Pyroxene-high silica rhyolite trace element partition coefficients measured by ion microprobe

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90129-S· OSTI ID:5979271

Sisson, T W ^[1]

---

1. Massachusetts Inst. of Tech., Cambridge (United States)

Pyroxene-liquid trace element partition coefficients have been measured in situ by ion microprobe in high silica rhyolites. Partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y, and Zr. The in situ analyses avoid the problem of contamination of the pyroxene phase by trace element-rich accessory mineral inclusions encountered in traditional bulk phenocryst-glass partitioning studies. Pyroxenes and glasses which have been analyzed are typical of high silica rhyolites worldwide. The samples analyzed are Bishop Tuff, California (augite, hypersthene): Sierra La Primavera, Mexico (ferrohedenbergite); and two samples of the Huckleberry Ridge Tuff, Wyoming (ferroaugite). Rare earth element (REE) partition coefficient patterns are convex-upward and resemble patterns determined in less silicic bulk compositions. Partition coefficients for the REEs Sr, Zr, and Cr show correlations with the Mg{number sign} of clinopyroxene, suggesting that crystal composition influences the fine structure of partitioning patterns. The overall similarity of partitioning patterns between samples indicates that the partition coefficients determined in this study can be generally applied in the geochemical modeling of high silica rhyolites.

• OSTI ID: 5979271
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:6; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CALIFORNIA
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
DEVELOPED COUNTRIES
DEVELOPING COUNTRIES
ELEMENTS
FEDERAL REGION VIII
FRACTIONATION
GEOCHEMISTRY
IGNEOUS ROCKS
INCLUSIONS
ION MICROPROBE ANALYSIS
LATIN AMERICA
MAGMATISM
METALS
MEXICO
MICROANALYSIS
MINERALS
NONDESTRUCTIVE ANALYSIS
NORTH AMERICA
OXYGEN COMPOUNDS
PARTITION
PETROCHEMISTRY
PETROGENESIS
PYROXENES
RARE EARTHS
RHYOLITES
ROCKS
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
USA
VOLCANIC ROCKS
WYOMING