BUFFALO, NY – In the 1960s, U.S. Army scientists drilled through nearly a mile of ice in northwestern Greenland – and pulled a tube of dirt from the bottom.
Chester “Chet” Langway, who joined the University at the Buffalo faculty of geology in the 1970s, was one of the leaders on the drill tour at a site called Camp Century. The samples collected by his team there, including the frozen sediment, followed him to Western New York. The goods lived here for several years before making their way to Copenhagen, Denmark. Then, the dirt was largely forgotten.
But in 2019, University of Vermont scientist Andrew Christ, PhD, looked at the sediment through his microscope – and he couldn’t believe what he was seeing: branches and leaves instead of just sand is rock. That suggested that the area had recently been free of geological ice – and that a vegetated landscape stood where a mile-deep ice sheet was as large as Alaska is today.
Over the past year, Christ and an international team of scientists – including Elizabeth Thomas, PhD, associate professor of geology at UB’s College of Arts and Sciences – have studied the one-of-a-kind fossil plants and sediment from the bottom of Greenland. In addition to Christ, the research was led by Paul Bierman, PhD, at the University of Vermont; Joerg Schaefer, PhD, at Columbia University; and Dorthe Dahl-Jensen, PhD, at the University of Copenhagen.
“Our study will closely examine the sediments from the Camp Century drill site on the north west side of the Greenland ice sheet. Our results show that, at some point in the last 1 million years, the Camp Century site was ice-free, ”said Thomas, who conducted a chemical analysis that allowed the team to understand what types of plants that were on the site.
“Ice sheets usually crush and destroy everything in their path,” says Christ, “but what we have found is delicate plant structures – perfectly preserved. They are fossils, but they seem to have died yesterday. It was a time capsule of what used to be Greenland. ”
The research was published March 15 in the Proceedings of the National Academy of Sciences (PNAS).
The discovery helps to confirm a new and difficult understanding that the Greenland Ice Sheet has melted almost completely through recent warm periods in Earth’s history. For example, in 2016, a study in Nature led by Schaefer and co-author with UB professor of geology Jason Briner estimated that a sample of bedrock beneath the Greenland ice sheet was exposed to open sky for at least 280,000 of the last 1.4 million years. .
An understanding of Greenland’s Ice Sheet in the past is crucial for predicting how it will respond to future climate warming and how quickly it will melt.
The material for the new PNAS study came from Camp Century, a Cold War military base that excavated inside the ice sheet far above the Arctic Circle in the 1960s. The camp was the site of a secret effort, known as Project Iceworm, to hide nuclear missiles hidden under the ice. As a cover, the Army presented the camp as a pole science station.
The army’s mission failed, but the science team conducted an important investigation, including a 4,560-foot-deep ice core drill.
The new study makes it clear that the deep ice at Camp Century completely collapsed at least once within the last million years and was instead covered with vegetation, causing including mosses and possibly shrubs.
The team of scientists used a series of advanced research methods to study sediment, fossils, and waxy cover of leaves found at the base of Camp Century ice.
The new study shows that not all ecosystems in the past have been activated by the age of glaciers and ice sheets overflowing. Instead, the story of these living landscapes is still trapped under the relatively young ice formed on the surface of the earth, frozen in its place, and still preserved.