伊犁盆地南缘西段中下侏罗统水西沟群沉积体系及其对铀成矿的控制作用  

Depositional system of the Lower-Middle Jurassic Shuixigou Group in the western segment of the southern margin of the Ili basin and its controls on uranium mineralization

作　　者：李胜祥[1] 韩效忠[1] 蔡煜琦[1] 郑恩玖[2] 王保群[2] 

机构地区：[1]核工业北京地质研究院,北京100029 [2]核工业216大队,新疆乌鲁木齐830011

出　　处：《中国地质》2006年第3期582-590,共9页Geology in China

基　　金：国家重点基础研究发展规划项目(2001CB409808)

摘　　要：通过野外地质露头和钻孔岩心观察以及对大量钻孔岩心编录和测井解释资料的综合统计分析,笔者将伊犁盆地南缘西段中下侏罗统水西沟群划分出4个大的沉积体系:八道湾组(J1b)的冲积扇沉积体系、三工河组—西山窑组一段的辫状河三角洲沉积体系、西山窑组二段至三段的浅湖沼泽沉积体系和西山窑组四段至五段的曲流河三角洲沉积体系。文中详细讨论了伊犁盆地南缘西段水西沟群各沉积体系的沉积相特征,研究了水西沟群沉积体系及沉积相与砂岩型铀矿的成矿关系,指出辫状河三角洲沉积体系是砂岩型铀矿成矿最有利的沉积体系,三角洲前缘河口坝及席状砂亚相、三角洲平原辫状河流亚相、扇中-扇端亚相及三角洲平原分流河道亚相是砂岩型铀矿主要的控矿沉积相。The Lower-Middle Jurassic Shuixigou Group in the western segment of the southern margin of the Ili basin is divided into four deposifional systems based on field geological observations of outcrops and borehole cores and statistic analysis of plenty of borehole core records and logging interpretation data. The four depositional systems are the alluvial fan depositional system of the Lower Jurassic Badaowan Formation, braided delta depositional system of the Lower Jurassic Sangonghe Formation and Middle Jurassic Lower Xishanyao Formation, shallow lacustrine and swampy depositional system of the Middle Jurassic Middle Xishanyao Formation and meandering river depositional system of the Middle Jurassic Upper Xishanyao Formation. The sedimentary facies charac- teristics of each depositional system of the Shuixigou Group in western segment of the southern margin of the Ili basin are discussed in detail and the relationship between the formation of sandstone-type uranium deposits and the depositional system and sedimentary facies of the Shuixigou Group is studied. The braided delta depositional system is the most favorable one for the formation of sandstone-type uranium deposits;whereas the distributary mouth bar and sheet sand subfacies of the delta front facies, the braided stream subfacies and the distributary channel subfacies of the deka plain facies and the mid-fan and distal fan subfacies of the alluvial fan facies are the major ore-controlling sedimentary facies for sandstone-type uranium deposits.

关 键 词：伊犁盆地 水西沟群 沉积体系 沉积相 砂岩型铀矿 

分 类 号：P619.14[天文地球—矿床学]