5.1Movement of Rock Builds Mountains

Movement of Rock Builds Movement of Rock Builds MountainsMountains

Pages 137-144 (section B)Pages 137-144 (section B)

MOST MOUNTAINS FORM MOST MOUNTAINS FORM ALONG PLATE BOUNDARIES ALONG PLATE BOUNDARIES

• A shallow sea once covered Mt. Everest– Rocks containing remains of ocean animals

found there. – Rocks formed at a far away spreading center

also found there.

What is a Mountain?What is a Mountain?

• Mountain- an area of land that rises steeply from the land around it.– A single mountain is rare.

MOUNTAIN RANGESMOUNTAIN RANGES

Mountain Range- long line of mountains formed at about the same time by the same processes

MOUNTAIN BELTSMOUNTAIN BELTS • Mountain Belt- ranges that are close together.

– Most major mountain belts are located along tectonic plate boundaries

– Some, like the Appalachians, are on the interior of the plates

– These were formed by ancient plate collisions that formed the continents

MOUNTAINS, ROCKS, AND MOUNTAINS, ROCKS, AND SEDIMENTSEDIMENT

• On the surface, water and wind break rocks apart and move the pieces away.

• As long as mountains are pushed up faster than they wear down, they grow taller.

Mountains over TimeMountains over Time

• Young mountains are tall and steep.

• Eventually water and wind take over, and over time the mountains become rounded hills.

Mountains over TimeMountains over Time

• The land becomes flatter as mountains wear down and valleys are filled with sediments.

• If tectonic plates stopped moving, eventually the surfaces of the continents would be completely flat.

MOUNTAINS CAN FORM AS MOUNTAINS CAN FORM AS ROCKS FOLDROCKS FOLD

• Tectonic plates move only a few cm a year.

• Edges of a continent along a convergent boundary are subjected to high amounts of stress over very long periods of time.

• Some rocks break, some fold.

FOLDED MOUNTAINSFOLDED MOUNTAINS• Folded Mountains- mountains formed

when continental crust crumples and bends into folds. – Form as an oceanic plate sinks under the

edge of a continent or as continents collide.

Himalaya Mountain Forming Himalaya Mountain Forming ProcessProcess

• The Himalaya belt formed by a collision between India and Eurasia

1. A convergent boundary develops.

2. Continental collision begins.

3. Collision continues.

MOUNTAINS CAN FORM AS MOUNTAINS CAN FORM AS ROCKS MOVE ALONG FAULTSROCKS MOVE ALONG FAULTS

• Fault-Block Mountains- form as blocks of rock move up or down along a normal fault.– Forces within the Earth cause the lithosphere to

stretch and pull apart.– Cold, rigid rocks in the crust break into large blocks. – As stretching continues, the blocks of rock move

along the faults that separate them

Fault-Block Mountain Range Fault-Block Mountain Range FormationFormation

• The Sierra Nevada in California is a fault-block mountain range

1. The range moved up along a normal fault on its eastern edge.

2. The block on the other side dropped down.

3. The eastern side of the range is steep. The western side tilts down gently toward California’s Central Valley.

• http://www.pond5.com/stock-footage/909732/mountain-formation.html