新疆东准噶尔地区构造演化及主要成矿期

TECTONIC EVOLUTION AND MAIN METALLOGENETIC PERIODS OF EAST JUNGGAR REGION XINJIANG CHINA

笔者认为东准噶尔地区曾是古新疆克拉通的一部分,只是到了泥盆纪才演化成大洋。值得特别提出的是,大洋消失之后,经历了残留海盆阶段才开始碰撞造山。碰撞期后的岩浆作用和板内裂陷作用在该区特别发育,而且形成相关的内生金属矿产。以大型内陆盆地沉降和山脉隆升为特征的陆内造山作用标志着大陆克拉通化的最终完成。成矿期与构造演化密切相关,自老而新划分了6个成矿期。

The east Junggar region was a section of ancient Xinjiang craton in period from Sinian to Cambrian. The region was covered by a volcano- flysch basin, which became a componant part of the Junggar-Tianshan Ocean along south margin of Siberian Plate from Ordovician to Silurian. During the early Devonian a crustal stretching took place on Early Paleozoic folded base along the Karameili area, and to the Middle Devonian a well-developed Paleozoic Junggar Ocean with trench-arc-basin system had already formed in the area, and was located between the Siberian Plate and the Kazakhstan Plate. At the end of Middle Devonian the Ocean disap- pered. Since then the area underwent evolutionary stage of a remnant Sea from Late Devonian to the middle stage of Early Carboniferous. In the late stage Early Carboniferous the area turned into post-collisional rift-subsiding aetiar within plate. Up to Middle Carboniferous the rift-subsiding trough formed along the Bogdashan. However, a post-collisional intermediate-acid magmatism was widely overspreaded over the Karameili and the Armantai area. This magmatism produced the Laoyaquan-Huangyangshan granite bodies and other intermediate-acid bodies. In chronological order, Metallogenic periods of the East Junggar region can be divided into to the following six periods:(1)the Huangcaopo period(from Ordovician to Silurian), (2)the Karameili period(From Early Devonian to Middle Devonian), (3)the Nanming- shui period(The middle of Early Carboniferous), (4)the Batamayineishan period(the late of Early Carboniferous), (5)the Laoyaquan=Huangyangshan period(from Middle Carboniferous to Early Permian), (6)the Jungar period (from Permian to Canozoic). Above-mentioned metallogenic periods are separatelly and closely related with evolutionary stages of the volcano-flysch basin, the oceani basin, the remnant sea basin, the post-collisional riftsubsi- ding action and magmatism within plate, and the inland orogeny.