Data : Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : Evidence for a late stage shallow origin

dc.contributor.authorRoberts, R. James
dc.contributor.emailJames.roberts@up.ac.zaen_ZA
dc.date.accessioned2018-09-10T06:50:41Z
dc.date.available2018-09-10T06:50:41Z
dc.date.issued2018en_ZA
dc.description.abstractClinopyroxene 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.en_ZA
dc.description.sponsorshipUniversity of Pretoriaen_ZA
dc.description.tableofcontentsThese xls files contains: • EPMA analyses for clinopyroxene crystals from Marion Island • EPMA analyses for olivine, spinel and sulphides included in clinopyroxene crystals from Marion Island • LA-ICP-MS analyses of clinopyroxenes from Marion Islanden_ZA
dc.identifier.citationRoberts, R. James. (2018) Clinopyroxene megacrysts from Marion Island. University of Pretoria. Department of Geologyen_ZA
dc.identifier.urihttp://hdl.handle.net/2263/66489
dc.language.isoenen_ZA
dc.publisherDepartment of Geology, University of Pretoriaen_ZA
dc.rights© University of Pretoria, Faculty of Natural and Agricultural Science.en_ZA
dc.rights.uri© 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.en_ZA
dc.subjectMarion Islanden_ZA
dc.subjectClinopyroxene megacrystsen_ZA
dc.subjectOcean Islandsen_ZA
dc.subjectAnkaramitesen_ZA
dc.titleData : Clinopyroxene megacrysts from Marion Island, Antarctic Ocean : Evidence for a late stage shallow originen_ZA
dc.typeDataseten_ZA

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Supplementary Data A- Marion CPX data.xlsx
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Supplementary Data B- Marion Ol-Ox-Sul analyses.xlsx
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Supplementary Data C- Marion LA-ICP-MS data.xlsx
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