Abstract:

Grove Mountains ( GRV) 051523 is a new ly identified eucrite, consisting mainly of coarse-grained pyroxene ( 62. 9 vol%) and plagioclase ( 34. 2 vol%), with less abundant opaquem inerals ( 2.7 vol%), 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 lamellae in pyroxenes is 1-3 μm. Opaquem inerals are mainly chromite, ilmenite and sulfides. Themeteorite was heavily shocked, as indicated by breccias andmelt veins. Coarse-grained pyroxenes commonly contain abundant tiny or needle-like chromite inclusions with orientation, probably due to heavy shock events. Pyroxenes in various petrographic occurrences exhibit highly homogeneous compositions, indicating that GRV 051523 experienced intense thermal metamorphism in the parent asteroid 4 Vesta. GRV 051523 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.

Key words: meteorite, eucrite, Antarctic meteorite, thermal metamorphism, Vesta