Garnet granulite xenoliths from the Nurbinskaya diatreme in the central part of the Archean Anabar province in Siberia
are fragments of the local lower crust that experienced multiple metamorphic events in the Paleoproterozoic and reheating
events in the Mesoproterozoic and later. This study addresses the timing of metamorphic transformations, and constrains
the cooling rate and the time of stabilization of the lower crust. The observed metamorphic mineral assemblage of garnet,
clinopyroxene, plagioclase, amphibole, rutile and ilmenite was formed at ~ 800 °C, 1.1–1.2 GPa under water-undersaturated
conditions at ~ 1.88 Ga. However, the mineral assemblage is not well equilibrated and retains evidence of earlier
and subsequent metamorphic stages. Late titanite formed in response to hydrous fluid influx according to phase equilibria
modeling. U-Pb dating shows two events of titanite formation at 1850 ± 5 Ma and at 1788 ± 2 Ma. After deformation,
which led to the porphyroclastic rock textures, the granulites underwent near-isobaric cooling. The cooling rate was higher
than ~ 6 °C/Myr, to retain the garnet compositional zoning. Rutile ages are discordant, with 207Pb/206Pb dates ranging
from 1.43 to 1.53 Ga. However, rutile may have responded to earlier thermal pulses, and was also reset later, so it does
not record the stabilization of the crust. Crustal stabilization after Paleoproterozoic orogenic events may have occurred
shortly after titanite formation.