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 phenocryst with resorption rim (Sample 197-1205A-13R-3, 27-29 cm) (cross-polarized light; field of view = 1.25 mm; photomicrograph 1205A-206). C. Compositional zonation in a plagioclase phenocryst from Subunit 8a (Sample 197-1205A-20R-5, 67-68 cm) (cross-polarized light; field of view = 1.25 mm; photomicrograph 1205A-216). D. Strain lamellae in a plagioclase megacryst (Sample 197-1205A-11R-1, 73-75 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-204). E, F. Plagioclase phenocrysts from Subunit 14b (Sample 197-1205A-29R-2, 55-58 cm) (cross-polarized light; field of view = 5 mm): (E) zoned, fractured, and strained plagioclase phenocryst (photomicrograph 1205A-236); (F) highly embayed plagioclase phenocryst (photomicrograph 1205A-237). G. Plagioclase-olivine glomerocrysts (Sample 197-1205A-29R-2, 55-58 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-235). H. Highly embayed olivine phenocryst from Unit 21 (Sample 197-1205A-37R-5, 28-29 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-257). I. Partially altered olivine phenocrysts in Subunit 3b (Sample 197-1205A-8R-1, 59-61 cm) (plane-polarized light; field of view = 1.25 mm; photomicrograph 1205A-190). J. Partially altered olivine phenocryst rimmed by biotite in Unit 27 (Sample 197-1205A-43R-2, 58-60 cm) (plane-polarized light; field of view = 5 mm; photomicrograph 1205A-274). K. Glomerocryst from Subunit 5b, composed of plagioclase, pyroxene, opaque minerals, and partially altered olivine (Sample 197-1205A-16R-2, 84-86 cm) (cross-polarized light; field of view = 5 mm; photomicrograph 1205A-214). L. Subophitic texture in Subunit 3b, with a large groundmass clinopyroxene crystal enclosing a partially altered olivine phenocryst (Sample 197-1205A-12R-2, 114-116 cm) (cross-polarized light; field of view = 1.25 mm; photomicrograph 1205A-205). 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). O. Sheared, relict olivine phenocryst in Subunit 29b (Sample 197-1205A-44R-2, 110-112 cm) (cross-polarized light; field of view = 1.25 mm; photomicrograph 1205A-262). Click on letter or image for enlargement.