An ion microprobe study of an osbornite-bearing inclusion from ALH 85085

Details An ion microprobe study of an osbornite-bearing inclusion from ALH 85085 An ion microprobe study of an osbornite-bearing inclusion from ALH 85085

Jul 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994metic..29r.547w&link_type=abstract

Meteoritics (ISSN 0026-1114), vol. 29, no. 4, p. 547-548

Computer Science

Chondrites, Inclusions, Ion Probes, Isotopic Enrichment, Meteoritic Composition, Abundance, Depletion, Mass Spectroscopy, Mineralogy, Nitrogen Isotopes, Titanium Isotopes

Scientific paper

Minerals such as osbornite (TiN) or oldhamite (CaS) are the reduced high-temperature counterparts of the more oxidized refractory minerals present in Ca, Al-rich Inclusions (CAIs). Osbornite has been predicted to condense at high temperatures under highly reducing conditions or to form as a product of gas-solid reactions under the still reducing conditions of C/O approximately equal to 0.8. In ALH 85085, a reduced carbonaceous chondrite, osbornite was found as a single grain in a small inclusion. We determined Ti and N isotopic compositions and trace element abundances of the osbornite by ion microprobe mass spectrometry. Because of the small size of the osbornite grain, we were not able to measure its compositions without contamination by surrounding phases. Nitrogen in ALH 85085 shows large enrichments of N-15. Isotopically heavy N occurs in two major sites, but a third minor component with a delta N-15 value of about +1500% defied identification. Compared with an osbornite-bearing inclusion from the Bustee aubrite, the ALH 85085 inclusion studied here has different paragenetic minerals, higher refractory trace-element abundances, and a Eu depletion, indicating different formation conditions of the two osbornite-bearing objects. While the trace-element abundances of osbornite and of paragenetic minerals from Bustee suggest formation as direct condensates, the fractionation of the Rare Earth Elements (REEs) in the ALH 85085 inclusion is probably due to igneous processes. The lack of Ti isotopic mass fractionation excludes strong distillation processes and indicates that the precursor of the osbornite-bearing inclusion from ALH 85085 must have had a similar chemical composition as the inclusion itself.

Affiliated with

Also associated with

No associations

Rating

An ion microprobe study of an osbornite-bearing inclusion from ALH 85085 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with An ion microprobe study of an osbornite-bearing inclusion from ALH 85085, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An ion microprobe study of an osbornite-bearing inclusion from ALH 85085 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-822560