Ocean Ridges
How are they formed?
It is formed by plate tectonics. For example, the ocean ridge in the middle of the Atlantic is formed due to the movement of the continental plates either side of the ocean. As the plates get pulled apart by the convection currents, they leave gaps in the Earth’s crust. This then allows molten rock from beneath the Earths crust to reach the surface, forming a new part of the floor. As the rock seeps through the gap at some pressure, it spews upwards to form a ridge.
What is an example of an ocean ridge?
An example of an ocean ridge is the Mid-Atlantic ridge which is located on the floor of the Atlantic Ocean. It’s considered to be the longest mountain range on the surface of the Earth even though it is underwater. The ridge extends into the South Atlantic Ocean between the South American and African plates. It rises to around 2/3km above the ocean floor and has a rift valley at its crest marking the location at which the two plates are moving apart. It is a slow spreading ridge.
What are the characteristics of this feature?
All ridges have different shapes depending on whether or not they’re slow spreading, how active they are magmatically and volcanically, and how much tectonic stretching and faulting is taking place. There are two types of ridges, slow spreading and fast spreading. Slow spreading ones have large and wide rift valleys and very rugged terrain at the ridge crest. Fast spreading ones are ‘hotter’ which means that more magma is present beneath the ridge axis and more volcanic eruptions occur. Because the plate under the ridge crest is hotter, scientists think that the plates respond to the divergent spreading process more fluidly and that the ridge behaves like hot taffy being pulled apart.
Rift Valleys
How are they formed?
A rift valley is linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate...