Petrology and phase relations of low-grade high-pressure metasediments from the Meliata Unit (West Carpathians, Slovakia)
Faryad, Shah W.
published: Feb 8, 1995
manuscript accepted: Sep 19, 1994
manuscript received: Apr 27, 1994
ArtNo. ESP147050701006, Price: 29.00 €
Abstract Low-grade, high-pressure metapelites and metapsammites occur together with marbles containing layers of mafic blueschists in the Meliata Unit, located in the southern part of the Central West Carpathians. They are usually tectonically overlain by marbles and other tectonic units. Apart from phengite and quartz they contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, and occasionally also Na-pyroxene and garnet. The Na-pyroxene corresponds to jadeitic aegirine with a jadeite content ranging from 33-45 mol %. Textural and some phase relations between chloritoid, chlorite and glaucophane suggest first formation of chloritoid and then of glaucophane during metamorphism. Some rocks contain phengite with low Si content in the cores but high Si rims and are interpreted as earlier low-pressure metamorphites overprinted by blueschist facies metamorphism. Estimated P-T conditions of blueschist metamorphism are 400-460°C at 10.5-12 kbar for glaucophaneand/ or pyroxene-bearing rocks, and 360-400°C at 8-10 kbar for chloritoid-bearing rocks.