Metamorphic record in metalherzolite pockets within the Virsini mataharzburgite from Kechros HP metamorphic complex in Eastern Rhodope, Greece

Περίληψη

The Virsini antigorite serpentinite from the Kechros HP metamorphic complex in eastern Rhodope is a serpentinized harzburgite with pockets of lherzolitic composition. In the metalherzolites the mantle assemblage is Ol-1+Opx+Cpx-1+Cr-Spl. The metamorphic assemblage is Atg+Ol-2+Cpx-2+Ol-3+Chl+Tr+Cr-Mag. Antigorite and Cr-magnetite formed in an early stage of the metamorphic event. With increase in metamorphic grade olivine (Ol-2) was formed at the expense of antigorite and with further increase tremolite, olivine (Ol-3) and chlorite were formed at the expense of clinopyroxene and antigorite. P-T conditions of .1.7 GPa/.570 oC are recorded in neighbouring eclogites. For the temperature of 570 oC the reaction Di+Atg-Ol+Tr+H2O occurs at pressure of ~1.2 GPa suggesting that the stability field of the mineral assemblage Atg+Ol+Tr in the metalherzolite is crossed during decompression.