In the geologic timescale, the Wuchiapingian or Wujiapingian (from Chinese: 吴家坪; pinyin: Wújiāpíng; literally: "Wu Family Flatland"" in the Liangshan area of Hanzhong, Shaanxi Province) is an age or stage of the Permian. It is also the lower or earlier of two subdivisions of the Lopingian epoch or series. The Wuchiapingian spans the time between 259.8 and 254.14 million years ago (Ma). It was preceded by the Capitanian and followed by the Changhsingian.
Contents
Regional stages with which the Wuchiapingian is coeval or overlaps include the Djulfian or Dzhulfian, Longtanian, Rustlerian, Saladoan, and Castilian.
Stratigraphic definitions
The Wuchiapingian was first used in 1962, when the Lopingian series of southwestern China was divided in the Changhsingian and Wuchiapingian formations. In 1973 the Wuchiapingian was first used as a chronostratigraphic unit (i.e. a stage, as opposed to a formation, which is a lithostratigraphic unit).
The base of the Wuchiapingian stage is defined as the place in the stratigraphic record where the conodont species Clarkina postbitteri postbitteri first appears. A global reference profile for this boundary (a GSSP) is located near Laibin in the Chinese province of Guangxi.
The top of the Wuchiapingian (the base of the Changhsingian) is at the first appearance of conodont species Clarkina wangi.
The Wuchiapingian contains two ammonite biozones: that of the genus Araxoceras and that of the genera Roadoceras and Doulingoceras.
Biodiversity
An extinction pulse occurred during the Wuchiapingian; faunas were recovering when another larger extinction pulse, the Permian–Triassic extinction event devastated life.