Zoned Margarite from the Badshot Formation (Cambrian) near Kaslo, British Columbia
Electron microprobe analysis of margarite crystals shows that they are zoned from Cal.l~Na~.i~K~.~5(A1~.~lTio.o~Feo.l3Mg~.~s)[Si4.~8A1~.120~~](OH)4 in their centers to Ca1.63Na~.26K2.~ ~5 (A~~.~~T~~.o~F~o .~~M~o.~~)[S~~.~ ~A~~.~~O~~](OH) at their margins. The crystals occur in the disequilibrium assemblage calcite - phengite (2M1) - margarite - quartz - kaolinite - epidote - apatite found in Badshot marble from the almandine garnet zone of regional metamorphism. L'analyse, B la microsonde Clectronique, de cristaux de margarite montre une zonation depuis le centre C~~.I~N~O,~~KO.O~(A~~.O~T~O.~~F~O.~~M~O.O~)[S~~.~~A~~.~~O~~](OH)~ B la pCriphCrie Ca1.63Na~.~6 KP.OO~(A~~.~~T~~ .~~F~O.~~M~~.~~) [S~~.,~A~~.~~~~~ ](~H)~. Les cristaux se trouvent dans un assemblage en dksCquilibre, calcite - phengite (2M1) - margarite - quartz - kaolinite - epidote - apatite, provenant du cipolin de Badshot, qui a subi un metamorphisme rCgional dans la zone B almandin.