Abstract

The paper presents isotopic U–Pb zircon data (LA-ICP-MS method) for the main types of high-potassic intrusive rocks of the Chorukh-Dairon W–Mo(–Cu–Au) skarn deposit situated in the Kurama segment of the Middle Tien Shan near the largest porphyry Cu–Mo–Au deposits of the Almalyk mineralized cluster. Together with the other Au, W, Mo and Cu deposits, all these deposits are parts of the extended Late Paleozoic metallogenic belt of Tien Shan. The concordant isotopic U–Pb zircon data obtained for the rocks of successive intrusion phases in the Chorukh-Dairon pluton span from about 298 Ma to 290 Ma. This interval included crystallization of monzodiorite (295.1 ± 3.3 Ma), quartz syenite (294.7 ± 2.3 Ma), quartz monzonite (294.1 ± 2.1 Ma), and monzogranite (293.0 ± 3.0 Ma). These dates correspond to the pluton emplacement at the Late Carboniferous-Early Permian boundary and highlight its younger age compared to the productive high-potassic intrusions of the porphyry Cu–Mo–Au deposits in the Almalyk mineralized cluster, the latter assigned to the Late Carboniferous (about 337–313 Ma and partially to 308–297 Ma). By contrast to the latter, which were intruded in the subduction-related environment, the emplacement of the high-potassic rock of the Chorukh-Dairon pluton occurred in the transitional subduction-related to post-collisional environment or even under an actual post-collisional regime. This allows distinguishing two pulses of ore-bearing Carboniferous-Permian high-potassic calc-alkaline to shoshonitic series magmatism in the Middle Tien Shan. Consistently, there is a metallogenic evolution in the region that was expressed in the transition from porphyry Cu–Mo–Au deposits associated with subduction-related potassic magmatism, and likely evolving toward epithermal Au-Ag deposits, to essentially tungsten (W–Mo–Cu–Au) deposits associated with younger potassic magmatism occurring rather in the post-collisional environment.

中文翻译：

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Chorukh-Dairon W-Mo(-Cu-Au) 矿床（塔吉克斯坦）火成岩中锆石的 U-Pb 同位素年龄（LA-ICP-MS 方法）：鞍马地段碰撞后成矿的初步证据中天山

摘要

本文介绍了位于鞍马段的 Chorukh-Dairon W-Mo(-Cu-Au) 矽卡岩矿床主要类型高钾侵入岩的同位素 U-Pb 锆石数据（LA-ICP-MS 方法）。中天山靠近 Almalyk 矿化群最大的斑岩铜-钼-金矿床。与其他金、钨、钼和铜矿床一起，所有这些矿床都是天山晚古生代延伸成矿带的一部分。对 Chorukh-Dairon 岩体中连续侵入阶段的岩石获得的一致同位素 U-Pb 锆石数据跨度约为 298 Ma 至 290 Ma。该区间包括二长闪长岩（295.1±3.3Ma）、石英正长岩（294.7±2.3Ma）、石英二长岩（294.1±2.1Ma）和二长花岗岩（293.0±3.0Ma）的结晶。这些日期对应于晚石炭世-早二叠世边界的岩体就位，并突出显示与 Almalyk 矿化簇中斑岩铜-钼-金矿床的高产高钾侵入体相比，其年龄更年轻，后者被指定为晚石炭世（约 337–313 Ma，部分为 308–297 Ma）。与后者在俯冲相关环境中侵入相比，Chorukh-Dairon 岩体高钾岩的侵位发生在与碰撞后环境相关的过渡俯冲过程中，甚至是在实际的碰撞后环境下。政权。这使得能够区分中天山含矿石炭纪-二叠纪高钾钙碱性至钾闪岩系列岩浆作用的两个脉冲。一致地，该地区存在着成矿演化，表现为从与俯冲相关的钾岩浆作用相关的斑岩铜-钼-金矿床的转变，并可能向浅成热液金-银矿床演化，到本质上是钨（W-Mo- Cu-Au）矿床与较年轻的钾质岩浆作用相关，而发生在碰撞后环境中。