Figure F25. Alteration of clinopyroxene (Cpx) in intensely altered troctolite (Thin Section 136; Sample 345-U1415P-20R-1, 67–68 cm). Clinopyroxene is serpentinized as well as olivine (Ol), showing a “bastite” texture. Serpentine (Serp) replacing clinopyroxene has pale brownish color, suggesting a difference in composition from colorless serpentine after olivine. Primary plagioclase (Pl) is intensely altered to pseudomorphs composed of prehnite (Pr), chlorite (Chl), and a small amount of garnet (Ga) (or hydrogarnet). A. Plane-polarized light. B. Under crossed polars.
Previous | Close | Next | Top of page