Preandean geological configuration of the eastern North Patagonian Massif, Argentina

DANIEL A. GREGORI A, JOSÉ KOSTADINOFF, GUILLERMINA ALVAREZ, ARIEL RANIOLO, LEONARDO STRAZZERE, JUAN C. MARTÍNEZ, MERCEDES BARROS

Geoscience Frontiers

Elsevier

Lugar: Beijing; Año: 2013 vol. 4 p. 693 - 708

1674-9871

The Preandean geological configuration of the eastern North PatagonianMassif is established through the useof geological and geophysical analysis. The positive gravity anomalies located near theAtlantic coast are due to535 and 540 Ma old rocks belonging to the Pampean Orogeny (Precambrianemiddle Cambrian), which arewidely recognized in central and northern Argentina. The Famatinian Cycle (OrdovicianeDevonian) is representedby a SilurianeDevonian marine basin equivalent to those of eastern-central Argentina and SouthAfrica, andwhichwas deformed at the end of the Devonian by anwEeWtoWNWeESE compressional event,part of the Famatinian Orogeny. Containing strong gravity gradients, the NWeSE belt is coincident with faultzones which were originated during the Gondwanide Orogeny. This event also produced NWeSE overthrustingofthe SilurianeDevoniansequences andstrike-slipfaults thatdisplacedblocks in the samedirection.This deformation event belongs to the Gondwanide Orogeny that includes movements related to a counterclockwiserotation of blocks in northern Patagonia. The strong negative anomalies located in thewestern partof the area stem from the presence of rocks of the Jurassic Cañadón Asfalto basin interbedded in the MarifilComplex. These volcaniclastic sequences show mild deformation of accommodation zones in a pre-Jurassicpaleorelief.