Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina
The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect...
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todo:paper_02787407_v30_n1_p_Mulcahy2023-10-03T15:17:05Z Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina Mulcahy, S.R. Roeske, S.M. McClelland, W.C. Jourdan, F. Iriondo, A. Renne, P.R. Vervoort, J.D. Vujovich, G.I. Deformation Stratigraphy Tectonics Arc magmatism Cambrians Crustal shortening Ductile shear zone Ductile thrusts Northwest Argentina Ordovician Orogens Progressive deformation Shear zone Structural evolution Structural unit Synconvergent extension Terrane accretion Metamorphic rocks accretion Cambrian crustal shortening deformation geochronology Gondwana Ordovician orogeny petrology shear zone structural geology tectonic evolution terrane Argentina Precordillera The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect reveals that the Sierra de Pie de Palo preserves a middle to lower crustal ductile thrust complex consisting of individual structural units and not an intact ophiolite and cover sequence. Top-to-the-west thrusting occurred intermittently on discrete ductile shear zones from ∼515 to ∼417 Ma and generally propagated toward the foreland with progressive deformation. Ordovician crustal shortening and peak metamorphic temperatures in the central portion of the Sierra de Pie de Palo were synchronous with retro-arc shortening and magmatic flare-up within the Famatina arc. Accretion of the Precordillera terrane resulted in the end of arc flare-up and the onset of synconvergent extension by ∼439 Ma. Continued synextensional to postextensional convergence was accommodated along progressively lower grade shear zones following terrane accretion and the establishment of a new plate margin west of the Precordillera terrane. The results support models of Cordilleran orogens that link voluminous arc magmatism to periods of regional shortening. The deformation, metamorphic, and magmatic history within the Sierra de Pie de Palo is consistent with models placing the region adjacent to the Famatina margin in the middle Cambrian and not as basement to the Precordillera terrane. Copyright 2011 by the American Geophysical Union. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_02787407_v30_n1_p_Mulcahy |
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Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Deformation Stratigraphy Tectonics Arc magmatism Cambrians Crustal shortening Ductile shear zone Ductile thrusts Northwest Argentina Ordovician Orogens Progressive deformation Shear zone Structural evolution Structural unit Synconvergent extension Terrane accretion Metamorphic rocks accretion Cambrian crustal shortening deformation geochronology Gondwana Ordovician orogeny petrology shear zone structural geology tectonic evolution terrane Argentina Precordillera |
| spellingShingle |
Deformation Stratigraphy Tectonics Arc magmatism Cambrians Crustal shortening Ductile shear zone Ductile thrusts Northwest Argentina Ordovician Orogens Progressive deformation Shear zone Structural evolution Structural unit Synconvergent extension Terrane accretion Metamorphic rocks accretion Cambrian crustal shortening deformation geochronology Gondwana Ordovician orogeny petrology shear zone structural geology tectonic evolution terrane Argentina Precordillera Mulcahy, S.R. Roeske, S.M. McClelland, W.C. Jourdan, F. Iriondo, A. Renne, P.R. Vervoort, J.D. Vujovich, G.I. Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| topic_facet |
Deformation Stratigraphy Tectonics Arc magmatism Cambrians Crustal shortening Ductile shear zone Ductile thrusts Northwest Argentina Ordovician Orogens Progressive deformation Shear zone Structural evolution Structural unit Synconvergent extension Terrane accretion Metamorphic rocks accretion Cambrian crustal shortening deformation geochronology Gondwana Ordovician orogeny petrology shear zone structural geology tectonic evolution terrane Argentina Precordillera |
| description |
The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect reveals that the Sierra de Pie de Palo preserves a middle to lower crustal ductile thrust complex consisting of individual structural units and not an intact ophiolite and cover sequence. Top-to-the-west thrusting occurred intermittently on discrete ductile shear zones from ∼515 to ∼417 Ma and generally propagated toward the foreland with progressive deformation. Ordovician crustal shortening and peak metamorphic temperatures in the central portion of the Sierra de Pie de Palo were synchronous with retro-arc shortening and magmatic flare-up within the Famatina arc. Accretion of the Precordillera terrane resulted in the end of arc flare-up and the onset of synconvergent extension by ∼439 Ma. Continued synextensional to postextensional convergence was accommodated along progressively lower grade shear zones following terrane accretion and the establishment of a new plate margin west of the Precordillera terrane. The results support models of Cordilleran orogens that link voluminous arc magmatism to periods of regional shortening. The deformation, metamorphic, and magmatic history within the Sierra de Pie de Palo is consistent with models placing the region adjacent to the Famatina margin in the middle Cambrian and not as basement to the Precordillera terrane. Copyright 2011 by the American Geophysical Union. |
| format |
JOUR |
| author |
Mulcahy, S.R. Roeske, S.M. McClelland, W.C. Jourdan, F. Iriondo, A. Renne, P.R. Vervoort, J.D. Vujovich, G.I. |
| author_facet |
Mulcahy, S.R. Roeske, S.M. McClelland, W.C. Jourdan, F. Iriondo, A. Renne, P.R. Vervoort, J.D. Vujovich, G.I. |
| author_sort |
Mulcahy, S.R. |
| title |
Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| title_short |
Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| title_full |
Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| title_fullStr |
Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| title_full_unstemmed |
Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina |
| title_sort |
structural evolution of a composite middle to lower crustal section: the sierra de pie de palo, northwest argentina |
| url |
http://hdl.handle.net/20.500.12110/paper_02787407_v30_n1_p_Mulcahy |
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