XII Congreso Geológico Chileno Santiago, 22-26 Noviembre, 2009 S9_053 Neotectonics along the eastern flank of the North Patagonian Icefield, southern Chile: Cachet and Exploradores fault zones Melnick, D.1, Georgieva, V.1, Lagabrielle, Y.2, Jara, J.3, Scalabrino, B.2, Leidich, J.4 (1) Institute of Geosciences, University of Potsdam, 14476 Potsdam, Germany. (2) UMR 5243 Géosciences Montpellier, Université de Montpellier 2, France. (3) Departamento de Ciencias de la Tierra, Universidad de Concepción, Chile. (4) Patagonia Adventure Expeditions, Casilla 8, Cochrane, Chile.
[email protected] Introduction In the southern Andes, the North Patagonian Icefield (NPI) is a poorly-known region in terms of geology and neotectonics that marks a major topographic anomaly at the transition between the Austral and Patagonian Andes. The NPI is located immediately east of the Nazca-Antarctic-South America Triple Plate Junction, where the Chile Rise collides against the margin (Fig. 1A). Since 14 Ma, this Triple Junction has migrated northward as a result of oblique plate convergence, resulting in collision and subduction of two relatively short ridge segments in the Golfo de Penas region at 6 and 3 Ma, and at present of one segment immediately north of the Taitao Peninsula [1]. Oblique plate convergence in addition to collision of these ridge segments resulted in the formation of a forearc sliver, the Chiloe block, which is decoupled from the South American foreland by the Liquiñe-Ofqui fault zone. Here we present geomorphic and structural field evidence that indicates neotectonic activity in the internal part of the orogen, along the flanks of the NPI (Fig.