Abstract
The Yamato 980318 feldspar-cumulate eucrite gave one of the oldest age (ca. 4.56 b.y.) for cumulate eucrites. The primary pigeonite (Pig) with a bulk composition exsolved augite lamellae ca. 30 microns thick on (001) of the original Pig. The host low-Ca pyroxene between the thick lamellae has decomposed into blebby augite inclusions in orthopyroxene (Opx, Ca2Mg50Fe48). The Opx nucleus produced in a crystal grew into adjacent pigeonite grains. This texture is similar to those of Serra de Mage (SdM) recorded in images of Planetary Materials Database. Inversion texture in SdM has been proposed as developing in a cumulate pile in a very slowly cooling magma as in terrestrial layered intrusions, which is different from Moore County studied by us.
