The formation of weathering products on the LEW 85320 ordinary chondrite - Evidence from carbon and oxygen stable isotope compositions and implications for carbonates in SNC meteorites

Journal Article · Wed Mar 01 00:00:00 EST 1989 · Meteoritics; (USA)

DOI:https://doi.org/10.1111/j.1945-5100.1989.tb00934.x· OSTI ID:5594343

Grady, M M; Wright, I P; Pillinger, C T; Gibson, Jr, E K ^[1]

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1. Open Univ., Milton Keynes (England)

Isotopic analysis of nesquehonite recovered from the surface of the LEW 85320 H5 ordinary chondrite shows that the delta C-13 and delta O-18 values of the two generations of bicarbonate (Antarctic and Texas) are different: delta C-13 = + 7.9 per mil and + 4.2 per mil; delta O-18 = + 17.9 per mil and + 12.1 per mil, respectively. Carbon isotopic compositions are consistent with equilibrium formation from atmospheric carbon dioxide at - 2 + or - 4 C (Antarctic) and + 16 + or - 4 C (Texas). Oxygen isotopic data imply that the water required for nesquehonite precipitation was derived from atmospheric water vapor or glacial meltwater which had locally exchanged with silicates, either in the meteorite or in underlying bedrock. Although carbonates with similar delta C-13 values have been identified in the SNC meteorites EETA 79001 and Nakhla, petrographic and temperature constraints argue against their simply being terrestrial weathering products. 35 refs.

• OSTI ID: 5594343
• Journal Information: Meteoritics; (USA), Vol. 24; ISSN 0026-1114
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHONDRITES
CHEMICAL COMPOSITION
ANTARCTIC REGIONS
CARBON
CARBONATES
CONSTRAINTS
ISOTOPE RATIO
OXYGEN
PETROGRAPHY
WEATHERING
CARBON COMPOUNDS
ELEMENTS
METEORITES
NONMETALS
OXYGEN COMPOUNDS
POLAR REGIONS
STONE METEORITES
640107* - Astrophysics & Cosmology- Planetary Phenomena