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Alkali feldspars as a main phosphorus reservoirs in rare‐metal granites: three examples from the Bohemian Massif (Czech Republic)
Author(s) -
Frýda J.,
Breiter K.
Publication year - 1995
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1995.tb00800.x
Subject(s) - albite , massif , geology , topaz , feldspar , alkali metal , geochemistry , phosphorus , mineralogy , alkali feldspar , mica , chemistry , materials science , quartz , metallurgy , paleontology , organic chemistry
Phosphorus‐rich alkali feldspars were found in three peraluminous highly differentiated albite‐topaz‐Li‐mica granites in the W and S parts of the Bohemian Massif. The average contents of P 2 O 5 in K‐feldspars (Křížovy kámen 0.57 wt%, Homolka 0.77 wt%, and Podlesí 0.83 wt%) are higher than the average contents of P 2 O 5 in albites (Křížovy kámen 0.23 wt%, Homolka 0.23 wt%, and Podlesí 0.39 wt%). The analyses of feldspars indicate that partition coefficient of phosphorus between K‐feldspar and albite range from 1.5 to 2.5. Measured data in K‐feldspars suggest a statistically significant difference from the Al 3+ +P 5+ =2 Si 4+ substitution mechanism for higher phosphorus concentration. The P‐content in K‐feldspars from the Podlesí‐granite represent the highest P‐content in natural feldspar known to date (up to 2.5 wt% of P 2 O 5 )‐ It is suggested that all studied granites retained nearly all phosphorus of granitic melts and that their alkali feldspars represent major reservoirs of phosphorus.