The Guzhangian is an uppermost stage of the Miaolingian Series 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 ...

. It follows the Drumian Stage and precedes the Paibian Stage of the Furongian Series. The base is defined as the first appearance of the trilobite ''

Lejopyge laevigata ''Lejopyge laevigata'' is a species of agnostid trilobite belonging to the genus '' Lejopyge''. It existed during the Guzhangian to the Paibian Age (around to million years ago) of the Cambrian. It has a cosmopolitan distribution and is ...

'' around million years ago. The Guzhangian-Paibian boundary is marked by the first appearance of the trilobite '' Glyptagnostus reticulatus'' around million years ago. The name Guzhangian is derived from Guzhang County,

Hunan Province Hunan (, ; ) is a landlocked province of the People's Republic of China, part of the South Central China region. Located in the middle reaches of the Yangtze watershed, it borders the province-level divisions of Hubei to the north, Jiang ...

, China. The

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 ...

is defined in the Huaqiao Formation in Hunan. The precise base of the Guzhangian is a limestone layer 121.3 m above the base Huaqiao Formation(花桥组) at the

Louyixi Luoyixi Town () is a Town in Guzhang County of China's Hunan Province. It is located on a bay of the Fengtan Reservoir (formerly, a southern tributary of the You River). As of the census of 2010, it has a total population of 10,000. Hongshilin ...

section (), where ''

'' has its first appearance.

References

Cambrian geochronology Geological ages Geologic formations of China {{geology-stub