Mountain formation occurs at convergent plate boundaries where colliding plates provide compressional forces that fold, fault, and metamorphose thick sediment layers along continental edges, forming folded mountains. Ocean-ocean convergence mainly produces volcanic mountains, while ocean-continental convergence can result in either volcanic or folded mountains. Continental-continental convergence results in large folded mountain ranges due to collisions between continental fragments.

1. 11.3 Mountain Formation

2. Accretionary Wedge Accumulation of different sedimentary and metamorphic rocks with some scraps of ocean crust.

3. Accretion The process in which fragments collide with a continental plate and they become stuck to or embedded into the continent.

4. Terrane Any crustal fragment that has a geologic history distinct from that of the adjoining terranes.

5. Isostasy The concept of a floating crust in gravitational balance.

6. Isostatic Adjustment The process of establishing of a new level of gravitational equilibrium

7. Key Concept Most mountain building occurs at convergent plate boundaries. Colliding plates provide the compressional forces that fold, fault, and the metamorphose the thick layers of sediments deposited at the edges of landmasses.

8. Key Concepts Ocean-ocean convergence mainly produces volcanic mountains. The types of mountains formed by ocean-continental convergence are volcanic mountains and folded mountains.

9. Key Concepts At a convergence boundary between two plates carrying continental crust, a collision between the continental fragments will result and form folded mountains. The mountains that form along ridges at divergent plate boundaries are fault-block type mountains.

10. Key Concept Because of isostasy, deformed and thickened crust will undergo regional uplift both during mountain building and for a long period afterward.