Figure F98. Photomicrographs showing replacement of plagioclase. A. Cores of plagioclase phenocrysts totally replaced by brown saponite. Saponite is also present as interstitial and vesicle fillings (Sample 206-1256D-65R-3, 14-16 cm; field of view = 1.25 mm; plane polarized light). B. Cores of plagioclase phenocrysts replaced by secondary feldspar (albite?) and pale brown saponite (Sample 206-1256D-65R-1, 137-138 cm; field of view = 2.5 mm; plane polarized light). C, D. Plagioclase glomerocryst extensively replaced by secondary feldspar (albite?) (Sample 206-1256D-63R-1, 81-83 cm; plane polarized light); (C) field of view = 2.5 mm; (D) field of view = 1.25 mm.

Figure F98. Photomicrographs showing replacement of plagioclase. A. Cores of plagioclase phenocrysts totally replaced by brown saponite. Saponite is also present as interstitial and vesicle fillings (Sample 206-1256D-65R-3, 14-16 cm; field of view = 1.25 mm; plane polarized light). B. Cores of plagioclase phenocrysts replaced by secondary feldspar (albite?) and pale brown saponite (Sample 206-1256D-65R-1, 137-138 cm; field of view = 2.5 mm; plane polarized light). C, D. Plagioclase glomerocryst extensively replaced by secondary feldspar (albite?) (Sample 206-1256D-63R-1, 81-83 cm; plane polarized light); (C) field of view = 2.5 mm; (D) field of view = 1.25 mm.