Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana

The Achala Batholith (31°30′S, 64°45′W, Córdoba, Argentina) is a major magmatic complex of the Sierras Pampeanas, emplaced as a post-orogenic pluton in a metamorphic-plutonic basement. It is mainly a porphyritic to coarse-grained equigranular monzogranite, with crystallization age of ∼ 370 and cooli...

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Autores principales: Geuna, S.E., Escosteguy, L.D., Miró, R.
Formato: JOUR
Materias:
APWP
Granite
Late Devonian-Early Carboniferous
Palaeomagnetism
South America
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_1342937X_v13_n2_p227_Geuna
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_1342937X_v13_n2_p227_Geuna2023-10-03T16:09:32Z Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana Geuna, S.E. Escosteguy, L.D. Miró, R. APWP Granite Late Devonian-Early Carboniferous Palaeomagnetism South America The Achala Batholith (31°30′S, 64°45′W, Córdoba, Argentina) is a major magmatic complex of the Sierras Pampeanas, emplaced as a post-orogenic pluton in a metamorphic-plutonic basement. It is mainly a porphyritic to coarse-grained equigranular monzogranite, with crystallization age of ∼ 370 and cooling age of ∼ 340 Ma, presently exposed as asymmetric, eastward-tilted blocks. Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 15 × 10- 5 (SI). Twenty-two sites showed unstable magnetic behaviour. The remaining 21 sites have haematite as magnetic carrier of a stable remanence. The ilmeno-haematite appears as an accessory mineral, with exsolved intergrowths of (haemo)ilmenite. Thermal demagnetisation up to 620-640 °C isolated steeply-dipping, dual-polarity remanence directions. The palaeomagnetic pole is located at 56°S, 307°E (N = 18, A95 10.7, K 11). The remanence was locked on cooling, over a range of temperatures from magnetic ordering to exsolution of ilmenite-haematite (∼ 600 to 390 °C). The pole better coincides with the 370-360 Ma segment of the Gondwana apparent polar wander path, suggesting that remanence was acquired quickly. The Achala pole matches a complex mid-Palaeozoic apparent polar wander path ("Y-type") for Gondwana, which may involve rapid movement, true polar wander episodes and/or continental collisions before the final amalgamation of Pangea. © 2007 International Association for Gondwana Research. Fil:Geuna, S.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Escosteguy, L.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Miró, R. 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_1342937X_v13_n2_p227_Geuna
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic APWP
Granite
Late Devonian-Early Carboniferous
Palaeomagnetism
South America
spellingShingle APWP
Granite
Late Devonian-Early Carboniferous
Palaeomagnetism
South America
Geuna, S.E.
Escosteguy, L.D.
Miró, R.
Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
topic_facet APWP
Granite
Late Devonian-Early Carboniferous
Palaeomagnetism
South America
description The Achala Batholith (31°30′S, 64°45′W, Córdoba, Argentina) is a major magmatic complex of the Sierras Pampeanas, emplaced as a post-orogenic pluton in a metamorphic-plutonic basement. It is mainly a porphyritic to coarse-grained equigranular monzogranite, with crystallization age of ∼ 370 and cooling age of ∼ 340 Ma, presently exposed as asymmetric, eastward-tilted blocks. Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 15 × 10- 5 (SI). Twenty-two sites showed unstable magnetic behaviour. The remaining 21 sites have haematite as magnetic carrier of a stable remanence. The ilmeno-haematite appears as an accessory mineral, with exsolved intergrowths of (haemo)ilmenite. Thermal demagnetisation up to 620-640 °C isolated steeply-dipping, dual-polarity remanence directions. The palaeomagnetic pole is located at 56°S, 307°E (N = 18, A95 10.7, K 11). The remanence was locked on cooling, over a range of temperatures from magnetic ordering to exsolution of ilmenite-haematite (∼ 600 to 390 °C). The pole better coincides with the 370-360 Ma segment of the Gondwana apparent polar wander path, suggesting that remanence was acquired quickly. The Achala pole matches a complex mid-Palaeozoic apparent polar wander path ("Y-type") for Gondwana, which may involve rapid movement, true polar wander episodes and/or continental collisions before the final amalgamation of Pangea. © 2007 International Association for Gondwana Research.
format JOUR
author Geuna, S.E.
Escosteguy, L.D.
Miró, R.
author_facet Geuna, S.E.
Escosteguy, L.D.
Miró, R.
author_sort Geuna, S.E.
title Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
title_short Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
title_full Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
title_fullStr Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
title_full_unstemmed Palaeomagnetism of the Late Devonian-Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana
title_sort palaeomagnetism of the late devonian-early carboniferous achala batholith, córdoba, central argentina: implications for the apparent polar wander path of gondwana
url http://hdl.handle.net/20.500.12110/paper_1342937X_v13_n2_p227_Geuna
work_keys_str_mv AT geunase palaeomagnetismofthelatedevonianearlycarboniferousachalabatholithcordobacentralargentinaimplicationsfortheapparentpolarwanderpathofgondwana
AT escosteguyld palaeomagnetismofthelatedevonianearlycarboniferousachalabatholithcordobacentralargentinaimplicationsfortheapparentpolarwanderpathofgondwana
AT miror palaeomagnetismofthelatedevonianearlycarboniferousachalabatholithcordobacentralargentinaimplicationsfortheapparentpolarwanderpathofgondwana
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