Re–Os isotope evidence for the composition, formation and age of the lower continental crust

摘要: Knowledge of the composition lower continental crust is important for understanding formation and evolution as a whole, petrogenesis basalts. Here we present rhenium–osmium isotope data two well characterized suites lower-crustal xenoliths from North Queensland, Australia1,2,3,4,5,6,7, which have average major- trace-element compositions similar to estimates bulk crust8,9. Our indicate that has 1 2 times much osmium, about half rhenium, less radiogenic than upper crust10. We interpret systematics assimilation fractional crystallization are processes in crust, lead dramatic changes osmium isotopic basalts pond fractionate there. A consequence this system should not be relied on yield accurate mantle extraction ages rocks.