The southern Central Andes rotation pattern

PREZZI, C.B.; IGLESIA LLANOS, MARÍA PAULA

ANDEAN GEOLOGY

SERVICIO NACIONAL GEOLOGIA MINERVA

Lugar: Santiago de Chile; Año: 2012 vol. 39 p. 279 - 294

0718-7092

ABSTRACT. Along the Central Andes a pattern of vertical axis tectonic rotations has been paleomagnetically identified. Such rotations are counterclockwise north of Arica Deflection (~19° S) and clockwise to the south. Different hypothesis and models have been proposed to explain the Central Andean Rotation Pattern (CARP). However, the CARP is a subject of ongoing debate. Recently, the quantity, quality, and geographic distribution of paleomagnetic data have expanded greatly. The increased paleomagnetic data set has been accompanied by an increase in the current knowledge of the deformation periods in the Andes, allowing a more detailed analysis of the temporal and spatial distribution of the detected rotations. We compiled and analyzed the available Cenozoic paleomagnetic data for the region extending between 19° and 27.5° S. The results suggest the possible existence of different rotational domains with distinct characteristics. Particularly, paleogene rocks in northern Chile and Eastern Cordillera recorded large rotations.  We propose that in the Southern Central Andes, a close correlation would exist between the temporal and spatial pattern of deformation and the magnitude of recorded vertical axis rotations. However, in order to further investigate such relationship, new paleomagnetic studies are necessary, particularly in the Eastern Cordillera domain, in paleogene rocks cropping out in the Altiplano-Puna and in Neogene rocks of the forearc.