Squirt was looking for an adventure! We decided to swim down the entire Mid-Atlantic Ridge, but it didn't work so well... Turns out whales at divergent boundaries aren't there to appreciate the plate tectonics, just to EAT INNOCENT MARINE LIFE! Luckily, Dory speaks Whale, so after a little bit of sweet talk, and a lot of time, we were exhaled through the whale's blowhole. However ironic it may be, we did end up swimming along most of the Mid-Atlantic Ridge, although we were inside a whale. It was dark, it was cold, it was slimy and it was quite educational. Even if the whale didn't enjoy the fascinating plate tectonics science, I sure did, and I think you will too!
As you can see in this drawing, which I did myself, in divergent boundaries tectonic plates are moving apart and leaving a gap, into which magma from the mantle upwells to fill the hole. The magma hardens, and over time, slides down both sides of the gap, creating two strips of precisely identical rock on either side. However, there are still fracture zones along the ridges, where there is lots of earthquake activity. There are also many underwater volcanoes formed by the magma which upwells.
The rocks in the diagram are colored to represent the two different alignments of minute metal fragments in the rock, pointing either north or south, showing which way the magnetic field surrounding Earth was aligned when the rocks cooled. The farther you get from the center of the ridge, the colder and older the rocks are. That means that the center of the Mid-Atlantic Ridge should have been warm. But we were still cold, so I guess maybe whale insides are just cold. See you at our next stop! HINT: It's a transform boundary!
Image credit: http://www.mnh.si.edu/earth/text/4_3_1_0.html
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