"Untersuchungen zum periglazialen Formenschatz und zu periglazialen Sedimenten in der 'Lagunita del Plata', Mendoza, Argentinien". ("Investigaciones sobre geoformas y sedimentos periglaciales en la 'Lagunita del Plata', Mendoza, Argentina")

DARIO TROMBOTTO

Selbsverlag des Geographischen Instituts der Universität Heidelberg

Lugar: Heidelberg, Germany; Año: 1991 p. 171

3-88570-090-5

The “Lagunita del Plata” is a cryogenic semiarid area located on a plateau in the Cordillera Frontal, Central Andes, Argentina. The estimated mean annual temperature and precipitation in this altitude is around –2 °C and about 650 mm. Petrology is represented by carbonic greywacke rocks intruded by granite from the lower Trias. Regional faults as well as dynamometamorphism are important geological characteristics for cryometeorization. The periglacial level begins at a height of 3500 m a.s. The lower limit of the snow patches on the south-exposed slopes is found at 4300 m a.s. Temperature measurements of air and soil were carried out. From these data and seismic investigations we deduce insular permafrost on the cryoplanation terraces and near the south facing slopes at a depth of approximately 1 m. The following relevant micro-and mesoforms are described: tors, patterned grounds, solifluction-lobes and terraces, detritic slopes and boulder fields, Richter denudation slopes, avalanche channels, cryoplanation surfaces and rock glaciers. Complex processes of sorting, cryoturbation, nivation or simple cryoclastism determine the genesis and variety of the geoforms mentioned above. The analysis of the quartz grain surface from cryosediments reflects the different cryogenic physicochemical conditions of the environment. The understanding of certain phenomena was backed by laboratory experiments.