哈萨克斯坦阿克斗卡超大型斑岩型铜矿田地质特征与成矿模式

GEOLOGICAL CHARACTERISTICS AND METALLOGENIC MODEL OF SUPER-LARGE PORPHYRY COPPER DEPOSITIN AKTOGAI ORE FIELD,KAZAKHSTAN

中亚成矿域巴尔喀什成矿带阿克斗卡矿田主要由阿克斗卡、艾达里和库兹尔基亚等矿床组成,是发育在火山岛弧环境的典型斑岩型Cu-Mo-Au矿床群,其中阿克斗卡为超大型斑岩铜矿。斑岩型铜成矿作用发生在晚古生代哈萨克马蹄形构造形成过程中,成矿构造背景为乌拉尔-天山断裂系统的大型左行走滑作用和大陆地壳侧向增生过程,具有典型的斑岩铜矿围岩蚀变和矿石矿物分带特征;成矿作用受东西向、北东东向和北西西向断裂控制,主要与早期碱性阶段的硅化蚀变有关,酸性蚀变阶段发生了再矿化与富集成矿作用;据含矿花岗闪长岩中锆石SHRIMP定年本文给出主要成矿时代为327.5±1.9 Ma(早石炭世晚期),成矿模式为"花岗闪长岩"型,属于浅成斑岩铜矿成矿系统。

The Aktogai ore field consists of a group of porphyry Cu-Mo-Au deposits,such as Aktogai,Aidarly,and Kyzylkia deposits,in the Balkhash Metallogenic Belt of the Central Asian Metallogenic Domain.They are formed in the Balkhash volcanic arc of the north-central margin of Kazakhstan Orocline due to the large left-leteral strike-slip movement of the Ural-Tianshan Fault System and lateral crust-growth in the Late Paleozoic.Among them,the Aktogai deposit is a superlarge porphyry Cu-Mo-Au deposit.All of them are porphyry deposits with typical zoning of wallrock alterations and mineral assemblages.The metallogenesis is mainly related to the silicification of the early-stage alkaline alteration and the redeposition in the acid alteration stage.The occurrence of ore-bodies is controlled by the E-W,ENE,and WNW trending faults.The SHRIMP zircon dating of granodiorite has given the Aktogai deposit a metallogenic age of 327.5 ± 1.9 Ma in the late period of the Early Carboniferous.The deposit model of the porphy deposits in the Aktogai ore field is concluded as'granodiorite'type in the hypabyssal porphyry copper system.