|
In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian epoch or series. The Kungurian lasted between and million years ago (Ma). It was preceded by the Artinskian and followed by the Roadian.〔See Gradstein ''et al.'' (2004) for a detailed geologic timescale〕 It corresponds roughly to the Leonardian stage, covering the span from 280 to 270.6 ± 0.7 Ma in the North American system. ==Stratigraphy== The Kungurian is named after the Russian city of Kungur in the vicinity of Perm. The stage was introduced into scientific literature by Russian geologist Alexandr Antonovich Stukenberg (Alexander Stuckenberg) in 1890.〔See for a historic overview Chuvashov ''et al.'' (2002)〕 The base of the Kungurian stage is defined as the place in the stratigraphic record where fossils of conodont species ''Neostreptognathodus pnevi'' and ''Neostreptognathodus exculptus'' first appear. As of 2009, there was no agreement yet on a global reference profile (a GSSP) for the base of the Kungurian. The top of the Kungurian (the base of the Roadian and the Guadalupian series) is defined as the place in the stratigraphic record where fossils of conodont species ''Jinogondolella nanginkensis'' first appear. The Kungurian contains three conodont biozones: *zone of ''Neostreptognathodus sulcoplicatus'' *zone of ''Neostreptognathodus prayi'' *zone of ''Neostreptognathodus pnevi'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kungurian」の詳細全文を読む スポンサード リンク
|