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Hornblende-melt trace-element partitioning measured by ion microprobe

Chemical Geology

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DOI: 0.1016/0009-2541(94)90135-X

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Abstract

Trace-element abundances were measured in situ by ion microprobe in five samples of hornblende and melt ranging from basaltic andesite to high-silica rhyolite. Except for one sample, for which quench overgrowth or disequilibrium is suspected, the abundance ratios show systematic inter-element and inter-sample variations, and probably approach true partition coefficients. Apparent partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y and Zr. Rare-earth elements (REE) and Y form smooth convex-upward partitioning patterns that rise to higher D-values and become increasingly convex in more evolved samples. Apparent partition coefficients for REE, Y, Ti, V and Cr can be parameterized as functions of the distribution of Ca between hornblende and melt, giving expressions to predict hornblende-melt trace-element partitioning values. These expressions are used to show that heavy REE-enriched hornblende/whole-rock REE abundance patterns in granitoids may result from partial re-equilibration of hornblende and late-stage residual liquids rather than from anomalous partitioning values. ?? 1994.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Hornblende-melt trace-element partitioning measured by ion microprobe
Series title:
Chemical Geology
DOI:
0.1016/0009-2541(94)90135-X
Volume
117
Issue:
1-4
Year Published:
1994
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
331
Last page:
344