What is oceanic oceanic plate margin?
At an ocean-ocean convergent boundary, one of the plates (oceanic crust and lithospheric mantle) is pushed, or subducted, under the other (Figure 4.6. 1). Often it is the older and colder plate that is denser and subducts beneath the younger and warmer plate.
What happens at convergent margins?
At convergent plate boundaries, oceanic crust is often forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into granite, the rock that makes up the continents. Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed.
What are the evidences in oceanic continental convergent margins?
When an oceanic plate converges with a continental plate, the oceanic crust will always subduct under the continental crust; this is because oceanic crust is naturally denser. Convergent boundaries are commonly associated with larger earthquakes and higher volcanic activity.
What happens at oceanic continental convergent boundaries?
When oceanic crust converges with continental crust, the denser oceanic plate plunges beneath the continental plate. This process, called subduction, occurs at the oceanic trenches. The subducting plate causes melting in the mantle above the plate. The magma rises and erupts, creating volcanoes.
What is the effect of oceanic oceanic?
Oceanic – oceanic convergence This water reduces the melting temperature of rocks in the asthenosphere and causes partial melting. Partial melt will travel up through the asthenosphere, eventually, reach the surface, and form volcanic island arcs.
What are the three types of convergent?
There are three types of convergent boundaries: Oceanic-Continental Convergence. Oceanic-Oceanic Convergence. Continental-Continental Convergence.
Do convergent boundaries form mountains?
Mountains are usually formed at what are called convergent plate boundaries, meaning a boundary at which two plates are moving towards one another. Sometimes, the two tectonic plates press up against each other, causing the land to lift into mountainous forms as the plates continue to collide.
What is the difference between oceanic plates and continental plates?
Oceanic plates are much thinner than the continental plates. At the convergent boundaries the continental plates are pushed upward and gain thickness. The rocks and geological layers are much older on continental plates than in the oceanic plates. The Continental plates are much less dense than the Oceanic plates.
What are the consequences of convergent oceanic and continental plates?
Effects of a convergent boundary between an oceanic and continental plate include: a zone of earthquake activity that is shallow along the continent margin but deepens beneath the continent, sometimes an ocean trench forms immediately off shore of the continent, a line of volcanic eruptions a few hundred miles inland …
What is the cause of oceanic oceanic?
Continued subduction of the South American Plate brings sea water, locked in the ocean crust, deep into the mantle. As the plate heats up the water is liberated, lowering the melting point of the mantle and causing partial melting.
When does convergence occur between oceanic and continental plates?
Convergence can occur between an oceanic and a largely continental plate, or between two largely oceanic plates, or between two largely continental plates. Oceanic-continental convergence
Why are the margins of the continental crust active?
Active continental margins, where plates are converging, coincide with plate boundaries, where the continental and oceanic crust are separated by a subduction zone. These margins are active tectonically and have less width and sediment input than passive margins.
Which is an example of a convergent boundary?
The Cascade Mountain Range is a line of volcanoes above the melting oceanic plate. The Andes Mountain Range of western South America is another example of a convergent boundary between an oceanic and continental plate. Here the Nazca Plate is subducting beneath the South American plate.
What makes the Atlantic margin a passive margin?
passive margin (Atlantic Margin) lies within a plate at the boundary between continental and oceanic crust. The major tectonic movement is broad, regional vertical adjustment and both earthquake and volcanic activity are minor and local. These margins are marked by smooth relief due to tectonic inactivity and major sediment accumulation.
