Chapter 4 Flashcards
What is weathering?
physical and chemical; generates material for erosion and transport by water, wind, waves, and ice as acting under the influence of gravity
What is physical weathering?
mechanical breaking down of material; usually occurs in drier, cooler climates
What is chemical weathering?
decomposition or chemical change of minerals in rock or material
In what region of the Earth does chemical weathering play a more important role?
Wetter, warmer climates
What is pressure release jointing?
Burial pressures removed responding with heat and sheathing of rock
What is hydration?
combination with water; water becomes part of the chemical composition of a mineral
What is oxidation?
When metallic elements combine with oxygen to form oxides
What is a geomorphic threshold?
When there is enough energy to overcome resistance against movement
Where would you most likely find a debris slope relative to waxing and waning slopes?
In between the waxing and waning slopes
Angles of repose are often between which angles?
30-37 degrees
What is a debris slope?
slope of eroded material from above; transitions into a waning slope
What is the driving force of mass movements?
gravity
What are the classes of mass movement?
Fall, Slide, Flow, Creep
What is a landslide?
sudden and rapid movement of a cohesive mass of regolith or bedrock that is not saturated with moisture
How does a transitional slide differ from a rotational slide?
Transitional: move along a plantar surface
Rotational: moves along concave surface
When is a landslide called a flow?
When moisture content of moving material is high
In what parts of the world are you ore likely to see soil creep?
Areas with freeze/thaw cycles
What actions result in stream erosion?
Hydraulic action and abrasion
How is stream transport defined?
through the ability to move particles and capacity
What is solution?
dissolved load of a stream
What is a suspended load?
fine-grained clastic particles held aloft in the stream
What is bed load?
bigger material that is carried close to the bed by tractional processes or near the bed by saltation
What is the shorter hops of courser materials in a stream called?
saltation/traction
What is a braided stream?
stream with multiple channels due to deposited material
What is alluvium?
sediment deposited by a stream or a river. Typically implies fine sediment
How are oxbow lakes formed?
when a river undercuts a bank and leaves off a channel
Why is sand deposited to make point bars?
material is being dropped off at the weak side of the river where they cannot move the sand
What is an undercut bank?
where rivers cut into the bank
What are floodplains composed of?
alluvium sediments
Where do alluvial fans occur?
Where sediment-loosen streams enter a zone where sediment transport capacity is much reduced
Why do some rivers have multiple terraces?
Due to incision
What grain size is most likely to be transported by wind?
Intermediate/medium sized
What is deflation?
the removal and lifting of individual loose particles
What is abrasion?
grinding of rock surfaces with sandblasting action due to particles in the air
What is yarding?
soft rocks are shaped in the direction that the wind is blowing
Approximately how much of the world’s deserts are occupied by dunes?
25%
Where is a dune’s slip-face?
Leeward side
What is a glacier?
large mass of ice resting on land or floating as an ice shelf adjacent to land
How is an alpine glacier different from a continental glacier?
Alpine: occur in mountains
Continental: occurs in continues masses of ice; can dominate large continental land masses
Where are cirque basins formed?
high altitude hollows in the mountains
What is a moraine?
Material eroded from the landscape; til
What is a terminal moraine?
furthest line of til; furthest extent where the glacier actually went
What is a horn?
A sharpened mountain peak
What is an arete?
Sharp mountain ridge; knife-edge
What is a col?
connection between the aretes; low points in the aretes; eroded depression
How are U shaped valleys formed?
glacial action
What is a drumin field?
series of smooth hills of glacial deposit
What is an esker?
sinuous ridge of sand gravel in glacial depositional terrain
What is a kettle lake?
hollows left by continental glaciers filled with melted water
What direction do constructive waves break?
foreward
What direction do destructive waves break?
downwards
How does water transport energy?
Molecule to molecule in a cyclic undulation
