Burgess Shale sites provide scientists with new finds
By: Rob Alexander
| Posted: Thursday, Sep 09, 2010 06:00 am
As news spread last week that a site discovered in the 1990s near the Stanley Glacier was home to new Burgess Shale creatures, one of the leading site experts suggested an August expedition to three other sites has potentially turned up more new species.
Jean-Bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum, said Aug. 31 during an interview with the Outlook, work at three sites in Yoho National Park provided unfamiliar fossils.
“In terms of the fossils, we probably found some new species from the three localities. It is probably too early to tell exactly how many and what the new species are,” Caron said.
“Some of them are completely different from what we know. We have different types of worms, such as Ottoia or Ottoia-like, but it doesn’t seem to fit the Ottoia type,” he said, adding researchers may have also discovered new arthropods, along with one that looks similar to Waptia, a shrimp-like creature first identified on Fossil Ridge where Charles Doolittle Walcott discovered the 505-million-year-old Middle Cambrian-era fossils in the Burgess Shale in 1909.
“This animal that we found is a unique specimen about four times the size of Waptia and we expect this is a new species,” he said, cautioning the fossils have to be prepared and studied before they can be verified as new species.
Caron, along with Robert Gaines of Ponoma College in California and Michael Streng of Uppsala University in Sweden and two University of Toronto doctoral students, Lorna O’Brien and Martin Smith, spent much of August exploring previously known, but poorly investigated, Burgess Shale sites on Mount Odaray, south east of Field, B.C. and two sites overlooking Field on Mount Stephen,
It was a reconnaissance mission that Caron said was used to focus on a band of mudstone known as the Stephen Formation on Mount Odaray.
“Our primary goal was to look at the stratigraphy deposition of these sites. To compare these sites with the Burgess Shale Fossil Ridge, the Walcott Quarry, to see if these new sites are younger, and to compare the animals,” he said.
While new species are perhaps more exciting and garner the most interest and attention, equally exciting for Caron is that a 100-metre layer of mudstone on Mount Odaray potentially represents a longer timeframe than the Walcott Quarry. “The Walcott is relatively constrained in time. The Walcott represents maybe 10,000 years in time from the bottom to the top of the quarry. But on Odaray, we were able to find fossils across 100 metres of sediment layers. A lot of this mudstone layer is where soft body preservation occurs, so there is great potential in the future to find more species and in units that are younger than the Walcott Quarry,” Caron said.
Based on the mudstone layer, Caron added the environment appears to change dramatically from one mountain to the next, even though each site still contains a Burgess Shale deposit.
The mudstone layers found at the Walcott Quarry are not necessarily traceable beyond Fossil Ridge, making it difficult to compare other sites with Fossil Ridge.
“It seems you have a lot of variation between Walcott and the other localities that could be the same age elsewhere. So in a short geographic distance there is a lot of variation in terms of how fossils were entombed in these fossil beds.
“It tells you the environment is quite varied all over the Burgess Shale. That is why maybe Fossil Ridge is so unique. You don’t see this kind of concentration of fossils in other parts of the parks in rocks in the same age.”
The Stanley Glacier site, located in Kootenay National Park, is the first site in the Canadian Rockies beyond Fossil Ridge – with the exception of the Mount Stephen trilobite beds located above the town of Field – to be studied extensively.
The ROM first investigated the Stanley Glacier site, located 40 kilometres southeast of Fossil Ridge, in 1996 after a German hiker reported finding soft-bodied fossils along the trail. But it wasn’t until 2008 that the museum began excavating the site to collect fossils which, back in the laboratory, proved to contain eight new species, including a previously unknown anomalocaridid – a large, sometimes two-metre-long arthropod that ruled the Cambrian seas as the top predator – now known as Stanleycaris hirpex.
“We found the same claw of Stanleycaris on Odaray, telling you perhaps the age is similar between Stanley Glacier and Odaray, so that is the beauty of doing a comparison with different sites. We have different lines of evidence, paleontology, sedimentology and stratigraphy. We are going to be able to better understand the unique compositions and how this varies in different places, maybe controlled by differences in environment, maybe controlled by differences in community composition, but that takes time, so we need to explore first.”
Alex Kolesch, the Parks Canada manager responsible for the Burgess Shale sites, said Parks Canada strives to make sites such as the Walcott Quarry and the trilobite beds in Yoho National Park accessible to allow the public to share in the discovery those explorations are revealing.
“All of the new finds and new information, to me, they reinforce the value of what we have here, but it also reinforces that there are so many mysteries and treasures literally buried in the mountain national parks. There are lots of stories to be told and the stories of the Burgess Shale are still very much alive and still yielding new information about our understanding of early life and the very beginnings of complex life on the planet,” Kolesch said.
Along with an updated Burgess Shale exhibit at the Field Information Centre, Parks Canada and the ROM are launching the Virtual Museum of Canada Burgess Shale website in the spring of 2011 as part of the work to share the Cambrian animals with a larger audience.
Both Kolesch and Caron encourage the public to report finds to Parks Canada like the hiker who discovered the Stanley Glacier site, in essentially the same fashion that Walcott discovered the Burgess Shale in 1909.
“As people are out enjoying themselves, if they find something or see something they think is of interest from a paleontological perspective, a fossil, they should let us know about it. You just never know what somebody stumbling across might turn into,” Kolesch said.
“These kinds of finds really emphasize the importance of Parks Canada and others protecting these sites. They are very much alive with potential stories. They are not just a bunch of static rocks and they deserve our attention in terms of both protecting them and telling the stories as well.”