Geomorphology Ch 14 &15
The dynamic equilibrium model refers to
A balancing act between tectonic uplift and rates of denudation by weathering and erosion in a given landscape
The San Juan River near Bluff, Utah, flooded in 1941 producing
A deepening of the channel, followed by subsequent filling
When a dam and reservoir are constructed, the natural response of the river and its channel gradient come under the control of:
A local, or temporary, base level
The high ground that separates one valley from another is known as ________, and it directs surface water runoff known as ________toward a stream.
An interfluve; sheet flow
If Earth did not experience endogenic processes, the landscape would
Be of very low relief as a result of weathering and erosion in the absence of uplift
Carbonation
Carbonate minerals dissolve into a solution with weakly acidic water
Which portions of a slope overlap substantially?
Debris slope and waning slope
drainage pattern of eroded dome
annular
The general term for clay, silt, and sand deposited by running water is
alluvium
Of the world's largest rivers, which has the greatest discharge?
amazon
Denudation
any process that wears away landforms or changes their position; exogenic processes
Base level concept
an imagined surface that extends inland from sea level which is inclined gently upward, and a level below which a stream cannot erode its valley; John Wesley Powell
Saltation
particles rolled and bounced along a stream bed
When rock is broken and disintegrated without dissolving, the process in operation is
physical weathering
Crystallization
physical weathering; saltwater, concentrated water enters a fracture evaporated crystals grow, exert pressure on walls of fracture
pressure-release jointing
plutons form underground with pressure from over burden; when pluton reaches surface it expands
Uplift of the landscape creates ________energy which is converted to ________energy when materials begin to move downslope.
potential; kinetic
Batholithic formation results from
pressure-release jointing
drainage pattern of volcano
radial
drainage pattern of jointed or faulted rock
rectangular
In most areas, the upper surface of bedrock is partially weathered to broken-up rock called
regolith
Drainage divides
ridges that control the direction of drainage
Bed load is moved by
rolling, traction, saltation
Which of the following weathering types is primarily found in arid environments?
salt crystal growth
Rills
small scale grooves in the land surface
The rate at which rocks weather depends upon
the climate of an area; the type of rock; the amount of vegetation in an area; the type of rock
Capacity
the total possible load that a stream can transport
The valley and ridge province is characterized by which drainage pattern?
trellis
drainage pattern of folded mountain belt
trellis
The concave lower portion of a typical slope is called a
waning slope
Other than the rock itself, the most important chemical substance needed for the majority of weathering processes is
water
Order of slope
waxing, free/face, debris, waning
A major drainage basin consists of a single watershed. T/F
False
Floodplain formation occurs while a stream is downcutting rapidly. T/F
False
A flood recurrence interval of 100 years means that floods of that size will occur only once every 100 years. T/F
False; means there is a 1 in 100 change of a floor per year
Rectangular drainage patterns form primarily as a result of
Flow through a faulted or jointed landscape
The form that a landscape exhibits results from a balance between
Forces acting on the landscape; Endogenic and exogenic processes; Inputs and outputs of matter and energy;
If material is to move downslope, it must overcome the force of
Friction; The cohesion of particles to each other; Inertial resistance of the material
Chemical weathering is greatest under conditions of
Higher mean annual rainfall and temperatures
Which of the following is correct regarding joints? a. Joints are small, localized fault planes along which movement occurs b. Joints enable more ware to move through the ground c. Joints enhance the rate of weathering d. Joints enable more water to move through the ground and enhance the rate of weathering
Joints enable more water to move through the ground and enhance the rate of weathering
Oxidation
Preferential removal of metals (like iron) from minerals; results in reddish-brown color
Braided streams are characterized by
Sediment deposition in the channel resulting in the formation of sand and gravel bars and numerous small "channels" and a heavy load in relation to its discharge
Stream capture refers to:
The process by which one channel erodes through a drainage divide and captures the headwater regions of another stream
geomorphology
The science that specifically studies the origin, evolution, form, and spatial distribution of landforms
A floodplain is composed of alluvium. T/F
True
Erosion of the walls of a channel normally occurs on the outside curve of a meander. T/F
True
Competence
a stream's ability to move particles of a specific size
The total possible load a stream can transport is its ________ , whereas a stream's ability to move particles of specific size is its ________. a. Capacity; competence b. Discharge; competence c. Competence; capacity d. Bed load; sediment load
a. Capacity; competence
You would expect only slight physical and chemical weathering under conditions of a. Lower mean annual rainfall and temperatures b. Temperatures below freezing c. Higher temperatures and lower precipitation d. Extreme cold and high precipitation
a. Lower mean annual rainfall and temperatures
Stream transport involves all of the following except a. Sheet flow b. Traction c. Bed load d. Saltation
a. Sheet flow
The large sheets of rock that break off batholiths, such as Half Dome in Yosemite National Park, develop as a result of a. Exfoliation b. Mineral expansion c. Salt crystal growth d. Frost wedging
a. exfoliation
The construction of a dam across a river is likely to cause ________ upstream and ________downstream.
aggradation; erosion
The largest material that can be carried by a stream is carried as
bed load
Hydrolisis
chemical weathering; breakdown of silicate minerals in rock; water changes a mineral into something else
Hydration
chemical weathering;, water becomes part of the mineral structure; Swelling and stress within a rock as it absorbs water
Debris slope
coarse material accumulate; fine material moves
Waning slope
concave; fine material accumulate
Waxing slope
convex; material originates
Which of the following weathering processes does not involve water a. Hydration b. Hydrolysis c. Crystallization d. Carbonation e. Pressure-release jointing
e. pressure-release jointing
Suspended load
fine particles physically held loft in a stream
The fact that water expands as much as 9 percent of its volume as it freezes is the basis of
frost wedging
Conflicting forces work to establish an optimum incline on a slope. When any of these conditions are disturbed or altered the materials on the slope reach a
geomorphic threshold or change point
In which climates would rock be weathered to the greatest depth?
hot and wet
The lengths of the individual channels in a dendritic drainage pattern are ________and this increases energy ________.
minimized; efficiency
A landscape behaves as an
open system
Free slope/face
outcrop of resistant bedrock; material originates