Abstract

GOMEZ DACAL, Maria Laura; TOCHO, Claudia  and  ARAGON, Eugenio. Adaptation of a tridimensional gravimetric model to the north patagonian massif area. Geoacta [online]. 2013, vol.38, n.2, pp.153-167. ISSN 1852-7744.

The North Patagonian Massif is an almost undeformed plateau surrounded by basins with some degree of deformation from which it stands between 500 to 700 m. The massif suffered a sudden uplift of about 1200 m in the Paleogene, hypothetically, caused by epeirogenic movements. The latter affirmation is based on the presence of undeformed marine formational units in the massif, which show some degree of tertiary deformation in the surrounding basins. An adaptation of a tridimensional gravimetric model to the North Patagonian Massif area was made with the aim ofcharacterize this scarcely studied area that have interesting characteristics. To make the adaptation and analysis of the results, a tridimensional and interactive gravity and magnetic modeling software called IGMAS+ was used and the Bouguer anomaly data were extracted of the EGM2008 geopotential model. A difference between the calculated and the observed surfaces of -21 mGal in mean value can be observed in the original model for the study area. A new fit was made in the area, and a difference between surfaces of -5,4 mGal in mean value was achieved which was considerably better than the original model fit for the NPM. The Mohorovicic discontinuity of the model was extracted and mapped. A crust with a thick between 35 and 45 km could be observed in the massif area surrounded by lower thickness areas in its North, West and East limits. No information about the South limit is available since this area remained outside the original model.

Keywords : Macizo Norpatagónico; Modelado gravimétrico; Discontinuidad de Mohorovicic (MOHO).

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