What is a mid-ocean ridge and what causes it?
What is a mid-ocean ridge and what causes it?
Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.
What is the likely cause of melting at mid-ocean ridges?
As mantle ascends beneath the mid-ocean ridge, less and less rock lies above it, so large pressure changes occur, which leads to melting. The melt is less dense than the solid, and rises to the surface to form the oceanic crust.
How the Earth is changing in a mid-ocean ridge?
“Mid-ocean ridges make up the largest volcanic systems on the planet, but they work slightly differently than volcanoes associated with hot spots and subduction zones. The drop in pressure along the ridge axis, where the plates diverge, causes solid mantle rocks to rise and melt.
What causes the mid-ocean ridge to have a rift zone at its center?
As tectonic plates move away from one another at mid-ocean ridges, molten rock from the mantle may well up and harden as it contacts the frigid sea, forming new oceanic crust at the bottom of the rift valley. Over millions of years, the Mid-Atlantic Ridge has formed rift valleys as wide as 15 kilometers (9 miles).
What processes occur at mid-ocean ridges?
There are two processes, ridge-push and slab-pull, thought to be responsible for the spreading seen at mid-ocean ridges, and there is some uncertainty as to which is dominant. Ridge-push occurs when the weight of the ridge pushes the rest of the tectonic plate away from the ridge, often towards a subduction zone.
What type of rock is formed at mid-ocean ridges?
basalt
Igneous rock is formed by the cooling and crystallization of molten magma at volcanoes and mid-ocean ridges, where new crust is generated. Examples of igneous rock are basalt, granite, and andesite (Fig. 7.57 A).
What is likely cause of melting at Calderas?
The initial melting occurs by decompression as a plume of hot rocks rises within the mantle. Then the heat from this mantle-derived magma causes rocks at the base of the crust to melt and to erupt at the calderas.
How do mid-ocean ridges affect sea level?
Impact on global sea level Increased seafloor spreading means that the mid-ocean ridge will then expand and form a broader ridge with decreased average depth, taking up more space in the ocean basin. This displaces the overlying ocean and causes sea levels to rise.
What is the function of the mid-oceanic ridge?
Mid-ocean ridges are the longest, largest and most voluminous magmatic environment on Earth. Ridges are the site of new lithospheric and crustal production that may be subsequently subducted into the mantle and recycled, or involved in magma-producing dehydration reactions that slowly build up continental crust (Fig.
Where along a mid-ocean ridge system would you expect the most earthquakes to occur?
Along divergent boundaries like the mid-Atlantic ridge and the East Pacific Rise, earthquakes are common, but restricted to a narrow zone close to the ridge, and consistently at less than 30 km depth. Shallow earthquakes are also common along transform faults, such as the San Andreas Fault.
