Final answer:
Lithospheric plates may diverge, converge, or transform at their boundaries, causing formations such as rift valleys, mid-ocean ridges, and mountains.
Step-by-step explanation:
The lithospheric plates are segments of the Earth's crust and upper mantle that move around the globe, and they engage in different motions at their boundaries: divergent (moving apart), convergent (colliding), or transform (sliding past each other). The motion of these plates causes significant geological features to form.
- Rift Valley: Found at a divergent boundary on land, where plates move apart, forming a valley as the land between them sinks. An example is the East African Rift.
- Mid-ocean Ridge: Also a result of a divergent boundary, but located under oceans. The separation of plates allows molten rock to rise and create new oceanic crust.
- Convergent Boundary: Where plates collide, leading to the formation of mountains or island arcs depending on the type of crust involved.
For example, the West Coast of North America features different types of plate boundaries, including transform boundaries like the San Andreas Fault where plates slide by each other and convergent boundaries associated with the Cascade Range's formation, influenced by the subduction of the Juan de Fuca plate beneath the North American plate.