Plate P4. Photomicrographs of various vein minerals in Hole 735B. 1. Full thin section view of an amphibole + plagioclase vein cutting slightly foliated gabbro. Note the sharp but irregular vein margins (Sample 176-735B-19R-5, 62-73 cm). 2. Large, euhedra

Plate P4. 4. Narrow natrolite vein filling crack in the center of a fine-grained felsic vein (Sample 176-735B-84R-6, 31-41 cm). All scale bars = 1 mm.