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dc.contributor.authorWhitehead, J.
dc.contributor.authorGrieve, R. A. F.
dc.contributor.authorSpray, J. G.
dc.date.accessioned2021-02-12T20:55:32Z
dc.date.available2021-02-12T20:55:32Z
dc.date.issued2002-01-01
dc.identifier.citationWhitehead, J., Grieve, R. A. F., & Spray, J. G. (2002). Mineralogy and petrology of melt rocks from the Popigai impact structure, Siberia. Meteoritics & Planetary Science, 37(5), 623-647.
dc.identifier.issn1945-5100
dc.identifier.doi10.1111/j.1945-5100.2002.tb00844.x
dc.identifier.urihttp://hdl.handle.net/10150/655512
dc.description.abstractThe late Eocene Popigai impact structure of Siberia comprises an approximately 0.5-1.5 km thick, ~100 km diameter sequence of clast-rich and clast-poor andesitic to rhyolitic impact melt rocks and impact breccias, underlain by Archean to Proterozoic crystalline basement and Proterozoic to Phanerozoic sedimentary rocks. The fine-grained to cryptocrystalline texture of the more melt-rich rocks, despite their occurrence in bodies locally in excess of 800 m thick and 28 km long, suggests that the melt crystallized in response to: (1) cooling by the clast load, and/or; (2) rapid nucleation on finely brecciated clasts, which have since been assimilated and/or; (3) crystallization enhanced by the relatively low water contents of the melts. Rapid crystallisation of the melt is indicated by the lack of zoning in minerals, the presence of glass, the lack of strain recovery features in clasts and the lack of evidence for fractionation in the major and trace elements, including the rare-earth elements. Optical and analytical electron microscopy reveal that the previously reported division of the melt rocks into high- and low-temperature variants based on hand sample appearance, or glass content, is not warranted. Clasts within the melt-rich rocks exhibit a wide range of shock metamorphic features, though they are not distributed in the impact melts in a systematic manner. This indicates that the melt-rich rocks were well mixed during their formation, thus juxtaposing unshocked with shocked material. Injection of mesostasis melt into partially melted checkerboard plagioclase and orthopyroxene clasts also occurred during this mixing stage.
dc.language.isoen
dc.publisherThe Meteoritical Society
dc.relation.urlhttps://meteoritical.org/
dc.rightsCopyright © The Meteoritical Society
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectPopigai
dc.subjectimpact structures
dc.subjectSiberia
dc.subjectimpact melt
dc.subjectimpact breccias
dc.subjectclasts
dc.titleMineralogy and petrology of melt rocks from the Popigai impact structure, Siberia
dc.typeArticle
dc.typetext
dc.identifier.journalMeteoritics & Planetary Science
dc.description.collectioninformationThe Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume37
dc.source.issue5
dc.source.beginpage623
dc.source.endpage647
refterms.dateFOA2021-02-12T20:55:32Z


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