沉积学报2018，Vol.36Issue(3)：456-467,12.DOI:10.14027/j.issn.1000-0550.2018.116
伊犁盆地南缘中侏罗统西山窑组沉积环境讨论
Discussion on the Sedimentary Environment of the Middle Jurassic Xishan-yao Formation in theSouthern Margin of the Yili Basin
摘要
Abstract
The southern margin of the Yili Basin is an important area with enrichment of coalmine and sandstone-type uranium deposits in China and the Middle Jurassic Xishanyao Formation is the main ore-bearing strata. Based on field geological section, indoor microscopical identification, grain size analysis, and drilling data, the sedimentary environ-ment types, genesis and distribution of sand bodies, and its relation with coal-bearing stratum distributions in the Mid-dle Jurassic Xishanyao Formation at the southern margin of the Yili Basin were identified. Results show that the Xish-anyao Formation on the southern margin of the Yili Basin is dominated by meandering-stream delta plain-delta front. The sandstones of the distributary channel microfacies are highly coal-bearing or carbonaceous, medium-coarse size, rich in debris and feldspar, poor selection and moderate roundness, with relatively low compositional maturity and structural maturity. The three-stage particle-size curve is the main feature, showing the characteristics of the jumping, rolling, and suspension transport in the delta plains. The resistivity curve appears in the longitudinal direction as an inverse grain size with a coarser grain size. Moreover, the thickness of the sand body is mostly between 20-40 m, with the sand ratio between 0.3-0.8. The coal seam or peat in the marsh facies between the distributary channel sandstone and the distributary river channel is adjacent to each other in the plane and alternant vertically. There are many fossils of ancient plant stems and plant imprints. The symbiotic coupling relationship between the depositional environment of the meander river delta, the delta sandstone and the coal-bearing strata has provided sedimentary support for the in-depth study of coal and uranium enrichment in the southern margin of the Yili Basin.关键词
伊犁盆地南缘/中侏罗统/西山窑组/沉积环境/曲流河三角洲Key words
southern margin of the Yili Basin/middle Jurassic/Xishanyao Formation/sedimentary environment/meandering river delta分类
天文与地球科学引用本文复制引用
吴斌,朱莉娟,侯明才,晁晖,江文剑,石鑫,罗宏谓,曹海洋,何佳伟..伊犁盆地南缘中侏罗统西山窑组沉积环境讨论[J].沉积学报,2018,36(3):456-467,12.基金项目
国家重点基础研究发展计划("973"计划)项目(2015CB453001)National Key Basic Research Program of China(973 Pro-gram) , No.2015CB453001 （"973"计划）
