Work

Multiple late Holocene glacier advances on the sub-Antarctic Kerguelen (49°S) islands: Evidence from a 1200 yr sediment core from a glacial threshold basin

Year: 2024

Type: article

Abstract: Southern Ocean (SO) climate is rapidly changing because of global warming and regional climate feedback loops like shifts of the Southern Hemisphere (SH) westerly winds (SHW) and related Southern Annular Mode (SAM). Over the past decades, the former has been persistently positive, shifting the latter southwards: the ensuing changes in temperature and precipitation are linked to the rapid retreat of mid-latitude mountain glaciers. Beyond the short instrumental period, the long-term impact of this coupled SHW-SAM system on regional glaciers remains poorly constrained. To help close this gap, we reconstruct glacier advances from an outlet glacier on the sub-Antarctic Kerguelen (49°S, 69°E), an archipelago that is strategically located in an under-investigated region of the SHW core belt. Based on alternations between relatively organic and minerogenic mud detected using a multiproxy approach on a 1200-year-long sediment record from a glacial threshold basin, we document glacier advances between 1150 and 850, 820–620, 500–250 and 160–90 cal yr BP. Coincident glacier advances in adjacent regions like sub-Antarctic South Georgia and southern Patagonia, suggest that SO glaciers responded symmetrically to climate forcings during the past 1200 years. We attribute this synchronicity to shifting SAM-like conditions and associated temperature changes. We suggest that cold and negative SAM-like conditions, favourable for glacier growth on the Kerguelen and other SO land masses, dominated during much of this period. Furthermore, the findings presented here support the growing consensus for a two-phased regional expression of the Little Ice Age (LIA). • Outlet glacier on the sub-Antarctic Kerguelen (49°S) islands is reconstructed using glacial threshold lake sediments. • The glacier advanced between 1150 and 850, 820–620, 500–250 and 160–90 cal yr BP. • First lake sediment-based glacier reconstruction from Kerguelen. • Glacier advances on Kerguelen are synchronous with other mid-latitude mountain glaciers.

Source: Quaternary Science Reviews

DOI: 10.1016/j.quascirev.2024.109106

Authors: Jarle Børve Sleire, Jostein Bakke, Fabien Arnaud, Pierre Sabatier, Willem G.M. van der Bilt

Institutions: Bjerknes Centre for Climate Research, University of Bergen, Centre National de la Recherche Scientifique, Laboratoire Environnements, Dynamiques et Territoires de Montagne, Université Savoie Mont Blanc

Language: English

Topic: Geology and Paleoclimatology Research

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: hybrid

Estimated APC paid: $3,810