Figure F36. Thin section photomicrographs showing details of replacement and cementation of altered glass, Hole U1348A. A. Detail of a shard rimmed with fibropalagonite and with the interior replaced by calcite, set in zeolite or phosphorite (Thin Section 161; Sample 324-U1348A-16R-2, 54–57 cm). B. Calcite replacing the interior of an angular shard; the shard is set in cement of calcite (upper left) and phosphorite (no birefringence, bottom and right) (Thin Section 165; Sample 324-U1348A-16R-2, 76–78 cm). C–E. Thin Section 162 (Sample 324-U1348A-15R-5, 55–59 cm). C. Fibrous high-Mg calcite or aragonite cement. D. Fibropalagonite rims altered to green clays, with interior replacement and calcite-phosphorite cement. E. Detail of nonbirefringent phosphorite cementing altered palagonite. F. Altered angular and subround hyaloclastite with fibropalagonite rims and spectacularly developed fibrous zeolite (probably phillipsite) cement (Thin Section 165; Sample 324-U1348A-16R-2, 76–78 cm). G. Authigenic minerals in vesicles, mainly clays (light brown), but with a combined rosette of calcite and phillipsite (right) and round botryoidal pyrite (black) (Thin Section 158; Sample 324-U1348A-14R-3, 54–56 cm). A, D, F, and G are under transmitted light; B, C, and E are under cross-polarized light.
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