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About 518 million years agoReputable source · 2 sourcesWell documented

China's rival windows: Qingjiang and Chengjiang

On the timeline · around About 518 million years ago · The Preserved WindowsThe Explosion BeginsThe Preserved WindowsChina's rival windows: Qingjiang and Chengjiang521 Ma520 Ma519 Ma518 Ma517 Ma516 Ma515 Ma

What happened

The Burgess Shale is not alone. In southern China, a cluster of similarly exceptional fossil beds preserves an even earlier slice of the Cambrian explosion, roughly 518 million years old, about 10 million years older than the Burgess Shale itself. The Chengjiang biota, discovered in Yunnan Province in 1984, was the first of these Chinese windows recognized, and it remains one of the richest, documenting at least sixteen animal phyla. More recently, the Qingjiang biota, described from Hubei Province and reported in Science in 2019, turned up so many previously unknown species, over half its species were new to science, that researchers described it as rivaling both the Burgess Shale and Chengjiang for both preservation quality and diversity.

Why it matters

Two independent fossil beds, on opposite sides of the planet from the Canadian Rockies, both capturing the same style of soft-tissue preservation from the same narrow slice of time, means the Cambrian explosion was not a local Canadian curiosity. It was a genuinely global event, and there is likely far more of it still buried and undiscovered.

How we know

Both Chinese sites, like the Burgess Shale, preserve soft anatomy as flattened films in fine-grained shale, the product of the same kind of rapid, oxygen-starved burial. Their ages are fixed independently through radiometric dating of volcanic ash layers interbedded with the fossil-bearing rock.

Sources

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Part of a timelineThe Cambrian Explosion9 events · How nearly every animal body plan alive today appeared within a geological blink, from the first mineral skeletons to the apex predators, calcite eyes, and first fish the fossil record preserves.View all →