Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land
At Mount Charity, north-eastern Palmer Land, Rb–Sr whole-rock dating has identified three successive phases of granitoid emplacement in Triassic (232 ± 4 Ma), Jurassic (168 ± 1 Ma), and Cretaceous (120 ± 4 Ma) times. The Triassic suite comprises tonalites, granodiorites (including one two-mica grano...
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crcambridgeupr:10.1017/s0954102096000260 2024-09-15T17:48:39+00:00 Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land Scarrow, Jane H. Pankhurst, R.J. Leat, P.T. Vaughan, A.P.M. 1996 http://dx.doi.org/10.1017/s0954102096000260 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102096000260 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 8, issue 2, page 193-206 ISSN 0954-1020 1365-2079 journal-article 1996 crcambridgeupr https://doi.org/10.1017/s0954102096000260 2024-07-31T04:01:29Z At Mount Charity, north-eastern Palmer Land, Rb–Sr whole-rock dating has identified three successive phases of granitoid emplacement in Triassic (232 ± 4 Ma), Jurassic (168 ± 1 Ma), and Cretaceous (120 ± 4 Ma) times. The Triassic suite comprises tonalites, granodiorites (including one two-mica granodiorite), monzogranite and a granite having either I-type or S-like mineralogies. The Jurassic suite includes only S-like granites, and the Cretaceous biotite tonalites and biotite granodiorite are all I-type. The three suites have negative ∈Nd and positive ∈Sr, and have subtly different Nd and Sr isotope characteristics: Suite A, ∈Sr t =+30 to +53 and ∈Nd t =−0.9 to −3.1, Suite B, ∈Sr t =+43 to +64 and ∈Nd t =−2 to −5.3, Suite C, ∈Sr t =+22 to +23 and ∈Nd t =−2.5 to −2.6. Mineralogical and compositional differences between the three suites suggest that different sources were tapped. All the granitoids are isotopically intermediate in composition between Palmer Land crust and depleted asthenosphere. We suggest that the I- type granitoids were produced by melting of meta-igneous crust; by contrast, the S- like granitoids represent partial melts of garnet-bearing sedimentary crust. Syn-magmatic structures in Suite A are compared with known structural events in western Palmer Land and suggest that extension controlled Triassic pluton emplacement. The Jurassic magmas were also emplaced during an episode of arc extension, and intrusion of the Cretaceous magmas was probably controlled by regional extension and dextral transtension. Successive phases of magmatism focussed at Mount Charity are consistent with reactivated faults acting as magma conduits. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctic Science Palmer Land Cambridge University Press Antarctic Science 8 2 193 206 |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
At Mount Charity, north-eastern Palmer Land, Rb–Sr whole-rock dating has identified three successive phases of granitoid emplacement in Triassic (232 ± 4 Ma), Jurassic (168 ± 1 Ma), and Cretaceous (120 ± 4 Ma) times. The Triassic suite comprises tonalites, granodiorites (including one two-mica granodiorite), monzogranite and a granite having either I-type or S-like mineralogies. The Jurassic suite includes only S-like granites, and the Cretaceous biotite tonalites and biotite granodiorite are all I-type. The three suites have negative ∈Nd and positive ∈Sr, and have subtly different Nd and Sr isotope characteristics: Suite A, ∈Sr t =+30 to +53 and ∈Nd t =−0.9 to −3.1, Suite B, ∈Sr t =+43 to +64 and ∈Nd t =−2 to −5.3, Suite C, ∈Sr t =+22 to +23 and ∈Nd t =−2.5 to −2.6. Mineralogical and compositional differences between the three suites suggest that different sources were tapped. All the granitoids are isotopically intermediate in composition between Palmer Land crust and depleted asthenosphere. We suggest that the I- type granitoids were produced by melting of meta-igneous crust; by contrast, the S- like granitoids represent partial melts of garnet-bearing sedimentary crust. Syn-magmatic structures in Suite A are compared with known structural events in western Palmer Land and suggest that extension controlled Triassic pluton emplacement. The Jurassic magmas were also emplaced during an episode of arc extension, and intrusion of the Cretaceous magmas was probably controlled by regional extension and dextral transtension. Successive phases of magmatism focussed at Mount Charity are consistent with reactivated faults acting as magma conduits. |
format |
Article in Journal/Newspaper |
author |
Scarrow, Jane H. Pankhurst, R.J. Leat, P.T. Vaughan, A.P.M. |
spellingShingle |
Scarrow, Jane H. Pankhurst, R.J. Leat, P.T. Vaughan, A.P.M. Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
author_facet |
Scarrow, Jane H. Pankhurst, R.J. Leat, P.T. Vaughan, A.P.M. |
author_sort |
Scarrow, Jane H. |
title |
Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
title_short |
Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
title_full |
Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
title_fullStr |
Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
title_full_unstemmed |
Antarctic Peninsula granitoid petrogenesis: a case study from Mount Charity, north-eastern Palmer Land |
title_sort |
antarctic peninsula granitoid petrogenesis: a case study from mount charity, north-eastern palmer land |
publisher |
Cambridge University Press (CUP) |
publishDate |
1996 |
url |
http://dx.doi.org/10.1017/s0954102096000260 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102096000260 |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctic Science Palmer Land |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctic Science Palmer Land |
op_source |
Antarctic Science volume 8, issue 2, page 193-206 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102096000260 |
container_title |
Antarctic Science |
container_volume |
8 |
container_issue |
2 |
container_start_page |
193 |
op_container_end_page |
206 |
_version_ |
1810290115553001472 |