Solar-type Ne in Zaire cubic diamonds

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(88)90052-X· OSTI ID:7222758

Ozima, M; Zashu, S

Elemental abundances and isotopic compositions of noble gases have been measured in five cubic diamonds from Zaire. /sup 20/Ne//sup 22/Ne ratios range from 11.5 to 13.5 and /sup 21/Ne//sup 22/Ne from 0.047 to 0.074. The authors interpret these data to indicate that neon in the diamonds is a mixture of atmospheric neon and diamond neon, the latter consisting of solar-type neon trapped from the mantle source and nucleogenic neon produced by /sup 18/O(..cap alpha.., n) /sup 21/Ne and /sup 24/Mg(n, ..cap alpha..) /sup 21/Ne reactions in the diamonds. Measured /sup 3/He//sup 4/He ratios range from 4.2 to 13.0 x 10/sup -6/, while /sup 38/Ar//sup 36/Ar = 0.187 +/- 0.005 and is identical with atmospheric argon. Kr and Xe isotopic compositions are indistinguishable from air, except for slight excesses in /sup 129/Xe and fissiogenic Xe isotopes. The noble gas elemental abundance pattern in the diamonds shows a systematic fractionation trend, with the heavier noble gases being enriched relative to air.

• Research Organization: Univ. of Tokyo (Japan)
• OSTI ID: 7222758
• Journal Information: Geochim. Cosmochim. Acta; (United States), Vol. 52:1
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
DIAMONDS
CHEMICAL COMPOSITION
GEOCHEMISTRY
PETROGENESIS
RARE GASES
ISOTOPE RATIO
CRYSTALLIZATION
FRACTIONATION
MAGMATISM
QUANTITATIVE CHEMICAL ANALYSIS
ZAIRE REPUBLIC
AFRICA
CARBON
CHEMICAL ANALYSIS
CHEMISTRY
DEVELOPING COUNTRIES
ELEMENTAL MINERALS
ELEMENTS
FLUIDS
GASES
MINERALS
NONMETALS
PHASE TRANSFORMATIONS
SEPARATION PROCESSES
580400* - Geochemistry- (-1989)