Which type of boundary will old crust be destroyed?
Convergent boundaries Convergent boundaries — where crust is destroyed as one plate dives under another.
How might a divergent boundary form?
A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earth's mantle to the surface, solidifying to create new oceanic crust. The Mid-Atlantic Ridge is an example of divergent plate boundaries.
What causes plate tectonics?
Tectonic plates move around and can cause earthquakes and volcanic eruptions. First of all, it is important to know that the Earth's crust is broken up into large pieces called tectonic plates. Remember, tectonic plates are giant pieces of the Earth's crust that fit together and move around on the Earth's surface.
How can the plate of the earth move?
The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth's mantle and fit snugly against one another. The heat from radioactive processes within the planet's interior causes the plates to move, sometimes toward and sometimes away from each other.
Where is crust destroyed?
subduction zones Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones. Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.
What process destroys old crust?
The denser lithospheric material then melts back into the Earth's mantle. Seafloor spreading creates new crust. Subduction destroys old crust.
What happens when plate boundaries divergent?
Divergent (Spreading):This is where two plates move away from each other. Molten rock from the mantle erupts along the opening, forming new crust. The earthquakes that occur along these zones, called spreading centers, are relatively small.
What happens when plates diverge?
The plates diverge and this causes the construction of new rock. It happens when two tectonic plates pull apart and rock from the mantle rises up through the opening to form new surface rock when it cools. It happens at the start of a new ocean and continues at the mid-ocean ridge while the ocean is opening.
What is happening at the boundaries of the plates?
Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries in zones that may be anything from a few kilometres to a few hundred kilometres wide.
Are continents still moving?
The plates are always moving and interacting in a process called plate tectonics. The continents are still moving today. Some of the most dynamic sites of tectonic activity are seafloor spreading zones and giant rift valleys.
How does gravity cause plates to move?
In the current understanding of plate motion the movement is driven by the weight of cold, older, dense plate material sinking into the mantle at deep ocean trenches and pulling the rest of the plate slab with them as gravity causes them to slide downwards.
How is crust destroyed?
Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones. Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.
How the crust is destroyed at subduction zones?
One of the most famous ridges is called the Mid-Atlantic Ridge and it runs north to south along the middle of the Atlantic Ocean. So new oceanic crust is made in the "middle" of oceans along Mid Ocean Ridges, and it's destroyed where oceanic crust meets another tectonic boundary and subducts.
Does subduction create or destroy crust?
Crust is destroyed where plates subduct. It is folded where plates collide. As plates move apart, new crust is built, forming mid- ocean ridges and rift valleys. Plates scrape horizontally past each other.
Why do divergent plates move apart?
The main force driving this plate motion (although there are other lesser forces) is the "slab pull" that arises when plates sink into the mantle under their own weight at subduction zones. In divergent zones, this pulling motion uncovers the hot deep mantle rock of the asthenosphere.
What land boundaries form divergent?
Divergent boundaries within continents initially produce rifts, which eventually become rift valleys. Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges.
What happens when plates diverge on land?
Plate Divergence on Land When plate divergence occurs on land, the continental crust rifts, or splits. This effectively creates a new ocean basin as the pieces of the continent move apart. In continental rifting, magma rises beneath the continent, causing it to become thinner, break, and ultimately split apart.
What will happen to the crust of divergent continues?
New crust is continually being pushed away from divergent boundaries (where sea-floor spreading occurs), increasing Earth's surface. But the Earth isn't getting any bigger. What happens, then, to keep the Earth the same size? The answer is subduction.
What is the border between two tectonic plates called?
The area where two tectonic plates touch is called the plate boundary, and earthquakes occur most often along these borders.
Will Pangea form again?
Pangea broke apart about 200 million years ago, its pieces drifting away on the tectonic plates — but not permanently. The continents will reunite again in the deep future.
What will Earth look like in 50 million years?
This is the way the World may look like 50 million years from now! If we continue present-day plate motions the Atlantic will widen, Africa will collide with Europe closingthe Mediterranean, Australia will collide with S.E. Asia, and California will slide northward up the coast to Alaska.
Which three forces help cause the movement of tectonic plates?
The forces that drive Plate Tectonics include: Convection in the Mantle (heat driven) Ridge push (gravitational force at the spreading ridges) Slab pull (gravitational force in subduction zones)
What are the three possible forces that drives the plate tectonic?
slab pull: the force due to the weight of the cold, dense sinking tectonic plate. ridge push: the force due to the buoyancy of the hot mantle rising to the surface beneath the ridge. viscous drag: the force opposing motion of the plate and slab past the viscous mantle underneath or on the side.
Can the continental crust be destroyed?
At present, creation and destruction of continental crust is either in balance (∼3.2 km3/year, or 3.2 AU) or more crust is being destroyed than created; the uncertainty comes from unknown deep losses of continental crust at collision zones and due to lower crustal foundering.
What happens to crust during subduction?
At a subduction zone, the oceanic crust usually sinks into the mantle beneath lighter continental crust. (Sometimes, oceanic crust may grow so old and that dense that it collapses and spontaneously forms a subduction zone, scientists think.)
How does subduction happen?
Subduction occurs when two plates collide at a convergent boundary, and one plate is driven beneath the other, back into the Earth's interior. Not all convergence leads to subduction. Continental rocks are too buoyant to be forced downward, so when continents collide, they crumple but stay at the surface.
What happens at divergent plate boundaries?
At divergent boundaries, two plates move away from each other and the space that this creates is filled with new crustal material sourced from molten magma that forms below. The origin of new divergent boundaries at triple junctions is sometimes thought to be associated with the phenomenon known as hotspots.
What happens to the crust at a transform boundary?
At transform boundaries, tectonic plates are not moving directly toward or directly away from each other. Instead, two tectonic plates grind past each other in a horizontal direction. This kind of boundary results in a fault — a crack or fracture in the earth's crust that is associated with this movement.
What happens at a divergent plate boundary?
Divergent (Spreading):This is where two plates move away from each other. Molten rock from the mantle erupts along the opening, forming new crust. The earthquakes that occur along these zones, called spreading centers, are relatively small.
What happens when two continental crust move away from each other?
When two continental plates diverge, a valleylike rift develops. This rift is a dropped zone where the plates are pulling apart. As the crust widens and thins, valleys form in and around the area, as do volcanoes, which may become increasingly active.