A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina

A petrologic, geochemical and geophysical study of two Late Cretaceous plutons of the Fuegian Andes is carried out: the Jeu-Jepén Monzonite (JJM) and the Mt. Kranck Pluton (MKP). The plutons show a wide lithological spectrum from ultramafic lithologies (clinopyroxenites and hornblendites), gabbros,...

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Autores principales:	Prezzi, Claudia Beatriz, Acevedo, Rogelio Daniel, Escayola, Monica Patricia
Publicado:	2012
Materias:	Cenozoic strike-slip Fuegian Andes Mildly-alkaline plutons Rear-arc magmatism comparative study Cretaceous crystallization diorite feldspar gabbro geochemistry magma chamber monzonite petrology pluton shoshonite syenite tectonic evolution trace element Argentina
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v38_n_p71_GonzalezGuillot http://hdl.handle.net/20.500.12110/paper_08959811_v38_n_p71_GonzalezGuillot
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_08959811_v38_n_p71_GonzalezGuillot
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spelling	paper:paper_08959811_v38_n_p71_GonzalezGuillot2023-06-08T15:48:39Z A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina Prezzi, Claudia Beatriz Acevedo, Rogelio Daniel Escayola, Monica Patricia Cenozoic strike-slip Fuegian Andes Mildly-alkaline plutons Rear-arc magmatism comparative study Cretaceous crystallization diorite feldspar gabbro geochemistry magma chamber monzonite petrology pluton shoshonite syenite tectonic evolution trace element Argentina A petrologic, geochemical and geophysical study of two Late Cretaceous plutons of the Fuegian Andes is carried out: the Jeu-Jepén Monzonite (JJM) and the Mt. Kranck Pluton (MKP). The plutons show a wide lithological spectrum from ultramafic lithologies (clinopyroxenites and hornblendites), gabbros, diorites to late stage K-feldspar syenite veins. They represent the top of magmatic chambers exposed at or close to the roof level. Mode and chemistry indicate a monzonitic-mildly alkaline trend with high K 2O content, equivalent to shoshonitic series. Trace element composition is typical of arc magmas. These features plus their high LILE content (Ba 320-1600 ppm, Sr 475-1560 ppm), high LILE/HFSE ratio (Rb/Zr 0.6-1.6) and age confirm they belong to a rear-arc, monzonitic to mildly alkaline suite (the Fuegian Potassic Magmatism). Therefore, they represent the farthest-from-the-trench plutons in the suite. The petrographical and chemical characteristics of the plutons suggest the lithological spectrum is the result of magmatic differentiation. The process involved crystal accumulation and magma mingling at the early stages, favored either by injections of fresh magma from deeper reservoirs and/or the action of convective currents within the chamber. Country rock assimilation also took part simultaneously with crystallization. The JJM and MKP lie along the trace of a Cenozoic left-lateral strike-slip fault (Magallanes-Fagnano fault system), on opposite blocks. However, lithological, chemical and geophysical subtle differences between these two plutons suggest they evolved in individual magmatic chambers and therefore the distance between them cannot be used as an estimation of total offset along the fault, as was indicated in previous studies. © 2012 Elsevier Ltd. Fil:Prezzi, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Acevedo, R.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Escayola, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v38_n_p71_GonzalezGuillot http://hdl.handle.net/20.500.12110/paper_08959811_v38_n_p71_GonzalezGuillot
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Cenozoic strike-slip Fuegian Andes Mildly-alkaline plutons Rear-arc magmatism comparative study Cretaceous crystallization diorite feldspar gabbro geochemistry magma chamber monzonite petrology pluton shoshonite syenite tectonic evolution trace element Argentina
spellingShingle	Cenozoic strike-slip Fuegian Andes Mildly-alkaline plutons Rear-arc magmatism comparative study Cretaceous crystallization diorite feldspar gabbro geochemistry magma chamber monzonite petrology pluton shoshonite syenite tectonic evolution trace element Argentina Prezzi, Claudia Beatriz Acevedo, Rogelio Daniel Escayola, Monica Patricia A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
topic_facet	Cenozoic strike-slip Fuegian Andes Mildly-alkaline plutons Rear-arc magmatism comparative study Cretaceous crystallization diorite feldspar gabbro geochemistry magma chamber monzonite petrology pluton shoshonite syenite tectonic evolution trace element Argentina
description	A petrologic, geochemical and geophysical study of two Late Cretaceous plutons of the Fuegian Andes is carried out: the Jeu-Jepén Monzonite (JJM) and the Mt. Kranck Pluton (MKP). The plutons show a wide lithological spectrum from ultramafic lithologies (clinopyroxenites and hornblendites), gabbros, diorites to late stage K-feldspar syenite veins. They represent the top of magmatic chambers exposed at or close to the roof level. Mode and chemistry indicate a monzonitic-mildly alkaline trend with high K 2O content, equivalent to shoshonitic series. Trace element composition is typical of arc magmas. These features plus their high LILE content (Ba 320-1600 ppm, Sr 475-1560 ppm), high LILE/HFSE ratio (Rb/Zr 0.6-1.6) and age confirm they belong to a rear-arc, monzonitic to mildly alkaline suite (the Fuegian Potassic Magmatism). Therefore, they represent the farthest-from-the-trench plutons in the suite. The petrographical and chemical characteristics of the plutons suggest the lithological spectrum is the result of magmatic differentiation. The process involved crystal accumulation and magma mingling at the early stages, favored either by injections of fresh magma from deeper reservoirs and/or the action of convective currents within the chamber. Country rock assimilation also took part simultaneously with crystallization. The JJM and MKP lie along the trace of a Cenozoic left-lateral strike-slip fault (Magallanes-Fagnano fault system), on opposite blocks. However, lithological, chemical and geophysical subtle differences between these two plutons suggest they evolved in individual magmatic chambers and therefore the distance between them cannot be used as an estimation of total offset along the fault, as was indicated in previous studies. © 2012 Elsevier Ltd.
author	Prezzi, Claudia Beatriz Acevedo, Rogelio Daniel Escayola, Monica Patricia
author_facet	Prezzi, Claudia Beatriz Acevedo, Rogelio Daniel Escayola, Monica Patricia
author_sort	Prezzi, Claudia Beatriz
title	A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
title_short	A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
title_full	A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
title_fullStr	A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
title_full_unstemmed	A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina
title_sort	comparative study of two rear-arc plutons and implications for the fuegian andes tectonic evolution: mount kranck pluton and jeu-jepén monzonite, argentina
publishDate	2012
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v38_n_p71_GonzalezGuillot http://hdl.handle.net/20.500.12110/paper_08959811_v38_n_p71_GonzalezGuillot
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A comparative study of two rear-arc plutons and implications for the Fuegian Andes tectonic evolution: Mount Kranck Pluton and Jeu-Jepén Monzonite, Argentina

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