Geology Exam #4 Questions With Answers
Mass wasting
the downslope movement of rock, regolith, snow, or ice due to the pull of gravity
Landslide
a sudden movement of rock and debris down a nonvertical slope
Soil creep
the very slow, gradual movement of regolith downslope → driven by expansion and contraction
cycles (freeze-thaw and wetting-drying)
Failure surface
A weak surface that forms the base of a landslide.
Slump
A semi-coherent volume of regolith that slipped down a slope above a spoon-shaped failure surface at
slow to moderate speed.
Head scarp
The distinct step along the upslope edge of a slump where the regolith detached.
Slide
the downslope movement of cohesive blocks of rocks, debris, or soil along a well-defined plane of
deformation/failure surface; can move at a very slow or fast rate
Flow
the downslope movement of loose pieces of sediment mixed with water (called a "slurry"), fast rate
Fall
when a mass falls through the air or bounces or rolls down a cliff face at a fast rate; includes topples
and rockfalls
Avalanche
a turbulent cloud of debris (rock, soil, or snow) mixed with air that rushes downslope at very fast
speeds
Turbidity current
a submarine avalanche of sediment and water that speeds down a submarine slope
Angle of repose
the steepest slope angle a pile of loose material can exist at before sliding or collapsing under gravity
Stream
a ribbon of water that flows in a channel
, Channel
a trough dug into the ground surface by flowing water
Runoff
the water that flows on the surface of the Earth to drain the land
Drainage network
an array of interconnecting streams that together drain an area
Watershed
the region that collects water that feeds into a given drainage network
Saltation
The movement of a sediment in which grains bounce along their substrate, knocking other grains into
the water column (or air) in the process.
Bed load
large particles, such as sand, pebbles, or cobbles, that bounce or roll along a streambed
Suspended load
tiny solid grains carried along by a stream without settling to the floor of the channel
Dissolved load
ions dissolved in a stream's water
Floodplain
the flat land on either side of a stream that becomes covered with water during a flood
Delta
A wedge of sediment formed at a river mouth when the running water of the stream enters standing
water, the current slows, the stream loses competence, and sediment settles out.
V-shaped valley
A valley whose cross-sectional shape resembles the shape of a V; the valley probably has a river
running down the point of the V.
Canyon
a trough or valley with steeply sloping walls, cut into the land by a stream
Alluvial fan
a gently sloping apron of sediment dropped by an ephemeral stream at the base of a mountain in arid
or semiarid regions
Mass wasting
the downslope movement of rock, regolith, snow, or ice due to the pull of gravity
Landslide
a sudden movement of rock and debris down a nonvertical slope
Soil creep
the very slow, gradual movement of regolith downslope → driven by expansion and contraction
cycles (freeze-thaw and wetting-drying)
Failure surface
A weak surface that forms the base of a landslide.
Slump
A semi-coherent volume of regolith that slipped down a slope above a spoon-shaped failure surface at
slow to moderate speed.
Head scarp
The distinct step along the upslope edge of a slump where the regolith detached.
Slide
the downslope movement of cohesive blocks of rocks, debris, or soil along a well-defined plane of
deformation/failure surface; can move at a very slow or fast rate
Flow
the downslope movement of loose pieces of sediment mixed with water (called a "slurry"), fast rate
Fall
when a mass falls through the air or bounces or rolls down a cliff face at a fast rate; includes topples
and rockfalls
Avalanche
a turbulent cloud of debris (rock, soil, or snow) mixed with air that rushes downslope at very fast
speeds
Turbidity current
a submarine avalanche of sediment and water that speeds down a submarine slope
Angle of repose
the steepest slope angle a pile of loose material can exist at before sliding or collapsing under gravity
Stream
a ribbon of water that flows in a channel
, Channel
a trough dug into the ground surface by flowing water
Runoff
the water that flows on the surface of the Earth to drain the land
Drainage network
an array of interconnecting streams that together drain an area
Watershed
the region that collects water that feeds into a given drainage network
Saltation
The movement of a sediment in which grains bounce along their substrate, knocking other grains into
the water column (or air) in the process.
Bed load
large particles, such as sand, pebbles, or cobbles, that bounce or roll along a streambed
Suspended load
tiny solid grains carried along by a stream without settling to the floor of the channel
Dissolved load
ions dissolved in a stream's water
Floodplain
the flat land on either side of a stream that becomes covered with water during a flood
Delta
A wedge of sediment formed at a river mouth when the running water of the stream enters standing
water, the current slows, the stream loses competence, and sediment settles out.
V-shaped valley
A valley whose cross-sectional shape resembles the shape of a V; the valley probably has a river
running down the point of the V.
Canyon
a trough or valley with steeply sloping walls, cut into the land by a stream
Alluvial fan
a gently sloping apron of sediment dropped by an ephemeral stream at the base of a mountain in arid
or semiarid regions
