Trace-element abundances in hibonites from the Murchison carbonaceous chondrite: Constraints on high-temperature processes in the solar nebula

Journal Article · Thu Dec 01 00:00:00 EST 1988 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(88)90151-2· OSTI ID:5029051

Ireland, T R ^[1]; Fahey, A J; Zinner, E K ^[2]

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1. Washington Univ., St. Louis, MO (USA) Australian National Univ., Canberra (Australia)
2. Washington Univ., St. Louis, MO (USA)

Abundances of trace elements, including 14 rare earth elements (REE) and 8 other refractory trace elements (RTE) have been measured in 33 hibonite- and 3 perovskite-bearing grains from the Murchison carbonaceous chondrite. The HREE roll-off in the PLACs and the igneous morphologies of the SHIBs indicate that these grains formed by the crystallization of melts. Distillation may be important for the BAGs and two of the PLACs which have large isotopic mass-fractionation effects. PLACs have the simplest trace element patterns and the largest Ti isotopic anomalies and probably were the first hibonites to form in the early solar system. The SHIBs have trace-element signatures that require multiple processing episodes. They are somewhat complementary to the PLACs in that they are enriched in the volatile elements which are depleted in the PLACs. On average, the SHIBs contain isotopically less-anomalous Ti than the PLACs. However, SHIBs contain {sup 26}Mg excesses that are consistent with the in situ decay of {sup 26}Al, whereas PLACs generally have only small, or no excesses of {sup 26}Mg despite high {sup 27}Al/{sup 24}Mg. While an overall relationship exists between the morphology, chemistry, and Ti and Mg isotopic systematics of meteoritic hibonites, they do not, as yet, fit into a simple scenario for the formation of the solar system.

• OSTI ID: 5029051
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 52:12; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CHONDRITES
CHEMICAL COMPOSITION
ELEMENT ABUNDANCE
MINERALOGY
ORIGIN
ALUMINIUM 26
CARBONACEOUS MATERIALS
CRYSTALLIZATION
GEOCHEMISTRY
GEOLOGIC HISTORY
HIGH TEMPERATURE
INCLUSIONS
ISOTOPE RATIO
MAGNESIUM 24
MAGNESIUM 26
PETROGENESIS
RARE EARTHS
SOLAR NEBULA
TRACE AMOUNTS
ABUNDANCE
ALKALINE EARTH ISOTOPES
ALUMINIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHEMISTRY
ELEMENTS
EVEN-EVEN NUCLEI
ISOTOPES
LIGHT NUCLEI
MAGNESIUM ISOTOPES
MATERIALS
METALS
METEORITES
NEBULAE
NUCLEI
ODD-ODD NUCLEI
PHASE TRANSFORMATIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
STABLE ISOTOPES
STONE METEORITES
YEARS LIVING RADIOISOTOPES
580000* - Geosciences