A test of the smoothness of the elemental abundances of carbonaceous chondrites

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90398-0· OSTI ID:5022602

Burnett, D S ^[1]; Woolum, D S ^[2]; Benjamin, T M; Rogers, P S.Z.; Duffy, C J; Maggiore, C ^[3]

---

1. California Institute of Technology, Pasadena (USA)
2. California State Univ., Fullerton (USA)
3. Los Alamos National Laboratory, NM (USA)

The identification of CI chondrite concentrations with average solar system abundances for heavy elements is based primarily on the smoothness of the CI abundance curves for odd mass nuclei. A good test of smoothness is measurement of all elements in a given mass range in the same sample with the same technique. High precision proton-induced X-ray spectra of CI chondrites yielded analyses of 17 elements (Ni through Ru, plus Fe and Pb) with precisions better than 10% for all except As, Pb, Nb, and Ru. Excellent theoretical descriptions of the spectra were obtained. Two independent estimates of precision agree well, giving confidence in the quoted errors. Intersample differences are the largest source of variability. Within these limits good agreement with literature results are obtained, except for As and Y. Although the authors Y values are 10 to 30% lower than previously adopted, a monoelemental s-process peak in the abundance curve at Y is still necessary. Except for Br (higher by 59% in Ivuna), there are no significant concentration differences between Orgueil and Ivuna. In general, their results confirm previous abundance curves. The abundances are exceptionally smooth and strongly decreasing in the mass 60-75 region. From mass 75-101 a smooth curve can be drawn, within limits of intersample variability, except for the Y peak. Over the whole periodic table a large number of peaks of probable nucleosynthetic origin can be identified, some understood, some not. These smoothness deviations are 10 to 30% and set an overall limit to the smoothness argument alone in justifying using CI abundances as average solar system values.

• OSTI ID: 5022602
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 53:2; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
640106 -- Astrophysics & Cosmology-- Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ARSENIC
CARBONACEOUS MATERIALS
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
CHONDRITES
COMPARATIVE EVALUATIONS
COSMOCHEMISTRY
ELEMENT ABUNDANCE
ELEMENTS
GEOCHEMISTRY
IRON
LEAD
MATERIALS
METALS
METEORITES
NICKEL
PLATINUM METALS
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTHS
RUTHENIUM
SEMIMETALS
SOLAR SYSTEM
STONE METEORITES
TRANSITION ELEMENTS
YTTERBIUM