Transcript Chapter 20 – Mountain Building

20.3 – Other Types of
Mountain Building
Divergent Mountains
• An ocean ridge is broad and high that
forms as lithosphere bulges upward due to
an increase in temperature along a
divergent boundary
Uplifted Mountains
• Formed when large regions of earth have
been slowing uplifted as a unit
• Less deformation
Hypothesis of Uplifted Mountains
• part of the lithosphere made of mantle
rocks becomes cold and dense enough
that it sinks into the underlying mantle and
is replaced by hotter and less dense
mantle
• The lower density of the new mantle
provides buoyancy which vertically lifts the
overlying crust
Plateau
• Relatively flat uplifted region
• Example: Sierra Nevada
http://www.scienceclarified.com/landforms/images/ueol_03_img0100.jpg
Fault-Block Mountains
• Form when large pieces of crust are tilted,
uplifted, or dropped downward between
large faults
• Ex: Grand Tetons