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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Autores principales: Coutand, I., Diraison, M., Cobbold, P.R., Gapais, D., Rossello, E.A., Miller, M.
Formato: JOUR
Materias:
collision zone
convergent margin
kinematics
structural geology
tectonic setting
Tertiary
Patagonia
South America
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_08959811_v12_n1_p1_Coutand
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spelling todo:paper_08959811_v12_n1_p1_Coutand2023-10-03T15:42:29Z 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. collision zone convergent margin kinematics structural geology tectonic setting Tertiary Patagonia South America 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
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.
format JOUR
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 http://hdl.handle.net/20.500.12110/paper_08959811_v12_n1_p1_Coutand
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AT cobboldpr structureandkinematicsofafoothillstransectlagoviedmasouthernandes4930s
AT gapaisd structureandkinematicsofafoothillstransectlagoviedmasouthernandes4930s
AT rosselloea structureandkinematicsofafoothillstransectlagoviedmasouthernandes4930s
AT millerm structureandkinematicsofafoothillstransectlagoviedmasouthernandes4930s
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