Figure F42. Thin section photomicrographs of volcanic glass. A, B. Abundant fresh glass with phenocrysts of plagioclase and augite (plagioclase phyric basalt volcaniclastics, Unit XII) (Sample 330-U1372A-17R-3, 93–95 cm; Thin Section 48): (A) plane-polarized light, (B) crossed polars. C. Altered glass (upper left) with fresh glass (lower right) (plagioclase phyric basalt volcaniclastics, Unit XII) (Sample 330-U1372A-17R-3, 93–95 cm; Thin Section 48; plane-polarized light). D, E. Relatively fresh glass rimmed by palagonite and Fe oxyhydroxides (aphyric basalt volcaniclastics, Unit XII) (Sample 330-U1372A-19R-3, 109–112 cm; Thin Section 58): (D) plane-polarized light, (E) crossed polars.
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