Kinematic variations across Eastern Cordillera at 24°S (Central Andes): tectonic and magmatic implications

Authors
Acocella, V.; Vezzoli, L.; Omarini, Ricardo Hector; Matteini, M.; Mazzuoli, R.
Publication Year
2007
Language
English
Format
article
Status
Published version
Description
The Eastern Cordillera (Central Andes, ∼ 24°S) consists of a basement-involved thrust system, resulting from Miocene-Quaternary eastward migrating compression, separating the Puna plateau from the Santa Barbara System foreland. The inferred Tertiary strains arising from shortening in the Eastern Cordillera and Santa Barbara System are similar, higher than in the Puna. Slip data collected on the major ∼ N-S trending faults of Eastern Cordillera show a westward progression from dip-slip (contraction) to dextral and sinistral motions. This, consistently with established tectonic models, may result from partitioning due to the oblique Mio-Quaternary underthrusting of the Brazilian Shield north of 24°S. This strain partitioning has three main implications. (1) As the dextral and sinistral shear in the Eastern Cordillera are ∼ 62% and 29% of the compressive strain respectively, the Eastern Cordillera results more strained than Santa Barbara System foreland, contrary to previous estimates. (2) The partitioning in the Eastern Cordillera may find its counterpart in that to the west of the Central Andes, giving a possible structural symmetry to the Central Andes. (3) The easternmost N-S strike-slip structures in the Eastern Cordillera coincide with the easternmost Mio-Pliocene magmatic centres in the Central Andes, at ∼ 24°S. Provided that, further to the east, the crust is partially molten, the absence of magmatic centres may be explained by the presence of pure compressive structures in this portion of the Eastern Cordillera.
Fil: Acocella, V.. Università Roma Tre; Italia
Fil: Vezzoli, L.. Università degli studi dell'Insubria; Italia
Fil: Omarini, Ricardo Hector. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Matteini, M.. Universidade do Brasília; Brasil
Fil: Mazzuoli, R.. Università degli Studi di Pisa; Italia
Subject
CENTRAL ANDES
COMPRESSIONAL TECTONICS
EASTERN CORDILLERA
STRAIN PARTITIONING
STRIKE-SLIP FAULTING
Geoquímica y Geofísica
Ciencias de la Tierra y relacionadas con el Medio Ambiente
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/78825