5.3 notes
How are mountains classified?
Objective: identify 3 types of mountains and how they are formed
Mountains are classified by how they are formed. There are 3 main
types of mountains: Volcanic, folded, and dome.
Volcanic mountains are formed from lava or debris (ash and dust) that
has been thrown out of a volcano. Eruptions that occur over millions of
years build up to form these mountains. (Example: Mt. Fuji)
Folded mountains are formed from the folding of rock layers, usually
when continents collide. Large up-folds, or anticlines, form folded
mountains. (Examples: The Himalayas, Urals, and Appalachian
Mountains)
Fault-block Mountains are formed when fractures in Earth’s crust break
it into large blocks. Sometimes faulting lifts these blocks, causing one
side to slip past the crust on the other side. If the blocks are pushed up
far enough, a fault-block mountain is formed. (Example: Grand Tetons,
Sierra Nevada)
Another type of mountain is the dome Mountain. Dome Mountains are
formed when mountains fold upward forming a bowl shape, or dome.
As the top layers of sedimentary rock are worn away (sometimes
unevenly, causing separate peaks), older igneous and metamorphic
rock is exposed. (Examples: The Black Hills Mountains)