landforms Flashcards
what is a landform?
A landform is a feature of the surface of the Earth
what is a terrain?
The collection of landforms in an area
what are the degrees of relief?
high
moderate
low
how can slopes be described
high
moderate
shallow
how are the details of a terrain shown?
by topographic maps
how do landforms form?
Geologic processes cause portions of the land surface to move up or down relative to adjacent areas.
what is uplift?
upward movement
what is subsidence?
downward movement
what is the cause for uplift and subsidence?
plate tectonics
what is volcanic uplift a result of?
Material being added to the surface
* Hot rocks (at and below the surface) take up more space
what is uplift at divergent boundaries a result of?
New material added to the surface
* Hot rocks take up more space
* Newly added material moves away from ridge, cools and contracts
Cooling = Decrease in elevation
when does subsidence occur?
stretching the crust
when load is added
materials are removed from the crust
what is load?
downward force
what does lift and subsidence produce?
relief
what is relief?
differences in elevation
what happens when relief develops?
rocks arre subjected to weathering and erosion
what happens to weathered and eroded rocks
they get deposited in low spots
how are the shapes of landforms changed?
by weathering, erosion, deposition
why isn’t the earth flat?
Ongoing uplift and subsidence continue to move rocks up and down, changing the shape of the land.
what are tectonic landforms?
landforms produced from plate tectonics
what are volcanic landforms?
landforms produced through volcanism
what are erosional landforms?
landforms produced from erosion
what are depositional landforms?
landforms produced from sediment deposition
how are the specific landforms in an area developped?
eroding agent
relief
climate
substrate composition
life activity
time
how do eroding agents develop landforms?
moving water, air, ice carve into the land and carry debris differently
how does relief develop landforms?
The height and steepness of slopes determines whether rocks or soil will stay in
place or tumble downslope, and how fast. (Controls velocity of water and ice.)
how does climate develop landforms?
limate factors (wind, rain, snow, temperature, etc.) determine whether flowing
ice, wind or water is the main agent of erosion and deposition.
affects the rate of weathering.
how does substrate composition develop landforms?
Some earth materials are more
resistant to erosion than others and
can form steep cliffs.
Weak materials
collapse and form gentle slopes.
how does life activity develop landforms?
Some organisms weaken earth materials by burrowing through or digesting them; others help bind loose materials together (tree roots).
-The landforms that form in an area may be influenced by biological activity.
how does time develop landforms?
Landscapes evolve over time in response to continued erosion or deposition.
