Ammonite miners dig up 74-million-year-old fish fossil in southern Alberta

Michael Shideler’s day-to-day work is what most little kids dream of doing when they grow up — using big machinery to search for fossils.

But last month, the superintendent of Enchanted Designs ammonite mine near Lethbridge, Alta., was on site when his crew dug up a different special find: a 74-million-year-old “enchodus” fish.

“When you’ve done it for so long you kind of develop an eye for these things that are out of the ordinary,” Shideler said, adding that the fossils they usually search for are flakes of iridescent rainbow, but the fish immediately stood out, as it was a dark, black jawbone.

“We’re always excited … because there’s going to be the potential for finding something new that nobody’s ever seen before.”

“You take your little chipping hammer and you go and work around it … you know it’s another fossil, but not an ammonite. So then it’s time to call Tyrrell,” said Tom Chant, owner of Enchanted Designs.

The fossil was plastered and then removed in a block to prevent damage. Mine staff and the museum crew worked together to extricate the fossil safely. (Royal Tyrrell Museum of Palaeontology)

Dr. Lorna O’Brien, head technician at the Royal Tyrrell Museum of Palaeontology in Drumheller, said June’s rainy weather prevented the museum’s crew from immediately responding to the site. 

But when they arrived, they were able to take a look at the find. 

“It’s a type of reef fish, generally small to medium size … kind of like a large herring but with teeth,” she said. “So that was what the excavators had initially hit.”

O’Brien said the crew first has to assess how far the fossils are spread on the quarry floor, expose what they can, plaster the fossils, and excavate them. 

“Ultimately we want to flip the whole thing in one move so that we protect the fossil material as best as possible,” she said. 

The crew was also able to collect a cuttlefish, a portion of a decapod (similar to a lobster) and part of another fish.

Shards of ammolite are pictured at the mine in southern Alberta. (Submitted by Michael Shideler)

The fossils were found in what’s called the Bearpaw Formation, a shale and claystone deposit from the late Cretaceous period when Alberta was under water. It’s rich with ammonite fossils, extinct molluscs, which produce the ammolite gemstones. 

It wasn’t the first find at the mine, which dug up a mosasaur fossil — known as the “T-rex of the sea” — last year. 

“It’s always really exciting … even in areas where we have a lot of fossil material we’re still making new discoveries every year,” O’Brien said. 

With the help of mine workers, the museum staff extracted the fossils. How fast they’re processed at the lab will depend on how high of a priority the fossils are for researchers, O’Brien said.

But she said there’s plenty they can learn from the find, from studying the species of fish to the general ecosystem that was present at the time, thanks to the other organisms.