Foreland thrust-fold belts are common on margins of the world's mountain chains. They are generally thrust upon (verge), and are arcuate toward, an adjacent continental interior. Many have low-angle thrust faults and fold geometry disharmonic to an underlying basement, and are frequently termed “decollements.”
The plate tectonics of the Neogene Zagros, Jura, New Guinea, sub-Andean, and Himalaya foreland belts are varied, ranging from collision to back-arc settings, but all were developed on leading edges of actively driving continental plates. They are thrust upon, and against the motion of, these plates. In contrast, Neogene back-arc spreading developed on margins of plates whose motion is parallel to, or away from, an adjacent arc-trench.
Foreland thrust-fold belts are mainly due to underthrusting of continental lithosphere on leading edges of actively driving continental plates in either collision or back-arc settings. If the principle is applied to pre-Mesozoic mountain ranges, it may provide another parameter to determine pre-Mesozoic plate motions.