The Changhsingian is named after Changxing (Chinese: 长兴; pinyin: Chángxīng; Wade–Giles: Ch’ang-hsing) in northern Zhejiang, China. The stage was named for the Changhsing Limestone.[5] The name was first used for a stage in 1970[6][7] and was anchored in the international timescale in 1981.[2]
The base of the Changhsingian Stage is at the first appearance of the conodont species Clarkina wangi. The global reference profile is profile D at Meishan, in the type area in Changxing, just below the Changhsingian foraminifer index fossil Palaeofusulina and the first appearance of the ammonoidTapashanites.[2] The top of the Changhsingian (the base of the Induan Stage and the Triassic System) is at the first appearance of the conodont species Hindeodus parvus.[8] In the second part of the 20th century, appearance of the ammoniteOtoceras, that existed no more than 100,000 years, in the boreal region was considered a marker of the Lower Triassic boundary. However, a more detailed study of Lower Induan biostratigraphy revealed the diachronicity of the appearance of these mollusks in different regions of the Earth.[8]
The Changhsingian contains only one ammonoid biozone: that of the genusIranites.
The Bellerophon Formation in northern Italy documents a pre-extinction bivalve community with 26 species adapted to stressful conditions (high temperatures, high salinity, shallow water depths, low oxygen and high terrigenous input).[15] The formation is otherwise known for abundant Bellerophon fossils.[16]
^Gradstein, F.M.; Ogg, J.G.; Smith, A.G. (2004). A Geologic Time Scale 2004. Cambridge University Press.
^Grabau, A.W. (1923). "Stratigraphy of China, Part 1: Palaeozoic and lower". Geological Survey of China. p. 529.
^Furnish, W.M.; Glenister, B.F. (1970). "Permian ammonite Cyclolobus from the Salt Range, West Pakistan". In Kummel, B.; Teichert, G. (eds.). Stratigraphic boundary problems, Permian and Triassic of west Pakistan. Geological Department of Kansas University, Special Publication. Vol. 4. pp. 158–176.
^Furnish, W.M.; Glenister, B.F (1973). "Permian stages names". In Logan, A.; Hills, L.V. (eds.). The Permian and Triassic systems and their mutual boundary. Canadian Society of Petroleum Geologists Memoir. Vol. 2. pp. 522–548.
^Korn, Dieter; Ghaderi, Abbas; Leda, Lucyna; Schobben, Martin; Ashouri, Ali Reza (2015). "The ammonoids from the Late Permian Paratirolites Limestone of Julfa (East Azerbaijan, Iran)". Journal of Systematic Palaeontology. 14 (10): 841–890. doi:10.1080/14772019.2015.1119211. S2CID130932875.