US professor, student discover 300-million-year-old ammonite fossil pre-dating dinosaurs

Yahoo

13-04-2025

A geology professor and his student at Rogers State University (RSU) made a remarkable discovery just before spring break.
Dr. Chris Shelton and student Kolby Dooling unearthed a rare, well-preserved ammonite fossil at a site in Oklahoma, and it wasn't an ordinary fossil. This particular find shimmered with the colorful glow of a gemstone.
'Just before spring break, I took one of my students, Kolby Dooling, to a site that I'd taken other students to before, one that had always been a good place to explore,' explained Shelton.
'We'd noticed these fossils before, but this time, Kolby brought a very large iridescent piece to me. It was clear he had discovered something extraordinary with this ammonite fossil.'
The fossil, according to Shelton, shows signs of preservation that give it a pearl-like iridescence, a feature rarely found in fossils this old. These types of fossils are called ammolite in Canada, where they are better known. Ammolite is a rare gemstone that forms from the fossilized shells of ammonites, an extinct group of shelled marine animals related to squids.
Shelton believes the fossil they found is a true ammolite, even though it was found far from known ammolite-rich areas like Alberta, Canada. He explained that these types of fossils are made from the mineral aragonite, which retains a dazzling iridescence due to its microscopic structure.
'Ammolite is very unique as it's a biological gemstone, similar to pearls, formed from the fossilized shells of ancient cephalopods—mollusks related to modern squids—that exhibit vibrant, iridescent colors and patterns due to the microstructure of the original aragonite. They're particularly rare and sought after by collectors,' explained Shelton.
What makes this discovery even more significant is the fossil's age. It dates back to the Carboniferous Period, which was over 300 million years ago—long before dinosaurs roamed the Earth. Most iridescent ammonite fossils known today come from the Mesozoic Era, the age of dinosaurs.
There's only one other known location in the world where aragonite of this age has been found intact—at the Buckhorn Asphalt Lagerstätte in Oklahoma's Arbuckle Mountains. That site is known for preserving some of the oldest aragonite fossils ever discovered. This new discovery adds to the rarity and importance of the find.
After the initial discovery, Shelton and Dooling returned to the same site and collected additional samples. These included fossilized shark remains and other ancient invertebrates. The goal now is to conduct more research and analysis to better understand the fossils they've found.
'We plan to do more expeditions, more collection trips to the site to gather more samples,' said Shelton. 'From there, we'll run many more analytical tests on the fossils to confirm our belief and based on the findings, Kolby and I will write and submit a peer-reviewed paper for acknowledgement of our discovery within the scientific community.'
Dooling, who is still a student, was thrilled by the experience and the opportunity to contribute to real scientific work.
In the press release, Shelton stated, 'This will be a significant discovery. It's important that Kolby also get credit for helping me make it and it's always good for me to take students out of the classroom and into the field, from the theoretical to the practical, to find fossils for themselves and to get to uncover their own piece of history.'
Shelton hopes to have the scientific paper detailing their findings ready by the end of this year. If confirmed, this discovery could offer new insights into fossil preservation and add to the limited number of known ammonite fossils from the Carboniferous Period that exhibit gemstone-quality iridescence.