Foraminiferal Biostratigraphy Of The Cretaceous Oceanic Red Beds In Jiangzi,Southern Tibet

Cretaceous marine strata in China are mainly developed in Tibet, Xinjiang, and Taiwan, and well preserved in the southern Tibet where therefore became the ideal place to study Cretaceous marine strata. Cretaceous oceanic red beds(CORBs) are usually considered as a kind of autochthonous deposition formed under an oxidizing condition. The emergence of oceanic red beds may suggest that the sea should be in an oxidized state at that time, the organic carbon in the ocean should be oxidized, producing a large amount of CO2 into atmosphere, which greatly influences the global carbon cycle and climate-environment. Therefore, the determination of the distribution and age of the Cretaceous oceanic red beds is very important for us to further carry out the research related with paleoceanography and paleogeography. CORBs are widely exposed in the northern Himalayan Tethys subzone which was once located at a continental slope- ocean basin. Oceanic red beds yield abundant microfossils such as foraminifera and radiolarians, which provides an important basis for accurately determining the age of the strata and reconstructing ancient geography. This paper focuses on the planktic foraminiferal biostratigraphy of Cretacous Chuangde Formation in Chuangde, Gyangze.Abundant foraminifera yield from this section, which include 37 species of 10 genus, and three planktic foraminifera biozones are recognized(in ascending order): ① Globotruncana ventricosa zone, ② Radotruncana calcarata zone, ③Globotruncanella havanensis zone.Based on the foraminiferal assemblages, the age of the CORBs is referred as late Campanian.