Mountain Building

Day 3 – 10/1/10

Objectives 10/1

• I will be able to… DESCRIBE THE DIFFERENT TYPES OF MOUNTAINS THAT FORM AT DIFFERENT ________________________

• I will be able to… ____________THE TYPES OF MOUNTAINS CREATED BY THE DIFFERENT PLATE BOUNDARIES

Key Points• Different plate boundaries produce different types of mountains

because of how the lithosphere behaves• Convergent boundaries are associated with volcanic and folded

mountains• Divergent boundaries are associated with fault block mountains• Non-boundary mountains- formed from hot spots• Fragments of crustal material can collide with continental plates

and become wedged on in a process called accretion• Isostacy- the Earth’s crust is actually floating in a balance over the

asthenosphere

Mountains at Convergent Boundaries

• _______ mountain building occurs at _______________ plate boundaries

• _______________ forces from the colliding plates cause rock to _____, fault, and metamorphise

• Three types of convergent boundaries- Ocean-ocean, Ocean-continental- Continental-Continental

Mountains at Convergent Boundaries• __________________ Convergence– Produces mainly __________mountains– One oceanic plate __________under another– Examples: Aleutian Islands in Alaska, Islands of

_____________

Mountains at Convergent Boundaries

• _________________ Convergence– Produces mountains in two, roughly _______belts• In-land: Volcanic mountains• Closer to the sea: accretionary wedge materials that

produce _________mountains• __________: a process that occurs when

crustal fragments collide with and stay connected to continental plates

Mountains at Convergent Boundaries

• Ocean-Continental Convergence (Continued)• Examples: ______Mountains of South America

Mountains at Convergent Boundaries

• ______________ Convergence– Since continental lithosphere is not dense enough

to subduct, _______mountains are produced at C-C convergent boundaries

– Examples: _________formed when India collided with the Eurasian plate• Ural mountains in Russia formed when European

continent collided with the Asian continent

Mountains at Divergent Boundaries

• Divergent boundaries experience ____________ stress

• This results in the formation of ___________ mountains

• Examples: Mid-Atlantic Ridge

Non-boundary mountains

• Mountains can also be formed places other than plate boundaries– ____________can create volcanic mountains

when lithosphere moves over them• Example: _______________Islands

Continental Accretion

• Pieces of crust can collide with and stick to continental landmasses

• Accretion: a process that occurs when ______ _____________________________________– Accumulation of different sedimentary and

metamorphic rocks combined with scraps of ocean crust

Continental Accretion

• _________: crustal fragments with a geologic history that’s different from the fragments next to them– Example: The _________Coast of the US, India

• Mountains may result from the compressional forces that bring accretionary wedges together with continents

Check in Questions

• Define accretionary wedge:

• What type of stress is dominant at divergent plate boundaries?

• What are the major types of mountain ranges that are formed at convergent plate boundaries?

Isostatic Adjustment

• When mountains are built or erode, the ____________will change ________in order to support it.

• If a mountain is getting bigger, the earth’s crust has to get __________to support it.

• If a mountain ___________and gets smaller, the earth’s crust will ______because it doesn’t have to support so much weight.

Isostatic Adjustment

• The force that controls isostatic adjustment is ____________!

• According the principle of isostatic adjustment, ________________________ ___________________________________.

Isostatic AdjustmentWatch the demonstration and then complete the following:

• Describe isostatic adjustment.

• What force controls it?

• When erosion occurs on the surface, what happens to the crust?

• Which floats higher, thick or thin slabs of crustal material?

Plate Tectonics and Mountains

• You will spend the remainder of the class working on your review guides for the test on Tuesday.

• The review guides will be worth a quiz grade, so don’t lose them and make sure to turn them in!

• Remember, no work will be accepted after Tuesday for your REPORT CARD!