Chaotian (geology)

Chaotian, in geology, refers to a stage or age in the geologic timescale. Specifically, it represents the uppermost stage of the Cambrian Period and, more precisely, the uppermost stage of the Furongian Series. It is preceded by the Jiangshanian stage and followed by the Tremadocian stage of the Ordovician Period. The Chaotian Stage spanned approximately from 497 million years ago to 485.4 million years ago (dates may vary slightly based on different publications and revisions to the timescale).

The Chaotian Stage is defined by its Global Boundary Stratotype Section and Point (GSSP), which serves as the international reference point for its base. This GSSP is located in the Wangcun section, in the village of Duijiawan, Chaotian District, Guangyuan, Sichuan Province, China. The GSSP is marked by the first appearance of the conodont Cordylodus andresi.

The Chaotian Stage is important for understanding the paleontology and biogeography of the late Cambrian Period. It is characterized by a diverse assemblage of marine fossils, including trilobites, brachiopods, and conodonts. These fossils provide insights into the evolution and distribution of life during this critical period in Earth's history. Studying the Chaotian Stage allows geologists to correlate rock formations and understand the sequence of geological events across different regions.