初论环准噶尔斑岩铜矿带的地质构造背景与形成机制

Tectonic setting and formation mechanism of the circum-Junggar porphyritic copper deposit belts.

准噶尔地区构造-岩浆-成矿带具环准噶尔地块分布的特征,这一格局是准噶尔地区古生代大地构造演化的结果。哈萨克斯坦-准噶尔板块在北侧古亚洲洋与南侧南天山洋的俯冲下不断侧向增生,并形成与岩浆作用伴生的火山岩型铜铁多金属矿带、斑岩铜钼金矿带与浅成低温金矿带。哈萨克斯坦-准噶尔板块与西伯利亚板块和塔里木板块碰撞发生了强烈挤压-剪切变形,并导致准噶尔地块发生逆时针旋转,从而造成构造-岩浆-成矿带发生位移、呈环状分布于准噶尔地块周边。环准噶尔斑岩铜矿形成于俯冲成因的大陆岛弧、大洋岛弧与弧后盆地及后碰撞阶段板内4种构造背景,晚古生代是成矿的高峰时期。

Tectonics, magmatism and mineralization belts in the Junggar area tire circularly present around Junggar block, it was results of Paleozoic tectonic evolution of Junggar block. The Kasakhstan-Junggar plate was subducted by the Paleo-Asian oceanic plate at north side and by the South Tianshan oceanic plate at south side in Paleozoic era. Magmatic rock belts and associated volcanic rock-type Cu-Fe polymetallic deposit belts, porphyritic Cu-Mo-Au deposit belts and epithermal gold deposit belts were formed both in the south and north arc-basin systems. The Kasakhstan-Junggar plate was collided with Siberia plate and Tarim plate and intensively compressed, sheared and broken, resulting in anticlockwise rotation of Junggar block, dislocation of tectonics, magmatism and mineralization belts to surround the Junggar block. Porphyry copperitic Cu deposits around Junggar block were formed in four tectonic settings including continental arc, ocean island arc and backarc basin related to plate subduction and intraplate at post collision period, and the later Paleozoic era was the major main mineralization formation period.