Potassium-fluor-richterite is reported from wollastonite-rimmed metachert
bands embedded in marbles of the Bufa del Diente aureole, NE-Mexico.
K-F-richterites were generated via reaction of previously formed
contact-metamorphic diopside with infiltrated hypersaline brines of
magmatic origin that used the metachert bands as metamorphic aquifers.
Their formation occurred at peak metamorphic conditions of 500 to 600°C at
1kbar according to the generalised reaction:
10 CaMgSi2O6 + 8 SiO2 + 2 KClaq + 6 NaClaq + 4 H2O + 4 HF
diopside + quartz
= 2 KNaCaMg5Si8O22(F)2 + 4 Ca2NaH(SiO3)3 + 8 HClaq
K-F-richterite + pectolite
Heinrich W. (1994) Potassium-rich fluorine bearing richterite in metacherts
from the Bufa del Diente contact-metamorphic aureole, NE-México. Mineralogy
and Petrology, 50, 259 - 270.
Best wishes
Wilhelm
Wilhelm Heinrich
GeoForschungsZentrum
Telegrafenberg A52 Tel/Fax: (0331) 288-1410/1402
D-14473 Potsdam int Tel/Fax: +49 331 288-1410/1402
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