Figure F43. Illustrations of veins with alteration halos. A. Anastamosing subvertical carbonate veins in vesicular basalt. Centimeter-sized dark alteration halos occur along much of the large vein at center. Vesicles are filled with dark clay in the alteration halo and by calcite in the host rock (interval 185-801C-37R-2, 68-105 cm). B. Dark alteration halos along smectite and celadonite veins (interval 185-801C-43R-2, 115-135 cm). A 4-mm-wide celadonite vein (gray) cuts the sample diagonally from 127 to 130 cm. C. Subvertical mixed vein filled with calcite (white) at top left, celadonite (black) at center (75-83 cm), and a mixture of calcite and iron oxyhydroxide at bottom right (83-95 cm) (interval 185-801C-34R-3, 73-95 cm). The quality of the image reflects the AMST source.