Zircon geochronology suggests a long-living and active magmatic system beneath the Ciomadul volcanic dome field (eastern-central Europe)

Ciomadul is the youngest volcano in eastern-central Europe. Although its last eruption occurred at ca. 30 ka, there are independent indications for a high-crystallinity magma reservoir persisting beneath until present. In order to further test hypothesis of long-lived melt presence and better constrain nature timescales associated with subvolcanic storage system, over 500 zircon U-Th U-Pb spot ages (crystal interiors outer surfaces) were interpreted from dacitic rocks most productive eruptive period (the Young Eruptive Period; YCEP, 160-30 ka). Zircon surface lava dome pumice samples range 600 ka up event ka. They form continuous age distribution some single crystals reveal significant zonation (>150 kyr difference core rim). The oldest YCEP overlap events Old Period (1000–330 spectra, combined textural data, point prolonged (several 100's kyr) residence highly crystalline mush state. crystallization temperature (from ?750 °C solidus ?680 °C) consistent results thermometry on amphibole plagioclase felsic crystal clots, which represent fragments. To maintain such long time above solidus, input by deeper recharge required. model calculations constrained thermal modelling imply an average rate about 1.3 × 10?4 km3/yr 2 Myr. Such estimate allows us calculate extrusive/intrusive ratio 1:25–1:30. suggest that zone 35 km3 still present within reservoir. Importantly, plumbing system thus remains thermally primed renewed injection could lead rapid reawakening apparently inactive volcano.