NSES Content Standard D 
Earth and Space Science: Structure of the Earth system
Grades 5-8, page 160

Land forms are the result of a combination of constructive and destructive forces. Constructive forces include crustal deformation, volcanic eruption, and deposition of sediment, while destructive forces include weathering and erosion.
 

 
Benchmark 4C The Physical Setting: Processes that Shape the Earth
Grades 6-8, page 73
Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges.

Benchmark 4C The Physical Setting: Processes that Shape the Earth
Grades 6-8, page 73
Sedimentary rock buried deep enough may be reformed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it.