Nongshanian

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The Nongshanian is a regional stage in the terrestrial palaeogene of East Asia in the history of the earth . The Nongshanian is the second stage in the sequence of land mammal stages in East Asia and follows the Shanghuan , above (or after) the Gashatan . According to the current correlation, it corresponds to the upper part of the global Danium stage, the entire Seelandian stage and the lower Thanetium stage of the Paleocene (Paleogene). Geochronologically it is currently dated between 63.3 and 57.3 million years. The Nongshanian is characterized by the radiation and speciation of endemic groups of vertebrates.

Concept history

The Nongshanian was suggested by Li & Ting (1983). It is named after the Nongshan Formation in the Nanxiong Basin (Priv. Guangdong , South China).

Definition, correlation, absolute dating and subdivision

The beginning of the Nongshanian is defined by the first appearance of the Mixodontia , Didymoconidae and Arctostylopida . Most of the Shanghuan mammal families extend into the Nongshanian, but over 85% of the Shanghuan genera died out. The diversity of the orders Anagalida , Pantodonta and Tillodontia decreased. The Bemalambdidae family became extinct and was replaced by the Pastoralodontidae and Pantolambdodontidae families . The Nongshanian is characterized by the radiation and speciation of endemic groups of vertebrates. Dormouse species ( Glires ) in particular developed rapidly, e.g. B. the families Anagalidae , Pseudictopidae , Arctostylopidae , Eurymylidae and Mimotonidae . Typical taxa are: bothriostylops . Hsiuannania , Mimotona , Harypyodus and Altilambda .

The Nongshanian correlates with the uppermost Torrejonian and most of the Tiffanian level of North American mammalian stratigraphy (NALMA). According to other authors, the Shanghuan / Nongshanian border correlates with the Torrejonian / Tiffanian border. Depending on the point of view, the Nongshanian barely extends into the global Danium , or only begins with the global Seelandium level above and ends in the lower global Thanetium level. In absolute terms, Nongshanian begins 63.3 million years ago and ends 57.3 million years ago. If the beginning of the Nongshanian is correlated with the Torrejonian / Tiffanian boundary, the Nongshanian begins about a million years later and is correspondingly shorter. The Shanghuan / Nongshanian border and the Torrejonian / Tiffanian border, if they are roughly the same time, may be due to the start of a cooler phase worldwide.

The Nongshanian is divided into three sections by Ting (1998):

According to Missaein (2011), however, the Taizicun fauna already belongs to the Gashatan . It only recognizes two interval zones:

supporting documents

Individual evidence

  1. ^ William C. Clyde, Yongsheng Tong, Kathryn E. Snell, Gabriel J. Bowen, Suyin Ting, Paul L. Koch, Qian Li, Yuanqing Wang, Jin Meng: An integrated stratigraphic record from the Paleocene of the Chijiang Basin, Jiangxi Province (China): Implications for mammalian turnover and Asian block rotations. In: Earth and Planetary Science Letters. 269, 2007, pp. 553-563. (PDF) ( Memento from July 21, 2010 in the Internet Archive )
  2. ↑ The absolute values ​​of the regional levels were determined using the Time Scale Creator 6.0 (October 2012) .
  3. ↑ International Stratigraphic Chart 2012 (PDF)
  4. ^ Pieter Missiaen: An updated mammalian biochronology and biogeography for the early Paleocene of Asia. In: Vertebrata Palasiatica. 49, 2011, pp. 29-52. (PDF)

literature

  • C.-K. Li, S.-Y. Ting: The Paleogene mammals of China. In: Bulletin of Carnegie Museum of Natural History. 21, 1983, pp. 1-93.
  • Donald L. Lofgren, Jason A. Lillegraven, William A. Clemens, Philip D. Gingerich, Thomas E. Williamson: Paleocene Biochronology: The Puercan Through Clarkforkian Land Mammal Ages. In: Michael O. Woodburne (Ed.): Late Cretaceous and Cenozoic mammals of North America: biostratigraphy and geochronology. Columbia University Press, New York 2004, ISBN 0-231-13040-6 , pp. 43-105. (online at Google Books)
  • S. Ting: Paleocene and early Eocene land mammal ages of Asia. In: KC Beard, MR Dawson (Eds.): Dawn of the Age of Mammals in Asia. Bulletin of Carnegie Museum of Natural History. 34, 1998, pp. 124-147.
  • Wang Yuanqing, Meng Jin, Ni Xijun, Li Chuanku: Major events of Paleogene mammal radiation in China. In: Geological Journal. 42, 2007, pp. 415-430. doi: 10.1002 / gj.1083
  • Spencer G. Lucas: Chinese Fossil Vertebrates. Columbia Univ. Press, New York et al. 2001, ISBN 0-231-08482-X .