鄂尔多斯盆地二叠系盒8段物源特征分析

1.长安大学 地球科学与资源学院,陕西 西安 710054; 2.中国石油长庆油田分公司第五采气厂,内蒙古 乌审旗 017300; 3.陕西省地质调查中心,陕西 西安 710068

物源分析; 轻重矿物; 古流向; 盒8段; 鄂尔多斯盆地

Analysis of the provenance of the 8th member in Ordos Basin
LIANG Ji-wei1,CHEN Jie1,ZHAO Kai-qiang1,

(1.College of Earth Science and Recourses,Chang'an University,Xi'an 710054,China; 2.Gas Production Plant 5,PetroChina Changqing Oilfield Company,Wushenqi 017300,China; 3.Shaanxi Center of Geological Survey,Xi'an 710068,China)

source analysis; heavy minerals; paleo-current directions; 8th Member of Xiashihezi Formation; Ordos Basin

DOI: 10.13800/j.cnki.xakjdxxb.2016.0107

备注

鄂尔多斯盆地二叠系下石盒子组新天然气区带的相继发现,使得全盆地基础上的母岩特征及物源进行分析显得尤为重要。应用数理统计的方法,对古水流方向、轻重矿物组成、分布特征等数据进行统计分析,并与周缘基岩矿物组成对比,探讨盆地盒8段的物源问题。研究认为,鄂尔多斯盆地盒8段沉积物主要由北、南部2大物源区供给,以吴旗-子长一带为中心区域属于汇水区; 北部物源根据其矿物组成及古流水方向可细分为北北东、北北西及北3个方向,物源范围较大,延伸至定边-子长一带; 南部物源矿物主要重矿物成分基本相同,根据其微量矿物含量可将其分为南南东、南南西及南3个方向,其影响范围仅局限于吴旗-延安以南; 盆地中部定边-延安一带受多个物源影响,形成汇水盆地。

The study on provenance of the Shihezi Formation in the Ordos Basin,which is on the basis of the research on the whole basin,is more and more important in the new discovery of gas reservoir.Based on the method of mathematical statistics analysis of the data of the ancient flow direction,the severity of the mineral composition,distribution and so on,combined with the comparative study of the surrounding bedrock,the provenance of the 8th member of the Xiashihezi Formation was studied.The research suggests that the sources during the deposition of the 8th Member of Xiashihezi Formation in Ordos Basin were from north and south,and the catchment area centers around Wuqi-Zichang area; The northern provenance can be subdivided into three directions including north-east,northwest and north direction.The influence area of northern provenance is bigger,which has been extended to the Dingbian-Zichang area; The mineral components in southern are same,and according to the difference of the trace mineral,it can be divided into South-east direction,south direction and south-west direction,but the scope was restricted to the south of Wuqi-Yan'an area; Affected by more than one sources,Dingbian-Yanan area formed a catchment basin.