发生在中温阶段。金矿成矿主要受北西向剪切带及脆性复合断裂构造和印支期闪长玢岩为主的浅成 -超浅成中性岩两种因素控制 ,其总体区域地质背景受制于古特提斯北侧活动陆缘。
The East Kunlun Mountains in the north of Tibetan plateau is located in the southern margin of Qaidam landmass. This area is an important regional metallogenic belt in western China. Nevertheless, the work on geology and mineral exploration in this region has been relatively insufficient in the past. This paper only focuses on the study of gold deposits in the central belt of East Kunlun. The study on typical gold deposits show that the deposits in this region are controlled by brittle compounded faults within NW trending shear zones, and the hypabyssal rocks or diorite porphyrites are related closely to the gold mineralization. According to the textures and the relationship between minerals in the gold ores, the mineralization can be divided into early metasomatic stage, polymetallic stage, gold stage, carbonate stage and oxidation stage. Geochemical characteristics of ores are as follows:The sulfur isotopes of the minerals in ores and pyrite in dioritic porphyrites have similar values ( δ 34 S ranging from 2‰ to 5‰). In addition, the rare earth elements in ores and rocks also have similar distribution patterns. The isotopic dating shows that the ores and rocks have almost the same age (209 9±22 73)×10 6a for rocks, Rb Sr method; 197×10 6a for ores, K Ar method. The mineralization took place in moderate temperature and hypabyssal environment(pressure <30 MPa). The hydrogen and oxygen isotopes suggest that the fluid was mixed with magmatic fluid and meteoric water ( δ 18 O H 2O -6 3‰~4 8‰, δ D -48‰~91‰). On the basis of the above studies, a gold metallogenic model is set up. In this model, the gold deposits in this region are considered to have been formed in the background of Paleo Tethyan active continental margin.
出处
《矿床地质》
CAS
CSCD
北大核心
2000年第4期315-321,共7页
Mineral Deposits
基金
地矿部"九五"资源与环境科技攻关项目!(编号 :95 - 0 2 - 0 5 )资助
关键词
金矿床
成矿特征
成矿模式
同位素
隐爆角砾岩
gold deposit, ore forming characteristics, metallogenic model, central belt of East Kunlun Mountains in Qinghai