[2] The top, or the base of the Jiangshanian is defined as the first appearance of the trilobite Agnostotes orientalis around 494.2 million years ago.
The GSSP is defined in the "Paibi section" (Wuling Mountains, Huayuan County), an outcrop of the Huaqiao Formation (花桥组).
[5] At the turn of the Guzhangian and Paibian ages, an extinction event occurred that reduced the species richness by 45%.
The driving mechanism of this change are not fully understood, but it is believed to be caused by the expansion of anoxic deep water into shallow regions.
The SPICE event was accompanied by cooling, which contributed to the recovery of ecosystems after its onset, but the further warming disrupted the circulation of ocean waters and triggered new redox changes that precipitated the ESBE.