The origin of cordierite—anthophllite rocks in the Land's End aureole

Abstract

Summary: The prevalence of low-variance assemblages, the frequency of the buffered association anthophyllite—cordierite—cummingtonite—plagioclase, and the ubiquity of aluminium-rich clots of diaspore incompatible with the ortho-amphibole of the rock suggest that the cordierite—anthophyllite rocks of the Land's End aureole are not the product of metasomatism, but resulted from the thermal metamorphism of pre-existing rock-compositions. The origin of many kyanite-, amphibole- and cordierite-rich bodies by pre-metamorphic alteration is of economic significance in regions where such curious silicate assemblages accompany sulphide deposits.