Short-duration regional metamorphic event recorded in a Variscan subduction channel (Malpica–Tui eclogites, NW Iberia)

An isotopic resetting event is disclosed at ca. 350 Ma, based on Rb–Sr isotopic analyses (whole rock, garnet, clinopyroxene and phengite fractions) of eclogites with coronitic garnet and planolinear eclogites from the Malpica–Tui Allochthonous Complex (NW Iberia). The eclogites were buried, deformed/recrystallized and subsequently exhumed in a Late Devonian subduction channel. Lu–Hf and Sm–Nd isotopes date a ca. 375-Ma metamorphic peak of the subduction–exhumation cycle that occurred under ~ 2.6 GPa and 610–640 °C and was overprinted by the 350-Ma event, which occurred still under high-pressure conditions. The latter resetting is interpreted as a very short-duration regional metamorphic phenomenon recorded by high-pressure rocks in the west European Variscan belt at time scales shorter than those characteristic of orogenic lithosphere in subduction/collision cycles.