Resumo

PERUCCA, Laura P.  e  MARTOS, Liliana M.. Preliminary analysis of the Quaternary landscape evolution in the Iglesia Valley, San Juan. Rev. Asoc. Geol. Argent. [online]. 2009, vol.65, n.4, pp.624-637. ISSN 0004-4822.

The north-south valley of Iglesia is a regional tectonic depression limited to the west by the Cordillera Frontal and to the east by western Precordillera. The geoforms of the resulting landscape are related to glacial, periglacial, fluvial and alluvial action, aggradational and deggradational processes, as well as to the neotectonic activity and climatic changes. The generation of large Quaternary alluvial fan levels is related to past climatic conditions, colder and more humid that the present ones. Abundant snowfalls and rains during the Pleistocene made possible the detritus deposition, generating alluvial covers with thickness increasing towards the east. These climatic conditions alternated with arid intervals, similar to the present, when vertical erosion of streams prevailed, forming a landscape of stepped levels. In addition, the presence of faults with Quaternary tectonic activity indicates a strong structural control in the evolution of the landscape during the Pleistocene - Holocene, effectively starting vertical erosion and finishing a cycle of erosion-accumulation and the beginning of the following one.

Palavras-chave : Geomorphology; Neotectonic; Alluvial levels; Landscape; Iglesia.

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