Mass-wasting processes and associated landforms in the Fuegian Andes of Argentina

Abstract

The occurrence of mass wasting processes in the Fuegian Andes is linked to its distinctive geological, structural, geomorphological, geographical and climatic characteristics respective to the rest of the Andes. These include: (i) the transform boundary between the South American plate and the Scotia plate with active seismicity; (ii) east-west-oriented mountain ranges composed predominantly of metamorphic rocks overlain by friable glaciogenic sediments; iii) a large area recently deglaciated since the Last Glacial Maximum; iv) a cold and humid oceanic climate resulting from its insular position at the southern end of the mid-latitudes. Together, these factors promote the occurrence of translational and rotational slides, debris flows, debris avalanches, rock falls, solifluction processes and snow avalanches all of which pose diverse natural hazards to the population and infrastructure of southern Isla Grande of Tierra del Fuego. Due to their active role in erosion, transport and deposition of debris and rocks, geomorphological impact, and historical damage in the region, snow avalanches are also considered within the scope of mass-wasting processes in this study. We describe the main types of mass-wasting processes identified in the Argentine sector of the Fuegian Andes and discuss the primary conditioning and triggering factors, highlighting representative examples of each.