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dc.contributor.authorWalton, E. L.
dc.contributor.authorSpray, J. G.
dc.date.accessioned2021-02-12T20:56:29Z
dc.date.available2021-02-12T20:56:29Z
dc.date.issued2003-01-01
dc.identifier.citationWalton, E. L., & Spray, J. G. (2003). Mineralogy, microtexture, and composition of shock‐induced melt pockets in the Los Angeles basaltic shergottite. Meteoritics & Planetary Science, 38(12), 1865-1875.
dc.identifier.issn1945-5100
dc.identifier.doi10.1111/j.1945-5100.2003.tb00020.x
dc.identifier.urihttp://hdl.handle.net/10150/655780
dc.description.abstractAnalytical electron microscopy of shock features in the basaltic shergottite Los Angeles (stone 1) reveals: 1) shock recorded in the bulk sample; and 2) localized pressure and temperature excursions that have generated melt pockets up to 4 mm in diameter. Bulk shock effects include microfaulting (offsets 1-200 m), mosaicism, deformed exsolution lamellae and planar fracturing in pyroxene, undulose extinction in whitlockite, mechanical twinning in titanomagnetite and ilmenite, and the transformation of plagioclase to maskelynite (less than or equal to 4% remnant reduced birefringence). The pressure estimates for bulk shock are 35-40 GPa. Localized shock excursions have generated three types of discrete melt zones (0.07 x 1.3 mm to 3.0 x 3.5 mm apparent diameter) possessing glassy to microcrystalline groundmasses. These melt pockets are differentiated on the basis of size, clast volume, and degree of crystallization and vesiculation. Melt veins and melt dikelets emanate from the melt pockets up to 3 mm into the host rock but do not necessarily connect with other melt pockets. The melt pockets were generated by pressure-temperature excursions of 60-80 GPa and 1600-2000 degrees C, resulting in discrete melting of adjacent host rock minerals at grain boundary margins. Concentric zoning in the margins of clinopyroxenes coincides with a progressive reduction in birefringence as melt pockets are approached. This suggests that the shock excursions were focused as point sources in the wake of the shock front that induced bulk damage.
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.subjectMartian (SNC) meteorites
dc.subjectshergottites
dc.subjectshock metamorphism
dc.titleMineralogy, microtexture, and composition of shock-induced melt pockets in the Los Angeles basaltic shergottite
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.volume38
dc.source.issue12
dc.source.beginpage1865
dc.source.endpage1875
refterms.dateFOA2021-02-12T20:56:29Z


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