In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica)
In situ U-Pb geochronology was carried out by laser-ablation ICPMS on baddeleyite and zircon from a quartz gabbro of the Varney Nunatak intrusion (central Victoria Land, Antarctica). Back-scattered electron images reveal that baddeleyite grains from the investigated rock are partially substituted by...
Published in: | European Journal of Mineralogy |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Schweizerbart
2011
|
Subjects: | |
Online Access: | http://hdl.handle.net/2434/298806 https://doi.org/10.1127/0935-1221/2011/0023-2083 |
id |
ftunivmilanoair:oai:air.unimi.it:2434/298806 |
---|---|
record_format |
openpolar |
spelling |
ftunivmilanoair:oai:air.unimi.it:2434/298806 2024-02-11T09:57:59+01:00 In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) M. Renna R. Tribuzio M. Tiepolo M. Renna M. Tiepolo R. Tribuzio 2011-03 http://hdl.handle.net/2434/298806 https://doi.org/10.1127/0935-1221/2011/0023-2083 eng eng Schweizerbart info:eu-repo/semantics/altIdentifier/wos/WOS:000290096700007 volume:23 issue:2 firstpage:223 lastpage:240 numberofpages:18 journal:EUROPEAN JOURNAL OF MINERALOGY http://hdl.handle.net/2434/298806 doi:10.1127/0935-1221/2011/0023-2083 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-79956301876 Antarctica Baddeleyite Central victoria land In situ u-pb geochronology Laser-ablation icpm Mineral trace element composition Zircon Settore GEO/08 - Geochimica e Vulcanologia info:eu-repo/semantics/article 2011 ftunivmilanoair https://doi.org/10.1127/0935-1221/2011/0023-2083 2024-01-16T23:25:32Z In situ U-Pb geochronology was carried out by laser-ablation ICPMS on baddeleyite and zircon from a quartz gabbro of the Varney Nunatak intrusion (central Victoria Land, Antarctica). Back-scattered electron images reveal that baddeleyite grains from the investigated rock are partially substituted by zircon. Baddeleyite replacement by zircon is attributed to a late magmatic reaction between early fractionating minerals (plagioclase + sub-ophitic clinopyroxene + ilmenite + baddeleyite) with a silica oversaturated melt enriched in volatiles and incompatible elements. The development of fine-grained aggregates of clinopyroxene + amphibole + ilmenite around sub-ophitic clinopyroxene provides further evidence for this reaction. Homogeneous domains of baddeleyite were analysed by laser-ablation ICPMS and yielded crystallisation ages for the quartz gabbros of 488 ± 3 Ma. U-Pb analyses on zircon define a population at 486 ± 6 Ma, coeval with the U-Pb baddeleyite crystallization age, and a population at 525 ± 10 Ma, representing an inherited component. This finding indicates that the parent magma of the quartz gabbro was contaminated with upper crustal rocks. The gabbroic rocks of Varney Nunatak are associated with peraluminous granites and late basalt dykes. The similar whole-rock and clinopyroxene major and trace element concentrations in the quartz gabbros and basalts is suggestive for a genetic relationship. The emplacement age, whole-rock compositions and highly enriched Nd isotope signature (εNd (488 Ma) of -7.7 to -6.8) of the Varney Nunatak association are similar to those of other igneous units from central Victoria Land. The association developed during the post-collisional phase of the Ross orogeny. Article in Journal/Newspaper Antarc* Antarctica Victoria Land The University of Milan: Archivio Istituzionale della Ricerca (AIR) Victoria Land Varney Nunatak ENVELOPE(162.517,162.517,-75.933,-75.933) European Journal of Mineralogy 23 2 223 240 |
institution |
Open Polar |
collection |
The University of Milan: Archivio Istituzionale della Ricerca (AIR) |
op_collection_id |
ftunivmilanoair |
language |
English |
topic |
Antarctica Baddeleyite Central victoria land In situ u-pb geochronology Laser-ablation icpm Mineral trace element composition Zircon Settore GEO/08 - Geochimica e Vulcanologia |
spellingShingle |
Antarctica Baddeleyite Central victoria land In situ u-pb geochronology Laser-ablation icpm Mineral trace element composition Zircon Settore GEO/08 - Geochimica e Vulcanologia M. Renna R. Tribuzio M. Tiepolo In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
topic_facet |
Antarctica Baddeleyite Central victoria land In situ u-pb geochronology Laser-ablation icpm Mineral trace element composition Zircon Settore GEO/08 - Geochimica e Vulcanologia |
description |
In situ U-Pb geochronology was carried out by laser-ablation ICPMS on baddeleyite and zircon from a quartz gabbro of the Varney Nunatak intrusion (central Victoria Land, Antarctica). Back-scattered electron images reveal that baddeleyite grains from the investigated rock are partially substituted by zircon. Baddeleyite replacement by zircon is attributed to a late magmatic reaction between early fractionating minerals (plagioclase + sub-ophitic clinopyroxene + ilmenite + baddeleyite) with a silica oversaturated melt enriched in volatiles and incompatible elements. The development of fine-grained aggregates of clinopyroxene + amphibole + ilmenite around sub-ophitic clinopyroxene provides further evidence for this reaction. Homogeneous domains of baddeleyite were analysed by laser-ablation ICPMS and yielded crystallisation ages for the quartz gabbros of 488 ± 3 Ma. U-Pb analyses on zircon define a population at 486 ± 6 Ma, coeval with the U-Pb baddeleyite crystallization age, and a population at 525 ± 10 Ma, representing an inherited component. This finding indicates that the parent magma of the quartz gabbro was contaminated with upper crustal rocks. The gabbroic rocks of Varney Nunatak are associated with peraluminous granites and late basalt dykes. The similar whole-rock and clinopyroxene major and trace element concentrations in the quartz gabbros and basalts is suggestive for a genetic relationship. The emplacement age, whole-rock compositions and highly enriched Nd isotope signature (εNd (488 Ma) of -7.7 to -6.8) of the Varney Nunatak association are similar to those of other igneous units from central Victoria Land. The association developed during the post-collisional phase of the Ross orogeny. |
author2 |
M. Renna M. Tiepolo R. Tribuzio |
format |
Article in Journal/Newspaper |
author |
M. Renna R. Tribuzio M. Tiepolo |
author_facet |
M. Renna R. Tribuzio M. Tiepolo |
author_sort |
M. Renna |
title |
In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
title_short |
In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
title_full |
In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
title_fullStr |
In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
title_full_unstemmed |
In situ U-Pb geochronology of baddeleyite-zircon pairs using laser-ablation ICPMS : the case-study of quartz gabbro from Varney Nunatak (central Victoria Land, Antarctica) |
title_sort |
in situ u-pb geochronology of baddeleyite-zircon pairs using laser-ablation icpms : the case-study of quartz gabbro from varney nunatak (central victoria land, antarctica) |
publisher |
Schweizerbart |
publishDate |
2011 |
url |
http://hdl.handle.net/2434/298806 https://doi.org/10.1127/0935-1221/2011/0023-2083 |
long_lat |
ENVELOPE(162.517,162.517,-75.933,-75.933) |
geographic |
Victoria Land Varney Nunatak |
geographic_facet |
Victoria Land Varney Nunatak |
genre |
Antarc* Antarctica Victoria Land |
genre_facet |
Antarc* Antarctica Victoria Land |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000290096700007 volume:23 issue:2 firstpage:223 lastpage:240 numberofpages:18 journal:EUROPEAN JOURNAL OF MINERALOGY http://hdl.handle.net/2434/298806 doi:10.1127/0935-1221/2011/0023-2083 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-79956301876 |
op_doi |
https://doi.org/10.1127/0935-1221/2011/0023-2083 |
container_title |
European Journal of Mineralogy |
container_volume |
23 |
container_issue |
2 |
container_start_page |
223 |
op_container_end_page |
240 |
_version_ |
1790593524318601216 |