Chronostratigraphy of blue ice at the Larsen Glacier in Northern Victoria Land, East Antarctica

• Main Authors: Lee, Giyoon, Ahn, Jinho, Ju, Hyeontae, Ritterbusch, Florian, Oyabu, Ikumi, Kim, Songyi, Moon, Jangil, Buizert, Christo, Ghosh, Sambit, Kawamura, Kenji, Lu, Zheng-Tian, Hong, Sangbum, Han, Chang Hee, Hur, Soon Do, Jiang, Wei, Yang, Guo-Min
• Format: Text
• Language: English
• Published: 2021
• Subjects: Bia; East Antarctica; Larsen Glacier; Victoria Land; Antarc*; Antarctica; ice core
• Online Access: https://doi.org/10.5194/tc-2021-294; https://tc.copernicus.org/preprints/tc-2021-294/

Blue ice areas (BIAs) allow for the collection of large-sized old ice samples in a cost-effective way because deep ice outcrops and make old ice samples available close to the surface. However, most chronostratigraphy studies on blue ice are complicated due to fold and fault structures. Here, we report a simple stratigraphy of ice from the Larsen BIA, Antarctica, making the area valuable for paleoclimate studies. Ice layers defined by dust bands and ground penetration radar (GPR) surveys indicate a monotonic increase in age along the ice flow direction on the downstream side, while the upstream ice exhibits a potential repetition of ages on scales of tens of meters, as shown in the complicated fold structure. Stable water isotopes (δ 18 O ice and δ 2 H ice ) and components of the occluded air (i.e., CO 2 , N 2 O, CH 4 , δ 15 N-N 2 , δ 18 O atm (= δ 18 O-O 2 ), δO 2 /N 2 , δAr/N 2 , 81 Kr and 85 Kr) were analyzed for surface ice and shallow ice core samples. Correlating δ 18 O ice , δ 18 O atm , and CH 4 records of Larsen ice with existing ice core records indicates that the gas age at shallow coring sites ranges between 9.2–23.4 ka BP and ice age for entire surface sampling sites between 5.6–24.7 ka BP. Absolute radiometric 81 Kr dating for the two cores confirms the ages within acceptable levels of analytical uncertainty. Our study demonstrates that BIA in northern Victoria Land may help researchers obtain high-quality records for paleoclimate and atmospheric greenhouse gas compositions through the last deglaciation.