A debris-covered glacier at Kerguelen (49 degrees S, 69 degrees E) over the past 15 000 years

Debris-covered glaciers constitute a large part of the world's cryosphere. However, little is known about their long-term response to multi-millennial climate variability, in particular in the Southern Hemisphere. Here, we provide first insights into the response of a debris-covered glacier to multi-millennial climate variability in the sub-Antarctic Kerguelen Archipelago, which can be compared to that of recently investigated debris-free glaciers. We focus on the Gentil Glacier and present 13 new Cl-36 cosmic-ray exposure ages from moraine boulders. The Gentil Glacier experienced at least two glacial advances: the first one during the Late Glacial (19.0-11.6 ka) at similar to 14.3 ka and the second one during the Late Holocene at similar to 2.6 ka. Both debris-covered and debris-free glaciers advanced broadly synchronously during the Late Glacial, most probably during the Antarctic Cold Reversal event (14.5-12.9 ka). This suggests that both glacier types at Kerguelen were sensitive to abrupt temperature changes recorded in Antarctic ice cores, associated with increased moisture. However, during the Late Holocene, the advance at similar to 2.6 ka was not observed in other glaciers and seems to be an original feature of the debris-covered Gentil Glacier, related to either distinct dynamics or to distinct sensitivity to precipitation changes.

Automated summary

Debris-covered glaciers in the sub-Antarctic Kerguelen Archipelago have shown responses to multi-millennial climate variability, with at least two glacial advances observed during different periods. Both debris-covered and debris-free glaciers advanced synchronously during the Late Glacial, but a distinct advance in the debris-covered Gentil Glacier during the Late Holocene suggests unique dynamics or sensitivity to precipitation changes.