Zeolite-facies metamorphism of central Kerguelen Plateau basalts

Abstract

Ocean Drilling Program Leg 120 recovered basement samples that consisted of zeolite-facies metabasalts at Sites 747, 749, and 750. These basalts were metamorphosed in the low to intermediate zones of the zeolite facies. Based on calculations with published experimental phase equilibria, the absence of wairakite in basalts from Hole 749C and of laumontite in basalts from Holes 747C and 750B suggests that metamorphic temperatures did not exceed approximately 225° and 120°C, respectively. The mineral assemblages can be accounted for by metamorphism in an active geothermal area such as present-day Iceland. -from Authors