Preandean geological configuration of the eastern North Patagonian Massif, Argentina

DANIEL ALFREDO GREGORI; KOSTADINOFF, J.; ALVAREZ, G.; RANIOLO, A.,; STRAZZERE, L.; MARTINEZ, JUAN C.; BARROS, M.

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 use of geological and geophysical analysis. The positive gravity anomalies located near theAtlantic coast are due to 535 and 540 Ma old rocks belonging to the Pampean Orogeny (Precambrianemiddle Cambrian), which are widely recognized in central and northern Argentina. The Famatinian Cycle (OrdovicianeDevonian) is represented by a SilurianeDevonian marine basin equivalent to those of eastern-central Argentina and South Africa, 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 fault zones which were originated during the Gondwanide Orogeny. This event also produced NWeSE overthrustingof the SilurianeDevoniansequences andstrike-slip faults thatdisplacedblocks in the same direction. This deformation event belongs to the Gondwanide Orogeny that includes movements related to a counterclockwise rotation of blocks in northern Patagonia. The strong negative anomalies located in thewestern part of the area stem from the presence of rocks of the Jurassic Cañadón Asfalto basin interbedded in the Marifil Complex. These volcaniclastic sequences show mild deformation of accommodation zones in a pre-Jurassic paleorelief.