Figure F53. Thin section photomicrographs of basalt, Site U1376. Highly olivine-augite-phyric basalt from lithologic Unit 15 (A) under plane-polarized light and (B) with crossed polars (Sample 330-U1376A-8R-6, 136–140 cm; Thin Section 255). C. Hyaloclastite breccia from lithologic Unit 21 showing fresh basaltic glass shards with curved edges (Sample 330-U1376A-17R-1, 140–143 cm; Thin Section 262) (plane-polarized light). Homogeneity of the glass suggests fragments quenched very rapidly, and shape of shards suggests they are bubble-walled fragments. Voids between glass shards are unfilled. Darkening of glass around shard edges is due to numerous minute tubes formed by micro-organisms. D. Orthopyroxene xenocryst surrounded by reaction corona composed of tiny crystals of clinopyroxene (Sample 330-U1376A-1R-4, 39–42 cm; Thin Section 234) (plane-polarized light). See Figure F51E for scanned image of archive-half interval shown here.
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