Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin
Alkaline dykes tentatively dated at ∼1.3 Ga cut the Vestfold Hills in a consistent N–S to N15°E direction. They form a spectrum between more abundant ultramafic lamprophyres (UML) corresponding broadly to H 2 O–CO 2 -rich nephelinites, and alkaline lamprophyres (AL), representing H 2 O–CO 2 -rich ba...
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Language: | English |
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Cambridge University Press (CUP)
1991
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Online Access: | http://dx.doi.org/10.1017/s0954102091000512 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102091000512 |
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crcambridgeupr:10.1017/s0954102091000512 2024-09-15T17:48:36+00:00 Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin Delor, C.P. Rock, N.M.S. 1991 http://dx.doi.org/10.1017/s0954102091000512 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102091000512 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 3, issue 4, page 419-432 ISSN 0954-1020 1365-2079 journal-article 1991 crcambridgeupr https://doi.org/10.1017/s0954102091000512 2024-08-28T04:03:14Z Alkaline dykes tentatively dated at ∼1.3 Ga cut the Vestfold Hills in a consistent N–S to N15°E direction. They form a spectrum between more abundant ultramafic lamprophyres (UML) corresponding broadly to H 2 O–CO 2 -rich nephelinites, and alkaline lamprophyres (AL), representing H 2 O–CO 2 -rich basanites. Olivine (Fo 46–93 , averaging Fo 75 ) is abundant only in the UML, but both types carry primary diopsidic clinopyroxene with complex zoning; amphibole (pargasite, hastingsite, kaersutite with up to 8.6% TiO 2 ); titanian phlogopite (up to 10% TiO 2 ); feldspars (orthoclase, anorthoclase, albite and andesine), nepheline (K-poor and Si-rich), ilmenite (up to 1% MgO and MnO), chrome titanomagnetite, and carbonate (magnesian calcite, ferroan dolomite, breunnerite). Lamprophyric peculiarities include the local coexistence of three feldspars, extremely Ti-rich amphiboles and micas, and the presence of globular structures and possibly primary carbonates. Some dykes carry small but abundant lherzolite xenoliths, others carry chromian diopside (1% Cr 2 O 3 ) and En 58–76 orthopyroxene xenocrysts. The dykes represent primitive, mantle-derived magmas which have undergone varying but generally low degrees of polybaric fractionation, together perhaps with mixing of more primitive and fractionated batches, during their ascent through the crust. Article in Journal/Newspaper Antarc* Antarctic Science Antarctica East Antarctica Princess Elizabeth Land Cambridge University Press Antarctic Science 3 4 419 432 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Alkaline dykes tentatively dated at ∼1.3 Ga cut the Vestfold Hills in a consistent N–S to N15°E direction. They form a spectrum between more abundant ultramafic lamprophyres (UML) corresponding broadly to H 2 O–CO 2 -rich nephelinites, and alkaline lamprophyres (AL), representing H 2 O–CO 2 -rich basanites. Olivine (Fo 46–93 , averaging Fo 75 ) is abundant only in the UML, but both types carry primary diopsidic clinopyroxene with complex zoning; amphibole (pargasite, hastingsite, kaersutite with up to 8.6% TiO 2 ); titanian phlogopite (up to 10% TiO 2 ); feldspars (orthoclase, anorthoclase, albite and andesine), nepheline (K-poor and Si-rich), ilmenite (up to 1% MgO and MnO), chrome titanomagnetite, and carbonate (magnesian calcite, ferroan dolomite, breunnerite). Lamprophyric peculiarities include the local coexistence of three feldspars, extremely Ti-rich amphiboles and micas, and the presence of globular structures and possibly primary carbonates. Some dykes carry small but abundant lherzolite xenoliths, others carry chromian diopside (1% Cr 2 O 3 ) and En 58–76 orthopyroxene xenocrysts. The dykes represent primitive, mantle-derived magmas which have undergone varying but generally low degrees of polybaric fractionation, together perhaps with mixing of more primitive and fractionated batches, during their ascent through the crust. |
format |
Article in Journal/Newspaper |
author |
Delor, C.P. Rock, N.M.S. |
spellingShingle |
Delor, C.P. Rock, N.M.S. Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
author_facet |
Delor, C.P. Rock, N.M.S. |
author_sort |
Delor, C.P. |
title |
Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
title_short |
Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
title_full |
Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
title_fullStr |
Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
title_full_unstemmed |
Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin |
title_sort |
alkaline-ultramafic lamprophyre dykes from the vestfold hills, princess elizabeth land (east antarctica): primitive magmas of deep mantle origin |
publisher |
Cambridge University Press (CUP) |
publishDate |
1991 |
url |
http://dx.doi.org/10.1017/s0954102091000512 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102091000512 |
genre |
Antarc* Antarctic Science Antarctica East Antarctica Princess Elizabeth Land |
genre_facet |
Antarc* Antarctic Science Antarctica East Antarctica Princess Elizabeth Land |
op_source |
Antarctic Science volume 3, issue 4, page 419-432 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102091000512 |
container_title |
Antarctic Science |
container_volume |
3 |
container_issue |
4 |
container_start_page |
419 |
op_container_end_page |
432 |
_version_ |
1810290041970229248 |