Insight Into the Early Exhumation of the Cycladic Blueschist Unit, Syros, Greece: Combined Application of Zoned Garnet Geochronology, Thermodynamic Modeling, and Quartz Elastic Barometry

Constraining conditions and mechanisms of the early stages exhumation from within subduction zones is challenging. Although pressure, temperature, age can be inferred exhumed rock record, it generally difficult to derive each these parameters any single rock, thus demanding assumptions that diverse data multiple samples safely combined into a pressure-temperature-time (P-T-t) path might then used infer tectonic context exhumation. Here, we present new thermobarometric geochronologic information preserved in sample Syros, Greece, deduce rates earliest phase as part well-preserved high-pressure metamorphic rocks Cycladic Blueschist Unit (CBU). The studied here garnet-bearing, quartz-mica schist records two distinct events. Results thermodynamic models quartz-in-garnet elastic geobarometry show garnet cores formed P-T evolved ∼485°C 2.2 GPa 530°C 2.0 GPa, rims ∼560°C 2.1 ∼550°C 1.6 GPa. Sm-Nd geochronology on yields ages 45.3 ± 1.0 40.5 1.9 Ma, respectively, indicating 4.8 Myr growth span. Given decompression calculated based core rim estimates, conclude phases preserve evidence initial portions CBU.