10: Nice Weather Brings Fresh Finds

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Transantarctic Mountains
© N.D. Smith
Compost Hill

Our success in removing the first 300-lb block on Monday was quickly followed by more weather delays. Clouds moved back over Mt. Kirkpatrick on Tuesday and Wednesday, preventing us from going back to our quarry. Pete and I passed the time on Wednesday by taking a couple of snowmobiles out on a recreational route that extends 5-6 miles east of camp, just to the base of the first rock exposures nearby.

The route ends at the base of a small exposure of Buckley Formation affectionately called “Compost Hill” (see above photo.) The Buckley Formation is Late Permian in age (approximately 250 million years old), and is notable for containing numerous coal beds and fossils of the extinct seed fern Glossopteris (check out the Antarctic Fossils Photo Gallery for an example of Glossopteris fossilized leaves).

Pete and I worked our way up the west slope of the hill, passing large chunks of volcanic dolorite that had been weathered into interesting points and crested structures. We found a few fragmentary bits of fossil wood weathering out of the coarse sandstones on the hill, and ultimately stumbled upon a thin rock unit that was sandwiched between the layers of sandstone and filled with exquisitely preserved Glossopteris leaves. Most of the leaves were broken in places, as their rock matrix had been cracked and weathered at its exposed surface, but quite a few were intact or nearly complete.

We were all set to head back to camp with our new bounty of Permian fossils, when the engine of one of our snowmobiles flooded and refused to start, even after twenty minutes of monkeying with it. Pressed for time before dinner (and Happy Hour preceding it), we used a cargo strap to attach the fussy machine to our other snowmobile, and then we towed it back over the ice-covered hills to camp—stopping only briefly at the base of a nearby ridge to chip out a cooler’s worth of blue ice for drinks to be enjoyed by friends and colleagues.

The remainder of our week proved much more exciting and productive. Thursday was one of the most beautiful and sunny days on the mountain yet. We were also joined by two camp staff members, Julie Grundberg and August Allen, who came along to see the dinosaur site and help us work in the quarry. Both Julie and August proved to be extremely skilled with our jackhammers, and their help was indispensable, as we succeeded in removing two more large blocks from the quarry.

We were able to rig up a sling out of some extra webbing and transport the smaller of these blocks (approximately 150 lbs) over to our helicopter landing site to be picked up at the end of the day. Our larger prize weighed approximately 480 lbs, so we had to slide it over to the edge of the mountain to wait for helicopter transport the next morning.

Toward the end of the day, our newfound paleontologist, August, made a spectacular find in the back trench of the quarry: a nearly complete tooth from a small theropod dinosaur. We had found several small teeth in our quarry blocks from years past, but they're extremely rare. These teeth likely belonged to small carnivorous dinosaurs that scavenged the carcass of the much larger Cryolophosaurus before its skeleton was completely buried. With two more blocks removed and this great find, it turned out to be an outstanding day at the site.

Friday brought continued success, as we started the morning by preparing our large 480-lb block to be sling-loaded down off the mountain by helicopter. This involved rolling and centering the immense block onto a cargo net, which we set up near the closest edge of the mountain from our quarry. Our skilled mountaineer, Peter Braddock, then had to stand next to the wrapped block while one of the camp’s helicopter pilots, Paul, brought in the massive helicopter to hover just above Peter’s head—no small feat given the altitude and conditions we're working in on Mt. Kirkpatrick.

Peter deftly maneuvered underneath the helicopter and attached the cargo net to a large metal hook on the aircraft’s belly (see Photo #1 below.) I stayed further up the side of the mountain above our quarry, partially because I needed to communicate with Paul on the radio in case anything went wrong with the load, but mostly because I don’t get paid enough to stand underneath a helicopter (nor would I be any good at it).

As Peter moved out from under the helicopter and several meters down the side of the mountain to relative safety, Paul pulled the cargo line taut and lifted the large block above the ground before veering off down the Northwest slope of Mt. Kirkpatrick, with our precious cargo dangling beneath (see Photo #2.)

In addition to the morning’s excitement, we discovered several large bones in the quarry that all seemed to be located underneath the partially articulated Cryolophosaurus skeleton. These bones were preserved slightly differently, most were much darker in color than the grey Cryolophosaurus bones, and all of them seemed to be too large to belong to Cryolophosaurus.

We could tentatively identify several of the bones as a partial femur (part of the knee), ilium (hip-bone), and an ulna (lower arm bone). It's possible that these elements belong to the other, more fragmentary dinosaur known from this quarry, the large plant-eating sauropodomorph Glacialisaurus. It's also possible that they're from an entirely new dinosaur, though figuring this puzzle out will take many more months of preparation back in the lab. Either way, discovering another partially associated dinosaur skeleton below Cryolophosaurus is a pretty impressive find.

To top the day off, we also succeeded in removing two more large blocks from the quarry, totaling around 560 lbs. It seemed like, after last week’s bad weather, our luck had finally started to turn around. Saturday began with more daring acrobatics by Peter Braddock, working under the helicopter to attach these latest two blocks to be carried back down to camp (see Photo #3.) Inspired by the sight of our main fossil block becoming smaller and smaller each day, we continued quarrying at the site.

The middle of the day also brought another great surprise. Eva Koppelhus had been walking around near the helicopter landing site when she happened to come across two enormous fragments of bone sitting on the surface, likely eroded down from the rocks above. These two fragments fit together perfectly to form the proximal part of an ischium (one of the hip bones). The piece itself was fairly large, about a foot across, and the entire bone would have likely been several feet in length. Judging from its size and morphology, this ischium obviously came from a large dinosaur.

In 2003, we discovered a site that yielded the partial remains of a large plant-eating Glacialisaurus that isn’t too far up the mountain from where Eva found this ischium, so it is possible that this bone may have eroded out of the same rock and tumbled down below. Some careful prospecting next week should help figure this out, and possibly turn up new finds.

More soon,
Nate

© N.D. Smith
Lifting a Fossil Block
© N.D. Smith
Block in Tow
© N.D. Smith
CTAM