Noble gases in phase Q': Closed-system etching of an Allende residue
- Eidgenoessische Technische Hochschule, Zuerich (Switzerland)
- Univ. of Chicago, IL (United States)
The authors have analyzed for the first time, in nearly pure form, the noble gases in phase Q', the elusive major carrier of the planetary gases in carbonaceous chondrites. Noble gases were extracted from an HF/HCl residue of Allende by oxidation with HNO{sub 3}, using the closed-system stepped etching technique. 10-15% of the primordial He and Ne were released, in addition to more than 90% of the Ar-Kr-Xe. All five noble gases liberated from Q have uniform isotopic composition throughout the extraction: {sup 3}He/{sup 4}He = (1.59 {plus minus} .04) {times} 10{sup {minus}4}; {sup 20}Ne/{sup 22}Ne = 10.70 {plus minus} .15; {sup 36}Ar/{sup 38}Ar = 5.32 {plus minus} .02. Kr-Q and Xe-Q differ from AVCC. Relative to solar wind values, He, Ne, and Ar in Q are depleted in the light isotopes as well as the light elements. Xe-Q may be (nearly) unfractionated solar Xe blended with some fission Xe. Ureilites and several ordinary chondrites contain noble gases with isotopic compositions and elemental abundances very similar or identical to those of Q-gases. This component thus seems to have been widespread in the solar nebula. A close relation between noble gases in ureilites and Q-gases is strongly suggested, particularly by the near match of their Ne and Xe isotopic compositions but also by their rather similar He and Ne abundances.
- OSTI ID:
- 6005342
- Journal Information:
- Geochimica et Cosmochimica Acta; (United States), Vol. 55:6; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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