鄂东神府地区山西组古沉积环境及沉积特征分析

Analysis of Palaeo-sedimentary Environment and Characteristics of Shanxi Formation in Shenfu Area on the Eastern Margin of Ordos Basin

将沉积地球化学与沉积学结合,对神府地区山西组沉积环境及沉积特征进行全面研究。地化资料分析表明,神府地区山西组沉积期水体为弱还原-弱氧化的淡水环境,古气候温暖湿润;重矿物资料和地化资料综合显示神府地区山西组物源方向为北东向,母岩性质主要为碱性玄武岩和花岗岩,物源区为盆地北部阴山古陆;进一步结合岩心、测井及实验资料,确定研究区山西组为曲流河三角洲前缘亚相沉积,发育分流河道,分流间湾、水下天然堤微相。

The sedimentary environment and characteristics of Shanxi Formation in Shenfu area are studied comprehensively by combining sedimentary geochemistry and sedimentology.The analysis of geochemical data shows that during the sedimentary period of Shanxi formationin the study area,the water body is a fresh water environment of weak reduction to weak oxidation,and the paleoclimate is warm and humid.The heavy mineral and geochemical data comprehensively show that the provenance direction of the Shanxi formation in the study area is NE,the parent rocks are mainly alkaline basalt and granitic rocks,and the provenance is Yinshan paleocontinent in the north of the basin.Combined with core,logging and experimental data,it is determined that Shanxi formation in the study area is a meandering river delta front subfacies deposit with the microfacies of distributary channel,interdistributary bay and subaqueous levee.