Distribution of Fe and Mg between garnet and biotite in Scottish Barrovian metamorphic zones

Abstract

SummaryThe distribution coefficient KD = (Mg/ Fe)garnet/(Mg/Fe)biotite has been calculated for eight garnet-biotite pairs from rocks ranging from the garnet isograd to the staurolite zone along the Stonehaven coast of NE Scotland. This distribution coefficient depends upon metamorphic temperature and is not dependent upon the Mn and Ca content of garnet. Garnet-biotite geothermometer yields temperatures of about 500, 550, and 575–620°C for the garnet, chloritoid + staurolite, and staurolite zones respectively.