MountainsMountainsEssential Questions:

Compare types of mountains.

Identify the forces that shape Earth’s mountains.

Mountains• There are four main types of mountains:

fault-block, folded, upwarped, and volcanic.

• Each type forms in a different way and can produce mountains that vary greatly in size.

Mountains• The ruggedness of a mountain chain

depends largely on whether or not it is still forming.

Stopped forming Still forming

Mountains

• Infer what determines how rugged and high a mountain chain is.

• Whether or not it is still forming.

Mountains• Define

fault-block mountains.

• Sharp, jagged mountains made of huge, tilted blocks of rock that are separated from surrounding rock by faults and form because of pulling forcesSierra Nevada in California

Mountains• Describe

how fault-block mountains form.

• Rock layers get pulled in opposite directions, large blocks slide downward, creating valleys and peaks.

Mountains• Define

folded mountains.

• Mountains that form by the folding of rock layers caused by compressive forces

Appalachian in Maryland

Mountains• Describe

how folded mountains form.

• Compression: two plates are pushed together, this causes rock layers to buckle and fold

Mountains• Define

upwarped mountains.

• Mountains that form when forces inside Earth push up on the crust

Rocky Mountains in Colorado

Mountains• Describe

how upwarped mountains form.

• Forces inside Earth push up the crust; with time sedimentary rock layers erode exposing igneous and metamorphic rock

Mountains• Define

volcanic mountains.

• Mountains that form when magma is forced upward and flows onto Earth’s surface

Mt St Helens in Washington

Mountains• Describe

how volcanic mountains form.

• Magma from inside the Earth, called lava after it reaches Earth’s surface, cools. Over time, layer upon layer of lava piles up creating a cone shaped feature.

Uplift• If you were to place wooden blocks of

various thickness in a container of water you would notice that different blocks of wood would float at different heights.

• The thicker wood would float higher in the water than the thinner blocks would.

Uplift• With the blocks, the buoyant force of water

is balancing the force of gravity.

• A similar process called ISOSTASY occurs in Earth.

• Define isostasy

• Principle stating that Earth’s lithosphere floats on a plasticlike upper part of the mantle called the asthenosphere

Uplift• The principle of isostasy is why the crust

under mountains is thicker than it is elsewhere.

• Isostasy also the floating of icebergs.

MountainsPictures

• http://www.pitt.edu/~cejones/GeoImages/3IntrusiveBodies/1Plutonsz/1SierraNevada.html

• http://en.wikipedia.org/wiki/Mountain_formation

• http://www.city-data.com/forum/nature/912962-how-mountain-ranges-were-created-serious-44.html

• http://www.coolgeography.co.uk/GCSE/AQA/Restless%20Earth/Tectonics/Landforms_at_%20plate_%20boundaries.htm

MountainsPictures

• http://livestockandenvironment.org/?attachment_id=443

• http://www.oocities.org/williamswindow/landforms.html

• http://en.wikipedia.org/wiki/Mount_St._Helens

• http://www.slipperysnake.co.uk/educational-materials/geography/volcanoes/

• http://volcano.oregonstate.edu/education/vwlessons/lessons/Earths_layers/Earths_layers5.html

• http://thedailyeater.com/?p=4824