ESCI EXAM 2 (Ch 4 & Ch 5)

Dissolution (of Limestone)

"BLANK" itself is a carbonate rock. Marble, a metamorphic form of "BLANK", is dissolved through carbonation. This is apparent on many tombstones which take on a worn appearance.

The total possible load a stream can transport is its ________ , whereas a stream's ability to move particles of specific size is its ________? Capacity; competence Competence; capacity Discharge; competence Bed load; sediment load

Capacity; competence

The fact that water expands as much as 9 percent of its volume as it freezes is the basis of?? Chemical weathering processes Pressure-release jointing Crystallization Frost wedging

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?? Condition of static equilibrium Condition of metastable equilibrium at the time of disturbance Geomorphic cycle Geomorphic threshold, or change point

Geomorphic threshold, or change point

The science that specifically studies the origin, evolution, form, and spatial distribution of landforms is? Geology Geography Geomorphology Environmental chemistry

Geomorphology

Chemical weathering is greatest under conditions of?? Higher mean annual rainfall and temperatures Lower mean annual rainfall and temperatures Temperatures below freezing Rainfall less than 25cm (10in) per year

Higher mean annual rainfall and temperatures

In which climates would rock be weathered to the greatest depth? Cold and wet Cold and dry Hot and wet Hot and dry

Hot and wet

Stream capture refers to: The legal process by which a state secures rights to the waters of a river basin The merging of two streams flowing in the same valley The process by which one channel erodes through a drainage divide and captures the headwater regions of another stream The illegal withdrawal of water from a river

The process by which one channel erodes through a drainage divide and captures the headwater regions of another stream

Which of the following landforms is incorrectly matched with a drainage pattern? Volcano - radial Folded mountain belt - trellis Eroded dome - annular Topographically disrupted areas - parallel

Topographically disrupted areas - parallel

The valley and ridge province is characterized by which drainage pattern? Dendritic Trellis Deranged Annular

Trellis

A floodplain is composed of alluvium. True False

True

Erosion of the walls of a channel normally occurs on the outside curve of a meander. True False

True

Time

Typically, the longer the duration of exposure for a particular surface, the more it will be weathered. Time is the most critical factor affecting weathering, because these processes require long periods of time.

The concave lower portion of a typical slope is called a? Waning slope Pediment Debris slope Free face Attempt

Waning slope

Other than the rock itself, the most important chemical substance needed for the majority of weathering processes is?? Oxygen Nitrogen Water Carbon dioxide

Water

Subsurface Water

Weathering rates are influenced by the position of the water table and the water movement within soil and rock structures.

Climate (precipitation and temperature)

Wetter, warmer environments speed the rate of chemical weathering, while colder environments have the freeze-thaw processes that cause physical weathering. Typically weathering is quicker in wet, warm climates than in dry, hot ones.

Which of the following is incorrectly matched? Endogenic processes - initial landscapes Exogenic processes - sequential landscapes Mackin - graded river William Morris Davis - base level concept

William Morris Davis - base level concept

Vegetation

cover can protect rock by shielding it from rain impact and by stabilizing the soil with its roots. Additionally, though, vegetation produces organic acids from the partial decay or organic matter that contributes to chemical weathering. Further, plant roots can enter crevices in rock and mechanically break up a rock, thereby exposing greater surface area to other weathering processes.

A collapse sinkhole

develops over a period of hours or days and forms when a solution sinkhole collapses through the roof of an underground cavern. They can have dramatic features, and many of them are caused by human activities.

Concave Slopes

feature on the slope is the waning slope, located along the base, which is where the fine material accumulates due to deposition.

Convex Slopes

feature on the slope is the waxing slope, located near the top, which is where loose material originates due to physical and chemical weathering.

The dynamic equilibrium model

follows a series of steps over time: 1) equilibrium stability, 2) a destabilizing event, 3) a period of adjustment, 4) the development of a new and different condition of equilibrium stability.

A solution sinkhole

forms by the slow subsidence of surface materials along joints or at an intersection between joints. They typically have depths of 1-100 m and diameters of 10-1000 m.

Deranged drainage

has no clear geometry and no true stream valley.

Frost wedging

can result in blocks of rock known as joint-block-separation.

Undercutting (Undercut Bank)

occurs in meandering streams because the highest velocity occurs at the outer portion of each meandering curve, thus causing the greatest erosive action. The "BLANK" is the product of that erosive action.

Annular drainage

occurs on structural domes, with concentric patterns of rock strata guiding stream courses.

Rejuvenation

occurs when a previously low energy stream flowing through an uplifted landscape gains energy and actively returns to downcutting.

Aggradation

occurs when a stream's load exceeds its capacity, that is, the total possible sediment load of a stream, which causes the sediment to accumulate on the bed and the stream channel to build up through deposition.

Differential Weathering

occurs when one layer of rock erodes faster or slower than another. It takes place as a result of interactions and opposition between the forces of weathering and erosion and the resistance of Earth materials. The Delicate Arch in Utah is an example of this, as a more resistant rock cap protects supporting strata below, creating an arch-shaped rock. Weathering processes affect rocks with different resistance levels differently, creating unique landforms.

Degradation

occurs when the stream's energy increases, causing higher rates of sediment transportation than deposition, which then causes heightened erosion of the channel.

Suspended Load

of a stream is the material consisting of fine-grained clastic particles (bits and pieces of rock). They are held aloft until the stream velocity slows to zero, at which point all particles are deposited.

Dissolved Load

of a stream is the material that travels in solution, especially the dissolved chemical compounds. The main process contributing this material is weathering.

Cohesion

of particles is that materials on the slope are bound together and thus resist movement.

Uplift

of the land is caused by tectonic processes. It creates potential energy of position as the land rises above sea level. When materials move downslope as a result of exogenic processes, that potential energy is converted to kinetic energy. Potential energy is stored energy that has the capacity to do work under the right conditions..

Drainage Basins

or "watershed", is the portion of landscape from which a river receives its water. "BLANK" range in size; a major "BLANK" system is made up of many smaller drainage basins, each of which gathers and delivers its runoff and sediment to a larger basin.

Sinkholes

or dolines, are created by the weathering by dissolution of limestone landscapes. They are circular depressions in the ground surface that may reach 600 m in depth.

Frost Action

or freeze-thaw, breaks rocks apart in the process of frost wedging. When water freezes, its volume expands as much as 9%, and repeated freezing and expanding of water overcomes the tensional strength of rock in the process of frost action. This process begins in small openings along existing joints and fractures, gradually expanding and splitting them.

Free Face

surface on the slope is a steep scarp of cliff whose presence indicates an outcrop of resistant rock. It and the waxing slope are the places at which loose material originates due to physical and chemical weathering.

Weathering Processes

that breaks down rock at Earth's surface and slightly below, either disintegrating rocks into mineral particles or dissolving it into water. It weakens surface rock, making that rock more susceptible to the pull of gravity. "BLANK" are both physical and chemical; often, the types combine synergistically to create unique landforms. "BLANK" is differentiated from erosion because weathering simply means the breakdown of materials, while erosion includes the transport of "BLANK" materials to different locations.

What are the 4 Conditions for Karst Formation

1. The limestone formation must contain 80% or more calcium carbonate for dissolution processes to proceed effectively. 2. Complex patterns of joints in the limestone are needed for water to form routes to subsurface drainage channels. 3. An aerated (air-containing) zone must exist between the ground surface and the water table. 4. Vegetation cover is needed to supply varying amounts of organic acids that enhance the dissolution process.

Slope Stability

A "BLANK" if its strength exceeds denudation processes, and it is unstable if its materials are weaker than those processes. A "BLANK" will exist at a compromise incline that balances all forces optimally.

The dynamic equilibrium model refers to? A balancing act between tectonic uplift and rates of denudation by weathering and erosion in a given landscape A theory involving the cyclic or evolutionary development of a landscape A sequential development of landforms An important concept first stated by William Morris Davis

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: Decreased discharge A deepening of the channel, followed by subsequent filling A lack of equilibrium to balance discharge, velocity, and sediment load A surprising lack of response in the river channel

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: The same base level that existed prior to construction A local, or temporary, base level The government An ultimate base level

A local, or temporary, base level

Which of the following is incorrectly matched? Abrasion - a hydraulic squeezeandrelease action Competence - a stream's ability to move particles of a specific size Capacity - the total possible load that a stream can transport Suspended load - fine particles physically held loft in a stream Saltation - particles rolled and bounced along a stream bed

Abrasion - a hydraulic squeezeandrelease action

The construction of a dam across a river is likely to cause ________ upstream and ________downstream. Erosion; aggradation Erosion; erosion Aggradation; erosion Aggradation; aggradation

Aggradation; erosion

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 All of the choices

All of the choices

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 Forces acting on the landscape and endogenic and exogenic processes All of the choices are correct

All of the choices are correct

The rate at which rocks weather depends upon?? The climate of an area The type of rock The amount of vegetation in an area Only the climate of an area and the type of rock All of these choices

All of these choices

Which of the following is incorrectly matched? Rills - small scale grooves in the land surface Drainage divides - ridges that control the direction of drainage Allegheny and Missouri rivers - from the Monongahela at Pittsburgh Delaware River basin - comprised of parts of five states

Allegheny and Missouri rivers - from the Monongahela at Pittsburgh

The general term for clay, silt, and sand deposited by running water is?? Debris Alluvium Soil Mud

Alluvium

Stream/River

Although there is overlap in usage of the terms "stream" and "river", the term river is applied to the main stream in a river system, while the term stream refers generally to water flowing in a channel, regardless of size. Streams come together to form river systems.

Of the world's largest rivers, which has the greatest discharge? Zaire (Congo) River Amazon River MissouriOhioMississippi river system Chang Chiang (Yangtze) of Asia

Amazon River

The high ground that separates one valley from another is known as ________, and it directs surface water runoff known as ________toward a stream. The maximum contour elevation; alluvial discharge The maximum contour elevation; sheet flow An interfluve; sheet flow The continental divide; overland flow

An interfluve; sheet flow

In reality, a landscape behaves as? A closed system An open system An evolutionary model changing in a sequence of stages that is the same everywhere on Earth A closed system in terms of energy and an open system in terms of matter

An open system

Which of the following is not exogenic in nature? Weathering Erosion Denudation Batholithic formation Mass wasting

Batholithic formation

If Earth did not experience endogenic processes, the landscape would? Be rugged and of great relief as a result of uplift in the absence of weathering and erosion Consist of high mountains and hills with smooth, gentle slopes Be of very low relief as a result of weathering and erosion in the absence of uplift

Be of very low relief as a result of weathering and erosion in the absence of uplift

The largest material that can be carried by a stream is carried as: Bed load Suspended load Dissolved load Truck load

Bed load

John Wesley Powell put forward the idea of base level, which refers to: An imagined surface that extends inland from sea level which is inclined gently upward A level below which a stream cannot erode its valley An evolutionary cycle of landscape development Flat plateaus Both 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

Both 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

Bed load is moved by: Saltation Traction Suspension Both saltation and traction All of these are correct

Both saltation and traction

Which portions of a slope overlap substantially? Waxing slope and waning slope Waxing slope and free face Free face and debris slope Debris slope and waning slope

Debris slope and waning slope

Which of the following is incorrectly matched? Volcanic eruptions - endogenic Tectonic uplift - endogenic Heavy rainfall - Exogenic Weathering and erosion - Exogenic Denudation - endogenic

Denudation - endogenic

The large sheets of rock that break off batholiths, such as Half Dome in Yosemite National Park, develop as a result of?? Exfoliation Mineral expansion Salt crystal growth Frost wedging

Exfoliation

Half Dome, Yosemite

Exfoliation in granite can be seen on the east side of the "BLANK".

A flood recurrence interval of 100 years means that floods of that size will occur only once every 100 years. True False

False

A major drainage basin consists of a single watershed. True False

False

Floodplain formation occurs while a stream is downcutting rapidly. True False

False

Rectangular drainage patterns form primarily as a result of ________. Differential resistance to erosion Domal uplift Flow through anticlinal and synclinal topography Flow though a faulted or jointed landscape

Flow though a faulted or jointed landscape

Which of the following is correct regarding joints? Joints are small, localized fault planes along which movement occurs Joints enable more ware to move through the ground Joints enhance the rate of weathering Joints enable more water to move through the ground and enhance the rate of weathering All of these choices

Joints enable more water to move through the ground and enhance the rate of weathering

You would expect only slight physical and chemical weathering under conditions of?? Lower mean annual rainfall and temperatures Temperatures below freezing Higher temperatures and lower precipitation Extreme cold and high precipitation

Lower mean annual rainfall and temperatures

The lengths of the individual channels in a dendritic drainage pattern are ________and this increases energy ________. Minimized; efficiency Minimized; inefficiency Maximized; efficiency Maximized; inefficiency

Minimized; efficiency

Braided streams are characterized by: Sediment deposition in the channel resulting in the formation of sand and gravel bars and numerous small "channels" A heavy load in relation to its discharge Severe erosion of the channel bed All of the choices Only: 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

Only: 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

When rock is broken and disintegrated without dissolving, the process in operation is?? Physical weathering Chemical weathering Hydrolysis Carbonation

Physical weathering

Uplift of the landscape creates ________energy which is converted to ________energy when materials begin to move downslope. Kinetic; potential Potential; kinetic Potential; chemical Kinetic; chemical

Potential; kinetic

Which of the following weathering processes does not involve water? Hydration Hydrolysis Crystallization Carbonation Pressure-release jointing

Pressure-release jointing

Downcutting

Process of deepening a valley by erosion of the streambed

In most areas, the upper surface of bedrock is partially weathered to broken-up rock called?? Parent rock Bedrock Sediment Regolith

Regolith

The 6 Factors Controlling Weathering and Weathering Rates are

Rock composition and Structure, Climate, Slope Orientation, Subsurface Water, Vegetation, and Time.

Which of the following weathering types is primarily found in arid environments? Exfoliation Frost wedging Hydrolysis Salt crystal growth Carbonic acid solution

Salt crystal growth

Stream transport involves all of the following except: Saltation Bed load Traction Sheet flow

Sheet flow

Slope Mechanics

Slopes, or hillslopes, are curved, inclined surfaces that form the boundaries of landforms. They generally feature a convex upper waxing slope near the top, which may grade into a free face below, which is a steep scarp or cliff whose presence indicates an outcrop of resistant rock. Downslope from the free face is a debris slope, which receives rock fragments and materials from above. The debris slope grades into a waning slope, which is a concave surface along the base of the slope.

Hydration involves? A chemical weathering process Swelling and stress within a rock as it absorbs water Frost action The action of wind

Swelling and stress within a rock as it absorbs water

Rock Composition and Structure

The character of the bedrock and its mineral composition influence the rate of weathering, both through their levels of resistance to weathering and the amount of surface area that is exposed to physical and chemical weathering processes.

Slope Orientation

The direction in which a slope faces controls the slope's exposure to the sun, wind, and precipitation.

Landscape Evolution

The form that a landscape exhibits results from a balance between forces acting on the landscape, endogenic and exogenic processes, and inputs and outputs of matter and energy.

Physical Weathering

also called mechanical weathering, is the disintegration of rock without any chemical alteration. It breaks up rock and thus produces more surface area on which all weathering may operate. "BLANK" primarily occurs by frost action, salt-crystal growth, and exfoliation.

Exfoliation

also called sheeting, is the process whereby rock peels or slips off in sheets instead of breaking up into grains. It creates arch-shaped and dome-shaped features, called exfoliation domes, which are probably the largest weathering features in areal extent on Earth. It is thought to occur as pressure is released from the overall removal of overlying rock in the process of pressure-release jointing.

Continental Divide

are a special class of divides which separate drainage basins that empty into different bodies of water surrounding a continent.

Caves

are defined as natural underground areas large enough for humans to enter. They form in limestone because it is so easily dissolved by carbonation. A cavern is any large "BLANK" formed by chemical processes."BLANK" generally form just below the water table, where later lowering of the water table exposes them to further development. An estimated 90% of "BLANK" worldwide still lie undiscovered, and more than 90% of known "BLANK" have not been biologically surveyed. "BLANK" are nearly closed, self-contained ecosystems with great stability.

Friction/Inertia/Cohesion

are forces that oppose motion and offer resistance to denudation processes.

Speleothems

are formations consisting of mineral deposits inside caves and occur in various characteristic shapes.

Joints

are fractures or separations in rock that occur without displacement of the rock on either side. "BLANK" increases the surface area of rock exposed to both chemical and physical weathering.

Slopes

are open systems with exogenic inputs and endogenic outputs. They seek an angle of equilibrium among the forces at work on them. In order for the material which is loosened by weathering to move downslope, the forces of erosion, including gravity, must overcome other forces: friction, inertia, and the cohesion of particles to one another. These conflicting forces work simultaneously to establish a compromise incline that balances these forces optimally. When any condition in the balance is altered, all forces compensate by adjusting to the new dynamic equilibrium.

Flowstones

are sheet-like formations of calcium carbonate on cave floors and walls.

Dripstones

are speleothems formed as water containing dissolved minerals slowly drips from the cave ceiling. Calcium carbonate precipitates out of the evaporating solution and accumulates on a spot below on the cave floor. The dripstones, a depositional feature, are called stalactites and stalagmites, with stalactites being those which form hanging from the ceiling, and stalagmites being those which build from the floor. Soda straws are a type of thin, long stalactite.

Floodplains

are the flat, low-lying areas adjacent to channels and subject to recurring flooding. A "BLANK" is the area that is inundated when a river overflows its channel. When the water recedes after such flooding, it leaves behind alluvial deposits that generally mask the underlying rock with their accumulating thickness.

Fluvial Erosion, Transportation, Deposition

are the ongoing processes which form fluvial landscapes.

Exogenic Processes

are those which operate at Earth's exterior. They build sequential landscapes, tearing down those initial landscapes. They are characterized by lower relief, gradual change, and stability. Some examples of "BLANK" include heavy rainfall, weathering and erosion, denudation, and mass wasting.

Endogenic Processes

are those which operate at Earth's interior. They build initial landscapes. Some examples are volcanic eruptions and tectonic uplift. If the Earth did not experience "BLANK", the landscape would be of very low relief as a result of weathering and erosion in the absence of uplift.

Bed Load

in a stream refers to the coarser materials that are moved by traction, which is the rolling or dragging of materials along the streambed, or by saltation, a term referring to the way in which particles may bounce along in short hops and jumps. Particles transported by saltation are too large to remain in suspension but are not confined to the sliding and rolling motion of traction.

Crystallization (Salt-Crystal Growth)

is a form of physical weathering which happens most frequently in arid climates where heating is intense. It is the process in which evaporation draws moisture to the surface of rocks, leaving behind previously dissolved minerals in the form of crystals. As these crystals accumulate and grow, they exert forces great enough to separate the grains making up the rock and begin breaking, in the process known as salt-crystal growth, or salt weathering.

Earthflow

is a mass wasting event with high water content. They are caused by sandstone foundations resting on weak shale and siltstone, which become moistened and soft, and eventually fail with the weight of the overlying strata.

Soil Creep

is a persistent, gradual mass movement of surface soil. In it, individual soil particles are lifted and disturbed, whether by the expansion of soil moisture as it freezes, by cycles of moisture and dryness, by diurnal temperature variations, or by animal activity. The overall wasting of a creeping slope may cover a wide area and may cause fence posts, utility poles, and even trees to lean downslope. Various strategies are used to halt this form of mass movement, such as grading the terrain, building terraces and retaining walls, and planting ground cover; however, they are rarely effective.

Frost weathering

is a physical weathering process that occurs in humid microthermal, polar, and highland climates at high elevations worldwide. Frost action can cause shattered rock debris and rockslides when winter ends and temperatures warm, freeing the newly fractured pieces.

Springs

is a place where ground water naturally discharges to the surface resulting from the water table meeting the land surface.

Stream Discharge

is a stream's volume of flow per unit of time. It is calculated using the formula Q = wdv, where Q = discharge, w = channel width, d = channel depth, and v = stream velocity.

Fluvial

is a term used to describe processes that are related to streams and rivers. The Latin term "fluvius" means "river".

Sheetflow

is a thin film spread over the ground surface. It is one of two ways in which water moves downslope as overland flow. The second form of overland flow occurs when water concentrates in rills, small grooves in the landscape made by the downslope movement of water. "BLANK" is directed by the high ground that separates one valley from another called an interfluve.

Carbonation

is a type of chemical weathering reaction which breaks down minerals that contain calcium, magnesium, potassium, or sodium. Water vapor readily dissolves carbon dioxide, thereby yielding precipitation containing carbonic acid, which is strong enough to dissolve many materials through this process. The process is also enhanced by acid precipitation. Rainfall and most groundwater are acidic.

Denudation

is any process that wears away or rearranges landforms. The principal "BLANK" processes affecting surface materials include weathering, mass movement, erosion, transportation, and deposition, which are all produced and influenced by moving air, waves, ice, and, most importantly, gravity.

Parallel drainage

is associated with steep slopes.

Trellis drainage

is characteristic of dipping or folded topography. Parallel structures direct the principal streams, while smaller tributary streams at nearby angles join the main streams at right angles.

Spheroidal Weathering

is chemical weathering that softens and rounds the sharp edges and corners of jointed rock as water penetrates the joints and dissolves weaker minerals or cementing materials. It resembles exfoliation, but does not result from pressure-release jointing. In other words, the acid in water dissolves certain materials in rock, affecting all sides of the rock, and resulting in a spherical shape.

River Gradient

is defined as the drop in elevation per unit of distance. It is the degree of inclination.

Soil

is developed from weathered rock or unconsolidated sediments. Whenever it is relatively young, its parent rock is traceable through similarities in composition. Regolith is the parent material to soil. On a typical hillside, it is included as one of the loose surface material that overlies bedrock and regolith. The thickness of "BLANK" is dependent on its production and erosion.

Debris Slope

is downslope from the free face. It receives rock fragments and materials from above. Coarse material will accumulate, while fine fragments will be transported. In humid climates, continually moving water carries the material away, lowering the angle, while in arid climates, debris slopes accumulate material.

Rectangular drainage

is formed by a faulted and jointed landscape.

Iron Oxide (Hematite)

is likely the most familiar oxidation; it is the process by which oxygrn combines with iron to form rust. This occurs in the humid southeastern U.S., the arid U.S. southwest, and the tropics. When oxidation reactions remove iron from the minerals in a rock, the disruption of crystal structures makes the rock more susceptible to further chemical weathering and disintegration.

Point Bars

is located at the inner curve in a meandering stream. Since the highest velocity occurs at the outer curve, the inner curve experiences the slowest velocity, and thus is a zone of aggradation which results in the point bar. The "BLANK" itself is an accumulation of sediment (on the inside of the meander bend).

Karst Topography

is named for the Krs Plateau in Slovenia, where "BLANK" were first studied. These are areas of the world with extensive limestone formations, where chemical weathering involving dissolution of carbonates dominates entire landscapes. Some characteristic features are pitted, bumpy surface topography, poor surface drainage, and well developed solution channels (dissolved openings and conduits) underground. Approximately 15% of Earth's land area has some karst features. The amount and distribution of rainfall appear important to the formation of "BLANK".

Graded Stream

is one in which the channel slope has adjusted, given the discharge and channel conditions, so that stream velocity is just enough to transport the sediment load. Attainment of a graded condition means that it has achieved a state of dynamic equilibrium between its gradient and sediment load. An individual stream can have both graded and ungraded portions.

Meandering Rivers

is snakelike, weaving back and forth across the landscape. The river system's tendency to meander is evidence of its tendency to find the path of least effort toward equilibrium. Characteristically, in a straight section of a channel, the greatest flow velocities are near the surface at the center, the deepest part of the stream. As the stream flows around a meander curve, the maximum flow velocity shifts from the center to the outside of the curve. As it straightens, the maximum velocity shifts back the center, until the next bend.

Equilibrium Stability

is that in which the system fluctuates around some average. As landscapes and the forces acting on them change, the surface responds in search of "BLANK", with every change producing compensating actions and reactions.

John Wesley Powell

is the American geologist and explorer who put forward the idea of base level in 1875. He recognized that not every landscape has degraded to sea level; therefore, other intermediate base levels, like the local base level, must be in operation.

Drainage Patterns

is the arrangement of channels in an area. They are distinctive, and are determined by a combination of regional steepness and relief, variations of rock resistance, climate, and hydrology, and structural controls imposed by underlying rock.

Water Table

is the boundary between saturated and unsaturated zones. It moves up and down over seasonal and geologic time.

Regolith

is the broken up surface layer of bedrock. It is created by continual weathering, before being transported and deposited. In some areas, "BLANK" may be missing or undeveloped, exposing an outcrop of un-weathered bedrock. "BLANK" is the parent material of soil.

Oxidation

is the chemical weathering process wherein certain metallic elements combine with oxygen to form oxides. It is the preferential removal of metals, like iron, from minerals which then recombine with oxygen to form different materials. The disruption of the crystalline structure makes materials much more susceptible to further weathering.

Hydration

is the combination of water with a mineral, which can cause chemical decomposition of the rock to occur. It involves little chemical change, because it does not form new chemical compounds, but it does involve a change in structure. Water becomes part of the chemical composition of the mineral.

Parent Rock

is the consolidated or unconsolidated material from which soils develop, ranging from the unconsolidated sediments and weathered rock to bedrock. Bedrock is known as the "BLANK" from which weathered regolith and soils develop because of the process by which bedrock is weathered into regolith, and regolith into the base materials for soil development.

Bedrock

is the consolidated, or solid, rock underlying surface material on a typical hillside. It is known as the parent rock from which weathered regolith and soils develop. "BLANK" is the parent material for regolith, and regolith is the parent material of soil.

Hydrolysis

is the decomposition of a chemical compound by reaction with water. It is the chemical reaction of water with a mineral, and produces a different mineral through the chemical reaction. When minerals in rock are changed by "BLANK", the interlocking crystal network consolidating the rock breaks down and granular disintegration takes place. It may make the rock appear corroded and even crumbly.

Alluvium

is the general term for the unconsolidated clay, silt, sand, gravel, and mineral fragments deposited by running water. It may accumulated as sorted or semisorted sediment.

Dynamic Equilibrium

is the idea of landscape formation as a balancing act between uplift and reduction by weathering and erosion. Tectonic uplift creates disequilibrium between relief and the energy required to maintain stability. "BLANK" is reestablished through denudation by erosion and weathering.

Base Level

is the level below which a stream cannot erode its valley. In general, the ultimate base level is sea level. "BLANK" can be visualized as a surface extending inland from sea level, inclined gently upward under the continents. In theory, it is the lowest practical level for all denudation processes. A local base level is a temporary one, one which may determine the lower limit of local or regional stream erosion. Rivers and lakes are examples of local base levels, and the reservoir behind a dam constitutes a human-caused local base level.

Dendritic drainage

is the most common. It is a treelike pattern with efficient energy because the total length of the branches is minimized.

River Mouth

is the place at which the river flows into the ocean.

Nickpoints

is the point of interruption which occurs when the longitudinal profile of a stream contains an abrupt change in gradient, such as a waterfall or area of rapids. They can result when a stream flows across a resistant rock layer, recent fault line, or area of surface deformation, as well as from temporary blockage."BLANK" are relatively temporary and mobile landscape features.

Transportation

is the process by which this material is moved to new locations.

Erosion

is the process by which water dislodges, dissolves, or removes weathered surface material.

Deposition

is the process by which, in these new locations, the eroded material is laid down.

Pressure-Release Jointing

is the process in which rocks crack into joints. It usually occurs in exposed plutons (batholiths). This is because plutons form deep underground, under deep pressure; when these plutons are exposed, the release of pressure causes them to gradually expand and eventually fracture.

River Source (Head)

is the river's point of origin, such as a glacier, lake, march, or spring.

Hydrology

is the science of water and its global circulation, distribution, and properties, with a focus on water at and below the Earth's surface.

Geomorphology

is the science that studies the origin, evolution, form, and spatial distribution of landforms.

Geomorphic Threshold

is the tipping point, sometimes reached during or after a destabilizing event, where the system lurches to a new operational level. It is reached when a "BLANK" moves from the slow accumulation of small adjustments to a point of abrupt change that takes it to a new system state. After crossing this "BLANK", the system establishes a new set of equilibrium relationships.

Inertia

is those materials' resistance to movement.

Mudflow

is used to describe a mass wasting event with highest moisture content. The suffix -flow is used when the moisture content is high, but "BLANK" are highest.

Groundwater

is water that moves in the subsurface, filling cracks, crevices, and small pore spaces in the rock.

Friction

is what keeps materials from easily sliding downslope.

Braided Stream

pattern is a maze of interconnected channels. It often occurs when reduced discharge lowers a stream's transporting ability, such as after flooding or when a landslide occurs upstream. They commonly occur in glacial environments, where coarse sediment is abundant and slopes are steep.

Chemical Weathering

refers to the chemical breakdown, always in the presence of water, of the constituent minerals in rock. "BLANK" intensifies with increases in both temperature and precipitation. Although specific minerals themselves vary in susceptibility, all rock-forming minerals are responsive to some degree of "BLANK". It occurs primarily by hydration and hydrolysis, oxidation, and carbonation.

Radial drainage

results when streams flow off a central peak or dome, such as a volcanic mountain.

1925, Jackson Hole, WY

was subjected to a mass wasting event with a high enough water content to classify it as an earthflow. It began when heavy rains saturated barren mountain slopes and set them moving. About 17 million m3 of wet soil and rock moved down one side of the canyon and surged up 30 m on the other side, damming the river and forming a lake.

Entrenched Meanders

which are deep incisions in the landscape, are formed from degradation of the channel. This can occur in a process of tectonic uplift in a previously graded stream. Since the landscape is lifted, the stream gradient increases, and erosional activity is stimulated. The previously low-energy channel becomes rejuvenated (it gains energy and actively returns to downcutting) and forms entrenched meanders.