西成矿田中泥盆统碳酸盐岩沉积微相、微相组及其环境分析  

Analysis of Microfacies,Microfacies Associations and Sedimentary Environments of Carbonate Rocks of the Middle Devonian in Xicheng Pb-Zn Orefield

作　　者：宋春晖[1] 武安斌[1] 

机构地区：[1]兰州大学地质系

出　　处：《沉积学报》1993年第2期34-42,共9页Acta Sedimentologica Sinica

摘　　要：西成地区中泥盆统碳酸盐岩分布广泛,岩石类型多,相变急剧。本文以结构成因分类为基础,将本区碳酸盐岩归纳为四类26种微相,并分析了每种微相的基本沉积条件和形成环境。据区内微相的相邻和共生关系,建立了10个主要微相组合,并解释了各种微相组的沉积环境及其演化。根据微相组控矿,提出半开阔台地凹陷盆地和生物滩(层)礁后浅水盆地是本区碳酸盐型铅锌矿成矿的有利环境。The Xicheng Pb-Zn orefield locates in Gansu Province, is one of the most famous ore-fields in China. Its controlling horizon are Anjiacha and Xihanshui formations of the middle Devonian,and its ore-bearing rocks belong to marine clastic and carbonate rocks. Carbonate rocks characterized wide spreding, multi-rock types, rapid facies changment and good ore-bearing bedds. On the basis of textural origin classification and consulting the types of grains and sedimentary structures,the carbonate rocks can be divided into four types and twenty-six kinds of microfacies: include seven kinds of grainstone(MG1-MG7),six kinds of wackestone (GM1-GM6) ,nine kinds of mudstone(M1 -M9) and four kinds of hermatobiolith(R1 -R4). The microfacies represent respectively different sedimentary conditions and environments. Ten kinds of microfacies associations have been estabilished according to neighbouring and paragenetic relationship of micro-facies. Each association corresponds a designated sedimentary environment and its evolution: such as (Fig. 1) open platform, uppertidal zone-swamp in restricted platform, sag basin of semi-open platform, reef-fore-reef-reef-back , biogenic bank(or stratigraphic reef)-shallow basin behind bank-shelf and shelf point reef shelf. On the basis of microfacies associations controlling Pb-Zn ore,this paper shows that sag basin of semi-open platform and shollow basin behind the bank are a favourable environments to form Pb-Zn ore.

关 键 词：碳酸盐岩 沉积微相 沉积环境 矿田 

分 类 号：P588.245[天文地球—岩石学]