Late-Jurassic granulite facies metamorphism of garnet-bearing metabasic rocks from the Chepelare area, Central Rhodope Късноюрски метаморфизъм в гранулитов фациес на гранатсъдържащи метабазити от района на Чепеларе, Централни Родопи

The Eo-Alpine evolution of the Rhodope region includes Late-Jurassic magmatic and metamorphic evens. The latter are documented in the Greek Rhodope by UHP relics and granulite facies overprints (Bauer et al., 2007, and references therein). Recently Bosse et al. (2010) reported Late-Jurassic metamorphic ages of granulite facies garnet-kyanite gneisses from the Chepelare area in the Bulgarian Rhodope. Garnet-bearing metabasic rocks that also keep record of granulite facies metamorphism (Georgieva et al., 2010) crop out in close spatial relations with garnetkyanite gneisses. We present first results of in situ LA-ICP-MS dating of zircons in garnet-bearing metabasic rocks, whose protoliths suffered Late-Jurassic metamorphism. The rocks of study belong to the variegated rock assemblage known as Chepelare Formation or Chepelare mélange. They crop out in the Arda tectonic unit and coincide with an ~1 km-thick zone of intense strain termed the Chepelare Shear Zone (Gerdjikov et al., 2010). The CSZ has previously been interpreted as a synmetamorphic thrust of presumed Mesozoic age, but recent data indicate that it was active during Late-Eocene. The garnet-bearing metabasic rocks crop out as elongated lenses of metric to decametric scale and alternate with marbles, garnet-kyanite gneisses and schists, biotite or twomica gneisses and ultramific bodies. Late-Jurassic granulite facies metamorphism of garnet-bearing metabasic rocks from the Chepelare area, Central Rhodope