Here's a breakdown:
* Oceanic crust is denser than continental crust. This is because oceanic crust is primarily composed of basalt, a dark-colored, dense rock, while continental crust is largely made up of granite, a lighter-colored, less dense rock.
* When oceanic and continental plates collide, the denser oceanic plate sinks beneath the less dense continental plate. This process is called subduction.
* The subducting plate (oceanic) is pulled down by gravity. This force, coupled with the pushing force of the colliding plates, drives the subduction process.
Think of it like this: if you put a piece of wood and a piece of metal in water, the denser metal will sink while the less dense wood floats. The same principle applies to oceanic and continental plates colliding.
Other contributing factors:
* The age of the oceanic plate: Older oceanic crust is colder and denser than younger oceanic crust. This makes it more likely to subduct.
* The angle of convergence: The angle at which the plates collide can also influence which plate subducts.
In summary, the density difference between oceanic and continental crust is the primary reason why oceanic crust subducts beneath continental crust during plate collisions.
