The Southern Central Andes vertical axis tectonic rotations: relations with the deformation pattern

Abstract

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. Such expansion has been accompanied by an increase in the 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. We propose that in the Southern Central Andes, a close correlation would exist between the style and the temporal and spatial pattern of deformation and the amount 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.

New paleomagnetic data from Upper Oligocene–Lower Miocene rocks of the Northern Argentine Puna–Southern Bolivian Altiplano: Constraining the age of vertical axis rotations

“…2009), allowing a more detailed analysis of the temporal and spatial distribution of the detected rotations. Prezzi and Iglesia Llanos (2012) highlighted that for the region extending between 19 • and 27.5 • S (Southern Central Andes) rotations detected in Paleogene and Neogene rocks from the Altiplano-Puna would be of similar amount and comparable to rotations recorded in Neogene rocks from the Eastern Cordillera and the Subandean Ranges. On the other hand, rotations recorded by Paleogene rocks in northern Chile and Eastern Cordillera would be larger than the ones recorded by Neogene rocks in these regions and elsewhere (Prezzi and Iglesia Llanos, 2012).…”

“…Prezzi and Iglesia Llanos (2012) highlighted that for the region extending between 19 • and 27.5 • S (Southern Central Andes) rotations detected in Paleogene and Neogene rocks from the Altiplano-Puna would be of similar amount and comparable to rotations recorded in Neogene rocks from the Eastern Cordillera and the Subandean Ranges. On the other hand, rotations recorded by Paleogene rocks in northern Chile and Eastern Cordillera would be larger than the ones recorded by Neogene rocks in these regions and elsewhere (Prezzi and Iglesia Llanos, 2012). These data suggest that a close correlation would exist between the time-space distribution of deformation, and the amount of recorded vertical axis rotations in the Southern Central Andes.…”