What is a divergent plate boundary?

At divergent boundaries new crustal material is brought to the surface. As the convection current comes to the surface it also moves outward in both directions (see image below). This causes the crust to separate into two different pieces.

An example of a divergent boundary is the mid Atlantic Ridge (there are mid ocean ridges in the Indian, and Pacific Oceans as well). The Mid Atlantic Ridge creates volcanos where the hot magma erupts from the underlining mantle. Many of these volcanos are undersea volcanos forming the mid Atlantic ridge. However in Iceland the the volcanos reach the surface forming the Island chain.

As the crust is pushed in two different directions it forms magnetic strips that are reflective and symmetrical on both sides of the Mid Atlantic ridge. This was part of the evidence that convinced Scientists that the theory of (Continental Drift) Plate tectonics was correct.

Divergent boundaries also create Rift Valleys and new oceans. The Rift Valley in East Africa is the result of a divergent boundary (image below). The Red Sea and the Dead Sea are thought to have been formed by the same divergent boundary.

Divergent boundaries, create mid ocean ridges, undersea volcanos, islands, rift valleys and new oceans.