Doushantuo Formation

The Doushantuo Formation is a geological formation exposed across western Hubei, eastern Guizhou, southern Shaanxi, central Jiangxi and other localities in south-central China, composed primarily of shale with additional mudstone, marl and carbonate or phosphate minerals, typically 200 to 250 meters thick and reaching up to 400 meters in places. It dates to the Ediacaran period, spanning roughly 635 million years ago at its base to about 551 million years ago at its top, placing it in the early to middle Ediacaran, a critical interval between the end of the Cryogenian glaciation and the later Cambrian explosion of animal life. The richest fossil sites lie at Zigui in Hubei, Xiuning in Anhui and Weng'an in Guizhou, among the most important Lagerstatten known from this ancient period. The formation is renowned for minutely preserved microfossils and phosphatic fossils with exceptional cellular-level detail, including controversial fossil embryos and early animal forms, providing direct evidence that major evolutionary diversification of animals was already underway before the Cambrian period began. This entity documents the Doushantuo Formation specifically as a geological formation, an Ediacaran marine sedimentary sequence preserving some of the earliest known animal microfossils.