Application of REE Geochemical Characteristics of Sandstone to Study on Provenance

Key words: 
• Mohe Basin

Abstract: Based on analyses of the samples in detail, the REE geochemical characteristics of the Middle Jurassic sandstone in Mohe Basin are described. The results indicate: (1)The LREE content obviously enriches compared with the HREE content and with negative Eu anomalies shown in the chondrite aerolite standard pattern of sandstone of Xiu Feng, E Muerhe and Kai Kukang Formations. However, Er Shierzhan Formation is obviously different frorm them. Little negative Eu anomalies is shown in the chondrite aerolite standard pattern of sandstone of Er Shierzhan Formation, which reflects the sandstone is from different provenance. (2) The provenance of the Middle Jurassic Sandstone in Mohe Basin may be felsic rocks of upper crust, including granites, metamorphic rocks and sediments. During the deposition of the Er Shierzhan Formation and E Muerhe Formation, some materials may be from the deep lower crust or mantle and leads to the great change of Provenance. (3)The tectonic settings of provenances of the Middle Jurassic Sandstone in Mohe Basin is the island arc of the margin of active continent.(4) The Ce/Ce* and Ceanom indexes indicate that the palaeoenvironment of the Middle Jurassic in Mohe Basin was a reduction environment and is profitable for the oil and gas formation. 