Late Quaternary environmental changes in Marguerite Bay, Antarctic Peninsula, inferred from lake sediments and raised beaches

• Published in: Quaternary Science Reviews
• Main Authors: Hodgson, Dominic A., Roberts, Stephen J., Smith, James A., Verleyen, Elie, Sterken, Mieke, Labarque, Minke, Sabbe, Koen, Vyverman, Wim, Allen, Claire S., Leng, Melanie J., Bryant, Charlotte
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2013
• Subjects: Antarctic; The Antarctic; Antarctic Peninsula; Marguerite; Marguerite Bay; Pourquoi Pas; Pourquoi-Pas; Pourquoi-Pas?; Calmette; The Narrows; Bay Lake; Horseshoe Island; Calmette Bay; Pourquoi Pas Island; Narrows Lake; Antarc*; Ice Sheet
• Online Access: http://nora.nerc.ac.uk/id/eprint/19996/; https://nora.nerc.ac.uk/id/eprint/19996/1/JQSR-D-12-00429R1%5B1%5D.pdf; http://www.sciencedirect.com/science/article/pii/S0277379113000541

The Antarctic Peninsula is one of the fastest-warming regions on Earth, but its palaeoenvironmental history south of 63° latitude is relatively poorly documented, relying principally on the marine geological record and short ice cores. In this paper, we present evidence of late-Quaternary environmental change from the Marguerite Bay region combining data from lake sediment records on Horseshoe Island and Pourquoi-Pas Island, and raised beaches at Horseshoe Island, Pourquoi-Pas Island and Calmette Bay. Lake sediments were radiocarbon dated and analysed using a combination of sedimentological, geochemical and microfossil methods. Raised beaches were surveyed and analysed for changes in clast composition, size and roundness. Results suggest a non-erosive glacial regime could have existed on Horseshoe Island from 35,780 (38,650–33,380) or 32,910 (34,630–31,370) cal yr BP onwards. There is radiocarbon and macrofossil evidence for possible local deglaciation events at 28,830 (29,370–28,320) cal yr BP, immediately post-dating Antarctic Isotopic Maximum 4, and 21,110 (21,510–20,730 interpolated) cal yr BP coinciding with, or immediately post-dating, Antarctic Isotopic Maximum 2. The Holocene deglaciation of Horseshoe Island commenced from 10,610 (11,000–10,300) cal yr BP at the same time as the early Holocene temperature maximum recorded in Antarctic ice cores. This was followed by the onset of marine sedimentation in The Narrows, Pourquoi-Pas Island, before 8850 (8480–9260) cal yr BP. Relative sea level high stands of 40.79 m above present at Pourquoi-Pas Island and 40.55 m above present at Calmette Bay occurred sometime after 9000 cal yr BP and suggest that a thicker ice sheet, including grounded ice streams, was present in this region of the Antarctic Peninsula than that recorded at sites further north. Isolation of the Narrows Lake basin on Pourquoi-Pas Island shows relative sea level in this region had fallen rapidly to 19.41 m by 7270 (7385–7155) cal yr BP. Chaetoceros resting spores suggest high productivity and ...