中亚巴尔喀什成矿带晚古生代最晚期岩浆侵入事件及其热演化历史

The latest granitic intrusive magmatism and thermal evolution in the Late Paleozoic Balkhash Metallogenic Belt(Kazakhstan),Central Asia

哈萨克斯坦巴尔喀什成矿带是中亚成矿域重要的晚古生代斑岩铜钼和云英岩-石英脉型钨钼成矿带,是受走滑断裂边界控制的中亚多核成矿系统的核心之一。本文根据锆石SHRIMP U-Pb定年、40Ar/39Ar热年代学、磷灰石裂变径迹定年和热历史模拟,厘定了巴尔喀什成矿带西部地区晚古生代最晚期深成岩浆侵入事件。研究表明,原来被认为是属于三叠纪的后碰撞花岗岩类侵入岩体,给出锆石SHRIMP U-Pb年龄为289.7±2.3Ma,为早二叠世。结合前人研究,本文探讨了巴尔喀什成矿带西部从深成岩浆侵入、钨钼成矿作用、区域冷却到剥露作用热历史的全过程。晚古生代最晚期花岗岩类侵入体具有与钨钼矿床相同的晚中生代剥露作用年龄(92.4±5.9Ma)。

The Balkhash Metallogenic Belt （Kazakhstan） in the Central Asia, with the occurrence of many well-known large and super-large porphyritic Cu-Mo deposits, large skarn Cu deposits, and large rare metal deposits, is one of the multi-core areas of the Central Asian metallogenic domain controlled by boundary strike-slip fault system. Zircon SHRIMP U-Pb, Ar-Ar thermochronology, and apatite fission track dating and thermal history modeling, provide a multidisciplinary approach to constrain the whole course thermo- history of the latest Late Paleozoic intrusive granitic magmatism in the western part of the Balkhash Metallogenic Belt. Zircon SHRIMP U-Pb dating of grantic pluton north to the Borly Cu deposit, reveals intrusive granitic magrnatism at 289. 7 ± 2. 3Ma in the Early Permian, which was previously considered as of an age in the Triassic. The latest Late Paleozoic granitic pluton has a similar age with the W-Mo metallogenesis at -289Ma for the Akshatau deposit. Based on geochronological results from previous and this study, we reconstruct the whole course thermal history, from intrusion, through regional cooling, to the Late Mesozoic exhumation at 92. 4 ± 5.9Ma, for the granitic pluton.