GROSSULAR IN THE ALLENDE (TYPE III CARBONACEOUS) METEORITE*

Grossular garnet has been observed in several white inclusions in the Allende meteorite. Compositions range from Gro_9sPy₅ to Gro₈₈Py₁₂ in five inclusions. Its mottled appearance indicates that it crystallized from a glass of near-grossular composition and not by a solid state reaction between wollastonite, anorthite and melilite. These grossular-bearing inclusions either condensed directly as metastable liquids from the solar nebula or if initial solid condensates were liquefied by some subsequent heating process. In either case, a prolonged residence time in a thermal blanket appears necessary to effect crystallization of the grossular.