Garnet has become a key target for geochronological studies. Technical and analytical advances in the past two decades have made garnet geochronology a powerful approach to constrain the evolution of metamorphic rocks. Not only may precise metamorphic dates be obtained from multi-point isochron diagrams but also the tempo of garnet growth can be explored taking account of the scatter in isotopic data or using micro-sampling of large crystals. We used lutetium–hafnium (Lu–Hf) garnet geochronology to investigate the dynamics of transient tectonic environments related to the closure history of the Neotethys Ocean in western Anatolia. Geochronology was applied following two approaches. Comparing the metamorphic evolution of contrasting HP/LT oceanic rocks in a subduction complex reveals 20-Myr-lasting active cooling of an ancient subduction interface following subduction inception. In addition, we micro-sampled sections along core-to-rim profiles of cm-sized garnet crystals formed during continental collision and show that Barrovian-type heating may last well over 15 Myr. Garnet geochronology therefore is useful for deciphering the duration to thermal, chemical and petrological processes, and may be used to reveal the pace of ‘proto-tectonic’ processes prevalent during the Proterozoic and earlier.