Crystallisation In Synthetic Basaltic Glass-Ceramics

Crystallisation sequences in simulated basaltic compositions have been shown to be similar to those exhibited by natural basalts under both high and low oxygen fugacity. Evidence suggests that feldspar, spinel and metasilicate phases represent the equilibrium phases under high oxygen fugacity, however, the formation of feldspar is kinetically inhibited. Dietzel's field strength criterion can be utilized to rationalise the observed enrichment of primary spinel in high field strength cations. The formation of spinifetic textures with long range orientation are inconsistent with random nucleation.