T273 Exploring Spatial and Temporal Variability of Latest Pleistocene and Holocene Alpine Glacier Fluctuations

Wednesday, 22 October 2014
8:00 AM - 12:00 PM
211

EMPIRICAL ICE THICKNESS CONSTRAINTS FROM THE CERRO FITZ ROY MASSIF, SOUTHERN PATAGONIA, ARGENTINA

Paper number: T273-2
Program: Technical Sessions
Time: 8:05 AM – 8:20 AM

Authors

Abstract

Southern Patagonia is the only landmass intersecting the southern westerly winds (SWW), which critically shape southern hemispheric and global climate. At present palaeo-climatic datasets stretching the 3000 km of SWW influence are in latitudinal disagreement suggesting a complex picture of SWW paleo-behaviour. In order to unravel the nature of the SWW fluctuations over the last glacial cycle, a tighter grid of palaeo-proxy studies in the region is required.

The work presented here is based on three mountain valleys in close proximity to the Fitz Roy massive (49°S, 72°W), which is located just east of the southern Patagonian Ice Field. At this site the Patagonian cordillera provides a topographic barrier to the SWW, hence the dominant limiting factor for glacier expansion on the lee side is precipitation.

Palaeo-ice surface, thickness and thinning rates spanning MIS3 to Termination I are presented based on 18 Be-10 exposure ages along three vertical transects over ~700m of relief. The results indicate a maximum ice thickness over MIS3 with progressive ice-lowering over MIS2 and small scale thickening at the end of the globally defined LGM. The palaeo-climatic implications will be discussed particularly with focus on SWW positioning and behaviour.