Fractionation of monazite in the development of V-shaped REE patterns in leucogranite systems: Evidence from a muscovite leucogranite body in central Australia

Abstract

Geochemical modelling based on K d values for rare earth (REE) and other trace elements suggests that a Proterozoic muscovite leucogranite from the Atnarpa area, southeastern Arunta Inlier, central Australia was derived from a restite-free melt by simple but extensive crystal fractionation involving feldspars, biotite and accessory REE-rich minerals such as monazite and zircon at a pressure of 0.5–1.0 kbars and a temperature below 750°C. This study indicates that REE-rich accessory minerals, particularly monazite, play an important role in the evolution of the REE in high-Si, low temperature, granitic melt systems.