U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates

The Toro Negro Formation is a foreland sequence in western La Rioja province, Argentina, which records the late-stage tectonic evolution of the Vinchina Basin. Together with the underlying Vinchina Formation, these two units represent one of the thickest and longest continually exposed foreland sect...

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Autores principales:	Ciccioli, Patricia Lucía, Marenssi, Sergio Alfredo, Limarino, Carlos Oscar
Publicado:	2016
Materias:	Bermejo Famatina Fiambala Precordillera Tephra U-Pb Valle Fertil Vinchina Zircon age determination Miocene Pleistocene provenance tectonic evolution tephra uranium-lead dating zircon Argentina La Rioja [Argentina]
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v70_n_p237_Amidon http://hdl.handle.net/20.500.12110/paper_08959811_v70_n_p237_Amidon
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	paper:paper_08959811_v70_n_p237_Amidon2023-06-08T15:48:54Z U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates Ciccioli, Patricia Lucía Marenssi, Sergio Alfredo Limarino, Carlos Oscar Bermejo Famatina Fiambala Precordillera Tephra U-Pb Valle Fertil Vinchina Zircon age determination Miocene Pleistocene provenance tectonic evolution tephra uranium-lead dating zircon Argentina La Rioja [Argentina] The Toro Negro Formation is a foreland sequence in western La Rioja province, Argentina, which records the late-stage tectonic evolution of the Vinchina Basin. Together with the underlying Vinchina Formation, these two units represent one of the thickest and longest continually exposed foreland sections in northwest Argentina. The Vinchina basin is uniquely situated between the Toro Negro and Umango blocks of the Western Sierra Pampeanas to the north and south, the Precordillera to the west, and the Sierra de Famatina to the east. New U-Pb dating of volcanic tephra provides improved age constraints on the pace of sedimentation, and U-Pb ages of detrital zircons serve to strengthen existing provenance interpretations. We show that deposition of the Toro Negro Formation spans roughly 6.9 to 2.3 Ma: Late Miocene to Early Pleistocene. A high-relief, erosional unconformity with the underlying Vinchina Formation developed sometime between 9.3 and 6.9 Ma, although stratigraphic considerations suggest it spanned only the later part of this time interval (perhaps 7.5-6.9 Ma). Above this unconformity, undecompacted sedimentation rates are remarkably high at ~1.2 mm/yr, slowing to ~0.3 mm/yr after ~6 Ma. An unconformity in the upper part of the section is constrained to occur sometime between 5.0 and 3.0 Ma, probably beginning not long after 5.0 Ma. The timing of both unconformities broadly Matches the timing of inferred tectonic events in the Sierra Famatina ~50 km to the east, the Fiambalá basin to the north, and the Bermejo basin to the south, suggesting they May record regional tectonism at these times. Provenance interpretations of detrital zircon spectra are consistent with previous interpretations based on sediment petrography. They show that provenance did not change significantly during the course of Toro Negro deposition, precluding major tectonically-induced drainage reorganization events. Sediments were derived primarily from the north (Toro Negro Block) and west (Precordillera). The data are consistent with a subtle increase in sediment supply from the Precordillera beginning around 6.5 Ma. © 2016 . Fil:Ciccioli, P.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Marenssi, S.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Limarino, C.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v70_n_p237_Amidon http://hdl.handle.net/20.500.12110/paper_08959811_v70_n_p237_Amidon
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Bermejo Famatina Fiambala Precordillera Tephra U-Pb Valle Fertil Vinchina Zircon age determination Miocene Pleistocene provenance tectonic evolution tephra uranium-lead dating zircon Argentina La Rioja [Argentina]
spellingShingle	Bermejo Famatina Fiambala Precordillera Tephra U-Pb Valle Fertil Vinchina Zircon age determination Miocene Pleistocene provenance tectonic evolution tephra uranium-lead dating zircon Argentina La Rioja [Argentina] Ciccioli, Patricia Lucía Marenssi, Sergio Alfredo Limarino, Carlos Oscar U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
topic_facet	Bermejo Famatina Fiambala Precordillera Tephra U-Pb Valle Fertil Vinchina Zircon age determination Miocene Pleistocene provenance tectonic evolution tephra uranium-lead dating zircon Argentina La Rioja [Argentina]
description	The Toro Negro Formation is a foreland sequence in western La Rioja province, Argentina, which records the late-stage tectonic evolution of the Vinchina Basin. Together with the underlying Vinchina Formation, these two units represent one of the thickest and longest continually exposed foreland sections in northwest Argentina. The Vinchina basin is uniquely situated between the Toro Negro and Umango blocks of the Western Sierra Pampeanas to the north and south, the Precordillera to the west, and the Sierra de Famatina to the east. New U-Pb dating of volcanic tephra provides improved age constraints on the pace of sedimentation, and U-Pb ages of detrital zircons serve to strengthen existing provenance interpretations. We show that deposition of the Toro Negro Formation spans roughly 6.9 to 2.3 Ma: Late Miocene to Early Pleistocene. A high-relief, erosional unconformity with the underlying Vinchina Formation developed sometime between 9.3 and 6.9 Ma, although stratigraphic considerations suggest it spanned only the later part of this time interval (perhaps 7.5-6.9 Ma). Above this unconformity, undecompacted sedimentation rates are remarkably high at ~1.2 mm/yr, slowing to ~0.3 mm/yr after ~6 Ma. An unconformity in the upper part of the section is constrained to occur sometime between 5.0 and 3.0 Ma, probably beginning not long after 5.0 Ma. The timing of both unconformities broadly Matches the timing of inferred tectonic events in the Sierra Famatina ~50 km to the east, the Fiambalá basin to the north, and the Bermejo basin to the south, suggesting they May record regional tectonism at these times. Provenance interpretations of detrital zircon spectra are consistent with previous interpretations based on sediment petrography. They show that provenance did not change significantly during the course of Toro Negro deposition, precluding major tectonically-induced drainage reorganization events. Sediments were derived primarily from the north (Toro Negro Block) and west (Precordillera). The data are consistent with a subtle increase in sediment supply from the Precordillera beginning around 6.5 Ma. © 2016 .
author	Ciccioli, Patricia Lucía Marenssi, Sergio Alfredo Limarino, Carlos Oscar
author_facet	Ciccioli, Patricia Lucía Marenssi, Sergio Alfredo Limarino, Carlos Oscar
author_sort	Ciccioli, Patricia Lucía
title	U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
title_short	U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
title_full	U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
title_fullStr	U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
title_full_unstemmed	U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates
title_sort	u-pb ages of detrital and volcanic zircons of the toro negro formation, northwestern argentina: age, provenance and sedimentation rates
publishDate	2016
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v70_n_p237_Amidon http://hdl.handle.net/20.500.12110/paper_08959811_v70_n_p237_Amidon
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U-Pb ages of detrital and volcanic zircons of the Toro Negro Formation, northwestern Argentina: Age, provenance and sedimentation rates

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