Paper Number: 1204
Neogene terrestrial chronostratigraphic sequence of China based on land mammalian ages
Deng, T.1, Hou, S.K.1,2 and Wang, S.Q.1
1Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China, dengtao@ivpp.ac.cn
2Department of Paleobotany and Paleoecology, Cleveland Museum of Natural History, Cleveland, OH 44106, USA
In the past, the positions of the Chinese mammalian faunas in the chronological chart and their correlations to the European faunas were determined mainly by evolutionary levels of mammals for lack of accurate absolute ages[1,2]. During the last three decades, great progress has also been made in Chinese Neogene terrestrial stratigraphic studies. Seven terrestrial chronostratigraphic units, the Xiejian, Shanwangian, Tunggurian, Bahean, Baodean, Gaozhuangian, and Mazegouan stages, are recognized for the Chinese Neogene based on updated large and small mammal faunas[3].
Most of the classic regions have been revisited, such as the Yushe and Baode areas in Shanxi, the Lantian area in Shaanxi, and the Tunggur area in Inner Mongolia, and so on. New discoveries are made in well-exposed fossiliferous regions, such as Tongxin in Ningxia, central Inner Mongolia, the northern Junggar Basin in Xinjiang, the Linxia Basin in Gansu, the Qaidam Basin in Qinghai, and so on[4]. Magnetostratigraphic work was also undertaken in several classic regions. Great gaps, however, still exist between China and its European and North American counterparts in terms of accumulation of fossils as well as such basic tasks as documentation of fossil occurrences and their biostratigraphic contexts.
Nowadays, the land mammal ages have been strongly broadened by data from new localities and new taxa in China[4]. The significance of these new data is that they are beneficial toward our understanding of mammal turnovers and boundary calibrations. The faunal components are thought to be stable throughout each chronostratigraphic unit, without large changes occurring. For each unit, a series of species or genera are regarded as characteristic forms on the basis of the correlation to the European taxa. Usually, the chronostratigraphic units deal with the first appearance datum (FAD) of mammals at the generic level. Some of these genera are immigrants, and their entry into China often marks the beginning of a unit[3]. The precise correlations between the Chinese and European mammalian ages based on more accurate dating will increase our ability to recognize mammal migrations between China and Europe. Asia acted as a faunal dispersal center for Europe during the Neogene, and the great majority of the exchanges were migrations from Asia into Europe.
China was one of the main dispersal centers of the Neogene. In recent years, the Chinese Neogene mammal ages have become more accurate with the introduction of magnetostratigraphy, which has enabled ages to be calibrated and well-dated at their boundaries[4]. Increasingly abundant paleomagnetic measurements make a good calibration for the correlation of the Chinese Neogene mammalian faunas with their European and North American counterparts. A new Neogene chronostratigraphic framework is proposed, and it is more consistent with the reality of the state of research and conditions in China. This will provide a foundation for the establishment of a formal Chinese Neogene terrestrial chronostratigraphic system. Given that China possesses well-developed Neogene terrestrial strata that are richly endowed with fossil mammals, such a system should play a role in the establishment of an Asian Neogene terrestrial scheme in the future.
References:
[1] Li CK et al (1984) Vert PalAsiat 22: 163-178
[2] Qiu ZX and Qiu ZD (1995) Palaeogeogr Palaeoclimatol Palaeoecol 116: 41-70
[3] Deng T (2006) Vert PalAsiat 44: 143-163
[4] Qiu ZX et al (2013) In: Fossil Mammals of Asia: Neogene Biostratigraphy and Chronology: Columbia University Press, 29-90