Recently, a team led by Deng Tao, a researcher from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and Fang Xiaomin, an academician from the Institute of the Tibetan Plateau, summarized the Neogene strata and fossil groups on the Qinghai-Tibet Plateau and its surroundings, established and improved the Neogene high-precision comprehensive stratigraphic framework of the Qinghai-Tibet Plateau that can be used for international comparison, and identified the evolution characteristics of the Neogene paleoclimate environment in the Qinghai-Tibet Plateau and its surrounding areas. The results have been published in the academic journal Science China: Earth Sciences.
This is the information that the reporter learned from the Institute of Paleospine of the Chinese Academy of Sciences.
The Neogene is the second epoch of the Cenozoic, which lasted from 23 million to 2.6 million years ago, including the Miocene and Pliocene. "Since the significant uplift of the Tibetan Plateau in the Neogene has had a great impact on the climate and environment of East Asia and even the world, the establishment of the Neogene stratigraphic framework of the Tibetan Plateau is of great significance to the research of all fields of earth science. *Introduction by Deng Tao, the first author and corresponding author.
*Ecological restoration of the Upper Pliocene mammal fauna in the Zada Basin. (Courtesy of the Institute of Paleospine, Chinese Academy of Sciences).
The Neogene chronostratigraphic system in China is divided into five stages: the Xiejia Order, the Shanwang Order, the Tonggul Stage, the Bahe Stage, and the Baode Order, and the Gaozhuang Order, and the Mazegou Stage, which are two Upper Eocene stages. It is proposed that mammalian fossils play a very important role in the division and dating of Cenozoic terrestrial strata on the Qinghai-Tibet Plateau.
In recent years, abundant mammalian fossils have been found in the Cenozoic basin of the Tibetan Plateau, and many mammalian genera in East Asia appeared in the Tibetan Plateau and its surrounding areas, which makes it easy for paleomammologists to chronologically rank the fossils according to their evolutionary stage. Combined with high-resolution paleomagnetic dating, the measurement accuracy of geological and stratigraphic dating on the Neogene Tibetan Plateau can be improved. Deng Tao said.
In this study, the Cenozoic basin of the Qinghai-Tibet Plateau and its adjacent areas was divided into five stratigraphic areas, namely the southern Xinjiang-West Kunlun area, the Qaidam-Qilian-West Qinling area, the Qiangtang area, the western Yunnan-western Sichuan area, and the Gangdis-Himalayas-West Walik area, which can be further subdivided into sub-stratigraphic areas. Under the constraints of biostratigraphy and magnetic strata, and using the geological age as the framework, the lithtigraphic units of the Tibetan Plateau and its surrounding stratigraphic divisions are finely compared.
Comparison of Neogene strata on the Tibetan Plateau and its adjacent areas. (Courtesy of the Institute of Paleospine, Chinese Academy of Sciences).
In addition, through the analysis of enamel and paleosoil carbon and oxygen isotopes of Cenozoic sediments and mammal fossils contained in the Qinghai-Tibet Plateau and its surrounding areas, researchers found that the Qinghai-Tibet Plateau as a whole had risen to an altitude of about 3,000 meters in the Miocene, which became a barrier to the communication of large mammalsThe modern altitude of more than 4,000 meters in the Pliocene was reached, resulting in a cryospheric environment that led to the emergence of glacial fauna ancestral types. (Reporter Wen Jinghua, Zhang Quan).
*: Xinhua News Agency).
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