Figure F141. Microcracks in plagioclase crystals, arranged radially from the twin planes. A. Sample 309-1256D-85R-1, 119–122 cm (Thin Section 21) (field of view [FOV] = 2.5 mm; plane-polarized light, blue filter). B. Sample 309-1256D-85R-2 (Piece 2, 104–107 cm) (Thin Section 22) (FOV = 1.25 mm; cross-polarized light, blue filter). C. Intragranular microcracks in plagioclase are filled by alteration phases, mostly saponite, and are the main sites for the initiation of primary mineral replacement (Thin Section 102; Sample 309-1256D-132R-1, 143–147 cm) (FOV = 1.25 mm; plane-polarized light, blue filter).
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