Given all the discoveries that we have made from an up-close investigation of these ocean ridges, we can't help but wonder what we might find at the far end of the same plate tectonic cycle where seafloor is drawn back into the Earth's interior at deep-ocean trenches.

CNN: Probing the ocean's undiscovered depths

Such concentrations are usually created by geological events, such as volcanic eruptions and tectonic plate shifts that steer hot metal-bearing fluids into upper, accessible parts of the Earth's crust, erosion, or massive sedimentary movements.

WSJ: Exhausting the Earth's Resources? Not So Fast

She takes her visit to the Galapagos, for example, as the starting point for an explanation of plate tectonics (the itchy movements of the various plates that comprise the earth's ever-shifting surface) that created these islands.

ECONOMIST: Island life