Isotope evidence for the origin of Andean granites
ABSTRACT The genesis of subduction-related magmas in the Andean region of South America and the Antarctic Peninsula is considered in relation to the Palaeozoic to Cenozoic granitoids belts which are thought to parallel palaeo-coastlines. Their Sr-Nd isotope systematics show a wide range of initial c...
Published in: | Earth and Environmental Science Transactions of the Royal Society of Edinburgh |
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Online Access: | http://dx.doi.org/10.1017/s0263593300014164 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263593300014164 |
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crcambridgeupr:10.1017/s0263593300014164 2024-03-03T08:38:01+00:00 Isotope evidence for the origin of Andean granites Pankhurst, R. J. Hole, M. J. Brook, M. 1988 http://dx.doi.org/10.1017/s0263593300014164 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263593300014164 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Earth and Environmental Science Transactions of the Royal Society of Edinburgh volume 79, issue 2-3, page 123-133 ISSN 1755-6910 1755-6929 General Earth and Planetary Sciences General Environmental Science journal-article 1988 crcambridgeupr https://doi.org/10.1017/s0263593300014164 2024-02-08T08:31:06Z ABSTRACT The genesis of subduction-related magmas in the Andean region of South America and the Antarctic Peninsula is considered in relation to the Palaeozoic to Cenozoic granitoids belts which are thought to parallel palaeo-coastlines. Their Sr-Nd isotope systematics show a wide range of initial compositions ( 87 Sr/ 86 Sr 0 0·7038 to >0·710; εNd, +4 to –10) requiring material input from both depleted mantle and continental crust. In local transects there are consistent trends with time of emplacement, from enriched (crustal) to depleted (mantle) sources, regardless of the sense of migration of magmatism (towards or away from the continent). These trends represent mixing between mantle-derived material and anatectic melts of the lower crust: in each case the crustal end-member reflects the age and isotopic composition of the local deep crustal basement (Precambrian in the easternmost Andes, Palaeozoic in the W and in the Antarctic Peninsula). The depleted end-member could be derived by melting within the subducted oceanic crust, the overlying mantle or previously crystallised mafic underplating. One of the most important factors controlling the mixing process is the angle of subduction, resulting in magma generation under variable tectonic conditions. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Cambridge University Press Antarctic The Antarctic Antarctic Peninsula Earth and Environmental Science Transactions of the Royal Society of Edinburgh 79 2-3 123 133 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
General Earth and Planetary Sciences General Environmental Science |
spellingShingle |
General Earth and Planetary Sciences General Environmental Science Pankhurst, R. J. Hole, M. J. Brook, M. Isotope evidence for the origin of Andean granites |
topic_facet |
General Earth and Planetary Sciences General Environmental Science |
description |
ABSTRACT The genesis of subduction-related magmas in the Andean region of South America and the Antarctic Peninsula is considered in relation to the Palaeozoic to Cenozoic granitoids belts which are thought to parallel palaeo-coastlines. Their Sr-Nd isotope systematics show a wide range of initial compositions ( 87 Sr/ 86 Sr 0 0·7038 to >0·710; εNd, +4 to –10) requiring material input from both depleted mantle and continental crust. In local transects there are consistent trends with time of emplacement, from enriched (crustal) to depleted (mantle) sources, regardless of the sense of migration of magmatism (towards or away from the continent). These trends represent mixing between mantle-derived material and anatectic melts of the lower crust: in each case the crustal end-member reflects the age and isotopic composition of the local deep crustal basement (Precambrian in the easternmost Andes, Palaeozoic in the W and in the Antarctic Peninsula). The depleted end-member could be derived by melting within the subducted oceanic crust, the overlying mantle or previously crystallised mafic underplating. One of the most important factors controlling the mixing process is the angle of subduction, resulting in magma generation under variable tectonic conditions. |
format |
Article in Journal/Newspaper |
author |
Pankhurst, R. J. Hole, M. J. Brook, M. |
author_facet |
Pankhurst, R. J. Hole, M. J. Brook, M. |
author_sort |
Pankhurst, R. J. |
title |
Isotope evidence for the origin of Andean granites |
title_short |
Isotope evidence for the origin of Andean granites |
title_full |
Isotope evidence for the origin of Andean granites |
title_fullStr |
Isotope evidence for the origin of Andean granites |
title_full_unstemmed |
Isotope evidence for the origin of Andean granites |
title_sort |
isotope evidence for the origin of andean granites |
publisher |
Cambridge University Press (CUP) |
publishDate |
1988 |
url |
http://dx.doi.org/10.1017/s0263593300014164 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263593300014164 |
geographic |
Antarctic The Antarctic Antarctic Peninsula |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula |
genre |
Antarc* Antarctic Antarctic Peninsula |
genre_facet |
Antarc* Antarctic Antarctic Peninsula |
op_source |
Earth and Environmental Science Transactions of the Royal Society of Edinburgh volume 79, issue 2-3, page 123-133 ISSN 1755-6910 1755-6929 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0263593300014164 |
container_title |
Earth and Environmental Science Transactions of the Royal Society of Edinburgh |
container_volume |
79 |
container_issue |
2-3 |
container_start_page |
123 |
op_container_end_page |
133 |
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1792503749098340352 |