Long description

Figure 3

This line graph shows the change in ocean depth with longitude.

The horizontal axis is labelled 'degrees longitude West of Greenwich'. The axis scale begins at approximately −75° and ends at approximately −7°, but is marked at 20° intervals from −70° to −10°. There are vertical grid lines at the marked axis points.

The vertical axis is labelled 'depth/m below sea level' and is marked from 6000 m to 0 m, with 0 m at the top, in intervals of 2000 m. There are horizontal grid lines at intervals of 1000 m.

There is a black dashed line that runs horizontally at a depth of 0 m.

The depth data are represented by a solid red line which is labelled 'USA' at the left side and 'Europe' on the right side. There is also a label of 'MAR' at a peak in the line between −34° and −26°.

Moving right, from the left side (labelled 'USA'),

the ocean floor drops slowly at first and then rapidly to almost 3000 m (−70°) and then to near 5000 m (−60°),

the ocean floor then slowly drops further to approximately 5500 m before rising sharply to 4500 m (−45°),

this is the start of a gradual rise in the ocean floor with longitude followed by a sharp rise to 2000 m (−34°),

the ocean floor now stays above 2000 m, reaching as shallow as 1500 m, until it drops sharply back to 2500 m (−26°). This is the section labelled 'MAR'.

there is a steady drop in ocean floor back to 5500 m (−18°), then a section of sharp oscillations between 4500 m and 3500 m followed by a sharp rise to 0 m on the right side, labelled 'Europe'.