Abstract:

Grove Mountains(GRV) 051523 is a new eucrite,consisting mainly of coarsegrained pyroxene(62.9vol%) and plagioclase(34.2vol%) with less abundant opaque minerals(2.7vol%) and minor silica and tiny FeO-rich olivine(Fa75).Coarse-grained pyroxenes show exsolution of augite lamellae in pigeonite or vice versa.Width of most exsolution lamella in pyroxenes is 1—3μm.The opaque minerals are chromite,ilmenite and sulfides.The meteorite was heavily shocked,producing breccia and melt veins.Coarse-grained pyroxenes commonly contain abundant tiny or needle-like chromite inclusions with orientation,probably due to heavy shock events.Homogeneous compositions of pyroxenes of various occurrences indicate that GRV 051523 experienced intense thermal metamorphism in the parent asteroid Vesta,and it is classified as Type 5—6.This new eucrite will have additional constraints on chemical composition,magmatic differentiation,multi-stage shock and thermal history of Vesta.