Final answer:
Hills are formed through erosion, sediment accumulation, and minor tectonic activities, whereas canyons are predominantly carved by river erosion and can also form from tectonic activity, such as cracks in the Earth's crust.
Step-by-step explanation:
While mountains and volcanoes are typically associated with plate tectonics, hills and canyons are formed through a variety of geological processes. Hills often result from a range of factors such as erosion, sediment accumulation, and minor tectonic activities, which differ from the intense plate collisions that create mountains. Canyons are generally carved by the steady erosion from rivers and streams over millions of years, with the classic example being the Grand Canyon, which was primarily shaped by the Colorado River. In areas of tectonic activity, land can also be uplifted to form hills, or tensions in the crust may create cracks that evolve into canyons, as seen in the tectonic fractures that formed the Valles Marineris on Mars.
Erosion plays a significant role in the formation of both hills and canyons; it wears down mountains over geological timescales, generating gentler slopes and turning some mountains into hills. Conversely, erosion deepens and widens existing canyons, as in the case of Valley Marineris, where water seeping from deep springs led to landslides and further erosion by wind. Additionally, sedimentary processes contribute to hill formation when layers of sediment are deposited over time and are eventually compacted and uplifted.
In summary, while the origins of mountains and volcanoes are closely tied to the movements and collisions of tectonic plates, hills and canyons are shaped by a combination of erosional, sedimentary, and less intense tectonic processes. Understanding the unique geological histories of these landscapes adds depth to our comprehension of Earth's dynamic surface.