What happens at a convergent plate boundary (1 point)
A. Earths rock plates grow denser
B. Earths rock plates pull away from each other
C. Earths rock plates collide with one another
D. Earths rock plates slide past each other
C. Earths rock plates collide with one another
C. Earths rock plates collide with one another
The correct answer is C. Earth's rock plates collide with one another at a convergent plate boundary. To understand why this happens, let's first discuss what a convergent plate boundary is.
Convergent plate boundaries occur when tectonic plates move towards each other. Tectonic plates are large sections of Earth's lithosphere—the rigid outer shell that consists of the crust and the uppermost part of the mantle. These plates can consist of oceanic crust, continental crust, or a combination of both.
When two tectonic plates converge, three main scenarios can occur, leading to different types of convergent plate boundaries:
1. Oceanic-Oceanic Convergence: This happens when two plates carrying oceanic crust collide. When this occurs, the denser plate, usually the older one, is forced beneath the other in a process called subduction. This creates a subduction zone where one plate is being pushed down into the mantle. This process can result in the formation of deep-sea trenches, volcanic arcs, and even island chains, like the Aleutian Islands in the Pacific Ocean.
2. Oceanic-Continental Convergence: In this case, an oceanic plate collides with a continental plate. The denser oceanic plate is once again subducted beneath the less dense continental plate due to the differences in density. This leads to the formation of subduction zones, mountain ranges, and volcanic activity. The Pacific Northwest, where the Juan de a Plate is subducting beneath the North American Plate, is an example of an oceanic-continental convergent boundary.
3. Continental-Continental Convergence: When two continental plates collide, neither plate is dense enough to be subducted. Instead, the collision can cause intense compression and folding of the rocks, leading to the formation of large mountain ranges. The Himalayas, formed by the convergence of the Indian Plate and the Eurasian Plate, are a well-known example of a continental-continental convergent boundary.
Based on this information, we can see that at a convergent plate boundary, Earth's rock plates collide with one another (option C). This collision gives rise to various geological phenomena such as subduction, volcanic activity, mountain formation, and earthquakes.