On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia
The conversion of basaltic crust into a thick, buoyant felsic crust of tonalite-trondhjemite-granodiorite (TTG) composition has been a crucial event in the Earth’s evolution during the Archaean Eon (4.0–2.5 Ga). The formation of TTGs as the result of the melting of hydrated mafic rocks is well estab...
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2024
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/577668 2024-09-15T17:51:01+00:00 On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia Halla, Jaana Joshi, Kumar Batuk Luttinen, Arto Heilimo, Esa Kurhila, Matti Finnish Museum of Natural History 2024-06-24T12:48:03Z application/pdf http://hdl.handle.net/10138/577668 eng eng Elsevier Scientific Publ. Co 10.1016/j.precamres.2024.10740 Archaean, TTG, metabasalt, metatexite, diatexite, partial melting Halla , J , Joshi , K B , Luttinen , A , Heilimo , E & Kurhila , M 2024 , ' On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia ' , Precambrian Research . https://doi.org/10.1016/j.precamres.2024.10740 http://hdl.handle.net/10138/577668 0473dca4-0bad-4b74-89c0-b3ed8bc75512 cc_by info:eu-repo/semantics/openAccess openAccess Other natural sciences Article publishedVersion 2024 ftunivhelsihelda 2024-06-25T14:22:46Z The conversion of basaltic crust into a thick, buoyant felsic crust of tonalite-trondhjemite-granodiorite (TTG) composition has been a crucial event in the Earth’s evolution during the Archaean Eon (4.0–2.5 Ga). The formation of TTGs as the result of the melting of hydrated mafic rocks is well established by geochemical modelling and experimental methods, but field studies are rare. Here, we investigate the migmatite structures and major and trace element geochemistry of Neoarchaean Lake Inari TTG-amphibolite terrain in northern Finland, in the Lapland-Kola Province of Arctic Fennoscandia. The Lake Inari amphibolites are low magnesium and low-titanium subalkaline basalts metamorphosed in the upper amphibolite facies that have flat or slightly LREE-enriched REE patterns. Geochemically, they resemble younger flood basalts. The TTGs have two coeval and intermingled geochemical endmembers, the low- and high-HREE types, which differ in their garnet-compatible element (HREE, Mg, Sc, Y, Co, and Zn) contents reflecting the presence or absence of garnet in their source. The TTG-metabasalt association shows various migmatite structures such as metatexites, metatexite-diatexite transitions and massive diatexites that have formed in response to rheological crustal strength drops, melt SEMR (Segregation, Extraction, Migration, and Redistribution) processes, and syn-anatectic strain. The Lake Inari terrain was a melt-rich crustal horizon with widespread migmatization due to partial melting of a basaltic plateau generated over a mantle plume, supporting a stagnant to sluggish lid tectonic setting for their formation. The Lake Inari terrain formed by migmatization of a basaltic source. Overall, the present denudation level of the terrain mostly represents the metatexite-diatexite transition and diatexite zones. Plateau basalts were converted to TTGs through mid-crustal migmatization, i.e., partial melt SEMR processes controlled by rheological crustal strength drops at different melt fractions and syn-anatectic strain. Peer ... Article in Journal/Newspaper Arctic Fennoscandia Inari Northern Finland Lapland HELDA – University of Helsinki Open Repository |
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HELDA – University of Helsinki Open Repository |
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ftunivhelsihelda |
language |
English |
topic |
Other natural sciences |
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Other natural sciences Halla, Jaana Joshi, Kumar Batuk Luttinen, Arto Heilimo, Esa Kurhila, Matti On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
topic_facet |
Other natural sciences |
description |
The conversion of basaltic crust into a thick, buoyant felsic crust of tonalite-trondhjemite-granodiorite (TTG) composition has been a crucial event in the Earth’s evolution during the Archaean Eon (4.0–2.5 Ga). The formation of TTGs as the result of the melting of hydrated mafic rocks is well established by geochemical modelling and experimental methods, but field studies are rare. Here, we investigate the migmatite structures and major and trace element geochemistry of Neoarchaean Lake Inari TTG-amphibolite terrain in northern Finland, in the Lapland-Kola Province of Arctic Fennoscandia. The Lake Inari amphibolites are low magnesium and low-titanium subalkaline basalts metamorphosed in the upper amphibolite facies that have flat or slightly LREE-enriched REE patterns. Geochemically, they resemble younger flood basalts. The TTGs have two coeval and intermingled geochemical endmembers, the low- and high-HREE types, which differ in their garnet-compatible element (HREE, Mg, Sc, Y, Co, and Zn) contents reflecting the presence or absence of garnet in their source. The TTG-metabasalt association shows various migmatite structures such as metatexites, metatexite-diatexite transitions and massive diatexites that have formed in response to rheological crustal strength drops, melt SEMR (Segregation, Extraction, Migration, and Redistribution) processes, and syn-anatectic strain. The Lake Inari terrain was a melt-rich crustal horizon with widespread migmatization due to partial melting of a basaltic plateau generated over a mantle plume, supporting a stagnant to sluggish lid tectonic setting for their formation. The Lake Inari terrain formed by migmatization of a basaltic source. Overall, the present denudation level of the terrain mostly represents the metatexite-diatexite transition and diatexite zones. Plateau basalts were converted to TTGs through mid-crustal migmatization, i.e., partial melt SEMR processes controlled by rheological crustal strength drops at different melt fractions and syn-anatectic strain. Peer ... |
author2 |
Finnish Museum of Natural History |
format |
Article in Journal/Newspaper |
author |
Halla, Jaana Joshi, Kumar Batuk Luttinen, Arto Heilimo, Esa Kurhila, Matti |
author_facet |
Halla, Jaana Joshi, Kumar Batuk Luttinen, Arto Heilimo, Esa Kurhila, Matti |
author_sort |
Halla, Jaana |
title |
On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
title_short |
On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
title_full |
On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
title_fullStr |
On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
title_full_unstemmed |
On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia |
title_sort |
on the origin of archaean ttgs by migmatization of mantle plume-related basalts: insights from the lake inari terrain, arctic fennoscandia |
publisher |
Elsevier Scientific Publ. Co |
publishDate |
2024 |
url |
http://hdl.handle.net/10138/577668 |
genre |
Arctic Fennoscandia Inari Northern Finland Lapland |
genre_facet |
Arctic Fennoscandia Inari Northern Finland Lapland |
op_relation |
10.1016/j.precamres.2024.10740 Archaean, TTG, metabasalt, metatexite, diatexite, partial melting Halla , J , Joshi , K B , Luttinen , A , Heilimo , E & Kurhila , M 2024 , ' On the origin of Archaean TTGs by migmatization of mantle plume-related basalts: Insights from the Lake Inari terrain, Arctic Fennoscandia ' , Precambrian Research . https://doi.org/10.1016/j.precamres.2024.10740 http://hdl.handle.net/10138/577668 0473dca4-0bad-4b74-89c0-b3ed8bc75512 |
op_rights |
cc_by info:eu-repo/semantics/openAccess openAccess |
_version_ |
1810292820102086656 |