Is continental or oceanic crust younger?
Is continental or oceanic crust younger?
Continental crust is almost always much older than oceanic crust. Because continental crust is rarely destroyed and recycled in the process of subduction, some sections of continental crust are nearly as old as the Earth itself.
What is the age of the continental crust?
4 billion years
Why continental and oceanic rocks are different ages?
Differences in Age Oceanic and continental plates differ radically in age because of tectonic processes. Divergent plate boundaries continually renew oceanic plates while the subduction zones of convergent boundaries continually recycle them. As a result, the oldest oceanic rocks are less than 200 million years old.
Why is the oceanic crust said to be younger than the continental crust?
The oceanic plate is subducted back into the mantle, thus destroying oceanic crust, to balance the crust being produced at the mid oceanic ridges. This is why all oceanic crust is much younger than the continental crust; it is constantly being recycled.
What are three differences between continental and oceanic crust?
What is the difference between Oceanic and Continental Crust? Oceanic crust is dominated by mafic and ultramafic intrusive igneous rocks whereas continental rocks are dominated by granitic (felsic) intrusive igneous rocks. The continental crust is by far the older of the two types of crust.
What is the only pure oceanic plate?
An example of an oceanic plate is the Pacific Plate, which extends from the East Pacific Rise to the deep-sea trenches bordering the western part of the Pacific basin. A continental plate is exemplified by the North American Plate, which includes North America as well as the oceanic crust…
Which is thicker oceanic or continental crust?
Continental crust is typically 40 km (25 miles) thick, while oceanic crust is much thinner, averaging about 6 km (4 miles) in thickness. The less-dense continental crust has greater buoyancy, causing it to float much higher in the mantle.
What keeps the plate edges from sliding smoothly past each other?
Friction between the plates keeps them from sliding. When the frictional strain is overcome, the ground suddenly snaps along faults and fractures releasing energy as earthquakes.
What will happen when oceanic crust converges with each other?
If the two plates that meet at a convergent plate boundary both are of oceanic crust, the older, denser plate will subduct beneath the less dense plate. The older plate subducts into a trench, resulting in earthquakes. Melting of mantle material creates volcanoes at the subduction zone.
What happens when you slide the two crackers against each other?
Transform Boundaries: Put the two crackers side by side, and slide one forward (away from you), and one backward (toward you). When plates slide past one another in this way, they often get caught on one another. When they break free, an earthquake happens. San Francisco is located on a transform fault.
What makes the two plate to move away from each other?
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. Two plates sliding past each other forms a transform plate boundary.
What drives the plate to move?
The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
What is it called when two plates move apart?
The movement of the plates creates three types of tectonic boundaries: convergent, where plates move into one another; divergent, where plates move apart; and transform, where plates move sideways in relation to each other.
What forms when two continental plates pull apart?
valleys
What is an example of oceanic continental convergence?
Examples of ocean-continent convergent boundaries are subduction of the Nazca Plate under South America (which has created the Andes Mountains and the Peru Trench) and subduction of the Juan de Fuca Plate under North America (creating the Cascade Range).