Burgess Shale

The Burgess Shale is a special place where very old fossils can be found in the Canadian Rockies of British Columbia, Canada. These fossils are important because they show the soft parts of animals that usually do not fossilize. This helps scientists learn about life from a very long time ago.

The Burgess Shale dates back to the middle Cambrian period. It is one of the earliest places where fossils of soft-bodied animals have been discovered.

The rocks that make up the Burgess Shale are black shale and can be seen near the town of Field in Yoho National Park and also at the Kicking Horse Pass. There is another place where these rocks appear in Kootenay National Park, about 42 kilometers to the south.

History and significance

Main article: History of the Burgess Shale

The Burgess Shale was found by a scientist named Charles Walcott in 1909 in Canada. He started digging there and found many fossils. These fossils were special because they showed parts of animals that usually don’t become fossils.

At first, people didn’t understand these fossils well. But later, scientists learned they showed many different and strange creatures from a very long time ago.

More scientists studied the fossils and found even more types of animals. Books and studies helped people learn about these ancient animals and what Earth was like back then. The Burgess Shale is very important for scientists who want to learn about Earth’s past. In 2012, another fossil site was found nearby, which added more amazing discoveries to our knowledge of ancient life.

Geology

Main article: Stephen Formation

The Burgess Shale is a group of fossils found in dark rocks that are about 508 million years old. These rocks formed at the bottom of a tall cliff, far from the waves that moved the water during storms. Scientists think that part of a nearby reef broke off and slid down, creating this special place where fossils formed.

We used to think these fossils formed in places without oxygen, which helped protect them. But now we know oxygen was there. Even with oxygen, the fossils were very well preserved, including soft parts of the creatures. There were fewer animals that dug in the mud, which also helped keep the fossils safe.

The Burgess Shale is sometimes considered its own rock layer, separate from the Stephen Formation.

Taphonomy and diagenesis

The fossils in the Burgess Shale were covered quickly by sediment from water currents. This happened before they could decay. The fossils are preserved as very thin carbon films. They are thinner than a thousandth of a millimetre.

There are many other places from the same time with well-preserved fossils. This is because, at that time, there was less digging and moving of sediment by living things. This helped keep the soft parts of organisms intact.

Biota

The Burgess Shale has many kinds of ancient sea creatures. Most lived on the ocean floor. They either moved around or stayed in one spot. Many ate bits of organic material from the muddy sea floor, while some filtered tiny particles from the water. Only a few were hunters or scavengers.

These creatures include early members of animal groups we know today, as well as some that are ancestors of modern animals.

Working with the Burgess Shale

The fossils in the Burgess Shale are saved as dark films on rock, which makes them hard to photograph. Scientists use special ways to take pictures to see them better. They also use tools like cameras and drawings to learn about the fossils.

After taking pictures, scientists think about how the fossils changed over time to understand what the ancient animals looked like. By looking at different parts, they can see how these fossils are related.