Coastal and Oceanic Landform (33. Mid Oceanic ridge )

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• A mid-ocean ridge called as an underwater mountain system.

• It consists of various mountain ranges.

• The uplifted seafloor results from convection currents.

• which rise in the mantle as magma at a linear weakness in the oceanic crust.

Including a black smoker

• Emerge as lava.

• Creating new crust upon cooling.

•  A mid-ocean ridge boundary between two tectonic plates.

• consequently is termed a divergent plate boundary.

• It connected & form a single global mid-oceanic ridge system.

• That is part of every ocean.

• There are  the longest mountain range in the world.

•  The continuous mountain range is 65,000 km long.

• The total length of the oceanic ridge system is 80,000 km.

• Mid-ocean ridges are active, with new magma.

• The crystallized magma forms new crust of basalt & gabbro.

• Oceanic crust in the ocean basins is less than 200 million years old.

• Slow spreading ridge Mid-Atlantic Ridge have large, wide rift valleys. 10–20 km.

• fast spreading ridges like the East Pacific Rise are narrow, sharp.

Mid-ocean ridge,magma rising from a chamber below, forming new ocean plate which spreads away from ridge

•  There are two processes;

                                                             ridge-push 

                                                             slab pull

• Ridge-push= growing bulk of the ridge.

                                        pushes the rest of the tectonic plate away from the ridge

                                        towards a subduction zone.

• Slab-pull =    this is simply the weight of the tectonic plate.

                                      subducted (pulled) below the overlying plate.

                                      dragging the rest of the plate along behind it.

• The other process contribute to the formation of new oceanic crust at mid-ocean ridges is the "mantle conveyor".

• Mid-ocean ridge creates new material spreading rate measured in mm/yr.

• The common subdivisions of spreading rate;

                                                            >100 mm/yr

                                                           100–55 mm/yr

                                                           55–20 mm/yr