Why is the burgess shale famous

Walcott identified his specimens as members of extinct or modern groups, such as the arthropods shrimp, crabs, insects and the like or annelids segmented worms.

In , paleontologist Stephen Jay Gould popularized Burgess' "weird wonders" in his bestselling book Wonderful Life. But he argued that Walcott had erroneously shoehorned the fossils into existing taxonomic groups. He suggested that the curious "problematica" fossils that had long defied scientific identification—such as Hallucigenia , an inch-long creature with two rows of spines on its back—deserved their own taxonomic groupings.

Lately, paleontologists have begun re-examining the classifications yet again, largely in response to the discovery of Burgess-type fossils in Australia, China, Greenland, Russia, Spain and the United States. With more specimens, scientists are better able to see similarities among animals, and so they are shifting their emphasis from unique to shared characteristics. After a week of slim pickings at Walcott Quarry, Caron and his tired, sore team were ready to try a new location.

Caron climbed aboard a helicopter to scout nearby mountain peaks for new sites to explore in the future. He was joined by Robert Gaines, a Pomona College geologist who studies the shale millimeter by millimeter to figure out whether the various layers represent millennia of accumulated sediment or a few moments' worth deposited by storm currents.

From the chopper Gaines saw a number of promising spots. He was keen to get on the ground and get out his measuring tape. The helicopter put down near Stanley Glacier, where Caron and Gaines joined the rest of the crew, who were already prospecting for fossils. It did not take long to hit pay dirt. On the first afternoon, Loxton found a fossil of a species fondly known as Creeposaurus until it can be properly studied, identified and given its scientific name.

Caron called out: "Champagne! Creeposaurus may be a common ancestor and has the potential to unite these two animals that we know today. The Virtual Museum of Canada's Burgess Shale exhibit explores the history and science of the Burgess Shale, hosts a comprehensive fossil gallery, and also an animated tour of the Cambrian seas that once occupied what is now Yoho and Kootenay National Parks.

Yoho National Park. Old — Over five hundred million years old! Way older than dinosaurs! Walcott Quarry. But why, researchers wondered, were Cambrian seas characterized by high calcium carbonate and low oxygen and sulfate levels? Here, geochemical forensics led researchers to the Great Unconformity, a long-acknowledged global geologic phenomenon in which igneous and metamorphic basement rocks of the Precambrian are overlain by a several-kilometre thick layer of Cambrian sediment.

While life flowered in the oceans but had yet to occupy land, these continental rocks underwent unprecedented erosion. Gaines and company hypothesized that the accompanying high rates of chemical weathering would have profoundly impacted ocean chemistry. As falling rain mixes with atmospheric CO 2 it becomes more acidic, leaching elements from rock and transporting them in dissolved form.

Many marine organisms — both micro- and macroscopic — use this compound to produce mineralized shells and skeletons that are subsequently fossilized. Thus, high concentrations of calcium carbonate may not only have restricted the decomposition of organic matter that led to Burgess Shale-type preservation, but helped spur the Cambrian Explosion by promoting early acquisition of skeletons.

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