Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system

The Central Patagonian batholith (CPB) comprises two Late Triassic calcalkaline plutonic suites (the Gastre superunit of 221 ± 2 Ma and the Lipetrén superunit of 215 ± 1 Ma) which have been interpreted as a record of major dextral motion along the transcontinental NW-SE-striking subvertical Gastre f...

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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1553040X_v13_n6_p1973_Zaffarana
http://hdl.handle.net/20.500.12110/paper_1553040X_v13_n6_p1973_Zaffarana
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spelling paper:paper_1553040X_v13_n6_p1973_Zaffarana2023-06-08T16:23:05Z Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system Deformation Magnetic anisotropy Magnetic susceptibility Strike-slip faults Structural geology Anisotropy of magnetic susceptibility Internal structure Kinematic indicators Late Paleozoic Magmatic fabrics Pluton emplacement Plutonic suites Tectonic fabrics Geochronology batholith deformation emplacement geological record Jurassic magma chamber magnetic anisotropy magnetic susceptibility petrofabric pluton strike-slip fault tectonic setting transpression Triassic Argentina Patagonia The Central Patagonian batholith (CPB) comprises two Late Triassic calcalkaline plutonic suites (the Gastre superunit of 221 ± 2 Ma and the Lipetrén superunit of 215 ± 1 Ma) which have been interpreted as a record of major dextral motion along the transcontinental NW-SE-striking subvertical Gastre fault system in Jurassic times. We performed a detailed study of the internal structure of the CPB through structural and anisotropy of magnetic susceptibility (AMS) techniques. The Gastre superunit reveals a very consistent pattern of NW-SE-striking steeply dipping magmatic foliations. Tectonic fabrics within the CPB are scarce and generally parallel to the magmatic fabrics. The magmatic and solid-state lineations within the CPB are steeply, intermediately, or shallowly plunging. The combination of flattened magmatic and solid-state fabrics with subvertical orientations and with steep to shallow lineations, together with the kinematic indicators in two mylonite belts with suspected CPB protoliths, suggests that the Gastre superunit was emplaced within a sinistral transpressive regime. The shallower stocks of the Lipetrén superunit are more isotropic and have magmatic fabrics associated with magma chamber dynamics. The deformation of the CPB is coaxial with the late Paleozoic deformation in the hosting Calcatapul Formation. The late Paleozoic deformation in the North Patagonian Massif generated widespread NW-SE subvertical fractures which could have aided the emplacement of the CPB. The internal structure of the CPB does not support a model of dextral strike-slip movements on major Jurassic faults. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1553040X_v13_n6_p1973_Zaffarana http://hdl.handle.net/20.500.12110/paper_1553040X_v13_n6_p1973_Zaffarana
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Deformation
Magnetic anisotropy
Magnetic susceptibility
Strike-slip faults
Structural geology
Anisotropy of magnetic susceptibility
Internal structure
Kinematic indicators
Late Paleozoic
Magmatic fabrics
Pluton emplacement
Plutonic suites
Tectonic fabrics
Geochronology
batholith
deformation
emplacement
geological record
Jurassic
magma chamber
magnetic anisotropy
magnetic susceptibility
petrofabric
pluton
strike-slip fault
tectonic setting
transpression
Triassic
Argentina
Patagonia
spellingShingle Deformation
Magnetic anisotropy
Magnetic susceptibility
Strike-slip faults
Structural geology
Anisotropy of magnetic susceptibility
Internal structure
Kinematic indicators
Late Paleozoic
Magmatic fabrics
Pluton emplacement
Plutonic suites
Tectonic fabrics
Geochronology
batholith
deformation
emplacement
geological record
Jurassic
magma chamber
magnetic anisotropy
magnetic susceptibility
petrofabric
pluton
strike-slip fault
tectonic setting
transpression
Triassic
Argentina
Patagonia
Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
topic_facet Deformation
Magnetic anisotropy
Magnetic susceptibility
Strike-slip faults
Structural geology
Anisotropy of magnetic susceptibility
Internal structure
Kinematic indicators
Late Paleozoic
Magmatic fabrics
Pluton emplacement
Plutonic suites
Tectonic fabrics
Geochronology
batholith
deformation
emplacement
geological record
Jurassic
magma chamber
magnetic anisotropy
magnetic susceptibility
petrofabric
pluton
strike-slip fault
tectonic setting
transpression
Triassic
Argentina
Patagonia
description The Central Patagonian batholith (CPB) comprises two Late Triassic calcalkaline plutonic suites (the Gastre superunit of 221 ± 2 Ma and the Lipetrén superunit of 215 ± 1 Ma) which have been interpreted as a record of major dextral motion along the transcontinental NW-SE-striking subvertical Gastre fault system in Jurassic times. We performed a detailed study of the internal structure of the CPB through structural and anisotropy of magnetic susceptibility (AMS) techniques. The Gastre superunit reveals a very consistent pattern of NW-SE-striking steeply dipping magmatic foliations. Tectonic fabrics within the CPB are scarce and generally parallel to the magmatic fabrics. The magmatic and solid-state lineations within the CPB are steeply, intermediately, or shallowly plunging. The combination of flattened magmatic and solid-state fabrics with subvertical orientations and with steep to shallow lineations, together with the kinematic indicators in two mylonite belts with suspected CPB protoliths, suggests that the Gastre superunit was emplaced within a sinistral transpressive regime. The shallower stocks of the Lipetrén superunit are more isotropic and have magmatic fabrics associated with magma chamber dynamics. The deformation of the CPB is coaxial with the late Paleozoic deformation in the hosting Calcatapul Formation. The late Paleozoic deformation in the North Patagonian Massif generated widespread NW-SE subvertical fractures which could have aided the emplacement of the CPB. The internal structure of the CPB does not support a model of dextral strike-slip movements on major Jurassic faults.
title Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
title_short Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
title_full Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
title_fullStr Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
title_full_unstemmed Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: Implications for pluton emplacement and the Gastre fault system
title_sort internal structure of the late triassic central patagonian batholith at gastre, southern argentina: implications for pluton emplacement and the gastre fault system
publishDate 2017
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1553040X_v13_n6_p1973_Zaffarana
http://hdl.handle.net/20.500.12110/paper_1553040X_v13_n6_p1973_Zaffarana
_version_ 1768542429841981440