Characterizing rates of Acadian metamorphism using Sm-Nd geochronology and major element diffusion in garnet

Garnet, a robust, rock-forming mineral, is often used to understand metamorphic processes through study of chemical zonation, mineral inclusions, and radiometric dating. Natural sample suites in which two distinct populations of garnet are found can be particularly insightful in unraveling the pressure-temperature-time (P-T-t) evolution of rocks through Earth’s crust. We studied two sample sets from the Smalls Falls formation (northern New Hampshire, USA) and the Hawley formation (western Massachusetts, USA) which both contain a high crystallization density coticule garnet quartzite (~106 crystals/cm3) and a lower crystallization density garnet schist (