Oxygen-isotopic ratios – a proxy for temperature, and concentrations of dust and various chemicals – including volcanic tracers, will collectively reveal past climate conditions.
The expedition in early winter to the Bruce Plateau, an ice field straddling a narrow ridge on the northernmost tongue of the southernmost continent, yielded a core that was 445.6 meters (1,462 feet) long, the longest yet recovered from that region of Antarctica.
Scientists aim to understand if climate trends around the Antarctic Peninsula have been similar or dissimilar to those experienced by the rest of the continent. The effort presents several important questions about the climactic history of the area: Was the climate on the peninsula warm during the early Holocene period, some 8,000 to 6,000 years ago, as it was elsewhere around the globe? Can evidence trapped in the ice cores shed light on what caused the Larsen Ice Sheet to begin to disintegrate in recent years?
Cores are brought up to the surface within the drill dome, laid out for examination and then cut into segments for storage.
(photo credit: Ellen Mosley-Thompson, Ohio State University)
If the cores contain ice formed during the last ice age, they might yield clues to what caused the change from those earlier, much colder climate conditions. "My gut feeling is that the ice at the Bruce Plateau site might have built up during the latter part of the last glacial stage," said Ellen Mosley-Thompson, Ohio State University Professor of Geography.
"But to date, only two cores drilled in the Antarctic Peninsula, one in 2007 to 363 meters depth by the British Antarctic Survey, and ours, have the potential to answer that question and neither has been analyzed yet to make that determination."
The ice core drilling effort was part of the much larger Larsen Ice Shelf System, Antarctica (LARISSA) project, designed to unravel past climate conditions in this part of the continent and monitor current ocean and atmospheric processes. The project involved experts in the oceanography, biology and geology of the region, in addition to the ice core effort. The goal is to build a climate history of the region, hopefully determining if the ice shelf break-up was part of a long-term natural cycle or linked to the recent warming in this part of the world.
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