Coupled U–Pb and 40Ar/39Ar chronology of late-stage intrusions at Elba Island (Italy) supports late Miocene long-lived magma reservoirs in the Tyrrhenian upper crust

Abstract

The late Miocene Monte Capanne and Porto Azzurro plutons are investigated by means of coupled U–Pb zircon and ⁴⁰Ar/³⁹Ar white mica dating to test the occurrence of long-lived magmatic systems in the upper crust. Zircon crystallized for >1 Ma in both plutonic systems, with supersolidus conditions overlapping for ~220 ka indicating previously unrecognized co-existence of the two reservoirs. The development of the Porto Azzurro high T-aureole is post-dated by continuous igneous zircon crystallization until ~6.0 Ma. By linking crystallization to post-emplacement cooling of late-stage pulses in both western and eastern Elba we constrain long-lived sizeable reservoirs (possibly the same reservoir) in the Tyrrhenian upper crust between ~8 and 6 Ma.