Yoho National Park’s 505-million-year-old Burgess Shale – home to some of the planet’s earliest animals, including a very primitive human relative – is one of the world’s most important fossil sites. Now, more than a century after its discovery, a compelling sequel has been unearthed: 42 kilometres away in Kootenay National Park, a new Burgess Shale fossil bed has been located that appears to equal the importance of the original discovery, and may one day even surpass it.
If you don’t already know about the Burgess Shale, you definitely should!
Charles Walcott first discovered the site in 1909, and these fossil beds have been dated to ~505 million years old, (during the geologic period called the Cambrian). From about 525 – 515 million years ago, there was a dramatic jump in animal biodiversity, referred to as the “Cambrian explosion.” Preserved in the Burgess Shale are many species that originated during this time.
The Burgess Shale is known as a lagerstätte, which is a sedimentary deposit that has excellent fossil preservation, sometimes even preserving soft tissues. Thanks in part to such great preservation, more than 140 different species have been found.
The fossils found represent a “life assemblage,” kind of like a Pompeii of the Cambrian ocean world. Instead of being a prolonged die off, there was one cataclysmic event that wiped out this community, likely a submarine landslide burying organisms that had been living just moments before.
One of the most interesting fossils found here is called pikaia, which is the first recorded member of our immediate ancestry! Pikaia is from the Phylum chordata, which is the same phylum that we belong to. If pikaia had not been able to survive the Cambrian, we might not be here today!
Make sure to check out Stephen Jay Gould’s Wonderful Life if you’d like to know more about the Burgess Shale!