Genetic particularities of rock glaciers and protalus lobes in James Ross Island, Antarctic Peninsula

FLORES, ELISEO; SONE, TOSHIO; STRELIN, JORGE A; FUKUI, KOTARO; VACA, MATIAS

Incheon

Simposio; XIII International Symposium on Antarctic Earth Science; 2019

Scientific Committee on Antarctic Research (SCAR)

Rock glaciers and protalus lobes are considered common landforms in the non-glaciated areas of James Ross Island, northern Antarctic Peninsula. The formation and dynamics of these landforms are related to morphostructural and morphogenetic environmental conditions, being the most important the presence of basaltic mesas that provide the raw material for the debris cover of the rock glaciers and protalus lobes. In the case of rock glaciers, the morphogenetic conditions involve small polythermal glaciers that due to little temperature variations, subtle reduction in the precipitations, and/or changes in the intensity and direction of the main regional winds, become debris covered. An important factor related to the debris cover is the oscillation of the regelation front. Unlike the tongue-shaped rock glacier protalus lobes develop without direct relation to glaciers. The environment required for their formation comprises steep talus slopes, enough debris supply, and the presence of perennial or late-lying snow patches. At the foot of a mesa near the Whisky Bay a protalus lobe affected by thermal erosion and mass wasting was discovered, allowing description of the internal structure of this landform.The severe climatic warming verified in the last decades in the northern sector of Antarctic Peninsula accelerated the collapse of both of these landforms.