Earth Science NotesLandforms

LandformsWhy do different landforms exist?

Earth Processes• Weathering• Erosion• Forces within the Earth (plate movement)• Climate • Other?

Landforms

• Plains – large flat areas usually have thick abundant soil ideal for farming

Landforms

• Interior plains – found in the middle of a continent – Ex: Iowa, Nebraska,

the Dakotas– Have a higher

elevation than coastal plains

Landforms

• Coastal plains – found on the edge of the continent– Ex: Florida, Georgia, the Carolinas – Formed as a result of collecting sediment on

the seafloor and dropping water levels.

Landforms

• Plateaus – flat raised areas of land made up of nearly horizontals rocks that have been lifted up by forces with in the earth. – Ex: Colorado plateau

Landforms

Four Mountain Types• Folded • Upwarped• Fault Block• Volcanic

Mountains • Folded Mountains – comprised of folded

rock layers like a rug that has been pushed up against a wall.– Forces occur on rock in a horizontal direction– Ex: Appalachian mountains

• Believed to be at one time higher than the Rocky Mountains but years of weathering and erosion have worn the mountains down.

Folded Mountains

Mountains• Upwarped Mountains – formed when the

forces within the earth push up blocks of the earth’s crust. Soil is worn away and the hard rock underneath is exposed.– Ex: Adirondack mountains (New York), Black

Hills (South Dakota)

Unwarped Mountains

Forces with in the Earth

Mountains• Fault-Block Mountains – made of huge,

tilted blocks of rock that are separated from the surrounding rock by faults. Some rocks move up some move down.– Faults are fractures in rocks – Ex: Grand Tetons (Wyoming)

Fault-Block Mountains

Mountains• Volcanic Mountains – form from molten

rock that reaches the surface of the earth’s crust through a crack or fissure. The molten rock accumulates on top of itself forming a cone shaped structure. – Ex: Mount ST. Helens (Washington)

Volcanic Mountains

Landforms How can topography aid us in describing landforms?

Topography

Topographical Maps – show change in elevation

                                                                   

TopographyFeatures on a Topographical Map

• Contour lines – connect equal points of elevation

• Contour intervals – distance between contour lines

• Index contours – contour line with elevation

TopographyReading a contour Map• Close contour lines = steep change in

elevation• Distant contour lines = gradual change in

elevation

Contour Lines

Contour Lines

Contour Lines

Contour Lines

Contour Lines

Contour Lines

LandformsSummary• Why do different landforms exist?• Three types of landforms

– Plains – coastal / interior– Plateaus– Mountains – folded / upwarped / fault-block /

volcanic• Topographical maps describe landforms