Figure F17. A prominent felsic vein in interval 176-735B-90R-1, 37-63 cm. The close-up photograph on the left is compared with a plot of magnetic susceptibility vs. depth for the corresponding interval. The vein has lower magnetic susceptibility than the immediately surrounding rock, although the surrounding rock itself has magnetic susceptibility slightly higher than local background measurements.

Figure F17. A prominent felsic vein in interval 176-735B-90R-1, 37-63 cm. The close-up photograph on the left is compared with a plot of magnetic susceptibility vs. depth for the corresponding interval. The vein has lower magnetic susceptibility than the immediately surrounding rock, although the surrounding rock itself has magnetic susceptibility slightly higher than local background measurements.