In the arctic underworld

Researchers collect climate data from cave deposits in northern Greenland

Large hoarfrost crystals cover the walls and ceiling of a cave in northeastern Greenland. © Robbie Shone / University of Innsbruck
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What looks like foam or snow hides lime deposits that have grown over thousands of years. Because under the hoarfrost they cover the walls of a cave in northern Greenland, the scientists have recently explored on an expedition. Their goal: to collect samples of the calcite deposits in order to gain valuable information about the past climate of Greenland.

Greenland is one of the regions of the world that is particularly sensitive to climate change and facing major changes. "Improving the understanding of how the Arctic will develop in a warmer world is therefore of the highest priority, " explains Gina Moseley from the Institute of Geology at the University of Innsbruck. "One of the ways to accomplish this is to study warmer periods in the recent geological past."

Calcite deposits as contemporary witnesses

So far, however, there is only scant information about the climate history of Greenland. Most climate records for Greenland have been obtained from ice cores drilled from inside the Greenland ice sheet. However, these records are limited to the last 128, 000 years. However, caves with stalactites and other calcite deposits in the north of the island are testimony to the fact that there have been periods since when the climate on Greenland was warmer and wetter than it is today.

It has long been known that stalactites and other lime deposits in caves are particularly good witnesses to the climate of the past. For the conditions at different times remain conserved in the annual ring-like layers of lime. Gina Moseley first examined the deposits in the remote Gr nl ndische H hlen in 2015. However, because the researchers were traveling on foot and without helicopter support at the time, they could only take a small amount of material with them for their analyzes. But at least: This was the first time such climate records had been made from caves in the High Arctic.

North record for cave research

In July 2019, the researcher returned to Northern Greenland with a team and researched more than 30 caves in the Greenland Caves Project that have never been visited before. This photo shows the team walking through one of these caves in northern Greenland. display

"The records from the calcite deposits in the caves offer the opportunity to extend the knowledge of the past climate of Greenland beyond the boundaries of the ice cores. This information is central to future climate forecasts, "emphasizes the scientist. She and her team even set a record during their expedition: their exploration included the longest and northernmost cave ever explored.

Source: University of Innsbruck

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- Nadja Podbregar