Chapter 13 Flashcards
High rainfall belts are regions of ___, where warm, moist air masses meet and rise.
Convergence
Low-rainfall belts are regions of ___, where cool, dry air masses sink downward.
Divergence
These belts lie in the two polar regions and in the subtropical regions creating two dry climate subtropical regions and two dry, cold polar climates
Low-rainfall belts
These belts lie along the equator and the polar fronts resulting warm-humid and cold-humid climate zones.
High-rainfall belts
___ is an arid land that receives less than 250mm of rainfall or snow equivalent per year and is sparsely vegetated unless it is irrigated
Desert
___ is land in which the annual rainfall ranges between 250-500mm
Semiarid
Arid and semiarid lands are collectively known as ___, are characterized by lack of available water.
Drylands
When evaporation exceeds precipitation on a regular basis, water availability is ___
Low
What are the 5 types of deserts?
Subtropical Continental Interior Rainshadow Coastal Polar
___ deserts are associated with two belts of low rainfall near the 30N and 30S latitudes
Subtropical
___ deserts receive very little precipitation and are considered “frozen” deserts
Polar
___ is the worlds largest desert
Antarctica
Which 3 types of deserts are related to geography and not global air circulation
Continental Interior
Rainshadow
Coastal
The ___ desert is the greatest of the world subtropical deserts
Sahara
A ___ desert forms when a mountain range creates a barrier to the flow of moist air, causing a zone of precipitation on the downward side of the range
Rainshadow
___ deserts form along the margins of continents where cold, upwelling seawater cools the air, decreasing its ability to form precipitation
Coastal
___ deserts receive little rain since they are far from oceans
Continental Interior
___ is the processes related to wind and are particularly effective as agents of erosion in arid and semarid regions
Aeolian
Sediment carried by the wind tends to be ___ than the sediment carried by water or ice
Finer
Typically, the largest particles that can be lifted in the airstream are ___
Grains of sand
___ is sediment transport in which the wind causes particles to roll along the ground.
Surface Creep
___ is sediment transport in which particles move forward in a series of short jumps along arc-shaped paths
Saltation
___ is sediment transport in which the wind carries very fine particles over long distance and periods of time
Suspension
The largest grains are transported by ___
Surface Creep
As wind speed increases, smaller grains are bumped or lifted into the air, where they experience ___
Saltation
Finer dust-sized particles may be carried aloft to heights of a kilometer or so, where they can travel along in ___ as long as the wind keeps blowing
Suspension
What are the two ways for flowing air to erode land surface?
Abrasion
Deflation
___ is wind erosion in which airborne particles chip small fragments off rocks that protrude above the surface
Abrasion
A bedrock surface or stone that has been abraded and shaped by windblown sediment is a ___
Ventifact
___ is wind erosion in which loose particles of sand and dust removed by the wind, leaving coarser particles behind
Deflation
___ on a large scale only takes place where there is little or no vegetation and where loose particles are fine enough to be picked up by the wind.
Deflation
Continued deflation sometimes leads to the development of ___ where most of the fine particles are removed
Desert Pavement
Desert landforms can either be ___, ___, or ___
Erosional
Depositional
Combination of Both
A ___ is a hill or ridge of sand deposited by winds.
Dune
A typical dune is ___, with a gentle windward slope and a steep leeward face.
Asymmetrical
___ dunes are formed when wind blows in several different directions.
Star
Crescent-Shaped dunes are called ___, wind blows mainly in one direction
Barchans
___ dunes run parallel to the prevailing winds
Longitudinal
When there is a shit ton of sand supply, barchan dunes can merge and form ___ dunes
Transverse
Coastal regions where moist wind off the ocean allows vegetation to grow, are a typical environment for ___ dunes
Parabolic
When the sand reaches the top of the dune, the sand cascades down the steep leeward side, this is called ___
Slip Face
Crisscrossed strata within the dune, called ___, are former slip faces
Cross beds
The sliding sand on a slip face comes to rest at the ___
Angle of Repose
The angle of repose is steeper for more ___ grained minerals
Coarse
___ are landforms that form when a resistant stratum is underlain by a softer, more easily eroded stratum that is removed and carried away.
Hoodoos
Landforms could be steep-sided but flat-topped ___ or table-like ___
Buttes, Mesas
The rapid rainfall runoff erodes steep-sided canyons, called ___, into the landscape
Arroyos
If canyon openings are closely spaced along the base of a mountain range, the alluvial fans sometimes coalesce into a broad alluvial apron called a ___
Bajada
___ is the invasion of desert conditions into nondesert areas
Desertification
___ is land damage or loss of productivity caused by human activity, which may lead to the advance of desert conditions into non desert areas
Land Degradation
In the region south of the Sahara lies a drought-prone belt of dry grassland known as the ___, and the annual rainfall is only __ to __ cm
Sahel, 10-30
Signs of desertification are
- lower water tables
- higher levels of salt in water and topsoil
- reduction in surface water supplies
- unusually high rates of soil erosion
- destruction of vegetation
___ is the perennially frozen part of the hydrosphere
Cryosphere
A semipermanent or perennially frozen body of ice consisting largely of recrystallized snow, which moves under the pull of gravity
Glacier
A(n) ___ is the largest type of glacier on earth
Ice Sheet
___ are thick sheets of floating ice hundreds of meters thick that adjoin glaciers on land
Ice Shelves
___ is a form of ice cover that never touches land at all
Sea Ice
A glacier where the ice is near its melting point throughout the interior. These glaciers form in the low and middle latitudes
Temperate Glaciers
At high latitudes and high altitudes, the mean annual temperature is below freezing, the temperature in the glacier remains low, and little or no seasonal melting occurs. What type of glacier is this?
Polar Glacier
A ___ glacier occupies a bowl-shaped depression on a mountainside and typically serves as the source for a valley glacier
Cirque
A ___ glacier flows down valleys and are fed either from cirque glaciers or ice caps
Valley
An ___ covers a mountaintop completely and usually displays a radial-outward-flow pattern
Ice Cap
when a glacial valley is partly filled by an arm of the sea, the valley is called a ___ and the glacier is a ___ glacier
Fjord, Fjord
When a glacier flows all the way out of the mountains and onto the surrounding lowlands, it is called a ___ glacier
Piedmont
The presence of air in the pore spaces allows the delicate points of each snowflake to ___
Sublimate
As years go by, the snow gradually becomes denser and denser, until it is no longer penetrable by air and becomes ___
Glacier Ice
Addition of snow to a glacier is ___
Accumulation
A loss of snow from a glacier is ___
Ablation
Near the top, or ___, of the glacier is an Accumulation Zone where snows turns into glacier ice
Head
Near the end, or ___, of the glacier, more ice is rapidly lost to evaporation and melting than is replaced by snow
terminus
Glaciers move because of ___
The pull of gravity
The difference between accumulation and ablation is the measure of the glacier’s ___
Mass Balance
Glaciers move in 2 ways, ___ and ___
Internal Flow and Basal Sliding
The weight of overlying snow and ice in a glacier increases, ice crystals are prone to more stress. Under this stress, ice crystals deep within the glacier undergo very slow movements called ___, along internal crystal planes
Creep
Glaciers pass over a change in slope and the surface ice cracks as the tension pulls it apart. When the crack opens up, this is called a ___, a deep, gaping fissure in the upper surface of a glacier.
CrevASSe
___ is when ice at the bottom of a glacier slides across its bed
Basal Sliding
A ___ is when a glacier goes wild and one part of the glacier begins to move rapidly downslope producing a chaos ;) of crevASSes and broken pinnacles
Surge
When basal sliding occurs, small fragments of rock embedded in the basal ice scrape away at the underlying bedrock and produce long, nearly parallel scratches called ___. While larger particles gouge out deeper ____
Glacial Striations, Glacial Grooves
Bowl-shaped ___ are found at the glaciers head
Cirque
Two cirques on opposite sides of a mountain can meet to form a sharp-crested ridge called an ___
Arete
Cirques developing on all sides of a mountain may carve its peak into a prominent ___
Horn
A ___ is a heterogeneous mixture of crushed rock, sand, pebbles, cobbles, and boulders deposited by a glacier
Till
The boulders, rock fragments, and other sediment carried by a glacier may be deposited along its margins or at its terminus, these form ridges called ___
Moraines
___ moraines form along the edges
Lateral
___ moraines form at the terminus
Terminal
___ moraines form as a glacier melts and recedes
Recessional
___ is a ridge or pile of debris that has been, or is being transported by a glacier
Moraine
A ___ moraine is formed when two lateral moraines converge and the lateral moraines get trapped between the glaciers forming a ridge of material that rides along the middle of the ice stream
Medial
If the glacier subsequently retreats, that sediment that is left behind in a raised bed is called an ___
Esker
The retreat of a glacier can leave behind a terrain full of pits and pockmarks from abandoned blocks of ice embedded in the glacial debris. When these melt, the depressions left behind are called ___
Kettles
Glacial till can sometimes include very large boulders. When they are different from the bedrock, such boulders are called ___
Erratics
Land areas that are near or adjacent to glaciers are referred to as ___
Periglacial
The most common type of periglacial landscape is ___, a treeless biome that experiences long winters and very short summers
Tundra
Tundra is usually underlain by a layer of ___
Permafrost
During the summer in the tundra, the ice in permafrost melts only in a thin layer near the surface called the ___
Active Layer
The freeze-thaw cycle produces characteristic geological formations called ___ and ___
Ice Wedges and Patterned Ground
Ground that is perennially below the freezing point of water
Permafrost
