Buried, not erased: palynofloras in ultra-high-pressure metamorphic rocks

Fossils are rare in metamorphic rocks due to recrystallization and deformation, especially under high-pressure metamorphic conditions. Here, we report the discovery of exceptionally preserved Paleozoic palynofloras in ten graphite-rich samples collected from the Dora-Maira Massif (Western Alps), which underwent blueschist-facies to ultra-high-pressure (UHP) metamorphism (~ 28 kbar, 520 °C). These findings challenge the assumption that fossils cannot survive such conditions, offering a new biostratigraphic tool for reconstructing the geological and tectonic history of metamorphic basement in collisional orogens worldwide.