The three diagrams below illustrate the magnetic polarity reversals across sections of the mid-ocean ridges in the pacific, south atlantic, and north atlantic oceans. on each image, identify and mark the periods of normal polarity with the letters a-f. start at the rift valley (the center) and move outward. the left side of the south atlantic has been done as an example. now you do the north atlantic and pacific along the left side. label section c on each diagram “2 million years ago.” using the scale at the bottom, measure the distance from the center of the rift valley to the end of the section of normal polarity that occurred 2 million years ago. south atlantic (done for you): 39 km 2. north atlantic: km (2pts) 3. pacific: km (2pts)