What portion of a lithospheric plate determines its final elevation?
The final elevation of a lithospheric plate is primarily determined by the interaction between tectonic forces, specifically the processes of plate tectonics and the forces related to their boundaries. However, it is important to note that the elevation of a lithospheric plate can be influenced by other factors as well, such as erosion and deposition, climate, and even the presence of volcanic activity.
To understand how tectonic forces determine the final elevation of a lithospheric plate, we need to explore the concept of plate boundaries. There are three main types of plate boundaries: convergent boundaries, divergent boundaries, and transform boundaries.
1. Convergent boundaries: When two plates move towards each other, they can form a convergent boundary. Depending on the type of plates involved, these boundaries can result in subduction zones or collisions. In subduction zones, one plate is forced beneath another due to differences in density. This process can lead to the formation of mountain ranges and the increase in elevation. On the other hand, when two continental plates collide, the immense pressure and compression can form large mountain ranges such as the Himalayas or the Alps.
2. Divergent boundaries: When two plates move away from each other, a divergent boundary is formed. In these areas, new lithospheric material is created through volcanic activity, as magma rises to fill the gap created by the separating plates. The newly formed crust at divergent boundaries is usually basaltic and relatively low in elevation. However, over time, as the process continues, the accumulation of volcanic material can lead to the creation of underwater mountain ranges and elevated landforms.
3. Transform boundaries: At transform boundaries, two plates move sideways against each other. The primary focus of transform boundaries is the displacement of lithospheric plates, with little to no vertical motion. As a result, transform boundaries do not contribute significantly to changes in the elevation of the lithospheric plates.
In summary, the final elevation of a lithospheric plate is primarily determined by the interaction and relative movement of tectonic plates at plate boundaries. Convergent boundaries can result in the formation of mountain ranges and increased elevation, while divergent boundaries can lead to the creation of underwater mountain ranges and elevated landforms. It is important to note that other factors such as erosion, deposition, climate, and volcanic activity can also influence the final elevation of a lithospheric plate.