Mountains

"Our compilation of mountains throughout the world shows that a major phase of uplift occurred in the Pliocene-Pleistocene."  "Uplift occurred over a relatively short and distinct time.  Some earth process switched on and created mountains after a period with little or no significant uplift.  This is a deviation from uniformitarianism."
The Origin of Mountains. Cliff Ollier, Colin Pain. 2000. Routledge, London. p. 303.

"Virtually all major mountain ranges in the world are a consequence of crustal shortening."
Some Simple Physical Aspects of the Support, Structure, and Evolution of Mountain Belts. Peter Molnar, H. Lyon-Caen.  Special Paper 218, Geological Society of America, 1988, pp. 179-207.

The presence of mountains on the front and back sides of continents (along their line of travel), the relatively short distances travelled, and the brief burst of mountain building point to a sudden impulse rather than a steady, constant force moving the continents. Important driving forces of plate tectonics theory are too weak to raise mountains.

In Shock Dynamics, the shock wave from the giant meteorite impact provided the impulse that initiated continental motion.  Some continents began moving after being hit by a continent already set in motion by the impact.  Assuming the acoustic fluidization mechanism, and assuming that mountains are built through lateral compression, the minor mountains (such as the Appalachian Mountains) raised by the impulse against a continent's back side indicate a comparatively slow acceleration.  The major mountains (such as the Rocky Mountains) raised on the front, or leading, side indicate a sudden deceleration, like a multi-car pile-up on a highway.  This braking effect all along the leading edge suggests that acoustic energy was lost most rapidly there, probably through thinning the overlying mass confining the acoustic energy.  Most other mountains were laterally compressed by means of collision with other continents or by torque.