New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results

Details New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results

Jul 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994metic..29q.463e&link_type=abstract

Meteoritics (ISSN 0026-1114), vol. 29, no. 4, p. 463

Computer Science

5

Carbonaceous Chondrites, Chemical Analysis, Chronometers, Meteoritic Composition, Dolomite (Mineral), Electron Probes, Granular Materials, Precipitation (Chemistry)

Scientific paper

Carbonates and sulfates are common in CI chondrites and are believed to have resulted from aqueous alteration processes on the CI parent body. The carbonates occur mostly either as single grains or as polycrystalline chunks and are dominated by dolomites with varying Fe, Mg, and Mn contents. Calcites and breunnerites are less abundant. Since dolomites have MnO contents of up to 15 wt% and generally low Cr2O3 contents, we carried our exploratory SIMS analyses on dolomites in order to determine, whether a Mn-53-Cr-53 chronometer could provide constraints on the formation times of carbonates in CIs. We focused on carbonate fragments in Ivuna, since they can be easily recognized in thin sections, but also measured one carbonate from Orgueil. Our data indicate that aqueous alteration must have occurred soon after formation of the Ivuna parent body, perhaps even before accretion and accumulation was completed. Our results are similar to, but more stringent than, those obtained from Sr isotope data on carbonates in Orgueil, which imply that Ca-Mg carbonate precipitation was completed within 50 m.y. after formation of the Orgueil parent body. Further Mn-Cr studies, now underway, are disigned to determine whether or not carbonate fragments and carbonate grains in distinct lithic units of Ivuna, and different carbonate phases like dolomites and breunnerites precipitated at the same time.

Affiliated with

Also associated with

No associations

Rating

New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results 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 New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and New constraints on the formation history of carbonates in the CI chondrite Ivuna from the Mn-53-Cr-53 chronometer: Preliminary results will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-822112