Portal de Periódicos da CAPES

Glaciar León, Chilean Patagonia: late-Holocene chronology and geomorphology

2008; SAGE Publishing; Volume: 18; Issue: 4 Linguagem: Inglês

10.1177/0959683607086771

1477-0911

Stephan Harrison, Neil F. Glasser, Vanessa Winchester, Eleanor Haresign, Charles R. Warren, G.A.T. Duller, Richard M. Bailey, Susan Ivy‐Ochs, Krister N. Jansson, Peter W. Kubik,

Climate change and permafrost

Glaciar León is a temperate, grounded outlet of the eastern North Patagonian Icefield (NPI). It terminates at an active calving margin in Lago Leones, a 10 km long proglacial lake. We take a multidisciplinary approach to its description and use ASTER imagery and clast sedimentology to describe the geomorphology of the glacier and its associated moraines. We date periods of glacier retreat over the last 2500 years using a combination of lichenometric, dendrochronological, cosmogenic and optically stimulated luminescence techniques and show that the glacier receded from a large terminal moraine complex some 2500 years ago and underwent further significant recession from nineteenth-century moraine limits. The moraine dates indicate varying retreat rates, in conjunction with significant downwasting. The bathymetry of Lago Leones is characterized by distinct ridges interpreted as moraine ridges that dissect the lake into several basins, with water depths reaching 360 m. The fluctuations of Glaciar León appear to have been controlled by the interplay between climatic forcing and calving dynamics.