Pressure-temperature path recorded by clinopyroxene megacryst in garnet lherzolites in the Bohemian Massif, Czech Republic

Abstract

In the Czech part of the Bohemian massif, numerous garnet-bearing peridotites are enclosed within high-pressure granulite in the Variscan orogenic belt, and there is a debate whether they were directly derived from the hot mantle wedge or they were transformed from the serpentinite or chlorite peridotite at shallow depth by subduction. Here we report newly discovered clinopyroxene megacrysts within garnet peridotites, and we showed the chemical composition of clinopyroxene are extremely low in Al and contain low-Al orthopyroxene, edenite, phlogopite, ferrite-chromite, olivine as well as apatite and rare huttonite. We will show the discovered low-Al clinopyroxene were formed at low-T condition before the UHP metamorphism.