Paibian

The Paibian is an important time period in Earth's history, known as a "stage" in the study of rocks and fossils. It is the lowest stage of the Furongian Series, which is part of the Cambrian System. The Cambrian Period was a time when many of the first complex animals appeared in the oceans.

The Paibian follows another stage called the Guzhangian and comes before the Jiangshanian Stage. Scientists mark the beginning of the Paibian about 497 million years ago by looking for a special type of trilobite called Glyptagnostus reticulatus. This tiny sea creature helps them know when they are looking at rocks from this exact time.

By studying layers of rock and the fossils inside them, scientists can understand what life was like in the ancient seas during the Paibian. This helps us learn how life on Earth has changed over millions of years. The end of the Paibian, around 494.2 million years ago, is marked by the appearance of another trilobite, Agnostotes orientalis, signaling the start of the next stage, the Jiangshanian.

GSSP

The name Paibian comes from the village of Paibi in Hunan, China. The Global Boundary Stratotype Section and Point (GSSP) is found in the Paibi section in the Wuling Mountains, near Huayuan County. This location marks the start of the Paibian stage at the first appearance of the fossil Glyptagnostus reticulatus.

Major events

At the turn of the Guzhangian and Paibian ages, an extinction event occurred that reduced the number of species by 45%. This event coincided with the Marjuman extinction, which can be traced to trilobite and brachiopod assemblages in Laurentia. After the extinction, species diversity returned to its previous level.

The Steptoean positive carbon isotope excursion (SPICE) began around the Guzhangian-Paibian boundary. This event is linked to a global change in the carbon cycle. It had a noticeable impact on trilobites, affecting their diversity.

Paleontology

The Paibian stage of the Cambrian period is known for fossils of certain small sea creatures. One group of these creatures is called agnostoids, and some well-known types include Glyptagnostus, Homagnostus, Pseudagnostus, and Acmarhachis. These fossils help scientists understand the ancient oceans and life from that time.