Petrology of blueschist facies metamorphic rocks of the Meliata Unit

Petrology of blueschist facies metamorphic rocks of the Meliata Unit

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Meliata apac1/60/1/cw blueschists originated from basalts, limestones, pelites, psammitic and amphibolite facies basement rocks.Compositionally, the metabasalts have a geochemical signature mostly indicative of a transitional arc-MORB origin, but some mafic rocks having affinity with within plate basalts also present.The mafic blueschists consist of blue amphibole, epidote and albite, rarely also garnet, Na-pyroxene and chloritoid.Apart from phengite and quartz the metapelites and metapsammites contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, occasionally also Na-pyroxene and garnet.Amphibolite facies rocks contain relic garnet, plagioclase and hornblende, the latter two replaced by albite and blue amphibole, respectively.

The zoning patterns of blue amphibole, garnet and chloritoid suggest their formation during prograde stage of click here metamorphism.P-T conditions of meta-morphism are estimated to be about 350-460 oC and 10-12 kbar.