Name: ______Date: ______
Chapter 11: Deformation of the Crust
Section 2: How Mountains Form
Mountain Ranges and Systems
•Many mountains form due to extreme ______.
•Mountain range - a series of mountains that are closely related in orientation, ______, and mode of formation.
•A group of mountain ranges that are adjacent is called a ______.
•The largest mountain systems are part of two larger systems called ______.
•Earth’s two major mountain ______are the circum-Pacific belt and the Eurasian-Melanesian belt.
Plate Tectonics and Mountains
•The circum-Pacific and the Eurasian-Melanesian Mountain belts are both located along ______plate boundaries.
•The location of these two mountain belts provides evidence that most mountains form as a result of ______between tectonic plates.
•Sometimes mountains, such as the ______, do not lie along active convergent plate boundaries. However, evidence indicates that the places at which these ranges formed were ______.
Collisions between Continental and Oceanic Crust
•Some mountains form when
oceanic lithosphere
______
beneath the continental
lithosphere at convergent plate
boundaries. This type of collision
produces such
______
______that high mountains
are uplifted.
•In addition, the subduction of the oceanic lithosphere causes partial ______of the overlying mantle and crust.
•This melting produces magma that may eventually erupt to form ______on Earth’s surface.
Collisions Between Oceanic Crust and Oceanic Crust
•______
commonly
form where two plates whose
edges consist of oceanic
lithosphere collide.
•As the ______
oceanic plate subducts beneath
the other oceanic plate, fluids from
the subducting lithosphere cause
partial melting of the overlying mantle and crust.
•The resulting magma rises and breaks through the oceanic lithosphere. These eruptions of magma form an arc of volcanic mountains on the ______.
Collisions Between Continents
•Mountains can form when
______continents collide.
•An example of this type of
collision is the formation of
the ______
______in
which the oceanic
lithosphere of the Indian
plate subducted beneath the
Eurasian plate.
•When the continental lithosphere of both plates collided, ______stopped, but the collision continued. The intense deformation that resulted from the collision uplifted the Himalayas. Because the plates are still colliding, the Himalayas are still ______.
•Why are the Himalayas growing taller today?
Types of Mountains
•Scientists ______mountains according to the way in which the crust was deformed and shaped by mountain-building stresses.
Folded Mountains and Plateaus
•Many of the highest mountain ranges in the world consist of folded mountains that form when continents ______.
•Folded mountain -a mountain that forms when rock layers are ______together and uplifted.
•The same stresses that form folded mountains also uplift plateaus, which are large, ______areas of rock ______above sea level.
•Most plateaus form when ______, ______layers of rock are ______uplifted so that the layers remain flat instead of faulting and folding.
•Most plateaus are located near ______.
•Plateaus can also form when layers of ______harden and pile up on Earth’s surface or when large areas of rock are ______.
Fault-Block Mountains and Grabens
•Where parts of Earth’s crust have been ______and broken into large blocks, faulting may cause the blocks to tilt and drop relative to other blocks.
•Fault-block mountain - a mountain that forms where faults break Earth’s crust into large blocks and some blocks ______relative to other blocks.
•The same type of faulting that forms fault-block mountains also forms ______, ______valleys called grabens.
•______develop when steep faults break the crust into blocks and one block slips downward relative to the surrounding blocks.
•Grabens and fault-block mountains commonly occur ______.
Dome Mountains
•A dome mountain is a less common type of mountain that forms when ______rises through the crust and ______the rock layers above the magma.
•Dome mountain - a circular or ______, almost symmetrical elevation or structure in which the stratified rock slopes downward gently from the ______of folding.
•Dome mountains may also form when tectonic forces ______uplift rock layers.
•Name three types of mountains found in the United States.
Volcanic Mountains
•Mountains that form when magma ______onto Earth’s surface are called volcanic mountains, which commonly form along ______plate boundaries.
•Some of the largest volcanic mountains are part of the ______ridges along ______plate boundaries.
•Other large volcanic mountains form on the ocean floor at ______, which are volcanically active areas that seem to correspond to places where hot material rises through Earth’s interior and reaches the ______.
The diagrams below shows the types of mountains found in the United States.