Newly obtained near-infrared reflectance spectra for features on or near the Aristarchus Plateau demonstrate he diversity of compositions in the region. t!ighland units are of three probable compositions: a feldspar and elinopyroxene assemblage; a probable clinopyroxene, olivine, and possibly feldspar assemblage; and an assemblage composed of olivine or olivine and feldspar. The feldspar-elinop...

At the first site, the Weinsberg (Moldanubian) granite and an older quartzmonzonite facies of the South Bohemian pluton in Austria both contain orthopyroxene and clinopyroxene and must have crystallized from magmas at high temperatures. The granite contains orthoclase megacrysts (as much as 10 to 20 cm long), which (1) are chemically zoned with Ba-rich cores (1 to 2 % mol Cs; and locally as muc...

Isotopic signatures are used to distinguish Group I, Transition, and Group II kimberlites, and provide information on the origin of melts parental to the final intrusion. Kimberlitic rocks are often weathered and altered, making them potentially unsuitable for whole rock isotopic studies. We therefore have explored the alternative use of the isotopic signatures of resistant minerals in kimberli...

Seismic velocities are calculated for two petrological models of the upper mantle, an olivine-rich assemblage, pyrolite, and a garnet-clinopyroxene rich, olivine bearing, assemblage, piclogite. These are compared with recent seismic profiles for various tectonic provinces. The .shield data is most consistent with a cold olivine and orthopyroxene-rich LID (the seismic lithosphere) extending to 1...