新疆北部晚古生代铜矿床主要类型和地质特征

Major Types and Characteristics of Late Paleozoic Copper Deposits in North Xinjiang,Northwest China

铜矿床广泛地分布于新疆北部，已构成我国重要的铜及多金属矿床产地和后备基地。根据容矿岩石和矿床成因特征，新疆北部的铜矿床可以划分为以下几种类型：①斑岩Cu-Mo-（Au）型；②岩浆Cu-Ni硫化物型；③VMS Cu-Pb-Zn型；④夕卡岩Cu-Mo-Au-Ag型。这些矿床的形成与西伯利亚、哈萨克斯坦-准噶尔和塔里木板块汇聚碰撞和碰撞后的弛张作用密切相关。早泥盆世（～400）斋桑洋盆沿着阿尔泰-富蕴一带向北俯冲，由于板片后退和拆沉作用，在阿尔泰南缘形成弧后盆地并伴有大量的火山喷发和成矿流体活动，导致阿舍勒和可可塔勒等VMS铜一铅锌型矿床的形成；而在西天山的博罗霍努一带，此次构造事件导致喇嘛苏铜矿床的形成。晚泥盆世-早石炭世，由于北天山洋盆向北俯冲，形成大南湖-头苏泉岛弧，并伴有高侵位的花岗岩体分布和铜-钼-金-银矿体的形成。在晚石炭世-早二叠世，新疆北部进入后碰撞构造演化阶段，大量镁铁-超镁铁质和碱性花岗岩岩浆侵位，形成大量的岩浆铜镍硫化物（喀拉通克、黄山和黄山东）和夕卡岩型矿床（索尔库都克、维权）。

Occupying the middle of the central Asia orogenic belt, the northern Xinjiang area has a great economic potential due to copper mineralization during syn-and post-orogenic events. About 40 copper deposits have been discovered in Northern Xinjiang, which forms one of the most important copper metallogenic belts and a copperproducing base in China. According to their host rocks, these copper deposits can be classified into four principal types： （1） porphyry Cu-Mo-（Au） deposits; （2） magmatic Cu-Ni sulfide deposits; （3） volcanic-hydrothermal massive sulfides （VHMS） Cu-Pb-Zn deposits; （4） skarn Cu-Mo-Au-Ag deposits. Tectonically, the development of these late Paleozoic copper deposits was closely asmciated with the subduction and collision of the Paleoasian ocean intervened between the Siberian block and the Tarim Craton. An important metallogenic epoch of Cu-Pb-Zn-polymetallic deposits were formed tearing occurred during the Devonian （400--370 Ma） in response to lock-up of the subduction zone near the southern margin of the Altay-Fuyun magmatic arc, during which the Ashele copper-lead zinc and Keketale Pb-Zn deposits formed. In the Bolokenu area of the West Tianshan, this tectonic event was accompanied by the formation of the Lamasu skarn copper deposit. Subduction led to accretion of the Junggar ocean arc system in the Middle Devonian. In the Late Devomian-Early Carboniferous, N-dipping subduction beneath the Dananhu arc triggered emplacement of granitic porphyries in the Tousuquan and Dananhu is- land-arc belt in the East Tianshan, leading to formation of the Tuwu and Yandong porphyry Cu Mo-Au-Ag deposits. In the Late Carboniferous to Early Permian, during the closure of the ancient Tianshan ocean, large mafic-ultramafic complexes were emplaced, resulting in several magmatic copper-nickel deposits, including the Kala-tongke Cu-Ni deposits in north J unggar and Cu-Ni sulfide deposits in the Huangshan-Jing＇ erquan area of East Tianshan Mountains. Coevally with the Cu-Ni events, there were voluminous anateetic granitoids and led to the formation of skarn Cu-Mo deposits （Suoerkuduk Cu-Mo deposit） and skarn Cu-Ag deposit （Weiquan Cu-Ag deposit）. The tectonic settings, geological features, and temporal and spatial of these different types of copper deposit reflect, to a great extent, the accretionary and collisional tectonics that occurred between the southern margin of the Siberian block and the northern margin of the Tarim Craton.