Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica)
We present new geochemical, isotopic and geochronological data for two Cambrian magmatic sequences exposed in northern Victoria Land (Antarctica) at the eastern margin of the Ross-orogenic Wilson Terrane: (i) the metavolcanic and metaplutonic rocks from the Dessent tectono-metamorphic complex, and (...
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Online Access: | http://hdl.handle.net/11571/1423974 https://doi.org/10.1016/j.lithos.2020.105925 https://www.sciencedirect.com/science/article/pii/S0024493720305600 |
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ftunivpavia:oai:iris.unipv.it:11571/1423974 2024-02-27T08:35:02+00:00 Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) Henjes-Kunst F. Tribuzio R. Gerdes A. Henjes-Kunst, F. Tribuzio, R. Gerdes, A. 2021 ELETTRONICO http://hdl.handle.net/11571/1423974 https://doi.org/10.1016/j.lithos.2020.105925 https://www.sciencedirect.com/science/article/pii/S0024493720305600 eng eng volume:382-383 issue:105925 numberofpages:20 journal:LITHOS http://hdl.handle.net/11571/1423974 doi:10.1016/j.lithos.2020.105925 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85098702244 https://www.sciencedirect.com/science/article/pii/S0024493720305600 continental margin boninite metavolcanic rocks mafic ultramafic sequence info:eu-repo/semantics/article 2021 ftunivpavia https://doi.org/10.1016/j.lithos.2020.105925 2024-01-31T17:50:56Z We present new geochemical, isotopic and geochronological data for two Cambrian magmatic sequences exposed in northern Victoria Land (Antarctica) at the eastern margin of the Ross-orogenic Wilson Terrane: (i) the metavolcanic and metaplutonic rocks from the Dessent tectono-metamorphic complex, and (ii) the boninite-derived mafic-ultramafic Niagara Icefalls igneous complex. The Dessent metaigneous rocks are subdivided into three main types. Type I metavolcanites show LREE-depleted chondrite-normalized patterns and high initial ɛNd (mostly +6 to +7). Metavolcanic and metaplutonic type II rocks show low MREE-HREE concentrations and initial ɛNd ranging from +2 to +4. Type III metavolcanites mostly differ from type II rocks in the somewhat elevated MREE-HREE abundances. Type I, II and III rocks geochemically resemble forearc basalts, boninites s.l. and firstarc volcanites, respectively, from the Izu-Bonin-Mariana island arc system. Zircon separated from two metaplutonic rocks documents a crystallization age of ~516 Ma. The Niagara Icefalls rocks display a wide range of Nd–Sr isotopic compositions (e.g., initial ɛNd + 5 to −8). Zircons separated from a gabbronorite and from a granitoid vein allowed us to date the building of the Niagara Icefalls igneous complex at ~537 Ma. The melts forming the Niagara Icefalls igneous complex were most likely sourced in a supra-subduction zone mantle wedge, which included both depleted mantle and slab-derived sedimentary components. We propose that the mafic-ultramafic Niagara Icefalls igneous complex and the metaigneous rocks of the Dessent tectono-metamorphic complex are fossil analogues of two distinct oceanic island arcs, which formed in the earliest and the late early Cambrian, respectively. Article in Journal/Newspaper Antarc* Antarctica Victoria Land IRIS UNIPV (Università degli studi di Pavia) Victoria Land Pacific Lithos 382-383 105925 |
institution |
Open Polar |
collection |
IRIS UNIPV (Università degli studi di Pavia) |
op_collection_id |
ftunivpavia |
language |
English |
topic |
continental margin boninite metavolcanic rocks mafic ultramafic sequence |
spellingShingle |
continental margin boninite metavolcanic rocks mafic ultramafic sequence Henjes-Kunst F. Tribuzio R. Gerdes A. Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
topic_facet |
continental margin boninite metavolcanic rocks mafic ultramafic sequence |
description |
We present new geochemical, isotopic and geochronological data for two Cambrian magmatic sequences exposed in northern Victoria Land (Antarctica) at the eastern margin of the Ross-orogenic Wilson Terrane: (i) the metavolcanic and metaplutonic rocks from the Dessent tectono-metamorphic complex, and (ii) the boninite-derived mafic-ultramafic Niagara Icefalls igneous complex. The Dessent metaigneous rocks are subdivided into three main types. Type I metavolcanites show LREE-depleted chondrite-normalized patterns and high initial ɛNd (mostly +6 to +7). Metavolcanic and metaplutonic type II rocks show low MREE-HREE concentrations and initial ɛNd ranging from +2 to +4. Type III metavolcanites mostly differ from type II rocks in the somewhat elevated MREE-HREE abundances. Type I, II and III rocks geochemically resemble forearc basalts, boninites s.l. and firstarc volcanites, respectively, from the Izu-Bonin-Mariana island arc system. Zircon separated from two metaplutonic rocks documents a crystallization age of ~516 Ma. The Niagara Icefalls rocks display a wide range of Nd–Sr isotopic compositions (e.g., initial ɛNd + 5 to −8). Zircons separated from a gabbronorite and from a granitoid vein allowed us to date the building of the Niagara Icefalls igneous complex at ~537 Ma. The melts forming the Niagara Icefalls igneous complex were most likely sourced in a supra-subduction zone mantle wedge, which included both depleted mantle and slab-derived sedimentary components. We propose that the mafic-ultramafic Niagara Icefalls igneous complex and the metaigneous rocks of the Dessent tectono-metamorphic complex are fossil analogues of two distinct oceanic island arcs, which formed in the earliest and the late early Cambrian, respectively. |
author2 |
Henjes-Kunst, F. Tribuzio, R. Gerdes, A. |
format |
Article in Journal/Newspaper |
author |
Henjes-Kunst F. Tribuzio R. Gerdes A. |
author_facet |
Henjes-Kunst F. Tribuzio R. Gerdes A. |
author_sort |
Henjes-Kunst F. |
title |
Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
title_short |
Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
title_full |
Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
title_fullStr |
Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
title_full_unstemmed |
Early Cambrian oceanic island-arc magmatism at the paleo-Pacific margin of East Gondwana: Evidence from northern Victoria Land (Antarctica) |
title_sort |
early cambrian oceanic island-arc magmatism at the paleo-pacific margin of east gondwana: evidence from northern victoria land (antarctica) |
publishDate |
2021 |
url |
http://hdl.handle.net/11571/1423974 https://doi.org/10.1016/j.lithos.2020.105925 https://www.sciencedirect.com/science/article/pii/S0024493720305600 |
geographic |
Victoria Land Pacific |
geographic_facet |
Victoria Land Pacific |
genre |
Antarc* Antarctica Victoria Land |
genre_facet |
Antarc* Antarctica Victoria Land |
op_relation |
volume:382-383 issue:105925 numberofpages:20 journal:LITHOS http://hdl.handle.net/11571/1423974 doi:10.1016/j.lithos.2020.105925 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85098702244 https://www.sciencedirect.com/science/article/pii/S0024493720305600 |
op_doi |
https://doi.org/10.1016/j.lithos.2020.105925 |
container_title |
Lithos |
container_volume |
382-383 |
container_start_page |
105925 |
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1792041450812211200 |