Jurassic subduction zone tectonics of the Rhodope Massif in the Thrace region (NE Greece) as revealed by new U–Pb and 40Ar/39Ar geochronology of the Evros ophiolite and high-grade basement rocks

In the Thrace region of NE Greece, the crystallization and post-solidification cooling below 600 °C of the intrusive suite of the Circum-Rhodope Belt arc-related Evros ophiolite span from 176.4 ± 0.93 to 163.5 ± 3.85 Ma. In the underlying Rhodope high-grade metamorphic basement, (ultra-) high-pressure metamafic rocks are cross-cut by orthogneisses with granitoid protoliths and crystallization ages between 160 ± 0.69 and 154 ± 1.5 Ma. This new U–Pb LA–ICP-MS zircon geochronological data provides evidence that the timing of the evolution of the Evros ophiolite coincides, within analytical error, with granitoid magmatism in the underlying high-grade basement. One of the dated metagranitoid rocks cross-cuts amphibolitized eclogite, indicating that the high-pressure conditions have a maximum age of 160 Ma postdating one of the proposed ages of ultra-high pressure conditions in the Rhodope Massif. The currently earliest recognised Rhodope high/ultra-high pressure metamorphic event is therefore related to the subduction setting which formed the Evros ophiolite. Based on these new temporal constraints and the regional tectonic–geochronologic framework, we discuss and update the geodynamic context connected to the Jurassic subduction–collisional setting at the Rhodope continental margin of Eurasia.