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