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REE Partition Coefficients from Synthetic Diogenite-Like Enstatite and the Implications of Petrogenetic ModelingDetermining the petrogenesis of eucrites (basaltic achondrites) and diogenites (orthopyroxenites) and the possible links between the meteorite types was initiated 30 years ago by Mason. Since then, most investigators have worked on this question. A few contrasting theories have emerged, with the important distinction being whether or not there is a direct genetic link between eucrites and diogenites. One theory suggests that diogenites are cumulates resulting from the fractional crystallization of a parent magma with the eucrites crystallizing, from the residual magma after separation from the diogenite cumulates. Another model proposes that diogenites are cumulates formed from partial melts derived from a source region depleted by the prior generation of eucrite melts. It has also been proposed that the diogenites may not be directly linked to the eucrites and that they are cumulates derived from melts that are more orthopyroxene normative than the eucrites. This last theory has recently received more analytical and experimental support. One of the difficulties with petrogenetic modeling is that it requires appropriate partition coefficients for modeling because they are dependent on temperature, pressure, and composition. For this reason, we set out to determine minor- and trace-element partition coefficients for diogenite-like orthopyroxene. We have accomplished this task and now have enstatite/melt partition coefficients for Al, Cr, Ti, La, Ce, Nd, Sm, Eu, Dy, Er, Yb, and La.
Document ID
19990025082
Document Type
Conference Paper
Authors
Schwandt, C. S. (NASA Johnson Space Center Houston, TX United States)
McKay, G. A. (NASA Johnson Space Center Houston, TX United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1996
Publication Information
Publication: Workshop on Evolution of Igneous Asteroids: Focus on Vesta and the HED Meterorites
Issue: Pt. 1
Subject Category
Astrophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19990025054Analytic PrimaryWorkshop on Evolution of Igneous Asteroids: Focus on Vesta and the HED Meteorites