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.
Highlights
Along the Central Andes a pattern of vertical axis tectonic rotations has been paleomagnetically identified (e.g., Isacks, 1988; Beck, 1988; Dewey and Lamb, 1992; Somoza et al, 1996)
Paleogene and Neogene rotations detected in the Altiplano-Puna are of similar amount and comparable to Neogene rotations registered in the Eastern Cordillera and the Subandean Ranges (Table 1) (Figs. 3 and 4)
In the Altiplano-Puna, where deformation began later (~at 29 Ma) during E-W convergence, and maximum shortening rates were attained between 15 and 8 Ma, Paleogene and Neogene rocks recorded rotations of similar amount (~10°) (Fig. 3). This can be interpreted in terms that, in the Altiplano-Puna, Paleogene and Neogene rocks would have been exposed to deformation periods of similar duration and/or intensity or were exposed to a unique Neogene period of deformation, with minor strike slip component
Summary
Along the Central Andes a pattern of vertical axis tectonic rotations has been paleomagnetically identified (e.g., Isacks, 1988; Beck, 1988; Dewey and Lamb, 1992; Somoza et al, 1996). Models suggesting the existence of local block rotations in response to distributed shear have been proposed (e.g., Beck, 1988; Dewey and Lamb, 1992; Somoza et al, 1996; Beck, 1998) Such distributed shear would result from partitioning of the oblique convergence vector between the Nazca and South American plates into coast parallel and perpendicular components. Taylor et al (2005) noted that many of the rotations detected in the forearc of northern Chile are large and appear to record a rotational event older than those observed elsewhere in the Central Andes They argued that such data define a domain marked by large clockwise crustal rotations related to late Paleocene-Early Eocene highly oblique convergence. Taking into account the scarce number of deformation and exhumation studies available for the Northern Central Andes (specially north of 19°) (e.g., Barnes and Ehlers, 2009), we compiled the available cenozoic paleomagnetic data for the region extending between 19° and 27.5°S (Southern Central Andes)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
