Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica

The recognition of a Mesoproterozoic large igneous province (LIP) across large parts of southern Africa has been strengthened by recent geochronology, geochemistry and petrology. The c. 1100 Ma Umkondo province has been recognized across parts of Botswana, Zimbabwe, South Africa and Mozambique where...

Full description

Bibliographic Details
Published in:Antarctic Science
Main Authors: Riley, Teal R., Millar, Ian L.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge Journals 2014
Subjects:
Online Access:http://nora.nerc.ac.uk/id/eprint/507785/
https://nora.nerc.ac.uk/id/eprint/507785/1/Riley.pdf
https://doi.org/10.1017/S0954102013000916
id ftnerc:oai:nora.nerc.ac.uk:507785
record_format openpolar
spelling ftnerc:oai:nora.nerc.ac.uk:507785 2023-05-15T13:48:08+02:00 Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica Riley, Teal R. Millar, Ian L. 2014-08 text http://nora.nerc.ac.uk/id/eprint/507785/ https://nora.nerc.ac.uk/id/eprint/507785/1/Riley.pdf https://doi.org/10.1017/S0954102013000916 en eng Cambridge Journals https://nora.nerc.ac.uk/id/eprint/507785/1/Riley.pdf Riley, Teal R. orcid:0000-0002-3333-5021 Millar, Ian L. 2014 Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica. Antarctic Science, 26 (04). 389-399. https://doi.org/10.1017/S0954102013000916 <https://doi.org/10.1017/S0954102013000916> Earth Sciences Publication - Article PeerReviewed 2014 ftnerc https://doi.org/10.1017/S0954102013000916 2023-02-04T19:39:56Z The recognition of a Mesoproterozoic large igneous province (LIP) across large parts of southern Africa has been strengthened by recent geochronology, geochemistry and petrology. The c. 1100 Ma Umkondo province has been recognized across parts of Botswana, Zimbabwe, South Africa and Mozambique where tholeiitic sills, dykes and rare lava flows have been correlated into a single magmatic province emplaced in the interval 1108–1112 Ma. The extension of the province into the Dronning Maud Land region of Antarctica has been suggested by several workers, but detailed analyses of geochemistry and petrogenesis are lacking, as are comparative studies. This study investigates 25 dykes and sills of the Borgmassivet intrusions which include several of the major diorite sills of the province, up to 300 m in thickness. The dykes and sills are also considered to be c. 1100 Ma and they were emplaced, in part, synchronously with the Ritscherflya Supergroup sedimentary sequence. The Borgmassivet intrusions are characterized by geochemical signatures that suggest the magmas were either extensively contaminated by continental crust or derived from an enriched lithospheric mantle source, where the enrichment was related to earlier subduction. The limited geochemical range of the Borgmassivet and Umkondo intrusions are probably not consistent with significant levels of crustal contamination. Furthermore, the trace element ratios indicate a source in the sub-lithospheric mantle, followed by gabbroic fractionation and interaction with lithospheric wall rocks. Article in Journal/Newspaper Antarc* Antarctic Science Antarctica Dronning Maud Land Natural Environment Research Council: NERC Open Research Archive Dronning Maud Land Wall Rocks ENVELOPE(-129.312,-129.312,52.728,52.728) Ahlmannryggen ENVELOPE(-2.500,-2.500,-71.833,-71.833) Borgmassivet ENVELOPE(-3.500,-3.500,-72.667,-72.667) Ritscherflya ENVELOPE(-9.000,-9.000,-73.000,-73.000) Antarctic Science 26 4 389 399
institution Open Polar
collection Natural Environment Research Council: NERC Open Research Archive
op_collection_id ftnerc
language English
topic Earth Sciences
spellingShingle Earth Sciences
Riley, Teal R.
Millar, Ian L.
Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
topic_facet Earth Sciences
description The recognition of a Mesoproterozoic large igneous province (LIP) across large parts of southern Africa has been strengthened by recent geochronology, geochemistry and petrology. The c. 1100 Ma Umkondo province has been recognized across parts of Botswana, Zimbabwe, South Africa and Mozambique where tholeiitic sills, dykes and rare lava flows have been correlated into a single magmatic province emplaced in the interval 1108–1112 Ma. The extension of the province into the Dronning Maud Land region of Antarctica has been suggested by several workers, but detailed analyses of geochemistry and petrogenesis are lacking, as are comparative studies. This study investigates 25 dykes and sills of the Borgmassivet intrusions which include several of the major diorite sills of the province, up to 300 m in thickness. The dykes and sills are also considered to be c. 1100 Ma and they were emplaced, in part, synchronously with the Ritscherflya Supergroup sedimentary sequence. The Borgmassivet intrusions are characterized by geochemical signatures that suggest the magmas were either extensively contaminated by continental crust or derived from an enriched lithospheric mantle source, where the enrichment was related to earlier subduction. The limited geochemical range of the Borgmassivet and Umkondo intrusions are probably not consistent with significant levels of crustal contamination. Furthermore, the trace element ratios indicate a source in the sub-lithospheric mantle, followed by gabbroic fractionation and interaction with lithospheric wall rocks.
format Article in Journal/Newspaper
author Riley, Teal R.
Millar, Ian L.
author_facet Riley, Teal R.
Millar, Ian L.
author_sort Riley, Teal R.
title Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
title_short Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
title_full Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
title_fullStr Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
title_full_unstemmed Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica
title_sort geochemistry of the 1100 ma intrusive rocks from the ahlmannryggen region, dronning maud land, antarctica
publisher Cambridge Journals
publishDate 2014
url http://nora.nerc.ac.uk/id/eprint/507785/
https://nora.nerc.ac.uk/id/eprint/507785/1/Riley.pdf
https://doi.org/10.1017/S0954102013000916
long_lat ENVELOPE(-129.312,-129.312,52.728,52.728)
ENVELOPE(-2.500,-2.500,-71.833,-71.833)
ENVELOPE(-3.500,-3.500,-72.667,-72.667)
ENVELOPE(-9.000,-9.000,-73.000,-73.000)
geographic Dronning Maud Land
Wall Rocks
Ahlmannryggen
Borgmassivet
Ritscherflya
geographic_facet Dronning Maud Land
Wall Rocks
Ahlmannryggen
Borgmassivet
Ritscherflya
genre Antarc*
Antarctic Science
Antarctica
Dronning Maud Land
genre_facet Antarc*
Antarctic Science
Antarctica
Dronning Maud Land
op_relation https://nora.nerc.ac.uk/id/eprint/507785/1/Riley.pdf
Riley, Teal R. orcid:0000-0002-3333-5021
Millar, Ian L. 2014 Geochemistry of the 1100 Ma intrusive rocks from the Ahlmannryggen region, Dronning Maud Land, Antarctica. Antarctic Science, 26 (04). 389-399. https://doi.org/10.1017/S0954102013000916 <https://doi.org/10.1017/S0954102013000916>
op_doi https://doi.org/10.1017/S0954102013000916
container_title Antarctic Science
container_volume 26
container_issue 4
container_start_page 389
op_container_end_page 399
_version_ 1766248764740206592