Summerasaurus Part II: A Day in the Quarry
Mark Farmer recently returned from an expedition to the badlands of southern Alberta with Dr. David Evans, Associate Curator of Vertebrate Paleontology at the ROM, in search of dinosaurs. Join us over the course of the next month as Mark and Dr. Evans put up their notes from the field, detailing discoveries, how dinosaurs are found and excavated, life in the field and more.
It’s my second day in the quarry, but many of the team have been here for over a week. My body is still getting used to the furnace-like heat and the relentless, baking sun of southern Alberta’s badlands. For everyone else, it’s old hat.
The team consists of the ROM’s Dr. Evans and Dr. Michael Ryan from the Cleveland museum of Natural History, with students from the University of Toronto, Carleton University and even the University of Hokkaido in Japan. New students and volunteers rotate in on a weekly basis to learn the art and science of freeing 78-million-year-old dinosaurs from their stone tombs. It can be an excruciatingly slow process, but it’s experience they can get in few other places, and each of the students seems glad for that opportunity.
The quarry we’re working in was river mud 78 million years ago, when a horned dinosaur met its demise. Now it’s a comparatively soft, flaky stone that easily breaks apart under a simple hand tool, or even a stiff paintbrush: it’s a misperception that fossil matrix (the surrounding rock) has to be tough and impenetrable. It can be devilishly hard, especially if it’s a limestone or a strongly concreted sandstone; that’s when you might need heavier equipment to get the bones out. For this kind of matrix, it’s a simple task to remove it using small hand tools.
Everyone takes part equally in the digging, whether they have a Ph.D. after their name or whether they haven’t even finished their undergraduate degree. That’s as much by choice and necessity as any democratic ideals: the field season is short enough, and many hands make light work of a canyon wall concealing what could be a new genus of horned dinosaur. Another reason for the equal-opportunity digging duty is that palaeontologists love the thrill of discovery and getting their hands dirty. This is one profession where fieldwork is not only necessary, but a personal passion.
Each student rotates through different tasks. Saul shovels out overburden (the layer of rock on top of the fossil bed) and other leftover rock from the digging process. Near the end of the day, with news that storm clouds may be coming, Dr. Ryan shows the students how to dig trenches in the piles of leftover rock, in order to channel any rainwater from the digging area, so that precious fossil material isn’t washed away.
Derek, another student, is busy removing material from around a partial rib fossil in order to make a jacket. In the field, workers won’t remove all the rock from around a fossil – they’ll leave a jacket of rock around it, and encase that in burlap soaked in plaster of Paris to protect it. That ensures that nothing breaks off before the fossil gets out of the field and into the lab.
Dr. Evans and Dr. Ryan are working on a rib and an ischium (part of the pelvis). Those two bones will make a big jacket, perhaps weighing over 40 kilograms. The smaller rib Derek’s working on might weigh only four or five kilos, so it’s something that can be taken out by hand. Big jackets often require the use of an ATV or the winch on a pickup truck to take them out: a sled (improvised using anything from a car hood to half an oil barrel) will be positioned under the jacket, which will be towed out. The biggest jackets require even bigger vehicles, which can be tough to get into places like the badlands. On some dig sites around the world, helicopters have been called in to lift out big jackets.
Nothing here today requires anything so dramatic as a helicopter. Most of the material is relatively small, and the biggest challenge today seems to be cutting away the roots of bushes that have infiltrated the fossils and threaten to break them apart before we’ve had a chance to excavate them. Slowly, layer by layer, the team cuts back the canyon wall around each bone, each member working on their own fossil. At the end of the day, complete fossils are jacketed and left to dry for removal the next day. Unfinished work is left as is, and by 5 p.m. the team trudges back across the prairie to the trucks parked by a gas well, dusty and thirsty, and ready to do it all again the next day.