Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S)
The western edge of Patagonia, south of 47°S, experienced a major tectonic reorganization during the Tertiary. The Chile ridge, separating Nazca from Antarctica, collided obliquely with western Tierra del Fuego at about 14 Ma and the triple point migrated northwards to its present position at about...
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ftunibueairesbd:todo:paper_08959811_v12_n1_p1_Coutand 2023-10-29T02:31:58+01:00 Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) Coutand, I. Diraison, M. Cobbold, P.R. Gapais, D. Rossello, E.A. Miller, M. https://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand unknown http://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar collision zone convergent margin kinematics structural geology tectonic setting Tertiary Patagonia South America JOUR ftunibueairesbd https://doi.org/20.500.12110/paper_08959811_v12_n1_p1_Coutand 2023-10-05T01:18:03Z The western edge of Patagonia, south of 47°S, experienced a major tectonic reorganization during the Tertiary. The Chile ridge, separating Nazca from Antarctica, collided obliquely with western Tierra del Fuego at about 14 Ma and the triple point migrated northwards to its present position at about 47°S. Consequently, the southern tip of South America has passed from a Miocene context of rapid oblique convergence (ENE-WSW at about 9 cm/yr) between Nazca and South America, to a Pliocene context of slow frontal convergence (EW at about 2 cm/yr) between Antarctica and South America. The Andean foreland fold-and-thrust belt lies on the eastern side of the Patagonian Cordillera and is well exposed along the northern shore of Lago Viedma (49°30'S). Structural observations, digital mapping, subsurface data, balancing of a cross-section and kinematic analysis of fault populations provide new information on the structure of the fold-and-thrust belt, the timing and style of deformation and their relationship with Tertiary plate tectonics. Along the studied transect, synsedimentary structures show that compressional deformation began at least during the Late Cretaceous, was ongoing during the syntectonic emplacement of the Lower Miocene granitic Monte Fitz Roy pluton and continued into the Pliocene. Folds and thrusts are thick-skinned in the west, and mostly thin-skinned above a decollement in Early Cretaceous black shales in the east. Analysis of fault populations, measured within Jurassic basement and its Cretaceous cover, provides subhorizontal principal directions of shortening, striking between E-W and ENE-WSW. Compressional deformation was associated with a major component of right-lateral wrenching parallel to the Cordillera. Fil:Rossello, E.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Miller, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Journal/Newspaper Antarc* Antarctica Tierra del Fuego Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) |
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Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) |
op_collection_id |
ftunibueairesbd |
language |
unknown |
topic |
collision zone convergent margin kinematics structural geology tectonic setting Tertiary Patagonia South America |
spellingShingle |
collision zone convergent margin kinematics structural geology tectonic setting Tertiary Patagonia South America Coutand, I. Diraison, M. Cobbold, P.R. Gapais, D. Rossello, E.A. Miller, M. Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
topic_facet |
collision zone convergent margin kinematics structural geology tectonic setting Tertiary Patagonia South America |
description |
The western edge of Patagonia, south of 47°S, experienced a major tectonic reorganization during the Tertiary. The Chile ridge, separating Nazca from Antarctica, collided obliquely with western Tierra del Fuego at about 14 Ma and the triple point migrated northwards to its present position at about 47°S. Consequently, the southern tip of South America has passed from a Miocene context of rapid oblique convergence (ENE-WSW at about 9 cm/yr) between Nazca and South America, to a Pliocene context of slow frontal convergence (EW at about 2 cm/yr) between Antarctica and South America. The Andean foreland fold-and-thrust belt lies on the eastern side of the Patagonian Cordillera and is well exposed along the northern shore of Lago Viedma (49°30'S). Structural observations, digital mapping, subsurface data, balancing of a cross-section and kinematic analysis of fault populations provide new information on the structure of the fold-and-thrust belt, the timing and style of deformation and their relationship with Tertiary plate tectonics. Along the studied transect, synsedimentary structures show that compressional deformation began at least during the Late Cretaceous, was ongoing during the syntectonic emplacement of the Lower Miocene granitic Monte Fitz Roy pluton and continued into the Pliocene. Folds and thrusts are thick-skinned in the west, and mostly thin-skinned above a decollement in Early Cretaceous black shales in the east. Analysis of fault populations, measured within Jurassic basement and its Cretaceous cover, provides subhorizontal principal directions of shortening, striking between E-W and ENE-WSW. Compressional deformation was associated with a major component of right-lateral wrenching parallel to the Cordillera. Fil:Rossello, E.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Miller, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. |
format |
Journal/Newspaper |
author |
Coutand, I. Diraison, M. Cobbold, P.R. Gapais, D. Rossello, E.A. Miller, M. |
author_facet |
Coutand, I. Diraison, M. Cobbold, P.R. Gapais, D. Rossello, E.A. Miller, M. |
author_sort |
Coutand, I. |
title |
Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
title_short |
Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
title_full |
Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
title_fullStr |
Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
title_full_unstemmed |
Structure and kinematics of a foothills transect, Lago Viedma, southern Andes (49°30'S) |
title_sort |
structure and kinematics of a foothills transect, lago viedma, southern andes (49°30's) |
url |
https://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand |
genre |
Antarc* Antarctica Tierra del Fuego |
genre_facet |
Antarc* Antarctica Tierra del Fuego |
op_relation |
http://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar |
op_doi |
https://doi.org/20.500.12110/paper_08959811_v12_n1_p1_Coutand |
_version_ |
1781052888517181440 |