Chapter 16: Deserts and Wind

2. List and briefly distinguish among basic dune types.

1. Barchan dunes 2. transverse dunes 3. barchanoid dunes 4. longitudinal dunes 5. parabolic dunes 6. star dunes see pages 436 - 437

Over the years a fan enlarges, eventually coalescing with fans from adjacent canyons to produce an apron of sediment called a

bajada along the mountain front.

As sand is deposited on the slip face, layers form that are inclined in the direction the wind is ___. These sloping layers are called cross-beds.

blowing ex: sandstone walls of Zion Canyon in Utah

In South America, an ephemeral stream is called a __

donga

For wind to be effective errosional force, _______ and scant vegetation are important prerequisites.

dryness

Continued sand accumulation, coupled with periodic slides down the slip face, results in the slow migration of the _____ in the direction of air movement.

dune

Suspended Load Unlike sand, finer particles of ___ can be swept high into the atmosphere by the wind.

dust

Fine particles are easily carried by wind, but they are not so easily picked up to begin with. The reason is that the wind velocity is practically zero within a very thin layer close to the ____.

ground

The opposite is true for region in the vicinity of 30 degrees north and south latitude, where ___ pressure predominates. Here, in the zones known as the subtropical highs, air is subsiding. When air sinks, it is compressed and warmed. These regions are known for their ___ skies, ___, and ongoing ___.

high pressure clear skies, sunshine, ongoing drought.

barchanoid dunes = type 3

intermediate between isolated barchans and extensive waves of transverse dunes form scalloped rows of sand oriented at right angles to the wind. the rows resemble a series of barchans that have been positioned side by side.

The few streams that do cross arid regions, such as Colorado and Nile Rivers, originate ___ the desert, often in well-watered mountains. Here the water supply must be great, or the stream will lose all its water as it crosses the desert.

outside

On the rare occasions of abundant rainfall, streams may flow across the bajada to the center of the basin, converting the basin floor into a shallow ___ ___

playa lake

The Role of Water Deserts have scant ___ and few major rivers.

precipitation

Desert floods arrive suddenly and subside ____.

quickly.

The dry region that results is often referred to as a ______. When prevailing winds from the Pacific Ocean to the west meet the mountains, rainfall totals are high. By comparison, precipitation on the leeward (eastern ) side of the mountains of meager.

rainshadow ex: western Washington State

In this way, the leeward slope of the dune, called the ___ ___, maintains an angle of about 34 degrees, the angle of repose for loose dry sand.

slip face.

late stage with inselbergs

southern Arizona

Early stage

southern Oregon northern Nevada

Its source is deposits of ___ ___. During the retreat of the ice sheets, many river valleys were choked with sediment deposited by meltwater. Strong westerly winds sweeping across the barren floodplains picked up the finer sediment and dropped it as a blanket on the eastern side of the valleys.

stratified drift

Middle latitude deserts and steppes are not controlled by the ____ ___ masses associated with high pressure. Instead, many of these dry lands exist because they are sheltered in the deep interior of large _____. They are far removed from the ocean, which is the ultimate source of moisture for cloud formation and precipitation. example: Gobi Desert of central Asia, north of India

subsiding air masses landmasses.

In dry regions as well as along some beaches, windblown sand cuts and polishes exposed rock ______________.

surfaces.

transverse dunes = type 2

1. regions where the prevailing winds are steady, sand is plentiful, and vegetation is sparse or absent, the dunes form a series of long ridges that are separated by troughs and oriented at right angles to the prevailing wind. 2. many coastal dunes are of this type 3. common in many arid regions where the extensive surface of wavy sand is sometimes called sand sea. 4. In some parts of the Sahara and Arabian Deserts, transverse dunes reach heights of 200 meters and are 1 to 3 kilometers across, and can extend for distances of 100 km or more

Barchan Dunes = type 1

1. solitary dunes shaped like crescents and with their tips pointing downwind 2. form where supplies of sand are limited and the surface is relatively flat, hard, and lacking vegetation 3. migrate slowly with the wind at a rate of up to 50 feet per year

Factors that influence the form and size that dunes ultimately assume:

1. wind direction 2. velocity 3. availability of sand 4. amount of vegetation present

Ventifacts and Yardangs Like glaciers and streams, wind also erodes by ____.

abrasion

In India, an ephemeral stream is called a ___.

nullah

Also as with a stream, _____ transports fine particles in suspension, while heavier ones are carried as bed load.

wind

Concept 16.3 2. Describe the features and characteristics associated with each stage in the evolution of a mountainous desert.

Alluvial fans form during the early stage of landscape development, when the relief is highest. Over time, these fans grow and merge, so that by the middle stage, continuous bajadas of sediment cover the line where the ranges meet the basins. On the basin floor, playa lakes may form during wet periods and dry up to produce salty playas. When almost all of the mountains have been worn down and almost all the low-lying basins have been filled in with sediment, the landscape has reached the late stage of development. It will be marked by isolated inselbergs of bedrock poking up through a sea of sediment.

What causes these bands of low-latitude desert?

global distribution of air pressure and winds

Just as in streams, the velocity of wind increases with _____ above the surface.

height

Section 16.4 Wind Erosion Wind erosion is more effective in arid lands than in _____ areas because in humid places moisture binds particles together, and vegetation anchors the soil.

humid

Gobi Desert

image

Subtropical Deserts and Steppes

image

desert or arid

image

dunes

image

inselbergs

image

playa lake

image

The precipitated salts may be unusual. Sodium borate, known as ______ is mined from ancient playa lake deposits in Death Valley, California.

borax

An examination of the fan's surface would reveal a braided channel pattern because of the shifting its coarse as successive ______ became choked with sediment.

channels

Heated air in the pressure belt known as the __ ___ rises to great heights and then spreads out. As the upper-level flow reaches 20 to 30 degrees latitude, north or south, it sinks toward the surface. Air that rises through the atmosphere expands and cools, a process that leads to the development of clouds and precipitation. For this reason, the areas under the equatorial low are among the ____ on Earth.

equatorial low rainiest

Sometimes yardangs are large features.

ex: Peru's Inca Valley contains yardangs that approach 330 feet in height and several kilometers in length.

Introduction Climate has a strong influence on the nature and intensity of Earth's ____ processes.

external example: glaciers example: strong link between climate and geology is seen when we examine the development of arid landscapes.

When such circumstances exist, wind may pick, transport, and deposit great quantities of ____ sediment.

fine

Thus, the wind cannot lift the sediment by itself. Instead, the dust must be ejected or ____ into the moving air by bouncing sand grains or other disturbances.

spattered

During the 1930's, parts of the Great Plains experienced vast dust _______. The plowing under of the natural vegetative cover for farming, following by severe drought, exposed the land to wind erosion and led to the area's being labeled the Dust Bowl.

storms.

Although both silt and clay can be carried in ____, silt commonly makes up the bulk of the _____ load

suspension suspension load

The middle latitude deserts provide an example of how ____ processes affect climate. Rain-shadow deserts exist by virtue of the mountains produced when _____ collide. Without such mountain-building episodes, wetter climates would prevail where many dry regions exist today.

tectonics plates

Main role of wind is the ___ and ____ of sediment, which creates and shapes the ridges and mounds we call dunes.

transportation and deposition

Streams lack an extensive system of _____. In fact, a basic characteristic of desert streams is that they are small and die out before reaching the sea.

tributaries.

Because dust is often composed of rather flat particles that have large surface areas compared to their weight, it is easy for _____ air to counterbalance the pull of gravity and keep these fine particles airborne for hours or even days.

turbulent

Transportation of Sediment by Wind Moving air, like moving water, is ______ and able to pick up loose debris and transport it to other locations.

turbulent

When the occasional torrents of water produced by sporadic rains move down the mountain canyon, they are heavily loaded with sediment. Emerging from the confines of the canyon, the runoff spreads over the gentler slopes at the base of the mountains and quickly loses ____.

velocity

In other parts of the world, a dry desert stream may be a ____in Arabia and North Africa

wadi

The factor that controls the depths of these basins is the local ___ ___. when blowouts are lowered to the water table, damp ground and vegetation prevent further deflation.

water table

Erosional Features Compared to running water and glaciers, ___ is a relatively modest force in sculpting landforms. Recall that even in deserts, most erosion is performed by intermittent ______ ____, not by ___.

wind running water wind

Concept 16.3 1. What is meant by interior drainage?

arid regions lack permanent streams and often have interior drainage. This means that they exhibit a discontinuous pattern of intermittent streams that do not flow out of the desert to the ocean. In the United Stages, the dry Basin and Range region provides an excellent example.

Many dunes have an _____ profile, with the leeward or sheltered slope being steep and the windward slope more gently inclined.

asymmetrical profile

In the United States, deposits of loess are significant in many areas:

1. South Dakota 2. Nebraska 3. Iowa 4. Missouri 5. Illinois 6. portions of the Columbia Plateau in the Pacific Northwest

The distribution of loess worldwide indicates that there are two primary sources for this sediment:

1. deserts 2. glacial outwash deposits

Wind deposits are of two types:

1. mounds and ridges of sand from the wind's bed load, which we call dunes 2. extensive blankets of silt, called loess, that once were carried in suspension.

____types of sand dunes

6 a. Barchan Dunes b. Transverse Dunes c. Longitudinal Dunes d. Parabolic Dunes e. Star Dunes

In addition, arid and semiarid areas occur in southern ___ and make a limited appearance in coastal ___ and ____.

Africa Chile and Peru

It is this fine, buff-colored sediment that gives the Yellow River _ _ its name

Huang Ho

2. How extensive are the desert and steppe regions of Earth?

Arid and semiarid climates cover 30 % of Earth's land surface.

In the southern hemisphere, dry climates dominate ____. Almost 40 percent of the continent is desert, and much of the remainder is ___.

Australia steppe

Concept 16.5 1. How do sand dunes migrate?

Dunes accumulate due to the difference in wind energy on the upwind and downwind side of some obstacle. Wind moves sand up the more gently sloping upwind side, across the crest of the dune, where it settles out in the calmer air on the downwind side of the dune, the steeply sloped slip face. When the sand on the slip face is piled up past the angle of repose, it will spontaneously collapse in small avalanches of sand. Over time, this will cause a dune to slowly move in the direction of the prevailing wind, with the slip face "leading the way" Inside the dune, the buried slip faces may be preserved as cross-beds.

Where in the United States can each stage of desert landscape evolution be observed?

Early stage: southern Oregon and northern Nevada Advanced Middle Stage: Death Valley, California and southern Nevada Late Stage showing inselbergs: southern Arizona

yardang

In addition to creating ventifacts, wind erosion is responsible for creating much larger features, called yardangs. A yardang is a streamlined, windsculpted landform that is oriented parallel to the prevailing wind. Yardangs are small features that stand less than 16 feet high and no more than 32 feet long. Because the sand-blasting effect of the wind is greatest near the ground, these abraded bedrock remnants are usually narrower at their base.

ephemeral streams

In the dry western U.S., different names are used. 1. wash and arroyo

Concept 16.4 What are yardands and ventifacts?

Like glaciers and streams, wind also erodes by abrasions. In dry regions as well as along some beaches, windblown sand cuts and polishes exposed rock surfaces. Abrasion sometimes creates interestingly shaped stones called ventifacts. In addition to creating ventifacts, wind erosion is responsible for creating much larger features, called yardangs. A yardang is a streamlined, wind-sculpted landform that is oriented parallel to the prevailing wind. stand less than 16 feet high and no more than 32 feet long. Because the sand-blasting effect of wind is greatest near the ground, these abraded bedrock remnants are usually narrower at their base.

Concept 16.5 How is loess difference from sand?

Loess is windblown silt, deposited over large areas sometimes in thick blankets. Most loess is derived from either 1. deserts or 2. areas that have recently been glaciated. Winds blow across stratified drift and pick up silt-sized grains, carrying them in suspension to the site of deposition.

Longitudinal Dunes

Long ridges of sand that form more or less parallel to the prevailing wind where sand supplies are moderate apparently, the prevailing wind direction must vary somewhat but still remain in the same quadrant of the compass. Although the smaller types are only 3 or 4 meters high and several dozens of meters long, in some large deserts, longitudinal dunes can reach great size. ex: portions of North Africa, Arabia, and central Australia, these dunes can approach a height of 300 feet and extend for distances of more than 62 miles

Chemical weathering is not completely absent from the deserts

Over long periods of time, the clays and thin soil do form and many iron-bearing silicate minerals oxidize, producing the rust-colored stain that tints some desert landscapes.

Types of Sand Dunes Dunes are not just random heaps of windblown sediment.

Rather, they are accumulations that usually assume patterns that are surprisingly consistent.

Because ____Hemisphere lacks extensive land areas in the middle latitudes, only small areas of desert and steppe occur in this latitude range, existing primarily near the tip of south America in the rainshadow of the towering Andes.

Southern

Concept 16.1 3. What is the primary cause of subtropical deserts and steppes?

The answer is the global distribution of air pressure and winds.

Concept 16.1 1. Explain why the boundary between humid and dry climates cannot be defined by a single rainfall amount.

The concept of dryness is a relative one that refers to any situation in which an ongoing water deficiency exists. Dry climate is one in which yearly precipitation is not as great as the potential loss of water by evaporation.

Concept 16.4 4. What factor limits the depth of blowouts?

The factor that controls the depths of these basins, that is, acts as base level, is the local water table. when blowouts are lowered to the water table, damp ground and vegetation prevent further deflation.

Concept 16.4 Why is wind erosion relatively more important in dry regions than in humid areas?

Wind erosion is more effective in arid lands than in humid areas because in humid places moisture binds particles together, and vegetation anchors the soil. Features created by wind erosion are significant elements of some landscapes.

Concept Checks 16.4 1. Describe the way in which wind transports sand. When wind is strong, how high above the surface can sand be carried?

Wind transports fine particles in suspension, while heavier ones are carried as bed load. When wind is strong, the height of the saltating sand seldom exceeds 3 feet and is usually no greater than 1.5 feet.

Concept 16.4 2. How does wind's suspension load differ from its bed load?

Wind transports fine particles in suspension. Unlike sand, finer particles of dust can be swept high into the atmosphere by the wind. Because dust is composed of rather flat particles that have large surface areas compared to their weight, it is relatively easy for turbulen air to counterbalance the pull of gravity and keep these fine particles airborne for hours or even days. although silt and clay can be carried in suspension, silt commonly makes up the bulk of the suspended load because the reduced level of chemical weathering in deserts provides only small amounts of clay. Heavier particles are carried in the bed load. The bed load that wind carries consists of sand grains.

At first the sand rolls along the surface. When a moving sand grain strikes another grain, one or both of them may jump into the ___. Once in the air, the grains are carried forward by the wind until gravity pulls them back toward the surface. when the sand hits the surface, it either bounces back into the air or dislodges other grains, which then jump upward.

air.

Most of the load is dumped within a short distance. The result is a cone of debris at the mouth of the canyon known as an ____ ___.

alluvial fan

Section 16.5 Wind Deposits Although wind is relatively unimportant in producing erosional landforms, significant ____ are created by the wind in some regions.

depositional

Nevertheless, features created by wind ____ are significant elements of some landscapes.

erosion

The correlation between the distribution of loess and important farming regions in the Midwest and eastern Washington State is not just a coincidence because soils derived from this wind-deposited sediment are among the most ___ in the world

fertile

Unlike the deposits in china, which originated in deserts, the loess in U.S. and Europe is an indirect production of ___.

glaciation.

Concept 16.4 Briefly describe two hypotheses used to explain the formation of desert pavement

hypothesis 1 1. Deflation begins. 2. Deflation continues to remove finer particles. 3. Desert pavement established, deflation ends. Hypothesis 2 1. Weathered pebbles and cobbles on bedrock 2. Wind-blown silt accumulates and sifts downward through coarse particles. 3. Silt continues to accumulate and lift desert pavement.

Dust Bowl

image

Sand deposits Sand dune

image As is the case with running water, wind drops its load of sediment when velocity falls and the energy available for transport diminishes. Thus, sand begins to accumulate wherever an obstruction across the path of the wind slows it movement. Unlike many deposits of silt, which form blanketlike layers over large areas, winds commonly deposit sand in mounds or ridges called dunes.

Star Dune

image confined largely to parts of the Sahara and Arabian Deserts, star dunes are isolated hills of sand that exhibit a complelx form name is derived from the fact that the bases of these dunes resemble multipointed stars. Usually 3 or 4 sharp-crested ridges diverge from a central high point that is some cases may approach a height of 300 feet As their form suggests, star dunes develop where wind directions are variable.

Parabolic Dunes = type 5

image form where vegetation partially covers the sand. The shape of these dunes resembles the shape of barchans except that their tips point into the wind rather than downwind. Form along coasts where there are strong onshore winds and abundant sand. If the sand's sparse vegetative cover is disturbed at some spot, deflation creates a blowout. Sand is then transported out of the depression and deposited as a curved rim, which grows higher as deflation enlarges the blowout.

Such an origin is confirmed by the fact that loess deposits are thickest and coarsest on the ___ side of such major glacial drainage outsets as the Mississippi and Illinois Rivers and rapidly thin with increasing distance from the valleys.

lee side

Loess (Silt) Deposits In some parts of the world, the surface topography is mantled with deposits of windblown silt, called ____.

loess

In Asia, the great Himalayan chain prevents summertime ____ flow of moist Indian Ocean air from reaching the interior of the continent.

monsoon

In addition the Northern hemisphere contains another much smaller area of subtropical desert and steppe in ___ ___ and the ___ ____.

northern Mexico and the southwestern United States

The desert environment stretches more than 5800 miles from the Atlantic coast of North Africa to the dry lands of ___ ___.

northwestern India

Over periods of thousands of years, dust storms deposited this material. When loess is breached by streams or ___ cuts, it tends to maintain vertical cliffs and lacks any visible layers.

road

The angular, mechanically weathered particles composing the loess are essentially the same as the ___ ___ produced by the grinding action of glaciers.

rock flour

__ ___ does most of the erosional work in deserts. It is a common belief that wind is the most important erosional agent sculptering desert landscapes. Most desert landforms are carved by running water.

running water

Sand moves up the gentler slope on the windward side by ____. Just beyond the crest of the dune, where the wind velocity is reduced, the sand accumulates. As more sand collects, the slope steepens, and eventually some of it slides under the pull of gravity.

saltation.

Observations in the field and experiments using wind tunnels indicate that windblown sand moves mainly by skipping and bouncing along the surface--a process called _____.

saltation. The terms is not a reference to salt but instead derives from Latin word meaning to jump.

Bed load that wind carries consists of _____ grains.

sand

Accumulations of windblown sediment are particularly conspicuous in the world's dry lands and along many ___ ___.

sand coasts

The presence of high mountains across the paths of prevailing winds is another factor that separates middle-latitude arid and ____ areas from water bearing, maritime air masses.

semiarid

Concept 16.5 How are some loess deposited related to glaciers?

the loess in the United States and Europe is an indirect product of glaciation. Its source is deposits of stratified drift. During the retreat of the ice sheets, many river valleys were choked with sediment deposited by meltwater. Strong westerly winds sweeping across the barren floodplains picked up the finer sediment and dropped it as a blanket on the eastern sides of the valleys. The angular, mechanically weathered particles composing the loess are essentially the same as the rock flour produced by the grinding action of glaciers.

The thickest and most extensive deposits of loess on Earth occur in ____ and _____ China. They were blown there from the extensive desert basins of Central Asia.

western and northern China

In North America, the foremost mountain barriers to moisture from the Pacific are the

1. Coast Ranges 2. Sierra Nevadas 3. Cascades

Formation of desert pavement

1. This model shows an area with poorly sorted surface deposits. Over time, deflation lowers the surface, and coarse particles become concentrated. 2. In this model, the surface is initially covered by cobbles and pebbles. Over time, windblown dust accumulates at the surface and gradually sifts downward

Transport of sediment by wind differs from that of running water in two ways.

1. Wind's lower density compared to water renders it less capable of picking up and transporting coarse materials. 2. Second, because wind is not confined to channels, it can spread sediment over large areas, as well as high into the atmosphere.

Within water - deficient regions, two climatic types or commonly recognized:

1. desert or arid 2. steppe or semiarid

The development of arid regions are dominated by many geologic processes: Because these processes combine in different ways from place to place, the appearance of desert landscapes varies a great deal as well.

1. tectonic forces 2. running water 3. wind

Because the coarsest material is dropped first, the head of the fan is steepest, having a slope of ___ to ____ degrees. moving down the fan, the size of the sediment and the steepness of the slope decrease, and the fan merges imperceptibly with the basin floor.

10 to 15 degrees.

Energy provided by the impact of the smaller saltating grains drives the larger grains forward. This is how ___ percent of the sand is transported in a sandstorm.

20 - 25%

Bouncing sand grains never travel far from the surface. Even when winds are very strong, the height of the saltating sand seldom exceeds ___ feet and usually no greater than ___ feet.

3 feet 1.5 feet

Some in the desert of Iran reach nearly ___ feet in height.

500 feet

Mountains force the air to lose much of its water.

As prevailing winds meet mountain barriers, the air is forced to ascend. When air rises it expands and cools, a process that can produce clouds and precipitation. The windward sides of mountains often have high precipitation. By contrast, the leeward sides of mountains are much drier. the situation exists because air reaching the leeward side has lost much of its moisture, and if the air descends, it is compressed and warmed, making cloud formation less likely.

Each of the stages of landscape evolution in an arid climate depicted in figure 16.8 can be observed in the ___ and ___ region.

Basin and Range

The heart of the subtropical dry climates lies in the vicintiy of the Tropics of ___ and ____.

Cancer and Capricorn

advanced middle stage

Death Valley, California southern Nevada

What is meant by dry?

Dry climate is one in which yearly precipitation is not as great as the potential loss of water by precipitation

Concept 16.1 5. In which hemisphere, Northern or southern are middle-latitude deserts most common. Explain

In the Northern hemisphere because the Southern Hemisphere lacks extensive land areas in the middle latitudes . Only small areas of desert and steppes occur in this latitude range, existing near the southern tip of South America in the rainshadow of towering Andes.

Concept 16.1 4. Why do middle-latitude dry regions exist? what role do mountains play?

Many of these dry lands exist because they are sheltered in the deep interior of large landmasses. They are far removed from the ocean, which is the ultimate source of moisture for cloud formation and precipitation. ex: Gobi Desert of central Asia, north of India Mountains force the air to lose much of its water. As prevailing winds meet mountain barriers, the air is forced to ascend. When air rises, it expands and cools, a process that can produce clouds and precipitation. the windward sides of mountains often have high precipitation. By contrast, the leeward side of mountains are usually much drier. This exists because air reaching the leeward side has lost much of its moisture, and if the air descends, it is compressed and warmed, making cloud formation even less likely.

Section 16.2 Geologic Processes in Arid Climates Weathering

Much of the weathered debris in the desert consists of unaltered rock and mineral fragments --the result of mechanical weathering processes. In dry lands, rock weathering of any type is greatly reduced because of the lack of moisture and scarcity of organic acids from decaying plants.

ventifacts

image Abrasion sometimes creates interestingly shaped stones called ventifacts The side of such a stone that is exposed to the prevailing wind is abraded, leaving it polished, pitted, and with sharp edges. If the wind is not consistently from one direction or if the pebble becomes reoriented, the stone may have several faceted surfaces.

Desert Pavement

image In portions of many deserts, the surface consists of closely packed layer of coarse particles. This veneer of pebbles and cobbles, call desert pavement is only one or two stones thick.

deflation

image One way that wind erodes is by deflation, the lifting and removal of loose material Deflation is difficult to notice because the entire surface is being lowered at the same time, but it can be significant. In portions of the 1930's dust Bowl, vast areas of land were lowered by as much as 1 meter in only a few years.

playa

image The dry, flat lake bed that remains is called a playa. 1. fine silts and clays 2. salts precipitated during evaporation

blowouts

image The most noticeable results of deflation in some places are shallow depressions appropriately called blowouts. In the Great Plains region, from Texas north to Montana, thousands of blowouts are visible on the landscape.

ephemeral

image deserts have ephemeral streams, which means they carry water only in response to specific episodes of rainfall. Because desert vegetative cover is sparse, runoff is largely unhindered and consequently rapid, often creating flash floods along valley floors.

steppe or semiarid

image is a marginal and more humid variant of the desert and is a transition zone that surrounds the desert and separates it from bordering humid climates.

The movement of sand grains begins when wind reaches a velocity sufficient to overcome the ______ of the resting particles.

inertia

Playa lakes are temporary features that lasts only a few days or at best a few weeks before evaporation and _________ remove the water.

infiltration

With the ongoing erosion of the mountain mass and the accompanying sedimentation, the local relifef continues to diminish. Eventually, the entire mountain mass is gone. Thus, by the late stages of erosion, the mountain areas are reduced to a few large bedrock knobs projecting above the surrounding sediment filled basin. These isolated erosional remnants on a late-stage desert landscape are called ____.

inselbergs, a German word meaning island mountains

Arid regions typically lack permanent streams and often have ___ ____. This means that they exhibit a discontinuous pattern of intermittent streams that do not flow out of the desert to the ocean.

interior drainage example: Basin and Range region provides an excellent example 1. southern Oregon 2. Nevada 3. western Utah 4. southeastern New Mexico