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The southern part of the Adamello batholith (the so-called “Re di Castello unit”) is an example of a composite pluton, ranging from gabbro to granodiorite in composition. U–Pb dating of single-zircon crystals from four tonalitic to granodioritic lithologies reveals that zircon crystallization is protracted in all studied lithologies, showing apparent durations of growth between 90 and 700ka. The youngest zircons crystallized near the solidus and yield identical or slightly older ages than titanite. The formation of these autocrystic zircons is considered to approximate the age of emplacement of the melt and its final crystallization, in contrast to antecrystic zircons present in the same sample, which had formed earlier in the magmatic column or were derived from re-mobilized earlier magma. The autocryst-derived “emplacement” ages range from 42.43±0.09Ma to 40.90±0.05Ma, recording 1.5Ma of intrusion and crystallization …