Figure F101. Igneous textures and fabrics in cross-polarized light illustrating the transition to crystal-plastic deformation. Scale bars are 2 mm. A. Magmatic foliation, defined by the shape-preferred orientation of plagioclase laths. A few mechanical twins are present in the plagioclase, and the grain boundaries are slightly serrated (onset of high-temperature crystal-plastic deformation). Sample 176-735B-89R-2 (Piece 1, 4-8 cm). B. Nearly undeformed igneous texture; the only traces of deformation are minor undulose extinction and mechanical twins in plagioclase, and subgrains in olivine. Clinopyroxene is typically undeformed and poikilitic. Sample 176-735B-121R-8 (Piece 2B, 68-72 cm). C. Equilibrated, fine-grained, igneous texture. All grains are undeformed. Sample 176-735B-121R-2 (Piece 2B, 40-43 cm). D. Equilibrated, coarse-grained, igneous texture. Most grains are anhedral, with curviplanar grain boundaries and 120º triple junctions. A few mechanical twins and minor undulose extinction are present in the plagioclase. Sample 176-735B-132R-5 (Piece 2, 95-100 cm). (Continued on next page.)