Today my Dublin colleague Sue Beardmore talks about her work as part of a team excavating dinosaurs in the Utah badlands. While I’ve talked about my own fieldwork in China and Mexico, and some of the skills in making jackets, it’s great to have a report on a major project run over a number of years and to get a real feel for how these things work from start to finish. Enjoy:
Every year, when I am not writing or demonstrating fossils, I volunteer at various dig sites to uncover fossils. Since 2003 I have spent anything from a few weeks to a few months in Utah, working as a volunteer for the Utah Museum of Natural History, Salt Lake City, Utah. At the airport, I meet members of the field crew before driving six-hours to the southern part of the state, passing mountains and valleys bearing evidence of earth movements, glaciations, and volcanic activity. We head for the Grand Staircase-Escalante National Monument (GSENM) where rocks of the Mesozoic, deposited between 250 and 65 million years ago, outcrop as a series of step-like cliffs. Erosion of these cliffs forms spectacular tourist spots like the Bryce and Zion National Parks, and slot canyons popular with hikers. We drive beyond these, deep into the monument, leaving the paved road, the maintained tracks and any other sign of habitation or civilisation, for the backcountry. The final part of the journey is on un-maintained tracks, cut by ephemeral washes and littered with boulders, which reinforce the necessity of wearing seat belts and various gripping handles in the vehicle. As we approach the camp on the ridge, ravens begin to gather and follow, settling in the trees around us when we eventually stop. Although it has been two years since I was last here, the set-up is familiar; to the left of the track is the cliff, overlooking the wide valley we drove across. To the right is the moderately sized white kitchen tent, our refuge in bad weather, with the stove next to it. The fire pit is a few metres beyond, encircled by overturned chairs (also necessary following loss of several into the hot embers). Other tents belonging to the 8 or so crew are glimpsed through the juniper pines, well away from the track. Not that we ever see any other vehicles or people out here.
The field camp is situated where it is because one of the most productive rock units regarding dinosaurs almost entirely fills the valley below. The Kaiparowits Formation is a 74-76 million year old Upper Cretaceous unit from which the museum has collected hadrosaurs, ceratopsians, tyrannosaurs, ankylosaurs and pachycephalosaurs as well as turtles and crocodiles. Mudstones indicate vast floodplains, and sandstones, the infilling of small, migrating river channels cut into the floodplains. Snails and bivalve fossils are found in the sandstones. Fossilised wood is abundant everywhere with logs often several metres long. Over 70 different types of ferns, vines and leaves have so far been collected, and there is evidence for algae in what were small ponds of standing water. The environment was therefore ideal for all kinds of dinosaurs. In the same way these creatures roamed the ancient Kaiparowits looking for food, palaeontologists today walk the outcrop looking for the fossil evidence they were there.
There are three main activities that constitute palaeontological fieldwork and, depending on the size of the crew, we may all work on the same thing or split resources between. The first activity is the locating of sites containing fossilised remains, or prospecting. The Kaiparowits covers a huge area and the only way to investigate it is to walk around the outcrop a fraction at a time. As the track only circum-navigates the unit we can walk some distance to reach a prospecting area, easily covering 10-15 kilometers in a day. We split into small groups, pairs or head out individually to cover more ground. Everyone has their own prospecting technique: some follow the ridge tops where the rock undergoes the greatest weathering, others across the soft slopes, whereas I tend to follow the base of the ridges looking for bone trails from the bottom up. The bones we find are in varying conditions proportional to the time exposed to weathering, and where they continue into the rock we dig-in, in the hope of finding that perfect skeleton. Sites are recorded by GPS and a sample collected for identification back at camp. Although I haven’t found anything decent since my first field season, which was the lower jaw and top-back skull pieces of a hadrosaur, I still like prospecting. There is as much evidence of modern wildlife with common trackways of ground squirrels in mud, lizards in the sand, and rare coyote and mountain lion prints. I have also learnt to ‘track’ the field crew, primarily to avoid a particular route or area already investigated, but also to identify the routes to and from the vehicle or quarries so I don’t get lost. Most trails are well-trodden as there are only a few routes down the cliff, but are not for the faint-hearted. Most notorious is the tyrannosaurid hill, named after the dinosaur found at the base. The trail begins on level ground at the cliff top, before turning onto increasingly narrow, steep ridges we named Mormon-tea Hill, the Michael Jackson eclivity and the Marble Catwalk. The path then splits. The first crosses a high ridge only a few inches wide before treading the soft sediment down the nose. The alternative is the boulder-filled wash with better grip but more exercise to the knees, inevitably ending in ripped trousers. At the base, the trails follow flatter, washes. To reach the farthest areas we have occasional backpacking trips or, even less frequently, a helicopter drops small teams into areas we wouldn’t otherwise get to for a few days with limited food and field gear.
The second part of fieldwork is the excavation of sites. Quarries with large, good conditioned or scientifically important bones are opened by shovelling and picking soil and rock one level at a time. The landscape prevents any heavy machinery and in any case, wheeled vehicles, including wheelbarrows and sack barrows, are not allowed off the road in the monument. Any trees and bushes are carefully ‘relocated’, as the roots tend to reach out for nutrients in bones. Large boulders provide a few minutes competition as they are rolled out of the quarries. As we get close to bone layers we swap picks and shovels for hand tools, which reduce the damage to bones known as the ‘finders fee’. Again, layers are taken down one at a time and swept, making the bones easier to see. All bones in the quarry are mapped to see any groups or orientations that might indicate movement by water, etc. During any field season the crew will have several active quarries. The first quarry I visited in 2010 was the Parasaurolophus, the remains of a duck-billed dinosaur with a head crest. The skull with a good set of teeth had been found three or more years before, but the sandstone surrounding the bones was so tough it was only possible to slowly remove chunks with the rock-saw. Many quarries are open for several years, due to the size of the skeletons and/or the resilient nature of the rocks however it is for these reasons the skeletons survive many millions of years.
The third and final part of fieldwork is to remove the fossils. Preparation in the field involves trenching around the bones so they sit on a pedestal, undercut slightly to form a lip. After covering the bones in paper towel we dip strips of burlap into a plaster mix to wrap around the pedestal and under the lip. Hopefully, when the plaster has dried and we flip the jacket the lip will prevent the rock, and bone, from falling out. Excess rock is removed before adding a cap of burlap and plaster to seal the bone. The jacket will be given a number, also written on the map, along with the name of the quarry. The crew carry small jackets out by hand or in backpacks, up the same steep trails we came down. Backboards are used for moderately sized jackets, requiring at least six people around the board, one or more spare people to switch in, and a navigator to find the easiest route. My first ever jacket-pull was a ceratopsian skull, or horned dinosaur, weighing roughly 200lbs. At 6am we were at the site adding the final plaster layer (which was very cold!) before flipping it onto the hood of a Ford Mustang. Although we could see the vehicle half a mile away we had to drag the jacket along a small, winding wash. Even with 12 or so volunteers this took 2.5 hours, and then we had to get it up into the vehicle! As the largest jackets are impossible to drag anywhere we have to wait for a helicopter to be working in the area. The 2010 field season will always be memorable for such an occasion.
A helicopter had been arranged to lift a jacket for the Alf Museum, California, from the north end of the valley, and quickly, we arranged to add in three of our quarries, all near completion. But on the same day the normally hot, dry weather turned to begin a week of thunderstorms and poor visibility. The tracks were impassable, leading to us getting stuck for six hours overnight without supplies, let alone the footpaths. We later abandoned camp leaving a palaeontological equivalent of a ghost town. The day of the lift came and we had only one site ready. The Alf lift started but was cancelled a few hours later. The one person flown to the site had already been waiting three hours in the rain and now had 8 miles to hike to reach pavement. He appeared four hours later. The next day the lift was attempted again, this time successfully. Now it was out turn. The weather was still bad but the helicopter appeared and took myself and three other crew members with tents, clothes and enough food and water for a few days. If we got stuck we would have to wait until the tracks became passable. We landed, flipped the jacket into the net and watched half an hour later as the helicopter lifted it out. Then it went quiet, leaving the realisation that in the increasingly bad weather we were going to be here for a while. We wandered around the ridge trying to keep warm, and hopeful. Almost two hours later we heard the helicopter. Travelling back we were all cold, but happy. When we landed the whisky was the first thing we found (medicinal of course!). I’m just wondering if next year will be as character building.