Eocene (48.7 Ma) eclogite at Chepelare, Central Rhodopes, Bulgaria: A key to the tectonics of the Rhodopes

The presence of an Eocene subduction event, in addition to Jurassic and Cretaceous ones, in the Rhodopes of Greece and Bulgaria is controversial. We report the first dating of an eclogite from the Lower Allochthon of the Rhodopes. The eclogite is a mafic lens enclosed in orthogneiss of the Arda‐2 Unit at Chepelare, Central Rhodopes. It was metamorphosed under conditions of ca. 25 kbar, 700–750°C. Garnet grains have outward‐increasing Mg contents and omphacite inclusions with the highest jadeite contents in their rims, indicating garnet growth under increasing pressure. Lu–Hf geochronology yielded an age of 48.7 ± 1.5 Ma. The age is linked to a late stage of garnet growth close to peak pressure, i.e. to subduction.