Sample 27MW0107 is a diabase with a composition of
plagioclase (50%), clinopyroxene (20%), chlorite (20%), oxides (8%),
hornblende (1%), and trace epidote and sericite. Plagioclase occurs as
elongate lath-shaped phenocrysts; it is turgid and seritized.
Clinopyroxene, probably augite, occurs mainly as 0.2-mm sized matrix
grains. Biotite and olivine have been fully altered to chlorite, leaving
relict grains. Anhedral hornblende and oxides are commonly rimmed by