Changhsingian
Encyclopedia
In the geologic timescale, the Changhsingian or Changxingian (from Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...

: 长兴县
Changxing County
Changxing County is a county in the prefecture-level city of Huzhou, Zhejiang, China. Situated in the northern part of Zhejiang Province, it is close to the border of Zhejiang, Jiangsu, Anhui Province and serves as an important city in transportation.Changxing has since 2004 a Twin City ...

, Pinyin: Chángxìng Xiàn, "Changxing County
Changxing County
Changxing County is a county in the prefecture-level city of Huzhou, Zhejiang, China. Situated in the northern part of Zhejiang Province, it is close to the border of Zhejiang, Jiangsu, Anhui Province and serves as an important city in transportation.Changxing has since 2004 a Twin City ...

") is the latest age or uppermost stage of the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

. It is also the upper or latest of two subdivisions of the Lopingian epoch
Epoch (geology)
An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

 or series
Series (stratigraphy)
Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

. The Changhsingian lasted from 253.8 ± 0.7 to 251.0 ± 0.7 million years ago (Ma). It was preceded by the Wuchiapingian
Wuchiapingian
In the geologic timescale, the Wuchiapingian or Wujiapingian 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 260.4 ± 0.7 and 253.8 ± 0.7 million years ago...

 and followed by the Induan
Induan
The Induan is, in the geologic timescale, the first age of the Early Triassic epoch or the lowest stage of the Lower Triassic series. It spans the time between 251 ± 0.4 Ma and 249.7 ± 0.7 Ma...

.

The greatest mass extinction event
Extinction event
An extinction event is a sharp decrease in the diversity and abundance of macroscopic life. They occur when the rate of extinction increases with respect to the rate of speciation...

 in the Phanerozoic
Phanerozoic
The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 542 million years and goes back to the time when diverse hard-shelled animals first appeared...

 eon occurred during this age. The extinction rate peaked about a million years before the end of this stage.

Stratigraphic definitions

The Changhsingian is named after Changxing County
Changxing County
Changxing County is a county in the prefecture-level city of Huzhou, Zhejiang, China. Situated in the northern part of Zhejiang Province, it is close to the border of Zhejiang, Jiangsu, Anhui Province and serves as an important city in transportation.Changxing has since 2004 a Twin City ...

 in China (Wades-Giles transcription
Transcription (linguistics)
Transcription in the linguistic sense is the systematic representation of language in written form. The source can either be utterances or preexisting text in another writing system, although some linguists only consider the former as transcription.Transcription should not be confused with...

: Ch’ang-hsing). The stage was named for the Changhsing Limestone. The name was first used for a stage in 1970 and was anchored in the international timescale in 1981.

The base of the Changhsingian stage is at the first appearance of conodont
Conodont
Conodonts are extinct chordates resembling eels, classified in the class Conodonta. For many years, they were known only from tooth-like microfossils now called conodont elements, found in isolation. Knowledge about soft tissues remains relatively sparse to this day...

 species Clarkina wangi. The global reference profile is profile D at Meishan
Meishan
Meishan , formerly known as Meizhou or Qingzhou , is a prefecture-level city with more than 100,000 inhabitants in Sichuan province of the People's Republic of China. Meishan is in the southwest of Sichuan Basin....

, in the type area in Changxing. The top of the Changhsingian (the base of the Induan stage and the Triassic system is at the first appearance of conodont species Hindeodus parvus.

The Changhsingian stage contains only one ammonite
Ammonite
Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...

 biozone
Biozone
Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

: that of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Iranites.

Palaeontology

The Changhsingian ended with the Permian-Triassic Extinction Event
Permian-Triassic extinction event
The Permian–Triassic extinction event, informally known as the Great Dying, was an extinction event that occurred 252.28 Ma ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras...

 when both global biodiversity and alpha diversity
Alpha diversity
Alpha diversity is the biodiversity within a particular area, community or ecosystem, and is usually expressed as the species richness of the area. This can be measured by counting the number of taxa within the ecosystem...

 (community-level diversity) were devastated. The world after the extinction was almost lifeless, deserted, hot, and dry. Ammonites, fishes, insects, and the tetrapods (cynodonts, amphibians, reptiles, etc.) remained rare and terrestrial ecosystems did not recover for 30M years.

Literature

; 1970: Permian ammonite Cyclolobus from the Salt Range, West Pakistan, in: (eds.): Stratigraphic boundary problems, Permian and Triassic of west Pakistan, Geological Department of Kansas University, Special Publication 4, pp 158–176.; 1973: Permian stages names, in: : The Permian and Triassic systems and their mutual boundary, Canadian Society of Petroleum Geologists
Canadian Society of Petroleum Geologists
The Canadian Society of Petroleum Geologists is a professional geological society in Canada. The CSPG works to advance the science of geology, foster professional development of members and promote community awareness of the profession...

 Memoir 2, pp 522–548.; 1923: Stratigraphy of China, Part 1: Palaeozoic and lower, Geological Survey of China
Geological Survey of China
The Geological Survey of China is a government-owned, not-for-profit, Chinese organization researching China's mineral resources. It is the largest Geoscience agency in China since being reconstructed in 1999.-History:...

, 529 pp.; 2004: A Geologic Time Scale 2004, Cambridge University Press; 2006: The Global Boundary Stratotype Section and Point (GSSP) for the base of Changhsingian Stage (Upper Permian) Episodes 29(3), p. 175-182, PDF.

External links

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