Clumped‐Isotope Geothermometry and Carbonate U–Pb Geochronology of the Alta Stock Metamorphic Aureole, Utah, USA: Insights on the Kinetics of Metamorphism in Carbonates

To assess thermal and kinetic influences on atomic mobility mineral (neo)crystallization, clumped-isotope abundances of calcite dolomite were measured alongside cation ordering U–Pb dates, across metamorphic grade within the c. 35–30 Ma Alta stock contact aureole, Utah, USA. Average Δ47 values inside aureole reflect blocking temperature (300°C–350°C) during cooling from peak temperatures. Dolomite outside record a ∼160°C. At talc isograd, abruptly change, corresponding to decrease ∼180°C over <50 m in down-temperature direction. This observed step does not correlate with or neither which well grade. The short distance change indicates strong sensitivity kinetics reordering, is consistent wide range reequilibration modeling results. We hypothesize that reordering precedes more extensive recrystallization reaction, such as formation talc. analyses populate single discordia ∼60 Myr younger than depositional age (Mississippian), recording resetting response some older postdepositional, but premetamorphic process.