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dc.contributor.authorRudraswami, N.G.
dc.contributor.authorMarrocchi, Y.
dc.contributor.authorShyamPrasad, M.
dc.contributor.authorFernandes, D.
dc.contributor.authorVilleneuve, J.
dc.contributor.authorTaylor, S.
dc.date.accessioned2019-12-31
dc.date.accessioned2020-02-04T09:38:20Z
dc.date.available2019-06-19
dc.date.available2020-02-04T09:38:20Z
dc.date.issued2019
dc.identifier.citationMeteoritics and Planetary Science, vol.54(6); 2019; 1347-1361
dc.identifier.urihttps://doi.org/10.1111/maps.13281
dc.identifier.urihttp://drs.nio.org/drs/handle/2264/8214
dc.description.abstractWe identified 66 chromite grains from 42 of ~5000 micrometeorites collected from Indian Ocean deep-sea sediments and the South Pole water well. To determine the chromite grains precursors and their contribution to the micrometeorite flux, we combined quantitative electron microprobe analyses and oxygen isotopic analyses by high-resolution secondary ion mass spectrometry. Micrometeorite chromite grains show variable O isotopic compositions with ?18O values ranging from ?0.8 to 6.0�, ?17O values from 0.3 to 3.6�, and ?17O values from ?0.9 to 1.6�, most of them being similar to those of chromites from ordinary chondrites. The oxygen isotopic compositions of olivine, considered as a proxy of chromite in chromite-bearing micrometeorites where chromite is too small to be measured in ion microprobe have ?17O values suggesting a principal relationship to ordinary chondrites with some having carbonaceous chondrite precursors. Furthermore, the chemical compositions of chromites in micrometeorites are close to those reported for ordinary chondrite chromites, but some contribution from carbonaceous chondrites cannot be ruled out. Consequently, carbonaceous chondrites cannot be a major contributor of chromite-bearing micrometeorites. Based on their oxygen isotopic and elemental compositions, we thus conclude with no ambiguity that chromite-bearing micrometeorites are largely related to fragments of ordinary chondrites with a small fraction from carbonaceous chondrites, unlike other micrometeorites deriving largely from carbonaceous chondrites.
dc.languageen
dc.relation.isreferencedbySCI
dc.rightsOnly the author version of the copright reserved papers uploaded. Contact drs@nio.org for any complaints regarding copyright violations
dc.titleOxygen isotopic and chemical composition of chromites in micrometeorites: Evidence of ordinary chondrite precursors
dc.typeJournal Article
dc.affiliation.authorCSIR-National Institute of Oceanography, Dona Paula, Goa, India


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