Calcium-aluminum-rich inclusions in enstatite chondrites (II)

Oxygen isotopes

Timothy Jay Fagan, K. D. McKeegan, A. N. Krot, K. Keil

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

In situ ion microprobe analyses of spinel in refractory calcium-aluminium-rich inclusions (CAIs) from type 3 EH chondrites yield 16O-rich compositions (δ 18O and δ 17O about -40‰). Spinel and feldspar in a CAI from an EL3 chondrite have significantly heavier isotopic compositions (δ 18O and δ 17O about -5‰). A regression through the data results in a line with slope 1.0 on a three-isotope plot, similar to isotopic results from unaltered minerals in CAIs from carbonaceous chondrites. The existence of CAIs with 16O-rich and 16O-poor compositions in carbonaceous as well as enstatite chondrites indicates that CAIs formed in at least two temporally or spatially distinct oxygen reservoirs. General similarities in oxygen isotopic compositions of CAIs from enstatite, carbonaceous, and ordinary chondrites indicate a common nebular mechanism or locale for the production of most CAIs.

Original languageEnglish
Pages (from-to)223-230
Number of pages8
JournalMeteoritics and Planetary Science
Volume36
Issue number2
Publication statusPublished - 2001
Externally publishedYes

Fingerprint

enstatite chondrite
enstatite
chondrites
oxygen isotopes
oxygen isotope
calcium
aluminum
inclusions
carbonaceous chondrite
carbonaceous chondrites
chondrite
spinel
isotopic composition
oxygen
ordinary chondrite
ion microprobe
refractories
feldspar
regression analysis
isotopes

ASJC Scopus subject areas

  • Geophysics

Cite this

Calcium-aluminum-rich inclusions in enstatite chondrites (II) : Oxygen isotopes. / Fagan, Timothy Jay; McKeegan, K. D.; Krot, A. N.; Keil, K.

In: Meteoritics and Planetary Science, Vol. 36, No. 2, 2001, p. 223-230.

Research output: Contribution to journalArticle

Fagan, Timothy Jay ; McKeegan, K. D. ; Krot, A. N. ; Keil, K. / Calcium-aluminum-rich inclusions in enstatite chondrites (II) : Oxygen isotopes. In: Meteoritics and Planetary Science. 2001 ; Vol. 36, No. 2. pp. 223-230.
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