IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
First reconstruction of the LGM Patagonian Ice Sheet geometry in the Wet Andes (41.5°S-43°S) of Argentina: Paleogeographic and paleoclimatic implications.
Autor/es:
RUIZ L.; TROMBOTTO, DARIO.; VILLALBA, RICARDO.
Lugar:
Uspallata
Reunión:
Congreso; IAI Collaborative Research Network 2047B Science Meeting; 2013
Institución organizadora:
IAI
Resumen:
We present the first reconstruction of the Last Glacial Maximum (LGM) ice-surface geometry for the eastern Wet Andes (41.5°S to 43°S) of Argentina. The reconstruction is based on detailed mapping of glacier trimlines together with ice-erosional and depositional glacial landforms. Field and remote sensing data provide evidence of the LGM ice-surface elevations and ice-flow directions. The LGM ice surface is portrayed as a grid-format digital elevation model (DEM) using a ?perfectly plastic? glacier model that reconstructs ice thickness in combination with geographic information system (GIS) tools. The accumulation area ratio (AAR) method was used to reconstruct the equilibrium line altitude (ELA) for glaciers during the LGM.Geomorphological and paleo-ice flow evidence indicate that the glacier flows from the LGM Patagonian ice sheet was more complex than previously thought. The LGM Patagonian ice sheet can be divided into three different parts. The innermost zone was characterized by multiple-discontinuous ice divides drained by ice tributaries. The central area was characterized by glaciers discharging through deep bedrock channels with ice thicknesses around 1500 to 2000m. The outer or marginal area was characterized by low-surface-gradient piedmont glacier lobes. The size (area and length) of the glaciers during the LGM in the study area is comparable to the biggest present-day glaciers in the Southern Patagonian Ice Field in the Andes or the Wrangell-Saint Elias Ice Field in Alaska. The ELA reconstruction indicates an ELA depression of ~650 m for the LGM, similar to values previously reported for other regions in the Patagonian Andes.