Figure F16. Thin section photomicrographs of vesicles and vein. A. Vesicles filled with thin layer of brown clay at rim and later by white clay and carbonates (in sparsely olivine-phyric lava lobe; Sample 330-U1377A-6R-2, 13–15 cm; Thin Section 274; crossed polars). B. Vesicles filled with carbonates (calcite and siderite; left) or different layers of brown and white clays (right) (in moderately olivine-phyric lava lobe; Sample 330-U1377A-6R-2, 64–66 cm; Thin Section 275; plane-polarized light). C, D. Vein filled with mix of clay minerals, Fe oxyhydroxides, and goethite (aphyric basalt lava body or intrusive sheet; Sample 330-U1377A-3R-1, 68–70 cm; Thin Section 270): (C) plane-polarized light, (D) reflected light.
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