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Structure and metamorphism of the Gondwanan basement in the Bariloche region (North Patagonian Argentine Andes)

  • Joaquín García-SansegundoEmail author
  • P. Farias
  • G. Gallastegui
  • R. E. Giacosa
  • N. Heredia
Review Article

Abstract

In the Bariloche region, the Gondwanan basement consists of metamorphic and deformed igneous rocks intruded by Mesozoic and Tertiary granitoids. Metasediments and amphibolites have been affected by three main deformation events (D1, D2 and D3). D1 (S1 foliation) is well shown preserved in the microlithons of the S2 regional foliation and in albite and garnet porphyroblasts. Both foliations have been folded by upright open folds with associated crenulation (S3) locally developed in the D3 folds hinge zones. An early-stage (syn-D1) subduction episode can be invoked based on evidence of high pressure (HP) metamorphism in schists and amphibolites as well as on the presence of pre-collisional I-type granitoids. D2–D3 developed under regional intermediate pressure–low pressure (IP–LP) metamorphic conditions. High temperature (HT) conditions were reached, as deduced from regional migmatization and the intrusion of syn- to late-orogenic S-type granitoids. The transition from HP to IP metamorphic conditions could be associated with the emplacement of NE directed crustal-scale thrusts during D2.

Keywords

Gondwanan Orogen Patagonian Andes Structure Metamorphism 

Notes

Acknowledgments

We would like to thank M. A. S. Basei, W. von Gosen, F. Hervé, J. I. Gil-Ibarguchi, A. Marcos, R.J. Pankhurst, V. Ramos, J. Gallastegui and H. Stoll for their suggestions and comments. We especially appreciate the participation of A. Cuesta in the elaboration of this paper. Financial support was provided by DGCYT (General Direction of Science and Technology of the Spain Ministry of Education and Science); project BTE2002-04316-CO. This is a contribution to UNESCO/IUGS IGCP-471. This work is supported by the Consolider-Ingenio 2010 Programme, under project CSD2006-0041, “Topo-Iberia”.

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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Joaquín García-Sansegundo
    • 1
    Email author
  • P. Farias
    • 1
  • G. Gallastegui
    • 2
  • R. E. Giacosa
    • 3
  • N. Heredia
    • 2
  1. 1.Departamento de GeologíaUniversidad de OviedoOviedoSpain
  2. 2.Instituto Geológico y Minero de EspañaOviedoSpain
  3. 3.Servicio Geológico y Minero Argentino, Delegación ComahueGeneral RocaArgentina

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