Post on 22-Feb-2016
description
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