Resolution of the Pb-Diffusion in Monazite Paradox using a High-Temperature Contact Aureole Environment

Our current knoweldge of the rates and timescales for crustal recycling is predicated on our understanding of Pb diffusion in zircon and monazite. Unfortunately, the closure temperature for Pb diffusion in natural occurrences of these minerals remains uncertain. To address this issue, Pb diffusion in natural monazite will be studied in a well-documented high-temperature contact aureole. Age profiles in monazite rims, measured using ion-microprobe depth-profiling, will be used to calculate Pb diffusion parameters that satisfy geological constraints on thermal histories in the aureole. The results of this study are expected to enhance our understanding of geodynamic processes in ancient and modern orogenic belts.