After a billion years, the ray brightness contributed by the highly reflective powdery ejecta will have been weathered away, but the rays will still be somewhat bright because of the anorthosite
Mineralization can also extend into the underlying anorthosite
It is composed of metamorphosed syenites, norites, anorthosites
, gabbros, pyroxenites and peridotites.
and related granitoids in the Grenville orogen: a product of convective thinning of the lithosphere?
Stephen Gabbro consists of complexly intermingled olivine gabbro, olivine gabbronorite, and olivine norite, with less abundant gabbro, gabbronorite, norite, troctolite, anorthosite
, and dunite.
In confirmation that these craters are simply strongly modified impact craters, Ray Hawke and his colleagues at the University of Hawaii have discovered that the east wall of Vitello is composed of pure anorthosite
crystallized from the magma and, because it was less dense than the liquid, floated upward to form the highland crust.
Immediately, both men knew what they had found: This was a chunk of anorthosite
, a fragment of the Moon's primordial crust.
Units containing anomalous platinum-palladium have been identified as olivine norite, anorthosite
Ultramafic rocks include peridotite and pyroxenite with the mafic complex dominated by gabbro and subordinate anorthosite
Thin layers of pyroxenite and pegmatoidal anorthosite
with disseminated copper-nickel sulphides are alternating with gabbroic horizons.
The pyroxenite layers making up the zone of interest are overlying this horizon in a groundmass of anorthosite
for the next 500 meters.