SUN Sha-sha1,2, YAO Yan-bin1, LIN Wen2
1. School of Energy Resources, China University of Geosciences(Beijing), Beijing 100083, China;
2. Research Institute of Petroleum Exploration and Development-Langfang, Unconventional Oil & Gas Laboratory of PetroChina, Langfang, Hebei 065007, China
Abstract: This study studied the characteristics of major and trace elements of the Tongchuan oil shale of the Yanchang Formation in the southern Ordos Basin and discussed the paleo-lake environment of this area. The high contents of phosphate and iron may be due to nutritions from volcanic ash after volcanic eruption around the lake. The average values of Sr/Ba, V/(V+Ni), Ni/Co, U/Th, Sr/Cu, MnO and FeO/Fe2O3 are 0.32, 0.91, 3.11, 3.83, 2.6, 0.027 and 0.55 respectively, showing organic matter is accumulated in a half deep-deep freshwater lake with an anoxic environment.The obvious positive anomaly of Mo content, the high Ba/Al ratio, and the high paleo-productivity calculated according to TOC showed that the paleo-productivity of the Tongchuan oil shale deposited is high.
Keywords: Ordos Basin oil shale element geochemistry paleo-lake sedimental environment
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.3, 2015, page 642-645