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 04:00:00 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), Journal Name: Meteoritics; (USA) Vol. 24; ISSN 0026-1114; ISSN MERTA
• Country of Publication: United States
• Language: English

Related Subjects

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