Figure F16. Photomicrographs showing plagioclase phenocrysts. A. Plagioclase megacryst with inclusion of olivine (Sample 197-1205A-15R-2, 138-140 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-211). B. Rounded plagioclase phenocry

Figure F16. Photomicrographs showing plagioclase phenocrysts. M. Close-up view of groundmass olivine completely altered to Fe oxyhydroxide or iddingsite (Sample 197-1205A-24R-2, 124-130 cm) (plane-polarized light; field of view = 1.25 mm; photomicrograph 1205A-222). N. Strain bands in trachytic texture, Subunit 3b (Sample 197-1205A-10R-2, 73-75 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-202).