Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina

Granitoid and volcanic rocks of the Cordillera Neuquina between 38°45′ and 39°30′ south latitude have been metamorphosed under zeolite, prehnite-pumpellyite, and transitional greenschist facies conditions. This low-grade metamorphism is related to the circulation of hydrothermal solutions associated...

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Detalles Bibliográficos
Publicado: 1990
Materias:
granitoid
greenschist facies
metamorphism
prehnite
pumpellyite
volcanic rock
zeolite
Argentina, Cordillera Neuquina
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v3_n4_p247_VattuonedePonti
http://hdl.handle.net/20.500.12110/paper_08959811_v3_n4_p247_VattuonedePonti
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_08959811_v3_n4_p247_VattuonedePonti
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spelling paper:paper_08959811_v3_n4_p247_VattuonedePonti2023-06-08T15:48:39Z Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina granitoid greenschist facies metamorphism prehnite pumpellyite volcanic rock zeolite Argentina, Cordillera Neuquina Granitoid and volcanic rocks of the Cordillera Neuquina between 38°45′ and 39°30′ south latitude have been metamorphosed under zeolite, prehnite-pumpellyite, and transitional greenschist facies conditions. This low-grade metamorphism is related to the circulation of hydrothermal solutions associated with Tertiary(?) subvolcanic bodies and/or shallow intrusives through a pre-existing fracture system. Three progressive metamorphic zones have been established, with temperatures ranging from 100° to 300°C and pressures less than 4 kb. The pressures are similar to those estimated for metamorphic rocks at Taringatura, New Zealand, and in the Tanzawa Mountains of Japan. The mineral assemblages are influenced by host-rock composition. In the granitoids, the sequence is: Zone I - heulandite, stilbite, K-feldspar, albite, quartz, calcite; Zone II - chlorite, prehnite, pumpellyite, albite, K-feldspar, titanite, quartz; and Zone III - chlorite, pistacite, piedmontite, titanite, actinolite, K-feldspar, albite, quartz, calcite. In the basalts, the sequence is: Zone I - heulandite, stilbite, calcite; Zone II - analcime, thomsonite, laumontite, natrolite, celadonite, albite; and Zone III - chlorite, pistacite, actinolite, pumpellyite, laumontite, albite, quartz. In the andesites, the sequence is: Zone I - stilbite, calcite, quartz; Zone II - pumpellyite, chlorite, titanite, celadonite, albite, quartz, calcite; and in Zone III - pistacite, quartz, chlorite, albite. Pyrite, chalcopyrite, arsenopyrite, and copper are always found in association with quartz and epidote in Zone III. © 1991. 1990 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v3_n4_p247_VattuonedePonti http://hdl.handle.net/20.500.12110/paper_08959811_v3_n4_p247_VattuonedePonti
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic granitoid
greenschist facies
metamorphism
prehnite
pumpellyite
volcanic rock
zeolite
Argentina, Cordillera Neuquina
spellingShingle granitoid
greenschist facies
metamorphism
prehnite
pumpellyite
volcanic rock
zeolite
Argentina, Cordillera Neuquina
Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
topic_facet granitoid
greenschist facies
metamorphism
prehnite
pumpellyite
volcanic rock
zeolite
Argentina, Cordillera Neuquina
description Granitoid and volcanic rocks of the Cordillera Neuquina between 38°45′ and 39°30′ south latitude have been metamorphosed under zeolite, prehnite-pumpellyite, and transitional greenschist facies conditions. This low-grade metamorphism is related to the circulation of hydrothermal solutions associated with Tertiary(?) subvolcanic bodies and/or shallow intrusives through a pre-existing fracture system. Three progressive metamorphic zones have been established, with temperatures ranging from 100° to 300°C and pressures less than 4 kb. The pressures are similar to those estimated for metamorphic rocks at Taringatura, New Zealand, and in the Tanzawa Mountains of Japan. The mineral assemblages are influenced by host-rock composition. In the granitoids, the sequence is: Zone I - heulandite, stilbite, K-feldspar, albite, quartz, calcite; Zone II - chlorite, prehnite, pumpellyite, albite, K-feldspar, titanite, quartz; and Zone III - chlorite, pistacite, piedmontite, titanite, actinolite, K-feldspar, albite, quartz, calcite. In the basalts, the sequence is: Zone I - heulandite, stilbite, calcite; Zone II - analcime, thomsonite, laumontite, natrolite, celadonite, albite; and Zone III - chlorite, pistacite, actinolite, pumpellyite, laumontite, albite, quartz. In the andesites, the sequence is: Zone I - stilbite, calcite, quartz; Zone II - pumpellyite, chlorite, titanite, celadonite, albite, quartz, calcite; and in Zone III - pistacite, quartz, chlorite, albite. Pyrite, chalcopyrite, arsenopyrite, and copper are always found in association with quartz and epidote in Zone III. © 1991.
title Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
title_short Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
title_full Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
title_fullStr Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
title_full_unstemmed Low-grade metamorphism in granitoids and volcanic rocks, Cordillera Neuquina, Argentina
title_sort low-grade metamorphism in granitoids and volcanic rocks, cordillera neuquina, argentina
publishDate 1990
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v3_n4_p247_VattuonedePonti
http://hdl.handle.net/20.500.12110/paper_08959811_v3_n4_p247_VattuonedePonti
_version_ 1768545196177358848

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