Trace element analysis of ureilites: New constraints on their petrogenesis

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

DOI:https://doi.org/10.1016/0016-7037(91)90500-5· OSTI ID:5142501

Spitz, A H; Boynton, W V ^[1]

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1. Univ. of Arizona, Tuscon (United States)

Six ureilites (ALHA77257, ALHA81101, ALH82130, PCA82506, Kanna, and Novo Urei) were analyzed using neutron activation analysis for Ca, Sc, Cr, Mn, Fe, Co, Ni, Zn, Ga, REE, W, Re, Os, Ir, and Au. The authors examined bulk samples as well as acid-treated samples. In bulk samples the refractory siderophiles' concentrations range from approximately 0.1 to 1.0 times CI chondrites while the volatile siderophiles' concentrations range from approximately 0.1 to 1.0 times CI chondrites while the volatile siderophiles range from about 0.07 to 0.3 times CI chondrites. Rare earth elements (REEs) in ureilites are quite depleted and display light and heavy rare earth enrichments. The Antarctic meteorites display either much less pronounced v-shaped patterns or no enrichment in the light rare earths at all. In terms of the new trace-element results, ureilites do not fall into the coherent groups that other workers have defined by chemical or petrographic characteristics. Trace elements do provide additional constraints on the models for the petrogenesis of ureilites. In particular, the siderophile element abundances call for simplified models of chemical processing rather than the complex, multistage processing called for in silicate fractionation models. REE concentrations, on the other hand, imply multistage processing to produce the ureilites. None of the ureilite petrogenesis models extant account for the trace element data. These new data and the considerations of them with respect to the proposed ureilite petrogenesis models indicate that the direction of modeling should be toward contemplation of mixtures and how the components the authors observe in ureilites behave under such conditions.

• OSTI ID: 5142501
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 55:11; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
METEORITES
CHEMICAL COMPOSITION
PETROGENESIS
CALCIUM
CHROMIUM
COBALT
GALLIUM
GEOCHEMISTRY
GEOLOGIC MODELS
GOLD
IRIDIUM
IRON
MANGANESE
NEUTRON ACTIVATION ANALYSIS
NICKEL
OSMIUM
RHENIUM
SCANDIUM
TRACE AMOUNTS
TUNGSTEN
ZINC
ACTIVATION ANALYSIS
ALKALINE EARTH METALS
CHEMICAL ANALYSIS
CHEMISTRY
ELEMENTS
METALS
PLATINUM METALS
TRANSITION ELEMENTS
580000* - Geosciences