Arctic island yields Jurassic giant

This article originally appeared in the Lamp, 2007 — Number 4

Fossil remains of one of the largest marine reptiles ever found are being recovered from a major new site on Svalbard, a barren group of islands barely 800 miles from the North Pole. The discovery was made in 2006. Last summer, ExxonMobil sponsored a return expedition by Norwegian paleontologists, company representatives and students. Their goal was to bring back three of 28 specimens that date from the Jurassic age, some 150 million years ago.

In a sea full of giants, this one was king. The pliosaurus, a fierce, finned predator that reached 40 feet (12 meters) in length, was one of the largest predators that ever lived. Its head was the size of a small car, and its teeth were like railroad spikes. That much was known, but the discoveries on Svalbard surprised even the scientists who made them.

The August 2007 expedition, funded in part by ExxonMobil, was the follow-up to recover a major concentration of fossils identified by Dr. Jørn H. Hurum and others from the Natural History Museum at the University of Oslo in 2006.

Nicolai L. Lech-Hernes, an ExxonMobil geoscientist based in Houston, studied under Dr. Hurum and was on the Svalbard expeditions in 2004 and 2007.

“Svalbard is like an open book,” Lech-Hernes says. “The entire stratigraphy lies uncovered, which means that bedrock and sedimentary layers that were once below sea level are directly visible. The skeletons of the marine reptiles we found are a huge bonus. They teach us about the prehistoric ecosystem and the evolution of life on Earth; they are the documents of our prehistory.”

Walking an ancient sea
From Svalbard’s rocky shore, the land rises gently at first, then grows steadily steeper and harder to climb. From 1,650 feet (500 meters) up, the view back down is startling. The water and sky are nearly the same shade of blue. Patches of snow whiten the folds of the mountains. Everything else is brown and gray, except for the dozen or so red and green tents pitched in two neat rows on the only level ground in sight. Trip wires around the tents help discourage curious polar bears.

A short climb up from the camp is the vast exposed layer that the university team came to explore, a thick outcrop of rocks and sediment that was once the bottom of an extinct sea. In Jurassic times, it was closer to the equator, but forces beneath the Earth’s crust keep continents on the move. Now that ancient seabed lies exposed on an Arctic mountain that is slowly crumbling away.

“When we are prospecting in rugged terrain like this, we fan out like a search party,” Lech-Hernes explains. “We walk in a line, looking at the rocks and hoping to find one that looks like bone.”

Each time an area is covered, a new fossil might be showing something that wasn’t visible a year before. If searchers spot it in time, there’s a good chance they will uncover more bones underneath. If not, the fossil will slowly erode like all the other rocks around it, becoming just more rubble on the side of the hill.

Modest finds on Svalbard in 2001 led to the expedition that Lech-Hernes joined in 2004. The next visit was in 2006, with the goal of prospecting and mapping possible new findings.

“In addition to the 11 specimens we found in 2004, the 2006 team discovered 28 others, all within a few hours’ walk from the original discovery,” Lech-Hernes says. “In paleontology, that abundance is truly spectacular.”

Searchers discovered the fossils — including what may be the largest pliosaurus ever found — in good condition, with the bones lying just as they were when the animal died. The richness of these discoveries puts Svalbard on the map as one of the most interesting and promising sites in the world for studying Jurassic marine reptiles.

Delicate rocks
Fossilized bones may feel like rocks, but they can be quite fragile. Removing fossils from the surrounding rock and getting them to the research lab takes experience and skill. Arctic conditions add to the challenge. In an endless cycle, frost melts into cracks in the rock, then expands as it freezes again. Fossils may look intact, but they can fall apart if you try to pick them up.

“You never know what you’re going to find until you start digging a larger hole,” Lech-Hernes says. “First you expose the bones, then decide whether to divide them into groups or extract them as individual bones.”

Once a surface of the fossil is free from the surrounding rock, it is covered with wet tissue paper, then coated by hand with plaster.

“After the plaster has dried, you continue digging around the base to create an undercut,” Lech-Hernes says. “Pretty soon, the rock looks like a plaster mushroom. Finally, you turn the whole thing over, remove any excess rock and plaster the bottom side. The plaster jacket will protect the bones during transport.”

A highly experienced team like this one can make a large plaster jacket in about two days. During the three-week stay, the 2007 expedition recovered more than two tons of fossils this way. The excavations, which can only be done in the summer, will continue for years. The work is hard, the days are long, but Lech-Hernes hopes to return soon.

“There is a moment,” he says, “when you are walking in the field and you pick up a rock and realize that what you are holding is not a rock at all, but a bone that was left there 150 million years ago. You have to stop for a minute to think about all the things that have happened in the world since then.”