Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index

The thermal post-depositional evolution of metapelitic and metavolcanic rocks of the upper Cambrian-Ordovician succession in the Central Andes of northwestern Argentina, was estimated through X ray diffraction of clay mineral analysis, Kübler Index (KI), SEM-EDS study of selected samples and chlorit...

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Autores principales: do Campo, M., Nieto, F., Albanesi, G.L., Ortega, G., Rubén Monaldi, C.
Formato: JOUR
Materias:
Chlorite
Geothermometry
Low-grade metamorphism
Retrodiagenesis
chlorite
clay mineral
deposition
diagenesis
geothermometry
low grade metamorphism
metapelite
metavolcanic rock
Ordovician
sediment
Argentina
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_07187092_v44_n2_p179_doCampo
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_07187092_v44_n2_p179_doCampo2023-10-03T15:36:45Z Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index do Campo, M. Nieto, F. Albanesi, G.L. Ortega, G. Rubén Monaldi, C. Chlorite Geothermometry Low-grade metamorphism Retrodiagenesis chlorite clay mineral deposition diagenesis geothermometry low grade metamorphism metapelite metavolcanic rock Ordovician sediment Argentina The thermal post-depositional evolution of metapelitic and metavolcanic rocks of the upper Cambrian-Ordovician succession in the Central Andes of northwestern Argentina, was estimated through X ray diffraction of clay mineral analysis, Kübler Index (KI), SEM-EDS study of selected samples and chlorite geothermometry. The study area comprise five representative regions in Puna and Cordillera Oriental, namely at Sierra de Santa Victoria (Nazareno and Santa Victoria river areas), Cordón de los Siete Hermanos (Yavi), Sierra de Rinconada and Sierra de Cochinoca-Escaya. The paleotemperatures obtained with the chlorite geothermometer, in coincidence with KI values, show an E-W trend from diagenesis/low anchizone in the eastern flank of Sierra de Santa Victoria, to high anchizone/epizone in the Puna, with intermediate values in the western flank of Sierra de Santa Victoria. This trend, in conjunction with the development of slaty cleavage in the Ordovician rocks from Yavi, Sierra de Cochinoca-Escaya and western localities coincide with the limits proposed for the “Ocloyic deformation belt”. The common occurrence of kaolinite in the slates and the metavolcanic rocks of Sierra de Cochinoca-Escaya, coupled with the substitution of chlorite by interstratified lower-temperature phases in most of these rocks and the occurrence of jarosite in a metadacite, indicate presence of hydrothermal fluids with high H+/cations ratios, producing acid type alteration (Utada, 1980), at temperatures between 100 and ~300 °C. The hydrothermal alteration should have been subsequent to the maximum burial and the attainment of epizonal metamorphism, and was very probably related with the posthumous activity of the Ordovician volcanic arc. The widespread occurrence of retrograde diagenesis products (smectite, kaolinite, as well as interstratified Chl/Sm and Chl/Vrm phases) in the anchizonal/epizonal metapelites of Sierra de Cochinoca-Escaya and Sierra de Rinconada constitute, up to our knowledge, the first report of an extensive hydrothermal activity affecting not only the metavolcanic rocks but also the Lower Ordovician sediments of northern Puna. © 2017, Servicio Nacional de Geologia y Mineria. All rights reserved. Fil:do Campo, 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_07187092_v44_n2_p179_doCampo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Chlorite
Geothermometry
Low-grade metamorphism
Retrodiagenesis
chlorite
clay mineral
deposition
diagenesis
geothermometry
low grade metamorphism
metapelite
metavolcanic rock
Ordovician
sediment
Argentina
spellingShingle Chlorite
Geothermometry
Low-grade metamorphism
Retrodiagenesis
chlorite
clay mineral
deposition
diagenesis
geothermometry
low grade metamorphism
metapelite
metavolcanic rock
Ordovician
sediment
Argentina
do Campo, M.
Nieto, F.
Albanesi, G.L.
Ortega, G.
Rubén Monaldi, C.
Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
topic_facet Chlorite
Geothermometry
Low-grade metamorphism
Retrodiagenesis
chlorite
clay mineral
deposition
diagenesis
geothermometry
low grade metamorphism
metapelite
metavolcanic rock
Ordovician
sediment
Argentina
description The thermal post-depositional evolution of metapelitic and metavolcanic rocks of the upper Cambrian-Ordovician succession in the Central Andes of northwestern Argentina, was estimated through X ray diffraction of clay mineral analysis, Kübler Index (KI), SEM-EDS study of selected samples and chlorite geothermometry. The study area comprise five representative regions in Puna and Cordillera Oriental, namely at Sierra de Santa Victoria (Nazareno and Santa Victoria river areas), Cordón de los Siete Hermanos (Yavi), Sierra de Rinconada and Sierra de Cochinoca-Escaya. The paleotemperatures obtained with the chlorite geothermometer, in coincidence with KI values, show an E-W trend from diagenesis/low anchizone in the eastern flank of Sierra de Santa Victoria, to high anchizone/epizone in the Puna, with intermediate values in the western flank of Sierra de Santa Victoria. This trend, in conjunction with the development of slaty cleavage in the Ordovician rocks from Yavi, Sierra de Cochinoca-Escaya and western localities coincide with the limits proposed for the “Ocloyic deformation belt”. The common occurrence of kaolinite in the slates and the metavolcanic rocks of Sierra de Cochinoca-Escaya, coupled with the substitution of chlorite by interstratified lower-temperature phases in most of these rocks and the occurrence of jarosite in a metadacite, indicate presence of hydrothermal fluids with high H+/cations ratios, producing acid type alteration (Utada, 1980), at temperatures between 100 and ~300 °C. The hydrothermal alteration should have been subsequent to the maximum burial and the attainment of epizonal metamorphism, and was very probably related with the posthumous activity of the Ordovician volcanic arc. The widespread occurrence of retrograde diagenesis products (smectite, kaolinite, as well as interstratified Chl/Sm and Chl/Vrm phases) in the anchizonal/epizonal metapelites of Sierra de Cochinoca-Escaya and Sierra de Rinconada constitute, up to our knowledge, the first report of an extensive hydrothermal activity affecting not only the metavolcanic rocks but also the Lower Ordovician sediments of northern Puna. © 2017, Servicio Nacional de Geologia y Mineria. All rights reserved.
format JOUR
author do Campo, M.
Nieto, F.
Albanesi, G.L.
Ortega, G.
Rubén Monaldi, C.
author_facet do Campo, M.
Nieto, F.
Albanesi, G.L.
Ortega, G.
Rubén Monaldi, C.
author_sort do Campo, M.
title Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
title_short Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
title_full Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
title_fullStr Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
title_full_unstemmed Outlining the thermal posdepositional evolution of the ordovician successions of northwestern Argentina by clay mineral analysis, chlorite geothermometry and Kübler index
title_sort outlining the thermal posdepositional evolution of the ordovician successions of northwestern argentina by clay mineral analysis, chlorite geothermometry and kübler index
url http://hdl.handle.net/20.500.12110/paper_07187092_v44_n2_p179_doCampo
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