In 2011, an oil sands mine exposed an armoured dinosaur hidden for 110 million years

On a morning in March 2011, what seemed like an ordinary day at an oil sands mining facility in northern Alberta, Canada, became an extraordinary paleontological find. An operator driving a heavy piece of equipment at Suncor's Millennium Mine encountered what he thought was a very hard section of rock. Instead, he uncovered something much more fascinating - the fossilised remains of an armored dinosaur buried under the ground for about 110 million years.The fossil turned out to be Borealopelta markmitchelli, a herbivorous nodosaur from the Early Cretaceous period. It became apparent very quickly that this find was anything but an ordinary dinosaur fossil. As described in the journal Current Biology, available through ScienceDirect, the specimen was preserved in exceptional detail, making it one of the most remarkable armoured dinosaur fossils ever discovered.An accidental discovery in an active mineUnlike many other celebrated finds, Borealopelta was not excavated in a planned dig. As mentioned on the Royal Tyrrell Museum, and an information available through PubMed, Borealopelta was discovered accidentally after heavy equipment operator Shawn Funk uncovered the fossil during mining operations at the Millennium Mine operated by Suncor in Alberta, near Fort McMurray.Borealopelta was taken to the Royal Tyrrell Museum of Paleontology, where Mark Mitchell, a technician at the facility, spent more than 7,000 hours meticulously extracting the bones from their encasing rock. This labor was so valuable to the researchers that they named the species in his honour. The genus name Borealopelta means 'northern shield', while the species name markmitchelli honors technician Mark Mitchell for his extensive work preparing the fossil.The original scientific description of the genus can be found in the journal Current Biology. In the paper published in 2017, scientists state that the discovery is a novel genus and species of nodosaurid dinosaur.Preserved in remarkable conditionWhat set this fossil apart was its extraordinary state of preservation. What made this fossil unique was the description given of it being exceptionally well-preserved, with much of its armor still intact in its original positions.It turns out that, according to research, large areas of the skin covering and the keratin armor of the creature had survived fossilisation. The preservation was so striking that several researchers described it as one of the best-preserved dinosaur fossils of its size ever found.In a report by National Geographic in 2017, it was noted that the fossil managed to preserve the dinosaur in its three-dimensional form, which is something that normally does not happen when fossils are found.This fossil has been measured to be approximately 5.5 meters long, while its weight at the time of living is believed to have exceeded 1,300 kilograms. A dinosaur buried beneath an ancient seaAdditional research provided explanations regarding the possible reason for such unusual preservation. According to a paper published in 2020, the fossil was recovered from marine sediments from the Wabiskaw Member of the Clearwater Formation in Alberta.Such a location suggests that the dinosaur was not found in the place where it initially perished. It is believed that the carcass entered a marine environment before getting buried, and the sediment prevented the breakdown of organic tissues.It should be noted that the origin of the sediments in question represents yet another aspect of the story. The thing is that even though Borealopelta was a terrestrial creature, it ended up being preserved under sediments deposited in the ocean.In other words, such unusual burial circumstances may be considered one of the factors explaining why the specimen was in such perfect condition.A window into life during the CretaceousDue to the degree of preservation, the researchers were able to explore characteristics of the dinosaur not usually seen on fossils.From the 2020 research looking at what was found within the stomach, it seems like the scientists could actually detect the remnants of its last meals. From the findings, one can infer that the herbivorous dinosaur had recently eaten ferns and other plants before its death.The scientists have even looked into the arrangement of the dinosaur's body armor and its body structure from the fossils. According to reports, this has helped researchers to have a better understanding of how nodosaurs might have looked and worked.Why the discovery remains importantBorealopelta markmitchelli, discovered over ten years ago, still remains relevant due to the unlikely circumstances surrounding its recovery.Indeed, the specimen is unique because of the combination of rare characteristics. First, unlike other fossils, it was not found by scientists during their research but was accidentally discovered in a mining operation. Moreover, it is considered one of the most well-preserved armoured dinosaurs ever studied. Its discovery has provided researchers with an unusually detailed record of an animal that lived during the Early Cretaceous, around 110 million years ago.At the same time, the discovery is another highlight of the history buried under the surface. Thus, a simple mining operation resulted in finding a specimen preserved for millions of years. An unexpected discovery during mining operations ultimately revealed one of the most remarkable dinosaur fossils ever found.