Trace element analysis of zircon and associated minerals in the Huangtuling gran ulite,Dabieshan and its geological implication

Zircons in the Huangtuling granulite were analyzed for trace eleme nts by LA-ICPMS. The granulite-facies metamorphic zircons have lower trace el ement contents than those of the magmatic protolith zircons. The negative Eu ano maly in metamorphic zircon is interpreted by the presence of feldspars. The trac e element partitioning between zircon and garnet indicates that metamorphic zirc on formed in equilibrium with the garnet. Combined with these evidences, it is s uggested that the granulite metamorphic zircons formed at the peak metamorphic c onditions, and thus the U-Pb age of the metamorphic zircons corresponds to the time of the peak metamorphism. The trace element composition of zircon and asso ciated minerals can therefore give effective ways to constrain the zircons' form ation conditions. The trace element partitioning between zircon and garnet can p rovide new constraints on the interpretation of zircon U-Pb age.