[M-IS15] Global Antarctic Science: connecting the chain of changing huge ice sheets and global environments

[MIS15-P12] High-resolution paleoenvironmental reconstruction since the Last Interglacial using lake sediments from the Larsemann Hills, East Antarctica

*Kotoha Kosugi¹, Takeshige Ishiwa^2,1, B.S., Mahesh³, Elie Verleyen⁴, Toru Tamura⁵, Cheryl Noronha- E.D. Mello³, Phillippe Huybrechts⁶, Anish Kumar Warrier⁷, Kota Katsuki⁸, Minoru Ikehara⁹, Rahul Mohan³, Yusuke Suganuma^2,1 (1.The Graduate University for Advanced Studies, 2.National Institute of Polar Research, 3.National Centre for Polar and Ocean Research, 4.Ghent University, 5.National Institute of Advanced Industrial Science and Technology , 6.Vrije Universiteit Brussel, 7.Manipal Academy of Higher Education, 8.Shimane University, 9.Kochi University)

Keywords:East Antarctica, Last Interglacial, High-resolution paleoenvironmental reconstruction, Larsemann Hills

Antarctica is affected by global warming and is partially experiencing significant ice mass loss. To understand how Antarctic environments will respond to ongoing and future climate changes, analyses of sedimentary records from past warm periods are fundamental. The Last interglacial period (129,000 to 116,000 years B.P.) was globally as warm as or warmer than the present. However, terrestrial and lacustrine paleoenvironmental records from this interval remain exceptionally scarce in East Antarctica due to glacial erosion and extensive ice cover during the subsequent glacial period. While ice cores and marine sediments offer broader climate insights, they lack the local environmental records needed for detailed reconstructions. Previous studies in the Larsemann Hills have reconstructed relative sea-level and ice-sheet changes in this region based on isolation basin and lake sediments (e.g. Hodgson et al., 2001, Verleyen et al., 2004) and revealed the presence of MIS3 (Verleyen et al., 2004) and expected to be MIS5e (Hodgson et al., 2006) units in a few sediment cores. In the Larsemann Hills, continuous and high-resolution (millimeter-scale) analyses would have a potential to detect abrupt climate shift through the Late Pleistocene and Holocene. In this study, a sediment core was collected in November 2024 from Kirijes Pond, a lake in the Larsemann Hills, using a portable percussion piston corer (Suganuma et al., 2019) designed to penetrate glacial till. The core is longer than 2m and is likely to contain older sedimentary units than beyond those documented in the previously reported MIS3-spanning core from Kirisjes ond itself (Verleyen et al., 2004). A description of lithology and X-ray CT image analysis were performed on the collected sediment cores. Additionally, water profile data of the lake were also collected using a CTD profiler before sediment sampling, which provided insights into the lake’s physical and chemical water properties. In the future work, we plan to conduct high-resolution paleoenvironmental reconstructions from lake records in the Larsemann Hills based on AI-assisted diatom assemblage analysis, radiocarbon dating, OSL dating and two-dimensional elemental mapping using micro-XRF.