Provenance Analysis of Permain Shan1 and He 8 Formation in Permian in Southwest Ordos Basin

Key words: 
• Ordos Basin /
• Permian /
• provenance /
• paleocurrent /
• heavy mineral /
• character of fragments /
• REE

Abstract: Since there are little provenance documents about Permian of southwest Ordos Basin, this paper focuses on the provenance analysis of Permain Shan 1 and He 8 Formation in Permian to figure out provenance of the two formations and whether there are differences between these two contiguous formation. Based on provenance analysis methods, the characteristics of paleocurrent, heavy mineral, feldspar, fragments, and REE have been analyzed. The result will benefit for the prediction of favorable reservoir. The character of paleocurrent shows that the provenance of Permian in the southwest Ordos Basin is multiplied, and we can divide He 8 formation into four parts based on the combination of heavy mineral:the north, southwest, southeast and the middle part of the study area. Besides the north study area can be divided into two parts based on the content of zircon and leucosphenite, the provenance of this two parts are the northwest and the northeast of Yin mountain divided by Ural mountains; The character of fragments and REE reflect that the north of study area have the character of distant deposition and the south of study area are close deposition. The provenance characters of Shan 1 and He 8 Formation are very similar. The information above draw the conclusion that in the study area the deposition in the north part of Shan1 Formation came from the Yin Mountains in the north of the basin, the southwest part from the middle north of Qilian Mountains and west Qinling Mountains and southeast part from the north Qinling Mountains in the south of the basin. And the sediment came across around Huanxian and Huachi. The provenance of He 8 Formation is similar to Shan1 Formation, the sediments in north part of the study area is from Yin Mountains in the north of Ordos basin;The middle east of Qilian Mountain and west Qinling Mountain provide sediments for southwest of study area,the provenance of southeast part of the study area is north Qinling Mountain in the south of the basin and the catchment area is also around Huanxian and Huachi. Results show that the provenance of the two formations did not change so much and the two formations have the character of succession. Besides The characters of REE shows that there are two locations in the study area have a lower altitude which shows a reducing environment.