Figure F42. Textures of hyaloclastites and glass shards (Sample 200-1224F-12R-1, 61-64 cm; all in plane-polarized light). The sample is at the top of ferrobasalts of Unit 3. A. A low-magnification photomicrograph of palagonitized hyaloclastite. The altered glass shards are not vesicular. Note zoning of palagonitic alteration in several shards. B. Another portion of the same hyaloclastite showing palagonite rims surrounding relict fresh brown basaltic glass. The glass contains almost no crystallites. C. Detail of zoning of palagonite of one altered glass shard seen in A, center left. D. Tiny and numerous plagioclase and clinopyroxene crystallites in a glass shard in the hyaloclastite that experienced incipient crystallization. E. A slightly more crystalline glass shard similar to D but with a pale-brown spherulitic overgrowth on many of the crystallites.

Figure F42. Textures of hyaloclastites and glass shards (Sample 200-1224F-12R-1, 61-64 cm; all in plane-polarized light). The sample is at the top of ferrobasalts of Unit 3. A. A low-magnification photomicrograph of palagonitized hyaloclastite. The altered glass shards are not vesicular. Note zoning of palagonitic alteration in several shards. B. Another portion of the same hyaloclastite showing palagonite rims surrounding relict fresh brown basaltic glass. The glass contains almost no crystallites. C. Detail of zoning of palagonite of one altered glass shard seen in A, center left. D. Tiny and numerous plagioclase and clinopyroxene crystallites in a glass shard in the hyaloclastite that experienced incipient crystallization. E. A slightly more crystalline glass shard similar to D but with a pale-brown spherulitic overgrowth on many of the crystallites.