Active layer studies in the Central Andes of Mendoza, Argentina

DARIO TROMBOTTO

Santa Barbara, California, USA

Simposio; The Tenth International Symposium on Antarctic and Earth Sciences (ISAES X); 2007

This contribution analyses different profiles of active layers in the Central Andes of Mendoza, Argentina, comparing them with samples of patterned cryosoils from King George Island, Antarctica. Temperature data of 2 sites (1989-2007) show the impact of global change in the active layer and suprapermafrost of the Dry Andes (32-33° S). These changes imply direct thermal and geomorphological consequences for the Andean creeping permafrost. The nose of the Morenas Coloradas rockglacier (Balcón I, 3560 m a.s.l.), already expresses inactivity; the permafrost table is found at great depth (7.5-7.8 m). On the other hand, calculated lower thermal diffusivity values (< 0.2 × 10-6 m2/s) may be decisive for the deduction of cryogenic dynamics and they could be correlated with occurrence of freezing at low altitudes. Cryogenic paleostructures of ice lenses and fragmoidic fabrics also show the former position of paleopermafrost.