Correlated O and Mg isotopic anomalies in Allende inclusions: II. Magnesium

Journal Article · Fri Jul 01 04:00:00 EDT 1977 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL004i007p00299· OSTI ID:7316377

Wasserburg, G J; Lee, T; Papanastassiou, D A

Mg in two Allende Ca-Al rich inclusions shows large isotopic, mass-dependent fractionation which enriched the heavier isotopes. After normalization, Mg in these inclusions shows negative delta/sup 26/Mg which appears to require the presence of nuclear effects in Mg distinct from /sup 26/Al decay. The Mg mass fractionation is correlated with distinct but smaller fractionation effects for O reported by Clayton and Mayeda for the same inclusions (see companion paper). The observation of distinctive but uniform Mg isotopic composition in different phases within single Allende inclusions indicates that nuclear effects in O and Mg are not due to the entrapment of interstellar carrier grains as discrete entities, which are preserved as remnants, but are instead due to a homogenized mixture of components of extraordinary isotopic composition mixed with a component of ordinary solar system material and subjected to isotopic fractionation. The distinct O isotopic composition of different phases within a single inclusion is believed to be due to incomplete back-reaction of the higher temperature condensates with a cooler solar nebula of ''normal '' composition. The processes responsible for the O and Mg nuclear effects and the astrophysical site of their occurrence remain undefined.

• Research Organization: The Lunatic Asylum, Div. of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125
• OSTI ID: 7316377
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 4:7; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKALINE EARTH ISOTOPES
ALUMINIUM 26
ALUMINIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHEMICAL COMPOSITION
CHONDRITES
CRYOGENIC FLUIDS
ELEMENTS
EVEN-EVEN NUCLEI
FLUIDS
FRACTIONATION
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MAGNESIUM 26
MAGNESIUM ISOTOPES
METEORITES
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXYGEN
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SEPARATION PROCESSES
STABLE ISOTOPES
STONE METEORITES
YEARS LIVING RADIOISOTOPES