Structure and evolution of the Fuegian Andes foreland thrust-fold belt, Tierra del Fuego, Argentina: Paleogeographic implications

PABLO TORRES CARBONELL; OLIVERO, EDUARDO B.; LUIS V. DIMIERI

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2008 vol. 25 p. 417 - 439

0895-9811

Field work in the frontal part of the foreland thrust-fold belt of the Fuegian Andes reveals complex relationships between stra- tigraphy and structure. Construction of balanced cross-sections allows us to infer the geometry and kinematics of structures con-tigraphy and structure. Construction of balanced cross-sections allows us to infer the geometry and kinematics of structures con- trolling the thrust-fold belt evolution. The sequential restoration of these cross-sections to their undeformed state reveals thetrolling the thrust-fold belt evolution. The sequential restoration of these cross-sections to their undeformed state reveals the architecture of the Austral foreland basin in relation to the evolving deformation front. This front was developed after incorpora-architecture of the Austral foreland basin in relation to the evolving deformation front. This front was developed after incorpora-  tion of the Paleocene?earliest Eocene foredeep of the basin to the thrust-fold belt. A wedge-top depozone formed over this formertion of the Paleocene?earliest Eocene foredeep of the basin to the thrust-fold belt. A wedge-top depozone formed over this former foredeep, bounded by the late-middle to late Eocene thrust front. The wedge-top basin was filled by a quartz-rich sandstone-dom-foredeep, bounded by the late-middle to late Eocene thrust front. The wedge-top basin was filled by a quartz-rich sandstone-dom-  inated succession of Andean provenance. The same succession filled the foredeep formed northwards of the deformation front,inated succession of Andean provenance. The same succession filled the foredeep formed northwards of the deformation front, active from late-middle Eocene. Further reactivation of the deformation led to backthrusting of the wedge-top clastic successionactive from late-middle Eocene. Further reactivation of the deformation led to backthrusting of the wedge-top clastic succession  in the late Eocene, and to subsequent foreland propagation of the deformation, manifested by a sequence of low angle thrusts thatin the late Eocene, and to subsequent foreland propagation of the deformation, manifested by a sequence of low angle thrusts that  affected the foredeep. The foredeep migrated forelandwards as the tectonic load advanced, to finally act as a passive depozone afteraffected the foredeep. The foredeep migrated forelandwards as the tectonic load advanced, to finally act as a passive depozone after  the earliest Miocene, when the propagation of the deformation front stopped. The paleogeographic reconstruction from late Paleo-the earliest Miocene, when the propagation of the deformation front stopped. The paleogeographic reconstruction from late Paleo-  cene to earliest Miocene shows a strong linkage between tectonics and sedimentation in the Atlantic coast of the frontal Fuegiancene to earliest Miocene shows a strong linkage between tectonics and sedimentation in the Atlantic coast of the frontal Fuegian  Andes.Andes.