Mid-Ocean Ridges

Mid-Ocean Ridges an underwater mountain range, typically having a valley known as a rift running along its spine, formed by plate tectonics. At the mid-ocean ridge, the lava rises and erupts. Soon the lava cools and hardens. That part becomes the new crust. That's how the continents move. As the mid-ocean ridges move apart, its literally renewing the crust, as the older crust is recycled back into the mantle.