1. Reverse Faults: These faults occur when the hanging wall (the block of rock above the fault plane) moves upward relative to the footwall (the block of rock below the fault plane). This upward movement causes compression and folding of the Earth's crust, leading to the formation of mountain ranges. The Himalayas are a prime example of mountains formed by reverse faulting.

2. Thrust Faults: These are a type of reverse fault where the fault plane is at a low angle (typically less than 45 degrees). Thrust faults can also cause significant uplift and folding, creating mountain ranges. The Appalachian Mountains are an example of mountains formed by thrust faulting.

While reverse and thrust faults are the primary drivers of mountain formation, other geological processes like volcanic activity and folding can also contribute to the creation of mountain ranges.