Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin, Southern Tibet
详细信息
- 责任者：Chen Fenning (Xi’an Institute of Geology and Mineral Resources ; Xi’an 710054 ; China) ; Chen Ruiming
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(6)
- 关键词：介形亚纲 ; Ostracoda ; 古气候 ; paleoclimate ; 西藏 ; Tibet
- 页码：p.872-886
- 图表：illus., 56 refs.
- 分类号：1102
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
Diverse ostracoda fossils were found in the Gyirong Basin , Southern Tibet.According to the distribution characteristics of the fossil succession , the ostracoda fauna in this area can be divided into 8 ostracoda communities.They are in ascending order as follows : Leucocytherella trinoda-Ilyocypris community ; Ilyocypris pentanada-Leucocytherella hyalina community ; Candoniella-Leucocytherella community ; Eucypris subgyrongensis-Candoniella posterindinatacommunity ; Leucocytherella-Cadoniella zadaensis community ; Leucocythere mirabilis-Leucocytherella hyalinacommunity ; Leucocythere mirabilis Leucocytherella glabra community and Leucocythere mirabilis Leucocytherella trinoda community.After detailed analysis of the characteristics of ostracoda fauna and with the study of magnetostratigraphy , the characteristics of palaeoclimate during 7.2～1.67Ma can be divided into 5phases : ① During7.2～6.7Ma , the climate was warm and humid ; ②during 6.7～5.8Ma , the climate became cool and humid ; ③During 5. 8～3.6Ma , the climate became warm and damp again ; ④ During 3.6～2.6Ma , the climate was much cooler and damp in the Gyirong Basin ; ⑤After 2.6Ma , the climate became much drier and colder.Comparison with the paleoclimate phases at the Woma section and global paleoclimate evolution concludes that the climate was mainly humid in the Gyirong Basin during 7.2～5.8Ma.This phenomenon may be related to strengthening of southwest monsoon from the Indian Ocean.There was cooling event in strengthening of southwest at the period of 6.7～5.8Ma.During 5.8～3.6Ma , the climate was relatively humid , and this may result from southeast monsoon resurface again.After 3.6Ma , the massive uplifting of Qinghai-Tibet plateau strengthened Asian monsoon , and this change may cause the climate change towards colder and drier in the Gyirong Basin.