Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements

Details Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements

Dec 1986

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1986gecoa..50.2799g&link_type=abstract

Geochimica et Cosmochimica Acta (ISSN 0016-7037), vol. 50, Dec. 1986, p. 2799-2813. SERC-supported research.

Mathematics

Logic

27

Carbon Isotopes, Chondrites, Enstatite, Meteoritic Composition, Nitrogen Isotopes, Abundance, Graphite

Scientific paper

Carbon and nitrogen abundance and isotopic compositions, from four EH4, one EH5, five EL6 chondrites and one aubrite, were determined by using stepped pyrolysis (N only) and combustion (N and C) extractions in attempts to distinguish the components present. Carbon contents range from 0.15 to 0.70 wt pct, with no systematic relationship between carbon content and meteorite group or petrologic type. Whole-rock delta C-13 values range from -28.5 to -4.1 percent. Most C occurs as graphite, and when temperature steps above 700 C are considered, there is a difference between EH4,5 (delta C-13 = 9.1 to -5.8 percent) and EL6 chondrites (delta C-13 = -6.7 to +4.2 percent). Carbon in Bustee aubrite is isotopically lighter (delta C-13 = -24 percent) than in any enstatite chondrite. Nitrogen occurs as osbornite, sinoite, and in isostructural substitution for oxygen in silicate lattice sites. Nitrogen abundances and isotopic compositions are more variable than C, due to the heterogeneous distribution of N-bearing minerals. Three EL6s containing osbornite have higher N concentrations than other type 6 enstatite chondrites. Sinoite, where present, is depleted in N-15 relative to osbornite. Nitrogen in the Bustee aubrite has a similar abundance and delta N-15 value to those of EL6s, again dominated by the presence of osbornite. In addition to the refractory C- and N-bearing minerals there is also organic material (largely terrestrial contamination) and evidence for at least two 'exotic' components. The first is a host for Xe (HL), and is characterized by delta C-13 less than or equal to 47 percent and delta N-15 less than or equal to 73 percent, whereas the second is less well-defined, but is marked by delta N-15 = +269 percent.

Affiliated with

Also associated with

No associations

Rating

Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements 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 Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1123865