Abstract

STRELIN, Jorge  and  MALAGNINO, Eduardo. Charles Darwin and the oldestglacial events in Patagonia: the erratic blocks of the Río Santa Cruz valley. Rev. Asoc. Geol. Argent. [online]. 2009, vol.64, n.1, pp.101-108. ISSN 0004-4822.

Althoughthe depositational environment assigned by Darwin to the large erratic blocksand gravels in the Río Santa Cruz valley has been reinterpreted, hisgeomorphological and stratigraphic observations are still in force. The largeerratic blocks he described as crowning the Condor Cliff terrace and spread atthe bottom of the valley just east of this locality (Sites 2 and 3), are nowinterpreted as indicators of the maximum glacial expansion in Patagonia.Similar blocks, though of a different lithology, accumulated over a lowerterrace located up-valley (Site 4), are now linked to moraines and glacifluvialterraces of the Penultimate Glaciation. Finally, in addition to the erraticblock discovered by Darwin in the lower Río Santa Cruz valley (Site 1), thereare others - recently discovered - which probably account for a catastrophicevent ascribed to a big glacier-lake outburst during the last interglacial.

Keywords : Patagonia; Glaciations; Moraines; Erratic blocks; Darwin.

        · abstract in Spanish     · text in English     · English ( pdf )