Figure F12. Photomicrographs of saponite replacement. A. Intense replacement of groundmass to saponite marks a gray halo boundary (right) contrasted with low-level background alteration of groundmass (left) (Sample 327-U1362A-6R-1 [Piece 10, 39–41 cm]) (FOV = 2.5 mm; plane-polarized light). B. Saponite replacing mesostasis and plagioclase microcryst (center) as part of general background alteration (Sample 327-U1362A-7R-1 [Piece 5, 29–31 cm]) (FOV = 2.5 mm; cross-polarized light). C. Saponite-filled vein (2.5 mm wide), crosscutting plagioclase groundmass crystals and enclosing blebs of iron oxyhydroxides (Sample 327-U1362A-8R-1 [Piece 18, 122–124 cm]) (FOV = 2.5 mm; plane-polarized light). D. Mesostasis and saponite-filled vesicle (Sample 327-U1362A-20R-2 [Piece 11, 70–72 cm]) (FOV = 2.5 mm; plane-polarized light). E. Saponite replacement destroying primary igneous texture (Sample 327-U1362A-3R-1 [Piece 17, 141–146 cm]) (FOV = 2.5 mm; plane-polarized light).
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