Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand
Cretaceous-Paleogene rifting of the Eastern Gondwana margin thinned the continental crust of Zealandia and culminated in the opening of the Tasman Sea between Australia and New Zealand and the Southern Ocean, separating both from Antarctica. The Western Province of New Zealand consists of a successi...
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ftcopenhagenunip:oai:pure.atira.dk:publications/9dc26ea3-b97c-4181-8899-d821815193f0 2023-05-15T13:34:30+02:00 Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand van der Meer, Quinten Har Adriaan Waight, Tod Earle Scott, James M. 2013 application/pdf https://curis.ku.dk/portal/da/publications/magma-sources-during-gondwana-breakup-chemistry-and-chronology-of-cretaceous-magmatism-in-westland-new-zealand(9dc26ea3-b97c-4181-8899-d821815193f0).html https://curis.ku.dk/ws/files/100717853/EGU2013_3141_1_2_.pdf eng eng info:eu-repo/semantics/openAccess van der Meer , Q H A , Waight , T E & Scott , J M 2013 , ' Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand ' . conferenceObject 2013 ftcopenhagenunip 2021-09-23T17:20:38Z Cretaceous-Paleogene rifting of the Eastern Gondwana margin thinned the continental crust of Zealandia and culminated in the opening of the Tasman Sea between Australia and New Zealand and the Southern Ocean, separating both from Antarctica. The Western Province of New Zealand consists of a succession of metasedimentary rocks intruded by Palaeozoic and Mesozoic granitoids that formed in an active margin setting through the Phanerozoic. Upon cessation of subduction, the earliest stages of extension (110-100 Ma) were expressed in the formation of metamorphic core complexes, followed by emplacement of granitoid plutons, the deposition of terrestrial Pororari Group sediments in extensional half-grabens across on- and offshore Westland, and the intrusion of mafic dikes from 90 Ma. These dikes are concentrated in the swarms of the Paparoa and Hohonu Ranges and were intruded prior to and simultaneous with volumetrically minor A-type plutonism at 82 Ma. The emplacement of mafic dikes and A-type plutonism at 82 Ma is significant as it coincides with the age of the oldest seafloor in the Tasman Sea, therefore it represents magmatism coincident with the initiation of seafloor spreading which continued until 53 Ma. New 40Ar-39Ar ages indicate that the intrusion of mafic dikes in basement lithologies both preceded and continued after the initial opening of the Tasman Sea, including an additional population of ages at 70 Ma. This indicates either a prolonged period of extension-related magmatism that continued >10 Ma after initial breakup, or two discrete episodes of magmatism during Tasman Sea spreading. Volumetrically minor Cenozoic within-plate magmatism continued sporadically throughout the South Island and bears a characteristic HIMU (high time integrated U/Pb) signature. A detailed geochemistry and chronological study of Cretaceous mafic and felsic magmatism is currently in progress and aims to better understand the transition of magma sources from a long lived active continental margin through breakup to a passive setting, and to constrain the onset and evolution of the chemical characteristics of the magmas and their sources, including the origin of the distinctive HIMU signatures. Conference Object Antarc* Antarctica Southern Ocean University of Copenhagen: Research New Zealand Southern Ocean |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
description |
Cretaceous-Paleogene rifting of the Eastern Gondwana margin thinned the continental crust of Zealandia and culminated in the opening of the Tasman Sea between Australia and New Zealand and the Southern Ocean, separating both from Antarctica. The Western Province of New Zealand consists of a succession of metasedimentary rocks intruded by Palaeozoic and Mesozoic granitoids that formed in an active margin setting through the Phanerozoic. Upon cessation of subduction, the earliest stages of extension (110-100 Ma) were expressed in the formation of metamorphic core complexes, followed by emplacement of granitoid plutons, the deposition of terrestrial Pororari Group sediments in extensional half-grabens across on- and offshore Westland, and the intrusion of mafic dikes from 90 Ma. These dikes are concentrated in the swarms of the Paparoa and Hohonu Ranges and were intruded prior to and simultaneous with volumetrically minor A-type plutonism at 82 Ma. The emplacement of mafic dikes and A-type plutonism at 82 Ma is significant as it coincides with the age of the oldest seafloor in the Tasman Sea, therefore it represents magmatism coincident with the initiation of seafloor spreading which continued until 53 Ma. New 40Ar-39Ar ages indicate that the intrusion of mafic dikes in basement lithologies both preceded and continued after the initial opening of the Tasman Sea, including an additional population of ages at 70 Ma. This indicates either a prolonged period of extension-related magmatism that continued >10 Ma after initial breakup, or two discrete episodes of magmatism during Tasman Sea spreading. Volumetrically minor Cenozoic within-plate magmatism continued sporadically throughout the South Island and bears a characteristic HIMU (high time integrated U/Pb) signature. A detailed geochemistry and chronological study of Cretaceous mafic and felsic magmatism is currently in progress and aims to better understand the transition of magma sources from a long lived active continental margin through breakup to a passive setting, and to constrain the onset and evolution of the chemical characteristics of the magmas and their sources, including the origin of the distinctive HIMU signatures. |
format |
Conference Object |
author |
van der Meer, Quinten Har Adriaan Waight, Tod Earle Scott, James M. |
spellingShingle |
van der Meer, Quinten Har Adriaan Waight, Tod Earle Scott, James M. Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
author_facet |
van der Meer, Quinten Har Adriaan Waight, Tod Earle Scott, James M. |
author_sort |
van der Meer, Quinten Har Adriaan |
title |
Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
title_short |
Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
title_full |
Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
title_fullStr |
Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
title_full_unstemmed |
Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand |
title_sort |
magma sources during gondwana breakup: chemistry and chronology of cretaceous magmatism in westland, new zealand |
publishDate |
2013 |
url |
https://curis.ku.dk/portal/da/publications/magma-sources-during-gondwana-breakup-chemistry-and-chronology-of-cretaceous-magmatism-in-westland-new-zealand(9dc26ea3-b97c-4181-8899-d821815193f0).html https://curis.ku.dk/ws/files/100717853/EGU2013_3141_1_2_.pdf |
geographic |
New Zealand Southern Ocean |
geographic_facet |
New Zealand Southern Ocean |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_source |
van der Meer , Q H A , Waight , T E & Scott , J M 2013 , ' Magma sources during Gondwana breakup: chemistry and chronology of Cretaceous magmatism in Westland, New Zealand ' . |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766053733716721664 |