Figure F35. Alteration halos in plane-polarized light. A. Background saponitic alteration of the nonhalo portion (Sample 301-U1301B-30R-1 [Piece 21, 103–106 cm]). Saponite fills vesicles and replaces the mesostasis and olivine phenocrysts (field of view [FOV] = 2.75 mm). B. Saponite replaces euhedral olivine crystals in the nonhalo portion (Sample 301-U1301B-33R-1 [Piece 22, 117–119 cm]) (FOV = 1.4 mm). C. Saponite followed by celadonite replaces euhedral olivine phenocrysts and fills vesicles in the halo–nonhalo transition zone (Sample 301-U1301B-27R-2 [Piece 6, 38–40 cm]) (left half of field of view), and celadonite filling vesicles/replacing olivine in the green halo portion (lower right field of view; FOV = 1.4 mm). D. Celadonitic green halo in the lower left corner of the field of view, and background saponite alteration in the upper right corner (Sample 301-U1301B-32R-1 [Piece 13, 78–80 cm]). The fill of the micrometer-wide microvein changes from celadonitic to saponitic outside the halo (FOV = 5.5 mm). E. Background saponitic alteration (left field of view) and iron oxyhydroxide-bearing brown halo (right field of view) in Sample 301-U1301B-15R-4 (Piece 6, 66–68 cm), with microvein fill changing across the transition (FOV = 5.5 mm).
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