摘要
新疆伊犁盆地蒙其古尔矿床是近年来发现的大型砂岩型铀矿床。以下侏罗统三工河组为主要研究层位,通过岩性特征、沉积构造和沉积序列分析及露头描述和剖面对比,从沉积学的角度解释蒙其古尔矿区铀矿化的发育条件和成矿机制。研究认为,蒙其古尔地区三工河组以扇三角洲前缘沉积为主,水下分流河道、分流间湾、水下决口扇等为主要沉积微相类型,河口砂坝不发育。该沉积微相对研究区铀矿化的影响主要体现在4个方面:(1)砂体的连通性为成矿流体提供运移空间;(2)水下分流河道微相是控制氧化带发育及矿体富集程度的主要影响因素;(3)沉积微相变化导致的砂体变异部位是矿体厚度、宽度与富集程度增大的主要原因;(4)由决口扇形成的泥岩天窗是越流形成的关键因素之一。
Mengqiguer deposit is a large sandstone type uranium deposit discovered in recent years in Yili Basin of Xinjiang. Baesd on the lithology,sedimentary structures,sedimentary sequence,outcrop description and profile comparison,we explained the conditions and mechanism of uranium mineralization of the Lower Jurassic Sangonghe Formation in the study area. It is suggested that the fan delta front facies is the main type of sedimentary facies,including underwater distributary channel,distributary interchannel,underwater crevasse splay etc.,while the river mouth bar is not developed. The influence of sedimentary microfacies on uranium mineralization in the study area is mainly manifested in four aspects：（ 1） The sand body connectivity provided the spale for ore-forming fluid migration.（ 2） The underwater distributary channel sand is the main factor controlling the oxidation zone.（ 3） The sand body variation caused by changes of sedimentary microfacies made the ore body wider,thicker and uranium grade increase.（ 4）The mudstone skylight caused by underwater crevasse splay is one of the key factors in crossflow forming.
作者
陈奋雄
聂逢君
张成勇
张占峰
Chen Fenxiong Nie Fengjun Zhang Chengyong Zhang Zhanfeng(School of Earth Science, East China University of Technology, Nanchang 330013, Jiangxi Geologic Party No. 216, CNNC, Uriimqi 830011, Xinjiang)
出处
《古地理学报》
CAS
CSCD
北大核心
2016年第5期833-842,共10页
Journal of Palaeogeography：Chinese Edition
基金
国家重点基础研究发展规划(973计划)(编号:2015CB453002)
整装勘查关键基础地质研究计划项目(编号:12120114007601)共同资助~~
关键词
沉积微相
水下分流河道
越流
砂岩型铀矿
侏罗系
伊犁盆地
sedimentary microfacies
underwater distributary channel
cross flow
sandstone type uranium deposit
Jurassic
Yili Basin
