Download 11.2 How Mountains Form

11.2 How Mountains Form
Mountains Ranges and Systems
11.2 How Mountains Form
· mountain range - group of adjacent mountains
that are related to each other in shape and
structure
· mountain system - group of adjacent ranges
· largest systems m mountain belts
circum-Pacific and Eurasian-Melanesian
tell scientists that most ranges formed at active
convergent plate boundaries
Continental-Oceanic Collisions
· oceanic lithosphere subducts
· melting of crust produces magma which may
eventually form volcanic mountains
· terranes scraped off as plate subduct which may
form mountains
· ex. Cascades, Andes Mount St. Helens
Oceanic-Oceanic Collisions
· denser plate subducts
· melting of crust produces magma
· forms an arc of volcanic islands
Types of Mountains
Continental Collisions
· no subduction
· causes uplift
· forms mountain
ranges
himalayan Mountains
· classified by the way the crust was deformed and
shaped by mountain-building stresses
· folded mountains
form when rock is squeezed
and uplifted
form when continents collide
same stresses form plateaus
(large, flat areas high
above sea level)
Folded
· fault-block mountains
form when faults break
Earth's curst into blocks
that tilt and drop
same stresses form
grabens (long, narrow
valleys)
Graben
· dome mountains
form when magma
pushes rock layers up
circular or elliptical
Mt. everest
· volcanic mountains
form when magma erupts
onto Earth's surface
commonly form along
convergent boundaries
exceptions: mid-ocean
ridges (divergent) and
hot spots (volcanically
active areas that are far
from plate boundaries)
11.2 How Mountains Form
Review Questions
1. What is the difference between a mountain
range and a mountain system?
2. What forms at continental-oceanic collisions?
3. What forms at oceanic-oceanic collisions?
4. What type(s) of collisions produce magma?
5. What forms at continental collisions?
6. How are mountains classified?
7. What are the 4 types of mountains?