Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/16848
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Late-glacial glacier events in southernmost South America: A blend of 'northern'and 'southern' hemispheric climatic signals?
Author(s): Sugden, David E
Bentley, Michael J
Fogwill, Chris
Hulton, Nicholas R J
McCulloch, Robert
Purves, Ross
Contact Email: robert.mcculloch@stir.ac.uk
Keywords: Patagonia
glacier fluctuations
Last Glacial Maximum
Antarctic Cold Reversal
late glacial
bipolar seesaw
Antarctic circumpolar wave
Climatic changes
Glaciology
Issue Date: Jun-2005
Date Deposited: 7-Oct-2013
Citation: Sugden DE, Bentley MJ, Fogwill C, Hulton NRJ, McCulloch R & Purves R (2005) Late-glacial glacier events in southernmost South America: A blend of 'northern'and 'southern' hemispheric climatic signals?. Geografiska Annaler: Series A, Physical Geography, 87 (2), pp. 273-288. https://doi.org/10.1111/j.0435-3676.2005.00259.x
Abstract: This paper examines new geomorphological, chronological and modelling data on glacier fluctuations in southernmost South America in latitudes 46–55°S during the last glacial–interglacial transition. Establishing leads and lags between the northern and southern hemispheres and between southern mid-latitudes and Antarctica is key to an appreciation of the mechanisms and resilience of global climate. This is particularly important in the southern hemisphere where there is a paucity of empirical data. The overall structure of the last glacial cycle in Patagonia has a northern hemisphere signal. Glaciers reached or approached their Last Glacial Maxima on two or more occasions at 25–23 ka (calendar) and there was a third less extensive advance at 17.5 ka. Deglaciation occurred in two steps at 17.5 ka and at 11.4 ka. This structure is the same as that recognized in the northern hemisphere and taking place in spite of glacier advances occurring at a time of high southern hemisphere summer insolation and deglaciation at a time of decreasing summer insolation. The implication is that at orbital time scales the ‘northern’ signal dominates any southern hemisphere signal. During deglaciation, at a millennial scale, the glacier fluctuations mirror an antiphase ‘southern’ climatic signal as revealed in Antarctic ice cores. There is a glacier advance coincident with the Antarctic Cold Reversal at 15.3– 12.2 ka. Furthermore, deglaciation begins in the middle of the Younger Dryas. The implication is that, during the last glacial–interglacial transition, southernmost South America was under the influence of sea surface temperatures, sea ice and southern westerlies responding to conditions in the ‘southern’ Antarctic domain. Such asynchrony may reflect a situation whereby, during deglaciation, the world is more sensitized to fluctuations in the oceanic thermohaline circulation, perhaps related to the bipolar seesaw, than at orbital timescales.
DOI Link: 10.1111/j.0435-3676.2005.00259.x
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