Figure F8. Alteration of olivine (Ol) phenocrysts in olivine-phyric basalt (Thin Section 92; Sample 345-U1415N-2R-1, 5–7 cm [Piece 1]). Olivine near the edge of the sample is highly altered to serpentine (Srp), clay, and pyrite (Py). In contrast, phenocrysts in the center of the sample are fresh with only minor serpentinization. A. Plane-polarized light. B. Under crossed polars.
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