Plate 19.—OCEAN-BOTTOM PHOTOGRAPHS; MID-ATLANTIC RIDGE
Figure 1. (Station T1-9, photo 42) Depth 1410 fathoms, location 48° 38´N., 28° 48´W., on Western Rift Mountains, Mid-Atlantic Ridge. In this plate Figures 1, 2, and 3 are closely spaced photographs less than 100 feet apart.
Note the coarse-grained light and dark gravel in winnow row in the foreground and the light-colored clay or ooze bottom in background. Of the sixty photographs taken at this location three resembled Figures 2 and 3, several resembled Figure 1, and in the remainder the ocean floor was composed entirely of the light and dark gravel.
Figure 2. (Station T1-9, photo 43) Location about 50 feet from photo shown in Figure 1, same depth and position. The dark color of the rocks may be due to a coating of manganese dioxide. However, the rocks may actually be composed of dark material; no dredgings were taken here. All dredgings from Mid-Atlantic Ridge have brought up basalt and in some cases also gabbroic and serpentinized rock. It seems likely that the rock in Figure 2 and 3 of this plate is basalt. Note the abundance of sessile life on the rocky areas in contrast to its absence in the gravel-covered areas.
Figure 3. (Station T1-9, photo 45) Location about 100 feet from photo shown in Figure 2, same depth and position. Rock bottom on the Western Rift Mountains, Mid-Atlantic Ridge.
Figure 4. (Station V4-7, photo 27) Depth 500 fathoms, location 37° 25´N., 31° 10´W., Western Rift Mountains, Mid-Atlantic Ridge, south of the Azores Plateau.
Figure 5. (Station T1-54, photo 15) Depth 2100 fathoms, location 23° 07´N., 43° 45´W., Upper Step (eastern side), Mid-Atlantic Ridge. Apparatus in lower right attached to camera. Note tracks of crawling animal in left side of photo and small holes in bottom sediment. Photograph contrasts sharply with those from Rift Mountains in lack of current or oscillation ripples and rock outcrops.
Figure 6. (Station T1-14, photo 6) Depth 2130 fathoms, location 46° 04´N., 17° 43´W., Lower Step (eastern side), Mid-Atlantic Ridge. Note fecal pellets, mounds, and small holes. Again lack of evidence of strong currents or outcrops is notable.
Positions of stations shown on Plate 30