新疆的印支运动与成矿

Indosinian movement and metallogeny in Xinjiang,China.

随着高精度同位素年代学研究的深入,一些长期被认为属于海西期甚至加里东期的地质体被证明形成于印支期。在新疆及其周边的广大地区,印支运动主要表现在下述3个方面:①以中酸性小岩体-伟晶岩-细晶岩-辉绿岩-煌斑岩脉为主的岩浆侵入体,个别地区存在印支期的辉长岩-闪长岩体,这些侵入体多数显示金-铜-稀有金属矿化的特征,部分岩体本身就是矿体或者其中含矿;②很多韧性剪切带在印支期活动,大多数剪切带的最后一次韧性变形发生在印支期;③天山地区绝大多数与韧性剪切带有关的金矿均形成于印支期,印支期是中亚地区最重要的成矿时代之一。印支运动在天山和阿尔泰山有不同的表现形式,其地球动力学背景也完全不同。

With an increase of high-resolution isotope chronological data, some geological bodies that have long been considered to be Hercyman and even Caledonian in age have been identified to be formed during the Indosinian period. Indosinian movement in Xinjiang and its adjacent areas is manifested as follows： （1） magmatic intrusions represented mainly by small intermediate-acid bodies and pegmatite, aplite, diabase and lamprophyre dikes, occasionally with gabbro-diorite bodies, which usually show the characteristics of gold-copper-rare metal mineralizations and some of which are just orebodies or contain ores; （2） many ductile shear zones were active during the Indosinian period, and in most cases the last ductile shear deformation occurred during the Indosinian; and （3） most gold deposits related to ductile shear zones in the Tianshan Mountains, including the giant Muruntau and Wanfeng-Tianger gold deposits, formed during the Indosinian period. Indosinian thus is one of the most important metallogenic epochs in Central Asia. The behaviors and geodynamic settings of the Indosinian movement are different in the Tianshan and Altay mountains.