A petrological, chemical and isotopic study of some early solar system HED basaltic igneous meteorites: how many parent asteroids?

Trudi Kennedy

    Research output: ThesisDoctoral Thesis

    879 Downloads (Pure)

    Abstract

    [Truncated abstract] Three new, previously unclassified meteorites, from the Western Australian Museum collection, Lake Carnegie, Deakin 010 and Old Homestead 003, have been studied to characterise these meteorites and determine their asteroidal/planetary parent body(ies) source. This study encompassed microscopy, geochemical analysis by energy-dispersive
    spectroscopy (EDS), wavelength-dispersive spectroscopy (WDS) element concentration mapping and analysis, synchrotron X-ray fluorescence microscopy (SXRF) element mapping, X-ray absorption near edge structure (XANES) Fe-valence determination, secondary ion mass spectrometry (SIMS) three-oxygen isotope analyses and 40Ar/39Ar dating. The previously described meteorites, Bunburra Rockhole, Camel Donga and Millbillillie were also included in this study to broaden the data set.

    Lake Carnegie is an unbrecciated cumulate eucrite comprised of low Ca-pyroxene, (Fs26-61, En30-40, Wo5-44) and calcic plagioclase (An84-94, Ab6-15, Or0-1), with minor ilmenite, chromite and very minor Fe-Ni metal and troilite. Deakin 010 is an anomalous basaltic, monomict, brecciated achondrite and is comprised of low-Ca pyroxene (Fs22-64, En27-38, Wo1-47) and calcic plagioclase (An75-93, Ab6-20, Or0-6), with minor ilmenite, chromite, troilite and Fe-Ni metal. Old Homestead 003 is a howardite of, geochemically diverse, basaltic components of regolith origin comprised dominantly of pyroxene (Fs20-68, En6-78, Wo1-44) and calcic plagioclase (An79-94, Ab6-20, Or0.1-1.4), including some clasts containing olivine (Fa5-46, Fo54- 96). Mn/Fe ratios suggest all three meteorites originated in a similar cosmochemical “feeder zone”, i.e. heliocentric distance, to that of the howardite-eucrite-diogenite (HED) parent body. The pyroxene Mg# of Lake Carnegie (35.8–44.2) and Deakin 010 (34.9–55.2) are compatible with each other and comparable to Nuevo Laredo-trend eucrites. Old Homestead 003 has a significantly wider range of pyroxene Mg# (29.5 78.5) than the other two samples, commensurate with its origin as regolith material, including material from both eucrites and diogenites.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Publication statusUnpublished - 2014

    Fingerprint

    Dive into the research topics of 'A petrological, chemical and isotopic study of some early solar system HED basaltic igneous meteorites: how many parent asteroids?'. Together they form a unique fingerprint.

    Cite this