新疆拜城新近系含铜岩系沉积体系及沉积环境

新疆拜城地区发育一套新近纪巨厚的陆相碎屑沉积岩系,其中康村组中上部含规模较大的沉积型铜矿,康村组的沉积环境及演化过程对铜矿的形成具有重要意义。基于野外和室内详细的沉积学研究,查明研究区新近系吉迪克组、康村组和库车组总体上为陆相沉积体系,主要包括冲积扇-扇三角洲沉积体系和湖泊沉积体系两大类型,划分为扇三角洲平原、扇三角洲前缘、前扇三角洲、滨浅湖和膏盐湖亚相及若干沉积微相。研究表明研究区康村期主要发育扇三角洲沉积,矿区主要含矿层位于康村组上部红色岩系向灰色岩系转变,沉积环境从扇三角洲前缘亚相到滨浅湖亚相过渡的层位上。

Sedimentary System and Depositional Environment of Copper-Bearing Rock Series of Neogene in Baicheng County,Xinjiang

A set of Neogene thick continental clastic sedimentary rocks develops in Baicheng County, Xinjiang province, in which a large-scale sedimentary copper ore occurs in the upper part of Kangcun Formation. Obviously, it is of important significance in the formation of copper deposits to the sedimentary environment and its evolution of the Kangcun Formation. Based on detailed sedimentological studies in field and laboratory, two major types of sedimentary system, alluvial fan-fan delta type and lacustrine type, are identified for Jidike Formation, Kangcun Formation and Kuqa Formation of Neogene in the study area. The sedimentary systems are further divided into subfacies of fan delta plain, fan delta front, front fan delta, shore shallow lacustrine, gypsum-salt lacustrine and some microfacies. The sedimentary framework of the Kangcun stage approximately inherited that of the Jidike stage. The types of sedimentary facies were mainly fan delta facies in the study area during the Kangcun stage, while sediments of lacustrine facies occurred in warm humid climate could fill the whole study area. Main ore-bearing beds are in the transitional strata of red rocks to gray rocks in the upper part of Kangcun Formation. And the sedimentary characteristics of ore-bearing beds indicate that the depositional environment have experienced a process from fan delta front facies to shore shallow lacustrine facies.