松辽盆地西南部上白垩统姚下段红色砂体特征、成因及找矿意义  

Characteristics,Genesis and Prospecting Significance of Red Sand Body in the Lower Member of Upper Cretaceous Yaojia Formation,Southwestern Songliao Basin

作　　者：邢作昌 李子颖[1] 王海涛 贾立城[1] 宁君[2] 田明明[1] 刘武生[1] 吴大坤 林效宾[1] XING Zuochang;LI Ziying;WANG Haitao;JIA Licheng;NING Jun;TIAN Mingming;LIU Wusheng;WU Dakun;LIN Xiaobin(CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China;Geologic Party No.243,CNNC,Chifeng,Inner Mongolia 024000,China;Research Institute No.240,CNNC,Shenyang,Liaoning 110032,China)

机构地区：[1]核工业北京地质研究院中核集团铀资源勘查与评价技术重点实验室,北京100029 [2]核工业二四三大队,内蒙古赤峰024000 [3]核工业二四〇研究所,辽宁沈阳110032

出　　处：《铀矿地质》2023年第6期987-1001,共15页Uranium Geology

基　　金：中核集团集中研发项目“砂岩型铀矿多重耦合地质成矿作用与时空定位”(编号:中核科发2021-143号)资助。

摘　　要：松辽盆地主力产铀层位——姚下段红色砂体的成因是制约砂岩型铀矿找矿思路的关键问题之一。文章通过开展盆地西南部姚下段红色砂岩的岩石学、矿物学及时空特征的系统研究,明确了松辽盆地西南部姚下段的红色砂体宏微观特征。在此基础上,结合姚下段沉积期古气候、伴生红色泥岩、古河道、古水深等多因素耦合分析,认为姚下段红色砂体呈面状展布、砂体厚度中心严格受古河道控制、岩石孔隙间发育强烈赤铁矿化等一系列宏微观特征是姚下段沉积期受极热气候事件影响的炎热干旱古气候背景中的震荡变热旋回的陆上河流相沉积的地质记录,提出松辽盆地西南部姚下段红色砂体主体以极热古气候控制下的原生河流相沉积成因为主。在此基础上提出盆地西南部钱家店断陷、龙湾筒断陷等深部富铀建造之上红杂色建造中原色红色砂岩断裂附近的灰色砂岩透镜体,姚下段红色砂岩中夹的薄层灰色泥岩附近的灰色砂岩集中区,均是有利的渗出成矿目标地质体。该研究明确了盆地西南部主力产铀层位红杂色建造的原生性,指出姚下段具备渗出成矿的先决条件,进而为区内利用渗出找矿新思路开展找矿工作指明了方向。The lower member of Yaojia Formation,hereafter abbreviated as LYF,is the main uranium target layer in the Songliao Basin,genesis of the red sand body is one of the key issues restricting the exploration of sandstone-type uranium deposits.In this paper,the macro and micro characteristics of the red sandstone were clarified with the systematic study of petrology,mineralogy and time-space distribution of red sandstone.By the coupling analysis of multiple factors such as paleoclimate,associated red mudstone,pelaofluvial channel,and pelao water depth during the sedimentary period of the LAF,several important understandings was obtained.Firstly,the red sand in the lower member of LYF was distributed in a face-like manner.Secondly,the thickness centers of red sandstone were strictly controlled by pelao fluvial channels.Thirdly,strong hematite mineralization between rock pores was founded in red stone in LYF.These macro and micro characteristics of red sandstone are the geologic record of the continental fluvial deposits in the hot and arid paleoclimate background affected by the extremely hot climate event in the sedimentary period of LYF.The main red sandstone body in LAF,southwestern Songliao Basin was dominated by the sedimentary origin of the primary river facies under the control of extremely hot paleoclimate.On this basis,it was proposed that the gray sandstone lens near the primany red sandstone,linked by deep fault in the deep uranium rich formations such as the Qianjiadian fault-controlled depression and Longwantong fault-controlled depression in the southwestern mining area of the basin,as well as the gray sandstone concentration area near the thin gray mudstone sandwiched in the red sandstone in the LYD,are favorable geological targets for exudative mineralization.This study clarified the primary genesis of the red variegated formation in the main uranium producing layer in the southwest of the basin,and it was suggest that the LYF is the prerequisite for exudative mineralization and the new exploration direc

关 键 词：红色砂体 原生成因 渗出成矿作用 古气候 姚下段 砂岩型铀矿 松辽盆地 

分 类 号：P619.14[天文地球—矿床学]