Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula
Garnet is widely found as a minor constituent in rocks of the Antarctic Peninsula Volcanic Group (APVG) of Trinity Peninsula. It occurs as conspicuous megacrysts, or in xenoliths within volcanic rocks of andesitic-rhyolitic composition and as detrital grains in the associated terrestrial sediments....
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Geological Society of London
1982
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Online Access: | http://nora.nerc.ac.uk/id/eprint/524377/ https://doi.org/10.1144/gsjgs.139.6.0713 |
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ftnerc:oai:nora.nerc.ac.uk:524377 2024-02-04T09:55:39+01:00 Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula Hamer, R.D. Moyes, A.B. 1982-12 http://nora.nerc.ac.uk/id/eprint/524377/ https://doi.org/10.1144/gsjgs.139.6.0713 unknown Geological Society of London Hamer, R.D.; Moyes, A.B. 1982 Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula. Journal of the Geological Society, 139 (6). 713-720. https://doi.org/10.1144/gsjgs.139.6.0713 <https://doi.org/10.1144/gsjgs.139.6.0713> Earth Sciences Publication - Article PeerReviewed 1982 ftnerc https://doi.org/10.1144/gsjgs.139.6.0713 2024-01-05T00:03:05Z Garnet is widely found as a minor constituent in rocks of the Antarctic Peninsula Volcanic Group (APVG) of Trinity Peninsula. It occurs as conspicuous megacrysts, or in xenoliths within volcanic rocks of andesitic-rhyolitic composition and as detrital grains in the associated terrestrial sediments. It is also found as an accessory mineral in many plutonic rocks from the E coast of the Antarctic Peninsula. Evidence is presented to show that the garnet can be divided petrographically and chemically into two main groups: Type A: almandine-rich primary igneous garnet, and Type B: less almandine- and more pyrope-rich garnet as xenocrysts or included in xenoliths within the volcanic rocks. Comparison with published experimental data on garnet occurrence in acidic igneous rocks suggests that high almandine-low spessartine garnet in volcanic rocks is a remnant phase of high pressure crystallization from magma at pressures of >7 kbar. Garnet with a higher pyrope content is regarded as xenocrystal in origin, having been derived from garnet-bearing country rocks at depth, either as accidental inclusions or through direct partial melting (restite) of the lower crust, and implies that a considerable thickness (>25 km) of crustal material was in existence before the generation of the Mesozoic magmatic arc. The origin of these calc-alkaline magmas may therefore be due, at least in part, to partial melting of pre-existing sialic crustal material. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Natural Environment Research Council: NERC Open Research Archive Antarctic Antarctic Peninsula The Antarctic Trinity Peninsula ENVELOPE(-58.000,-58.000,-63.500,-63.500) Journal of the Geological Society 139 6 713 720 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Hamer, R.D. Moyes, A.B. Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
topic_facet |
Earth Sciences |
description |
Garnet is widely found as a minor constituent in rocks of the Antarctic Peninsula Volcanic Group (APVG) of Trinity Peninsula. It occurs as conspicuous megacrysts, or in xenoliths within volcanic rocks of andesitic-rhyolitic composition and as detrital grains in the associated terrestrial sediments. It is also found as an accessory mineral in many plutonic rocks from the E coast of the Antarctic Peninsula. Evidence is presented to show that the garnet can be divided petrographically and chemically into two main groups: Type A: almandine-rich primary igneous garnet, and Type B: less almandine- and more pyrope-rich garnet as xenocrysts or included in xenoliths within the volcanic rocks. Comparison with published experimental data on garnet occurrence in acidic igneous rocks suggests that high almandine-low spessartine garnet in volcanic rocks is a remnant phase of high pressure crystallization from magma at pressures of >7 kbar. Garnet with a higher pyrope content is regarded as xenocrystal in origin, having been derived from garnet-bearing country rocks at depth, either as accidental inclusions or through direct partial melting (restite) of the lower crust, and implies that a considerable thickness (>25 km) of crustal material was in existence before the generation of the Mesozoic magmatic arc. The origin of these calc-alkaline magmas may therefore be due, at least in part, to partial melting of pre-existing sialic crustal material. |
format |
Article in Journal/Newspaper |
author |
Hamer, R.D. Moyes, A.B. |
author_facet |
Hamer, R.D. Moyes, A.B. |
author_sort |
Hamer, R.D. |
title |
Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
title_short |
Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
title_full |
Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
title_fullStr |
Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
title_full_unstemmed |
Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula |
title_sort |
composition and origin of garnet from the antarctic peninsula volcanic group of trinity peninsula |
publisher |
Geological Society of London |
publishDate |
1982 |
url |
http://nora.nerc.ac.uk/id/eprint/524377/ https://doi.org/10.1144/gsjgs.139.6.0713 |
long_lat |
ENVELOPE(-58.000,-58.000,-63.500,-63.500) |
geographic |
Antarctic Antarctic Peninsula The Antarctic Trinity Peninsula |
geographic_facet |
Antarctic Antarctic Peninsula The Antarctic Trinity Peninsula |
genre |
Antarc* Antarctic Antarctic Peninsula |
genre_facet |
Antarc* Antarctic Antarctic Peninsula |
op_relation |
Hamer, R.D.; Moyes, A.B. 1982 Composition and origin of garnet from the Antarctic Peninsula Volcanic Group of Trinity Peninsula. Journal of the Geological Society, 139 (6). 713-720. https://doi.org/10.1144/gsjgs.139.6.0713 <https://doi.org/10.1144/gsjgs.139.6.0713> |
op_doi |
https://doi.org/10.1144/gsjgs.139.6.0713 |
container_title |
Journal of the Geological Society |
container_volume |
139 |
container_issue |
6 |
container_start_page |
713 |
op_container_end_page |
720 |
_version_ |
1789959712934985728 |