东天山印支期矿床地质特征、成因类型及成矿规律

东天山成矿带是我国重要成矿带之一,以古生代大规模成矿为特色。近年来,东天山成矿带陆续报道了一批印支期的成矿年龄,吸引了越来越多的关注。基于此,初步总结了东天山印支期矿床的地质特征、成因类型及成矿规律。结果表明:东天山印支期矿床的成矿元素丰富,金、钼、钨、铼、铷等均达到大型—超大型规模,还蕴含了锂、铍、铌、钽、钒、钛、铁等金属矿床,显示出东天山印支期成矿的重要性。印支期矿床的成因类型多样,既发育了岩浆型钒钛磁铁矿床、花岗岩型铷矿床、伟晶岩型锂铍铌钽矿床等岩浆矿床,又发育斑岩型钼铼矿床、矽卡岩型钨钼铷矿床、石英脉型钨矿床、造山型和浅成低温热液型金矿床等热液矿床。在空间分布上,印支期矿床集中分布于康古尔韧性剪切带和中天山地块及其东南缘,而其他构造单元成矿信息较少。虽然印支期矿床的分布具有时空相似性,但关键控矿要素明显不同,矽卡岩型钨矿床明显受中天山前寒武纪基底控制,钒钛磁铁矿床、花岗岩型铷矿床、伟晶岩型锂铍铌钽矿床和斑岩型钼矿床受不同性质的侵入岩控制,而造山型金矿床明显受韧性剪切带和断裂构造控制。因此,东天山印支期造山作用的资源潜力已初步显现,未来应加强东天山甚至新疆地区的印支期成矿作用研究和找矿勘查工作。

Geological Characteristics,Genetic Types and Metallogenic Regularity of Indosinian Deposits in East Tianshan,China

East Tianshan metallogenic belt, which is one of the important metallogenic belts in China, is characterized by large-scale mineralization during Paleozoic. In recent years, a number of Indosinian age data have been reported in East Tianshan metallogenic belt, which have attracted a lot of attention. The geological characteristics, genetic types and metallogenic regularity of Indosinian deposits in East Tianshan were summarized. The results show that Indosinian deposits in East Tianshan contain not only large-superlarge scale Au, Mo, W, Re, and Rb deposits, but also Li, Be, Nb, Ta, V, Ti, Fe and other metal deposits, indicating the importance of Indosinian mineralization in East Tianshan. The genetic types of Indosinian deposits include magmatic deposits, i.e., magmatic V-Ti magnetite deposit, granite-type Rb deposit and pegmatite-type Li-Be-Nb-Ta deposit, and hydrothermal deposits, i.e., porphyry-type Mo-Re deposit, skarn-type W-Mo-Rb deposit, quartz vein-type W deposit, orogenic-type and epithermal-type Au deposits. Indosinian deposits in East Tianshan are mainly distributed in Kanggu'er ductile shear zone, Central Tianshan terrane, and their southeastern margin, but there is little metallogenic information in other tectonic units. The distribution of Indosinian deposits is similar in time and space, but the key ore-controlling factors are obviously different. Skarn-type W deposit is obviously controlled by Precambrian basement of Central Tianshan terrane; V-Ti magnetite deposit, granite-type Rb deposit, pegmatite-type Li-Be-Nb-Ta deposit and porphyry-type Mo deposit are controlled by different intrusive rocks; and orogenic-type Au deposit is obviously controlled by ductile shear zone and fault structure. Therefore, the resource potential of Indosinian orogeny in East Tianshan has been preliminarily shown, and more attention should be paid to the study on Indosinian mineralization and ore exploration in East Tianshan and even Xinjiang in the future.