Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin
Clinopyroxene megacrysts (up to 5 cm) from a scoria cone on Marion Island, Antarctic Ocean are zoned, with compositionally distinct low (Al+Ti) and high (Al+Ti) patches arranged haphazardly throughout crystals. Inclusions of olivine, pyrrhotite, oxides, sulphides, and rounded inclusions with euhedra...
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University of Pretoria
2020
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ftdatacite:10.25403/upresearchdata.11961504 2023-05-15T14:00:33+02:00 Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin Roberts, James R 2020 https://dx.doi.org/10.25403/upresearchdata.11961504 https://researchdata.up.ac.za/articles/Clinopyroxene_megacrysts_from_Marion_Island_Antarctic_Ocean_evidence_for_a_late_stage_shallow_origin/11961504 unknown University of Pretoria CC0 https://creativecommons.org/publicdomain/zero/1.0 CC0 40312 Structural Geology FOS Earth and related environmental sciences dataset Dataset 2020 ftdatacite https://doi.org/10.25403/upresearchdata.11961504 2021-11-05T12:55:41Z Clinopyroxene megacrysts (up to 5 cm) from a scoria cone on Marion Island, Antarctic Ocean are zoned, with compositionally distinct low (Al+Ti) and high (Al+Ti) patches arranged haphazardly throughout crystals. Inclusions of olivine, pyrrhotite, oxides, sulphides, and rounded inclusions with euhedral micro-crystals interpreted as former melt inclusions are observed. Olivine inclusions have variable compositions, ranging from primary Ti-poor crystals to Ti-rich crystals hosting secondary haematite crystals formed by hydrogenation. The crystals contain voids, which are concentrated in the middle of each crystal, indicating that the initial crystal growth was skeletal. Subsequent crystallisation filled in the skeletal framework, creating the patchy zoning in the crystals. The Marion Island megacrysts are not homogenous, but the combination of crustal clinopyroxene compositions, primary and hydrogenated olivine, and the mode of eruption in scoria eruptions indicates that these crystals most likely formed in a shallow magma chamber. Primary olivines crystallised from a mafic magma as well as secondary altered olivines are incorporated into a rapidly growing megacryst in a super-saturated, fluid-rich environment, prior to being ejected onto surface in a scoria eruption. Dataset Antarc* Antarctic Antarctic Ocean Marion Island DataCite Metadata Store (German National Library of Science and Technology) Antarctic Antarctic Ocean |
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Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
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language |
unknown |
topic |
40312 Structural Geology FOS Earth and related environmental sciences |
spellingShingle |
40312 Structural Geology FOS Earth and related environmental sciences Roberts, James R Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
topic_facet |
40312 Structural Geology FOS Earth and related environmental sciences |
description |
Clinopyroxene megacrysts (up to 5 cm) from a scoria cone on Marion Island, Antarctic Ocean are zoned, with compositionally distinct low (Al+Ti) and high (Al+Ti) patches arranged haphazardly throughout crystals. Inclusions of olivine, pyrrhotite, oxides, sulphides, and rounded inclusions with euhedral micro-crystals interpreted as former melt inclusions are observed. Olivine inclusions have variable compositions, ranging from primary Ti-poor crystals to Ti-rich crystals hosting secondary haematite crystals formed by hydrogenation. The crystals contain voids, which are concentrated in the middle of each crystal, indicating that the initial crystal growth was skeletal. Subsequent crystallisation filled in the skeletal framework, creating the patchy zoning in the crystals. The Marion Island megacrysts are not homogenous, but the combination of crustal clinopyroxene compositions, primary and hydrogenated olivine, and the mode of eruption in scoria eruptions indicates that these crystals most likely formed in a shallow magma chamber. Primary olivines crystallised from a mafic magma as well as secondary altered olivines are incorporated into a rapidly growing megacryst in a super-saturated, fluid-rich environment, prior to being ejected onto surface in a scoria eruption. |
format |
Dataset |
author |
Roberts, James R |
author_facet |
Roberts, James R |
author_sort |
Roberts, James R |
title |
Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
title_short |
Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
title_full |
Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
title_fullStr |
Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
title_full_unstemmed |
Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : evidence for a late stage shallow origin |
title_sort |
clinopyroxene megacrysts from marion island, antarctic ocean : evidence for a late stage shallow origin |
publisher |
University of Pretoria |
publishDate |
2020 |
url |
https://dx.doi.org/10.25403/upresearchdata.11961504 https://researchdata.up.ac.za/articles/Clinopyroxene_megacrysts_from_Marion_Island_Antarctic_Ocean_evidence_for_a_late_stage_shallow_origin/11961504 |
geographic |
Antarctic Antarctic Ocean |
geographic_facet |
Antarctic Antarctic Ocean |
genre |
Antarc* Antarctic Antarctic Ocean Marion Island |
genre_facet |
Antarc* Antarctic Antarctic Ocean Marion Island |
op_rights |
CC0 https://creativecommons.org/publicdomain/zero/1.0 |
op_rightsnorm |
CC0 |
op_doi |
https://doi.org/10.25403/upresearchdata.11961504 |
_version_ |
1766269724409200640 |