Coupled Slope Collapse—Cryogenic Processes in Deglaciated Valleys of the Aconcagua Region, Central Andes

Abstract

This paper presents coupled geomorphological processes such as glacial advances, gravitational collapses, and solifluction engaged to the environment climate changes. Complex landslides with a puzzling classification were identified by a landslide inventory of the Aconcagua Park involving the highest peak of South America (Aconcagua peak 6958 m a.s.l.). These deformed deposits were interpreted as gravitational collapsed moraines occurred after the Holocene-Pleistocene ice retreat on these Andean valleys. The stabilized huge masses began to be partially remobilized by solifluction phenomena generating protalus ramparts. At present well developed debris rock glaciers are established at the top landslide surfaces. This finding confirms glacial/interglacial cycles in the Central Andes are related to glacial advances supported by preserved moraines and gravitational collapses caused by ice loss during glacial retreat. However, the occurrence of cryogenic processes after collapse could evidence a periglacial environment restoration linked to a colder period. Therefore, available debris/sediments infilling deglaciated valleys will be mainly mobilized by glaciers, slope collapses or periglacial processes depending on the climate environment conditions.