Physical properties of shallow ice cores from Antarctic and sub-Antarctic islands

• Main Authors: Thomas, Elizabeth Ruth, Gacitúa, Guisella, Pedro, Joel B., King, Amy Constance Faith, Markle, Bradley, Potocki, Mariusz, Moser, Dorothea Elizabeth
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarctic; Balleny Islands; Bellingshausen Sea; Bouvet; Bouvet Island; Ross Sea; Young Island; Antarc*; ice core; Sea ice
• Online Access: https://doi.org/10.5194/tc-2020-110; https://tc.copernicus.org/preprints/tc-2020-110/

The sub-Antarctic is one of the most data sparse regions on earth. A number of glaciated Antarctic and sub-Antarctic islands have the potential to provide unique ice core records of past climate, atmospheric circulation and sea ice. However, very little is known about the glaciology of these remote islands or their vulnerability to warming atmospheric temperatures. Here we present ground penetrating radar (GPR), melt histories and density profiles from shallow ice cores (14 to 24 m) drilled on three sub-Antarctic islands and two Antarctic coastal domes. This includes the first ever ice cores from Bouvet Island (54°26’0 S, 3°25’0 E) in the South Atlantic, from Peter 1st Island (68°50’0 S, 90°35’0 W) in the Bellingshausen Sea and from Young Island (66°17′ S, 162°25′ E) in the Ross Sea sector’s Balleny Islands chain. Despite their sub-Antarctic location, surface melt is low at most sites (melt layers account for ∼10 % of total core), with undisturbed ice layers in the upper ∼40 m, suggesting minimal impact of melt water percolation. The exception is Young Island, where melt layers account for 47 % of the ice core. Surface snow densities range from 0.47 to 0.52 kg m 3 , with close-off depths ranging from 21 to 51 m. Based on the measured density, we estimate that the bottom ages of a 100 m ice core drilled on Peter 1st Island would reach ~1836 AD and ~1743 AD at Young Island.