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Distribution of elements in biotite-hornblende pairs and in an orthopyroxene-clinopyroxene pair from zoned plutons, northern Sierra Nevada, California

Contributions to Mineralogy and Petrology

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DOI: 10.1007/BF00372256

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Abstract

Distribution of major and minor elements has been determined for five hornblende-biotite pairs from hornblende-biotite quartz diorite and monzotonalite and for a clinopyroxene-orthopyroxene pair from pyroxene diorite collected from the border zones and centers of zoned plutons in the northern Sierra Nevada, California. The distribution coefficients Kd [Mg/Fe] for biotite/hornblende are of the same magnitude (0.61-0.67) for both the mafic border zone and the silicic center. For comparison, KD [Mg/Fe] values for biotite/hornblende from plutonic rocks of the central Sierra Nevada and the southern California batholith were calculated from data published by others. Rocks of the oldest age group (ca. 150 m.y.) in the central Sierra Nevada have an average distribution coefficient, KD, of 0.64, close to the average KD in the study area, where K-Ar dates are 143 to 129 m.y. The intermediate age group has an average KD=0.81, and the youngest group has KD=0.77. KD [Mg/Fe] for biotite/hornblende from the southern California batholith is 0.83, close to the average of the intermediate age group in the central Sierra Nevada. The calculated difference in pressure of crystallization between rocks of the Feather River area and the southern California batholith is 1 kb; the rocks of the Feather River area being crystallized at a higher pressure. This is in good agreement with the low-pressure contact metamorphism in the south (pyroxene hornfels facies), as compared with a medium-pressure metamorphism around the northern plutons, where andalusitesillimanite-cordierite and andalusite-staurolite subfacies of the amphibolite facies indicate pressures of about 4 kb. Trace elements Cr, V, Ni, Co, Ga are distributed equally between biotite and hornblende, whereas Ba and possibly Cu are concentrated in biotite and Sr and Sc and possibly Zr in hornblende. ?? 1971 Springer-Verlag.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Distribution of elements in biotite-hornblende pairs and in an orthopyroxene-clinopyroxene pair from zoned plutons, northern Sierra Nevada, California
Series title:
Contributions to Mineralogy and Petrology
DOI:
10.1007/BF00372256
Volume
30
Issue:
2
Year Published:
1971
Language:
English
Publisher:
Springer-Verlag
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
161
Last page:
176