Sm-Nd and Rb-Sr isotopic systematics of ureilites

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90345-6· OSTI ID:5978894

Goodrich, C A; Patchett, P J; Drake, M J ^[1]; Lugmair, G W ^[2]

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1. Univ. of Arizona, Tucson (United States)
2. Univ. of California, San Diego, La Jolla (United States)

Sm-Nd and Rb-Sr isotopic data are reported for seven ureilites. On the basis of Sm-Nd isotopic systematics these ureilites are divided into three groups: (1) ALH82130, PCA82506, and META78008; (2) Kenna, Novo Urei, and ALHA77257; (3) LEW85440. Group 1: Whole-rock samples of these ureilites are highly depleted assemblages having Sm-Nd model ages consistent with 4.55 Ga. Their Rb-Sr isotopic systematics, however, require that radiogenic Sr was introduced into these rocks at some time later than 4.55 Ga. Group 2: Whole-rock samples of Kenna, Novo Urei, and ALHA77257 and a pyroxene separate from Kenna plot on a Sm-Nd isochron, with an age of 3.74 {plus minus} 0.02 Ga and an initial {sup 143}Nd/{sup 144}Nd ratio of 0.50945 {plus minus} 2. Whole-rock samples of these ureilites are heterogeneous mixtures of an unidentified LREE-enriched component and a LREE-depleted olivine + pyroxene assemblage. In the context of this problem we undertook a study of the Rb-Sr and Sm-Nd isotopic systematics of ureilites to determine the age or ages of formation of ureilites and provide information about the isotopic characteristics of the materials from which they were derived.

• OSTI ID: 5978894
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:3; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
CHEMISTRY
CHONDRITES
GEOCHEMISTRY
GEOLOGIC HISTORY
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
METEORITES
NEODYMIUM ISOTOPES
ORIGIN
PETROGENESIS
RARE EARTH ISOTOPES
RUBIDIUM ISOTOPES
SAMARIUM ISOTOPES
STONE METEORITES
STRONTIUM ISOTOPES