摘要：

研究伊犁盆地南缘洪海沟地区主力含铀层系——中侏罗统西山窑组上段的沉积特征,为该区下一步铀矿地质勘查提供理论依据。根据沉积结构、岩性组合、沉积韵律、沉积构造、测井曲线等特征,认为西山窑组上段在洪海沟地区主要发育曲流河沉积。根据连井剖面特征,以及砂体厚度、砂地比等沉积特征在平面上的变化,洪海沟地区西山窑组上段沉积相的平面分布规律明显,中间为沿北西—南东向展布的曲流河道,河道南部为河漫沼泽,北部为河漫滩。综合研究区岩性、构造、铀源等成矿条件,西山窑组上段赋存的铀矿体主要受河道砂体展布方向、河道砂体厚度、砂体粒度、砂体中的泥岩夹层、地层产状等因素控制。

关键词: 伊犁盆地南缘, 洪海沟地区, 西山窑组, 砂岩型铀矿, 沉积相

Abstract:

Studying sedimentary characteristics of the Upper Xishanyao Formation,which is the main uranium-bearing stratum in Honghaigou area of southern margin in Ili Basin, will provide important theory evidence for further uranium exploration in study area. Based on the characters of sedimentary textures,lithologic associations,sedimentary rhythms,sedimentary structures,and logging curves,the Upper Xishanyao Formation can be considered as meandering channel facies in Honghaigou Area. Combined with the connected wells profiles,the lateral changes of sedimentary characteristics including the thickness of sand body,the ratio of sand to stratum,sedimentary facies of Middle Jurassic Upper Xishanyao Formation was clear,which showed that there was meandering channel along northwest-southeast in the middle part,a flood swamp in the south and a floodplain in the north. By summarizing and analyzing the metallogenic conditions in study area,including lithology,tectonic setting,and uranium source,the uranium ore bodies occurred in the Upper Xishanyao Formation in Honghaigou area were mainly controlled by the distribution direction, thickness, grain size,the mudstone intercalations in sandbody,and the occurrence of stratum.

Key words: southern margin of Ili Basin, Honghaigou area, Xishanyao Formation, sandstone-type uranium deposit, sedimentary facies

中图分类号: 

• P512.2