喀什凹陷巴什布拉克地区下白垩统克孜勒苏群一段沉积特征与铀成矿关系探讨  

Relationship Between Sedimentary Characteristics and Uranium Mineralization of the First Part of Lower Cretaceous Kizilsu Group in Bashbulak Area, Kashgar Sag

作　　者：李炳谦 张明正[1] 王守玉 鲁克改[1] 杨小强[1] 唐运涛[1] LI Bingqian;ZHANG Mingzheng;WANG Shouyu;LU Kegai;YANG Xiaoqiang;TANG Yuntao(Geologic Party No.216,CNNC,Urumqi,Xinjiang 830011,China)

机构地区：[1]核工业二一六大队,新疆乌鲁木齐830011

出　　处：《铀矿地质》2022年第6期999-1011,共13页Uranium Geology

基　　金：中国核工业地质局铀矿地质项目“新疆塔里木盆地北缘乌恰-尉犁铀矿资源调查评价与勘查”(编号:202207)资助。

摘　　要：塔里木盆地喀什凹陷巴什布拉克地区下白垩统克孜勒苏群一段(简称“克一段”)为铀矿赋矿层位,分析其沉积特征及其与铀成矿的关系可为今后的研究提供理论依据。根据沉积特征、砾岩厚度、含砾率及含砂率等因素综合分析认为克一段早期沉积主要为岩屑砂岩,次为长石砂岩及岩屑长石砂岩;晚期沉积主要为长石砂岩,次为岩屑长石砂岩,属辫状河三角洲沉积,具典型下细上粗的特征,包括3类亚相及7类微相,以辫状河三角洲前缘为沉积主体,水下分流河道微相含矿性最好,辫状河道微相及分流间湾微相次之。铀矿化主要为潜水氧化成因,且受控于古潜水氧化带,始新世末期侵入目的层的油气为铀矿体的进一步富集提供了还原剂及吸附剂,研究区南部的河道沉积及其边部是今后找矿的有利部位。The first part of the Lower Cretaceous Kizilsu Group(hereinafter referred to as"Ke 1")in Bashbulak area,Kashgar sag,Tarim Basin is the ore bearing horizon of uranium deposit.Analyzing its sedimentary characteristics and its relationship with uranium mineralization will provide a theoretical basis for future research.According to the comprehensive analysis of single factors such as sedimentary characteristics,conglomerate thickness,gravel content and sand content,it was considered that the early sedimentation of Ke 1 is mainly lithic sandstone,followed by arkose and lithic arkose,and the late sedimentation is mainly arkose and followed by lithic arkose.It falls into braided river delta sedimentation,with typical characteristics of fine at the bottom and coarse at the top,including 3 types of subfacies and 7 kinds microfacies,with braided river delta front as the main sedimentary body.The ore bearing property of underwater distributary channel microfacies was the best,followed by braided channel microfacies and distributary bay microfacies.The uranium mineralization was mainly caused by phreatic oxidation and controlled by the ancient phreatic oxidation zone.The oil and gas invading the target layer at the end of Eocene provided the reluctant and adsorbent for the further enrichment of uranium ore body.The river deposition and its edge in the south of the study area were regarded as the favorable sites for ore prospecting in the future.

关 键 词：辫状河三角洲 沉积特征 古潜水氧化带 巴什布拉克 喀什凹陷 

分 类 号：P619.14[天文地球—矿床学]