The Wuliuan stage is the fifth stage of the

Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ag ...

, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the

ICS ICS may refer to: Computing * Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy * Industrial control system, computer systems and networks used to control industrial plants and infrastructu ...

in 2018. Its base is defined by the first appearance of the trilobite species '' Oryctocephalus indicus''; it ends with the beginning of the Drumian Stage, marked by the first appearance of the trilobite '' Ptychagnostus atavus'' around million years ago. The '

golden spike The golden spike (also known as The Last Spike) is the ceremonial 17.6- karat gold final spike driven by Leland Stanford to join the rails of the first transcontinental railroad across the United States connecting the Central Pacific Railroad ...

' that formally defines the base of the period is driven into the Wuliu-Zengjiayan(乌溜-曾家崖)section of the Kaili formation, near Balang Village in the Miaoling Mountains, Guizhou, China.

GSSP

Three sections were discussed as

GSSP A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted ...

candidates: the Wuliu-Zengjiayan section near Balang in

Guizhou Guizhou (; formerly Kweichow) is a landlocked province in the southwest region of the People's Republic of China. Its capital and largest city is Guiyang, in the center of the province. Guizhou borders the autonomous region of Guangxi to t ...

province (China), a section on

Split Mountain Split Mountain (or similar) is the name of one of 17 peaks in the United States: There is also a Split Mountain in Canada: * Split Mountain (British Columbia) {{mountainindex ...

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(USA) and the "Molodo river section" along the Molodo river (Sakha Republic, Russia). The Wuliu-Zengjiayan section is an outcrop of the Kaili Formation in the Wuliu quarry. The first candidate for the beginning of the Wuliuan was the trilobite '' Oryctocephalus indicus'', the second candidate was the trilobite '' Ovatoryctocara granulata''. The Wuliu-Zengjiayan section was chosen as the formal base in 2018, with the first appearance of ''Oryctocephalus indicus'' being chosen as the defining marker for the GSSP.

References

{{Geological history, p, p, state=collapsed Cambrian geochronology Geological ages Miaolingian