Figure F53. Alteration of felsic material (Sample 335-1256D-235R-1, 23–35 cm; Thin Section 3). A. Photograph of foliated diorite intruded by tonalitic vein and cut by later amphibole vein at center. B. Photomicrograph of plagioclase replaced by secondary plagioclase, epidote, and minor amphibole (cross-polarized light). Quartz containing needles of actinolite on right (white).
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