Abstract

VIOLANTE, Roberto A et al. Rasgos morfosedimentarios, procesos y evolución de la plataforma continental Argentina desde el último máximo glacial. Rev. Asoc. Geol. Argent. [online]. 2014, vol.71, n.2, pp.292-310. ISSN 0004-4822.

The argentine continental shelf is one of the more extensive shelves of the world, located in a geotectonic context dominated by a passive margin with sectors of active margins in the southernmost region. The large extension and low relief favored a deep modeling effect under the influence of the Quaternary transgressions and regressions that imprinted diverse morphosedimentary features. The postglacial transgression left the final imprint that can be recognized in the surface and subsurface characteristics, manifested in terraces at increasing depths offshore, genetically associated to variations in the velocity of the sea level rise as well as in evidences of paleocoastlines presently submerged. Diverse features show aspects of the pre-transgressive subaerial exposure during the Last Glacial Maximum, like relicts of fluvial networks, glacifluvial deposits and buried soil remains. The complex interaction among the processes involved influenced the distribution of sediments supplied to the shelf by the intense coastal erosion during the successive marine advances and retreats, as well as the sediment supply via eolian and fluvial activity. In this way the sedimentary cover of the shelf is characterized by terrigenous, relictic and palimpsestic facies. The features in the shelf break in transition to the slope demonstrate predominance of erosive activity produced by both coastal processes during lowstands and deep-water processes associated to the backward erosion related to the dynamic of submarine canyons, whereas the different disposition of the terraces in the bonaerensian and patagonian sectors of the shelf is associated to hydroisostatic readjustments.

Keywords : Continental margin; Postglacial; Sea-level fluctuations; Sedimentary processes; LGM.

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