BYU GEO 101 Exam 3

HIghly erodable, soft terrain. Lacks vegetation because the rain washes away the thin soil layer. Occur in steep areas.
Picks up and moves silt and sand.
(Sand does not get lifted into the atmosphere; silt may blow a few hundred feet)
A type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as climate change and human activities.
Abrasion (Wind)
As wind blows silt and sand into exposed rock, it slowly wears down the rock.
Transverse Dune
A large, strongly asymmetrical, elongated dune lying at right angles to the prevailing wind direction. Transverse dunes have a gently sloping windward side and a steeply sloping leeward side. They generally form in areas of sparse vegetation and abundant sand. Most beach dunes are transverse dunes.
Dry lake bed – Bonneville Salt Flats.
All water has trace amounts of salt. As the water seeps into the ground or evaporates, the salt is left behind. Rain helps leach the salt into the ground.
Racetrack Playa – Small boulders gets pushed along the playa beds during rain storms.
A fertile soil that is deposited by wind and easily erodes in water.
A sea of sand
Barchan Dune
A large, crescent-shaped dune lying at right angles to the prevailing wind and having a steep, concave leeward side with the crescent tips pointing downwind. Barchan dunes form on flat, hard surfaces where the sand supply is limited.
Exotic Stream
A good size river that flows thru the desert. It is exotic because it comes from somewhere else. The Nile or Colorado,
Desert pavement; pebbles and rocks with little to no sand. Sand is protected by the underlying rock. A few inches below the rocky top layer is a loose sandy material.
Alluvial Fan
Ephemeral streams end here, depositing their sediment as it spreads out over the valley. Water moves more slowly when it hits the flat valley.
Longitudinal Dune
Created by seasonal shifts in wind direction. Angles on the edges are triangular.
Basin and Range
Streams that go out of the mountains in the valleys eventually evaporate, they do not make it to the ocean.
Great Basin
A collection of valleys where the water does not reach the ocean.
Mesa and Scarp
Scarp is a cliff. The top layer of the rock (cap) is harder than the rock beneath it. It protects the layers below, but eventually wears down.
Howare desert environments different from humid environments?
Dry climate produces angular cliffs. Weathering is mostly physical (instead of chemical). Mass wasting is rockfall. Soil easily erodes due to lack of vegetation. Rainfall is scarce.
Desert streams
Ephemeral – occasional, intermittant. Does not flow all year.
Exotic – Nile or Colorado. A good size that flows thru the desert, started elsewhere.
Five prominent desert landscapes
1. Erg – sea of sand
2. Reg – rocky surface with no sand
3. Basin and Range – stream do bot flow to ocea.
4. Mesa and Scarp – flat topped mountain and its cliffs.
5. Badlands – highly erodable terrain.
Alpine Glaciation
Erosional. The high elevation prevents the snow from melting in the summer.
Glacial Trough
A U-shaped canyon or valley.
Fjord or fiord
U shaped anyon or valley that is below sea level. Filled with ocean water. Popular cruise ships.
Like and open bowl with steep rock cliffs. Mt. Nebo. They erode back into a rock cliff, even though they are advancing forward.
a little lake at the bottom of a cirque
A ridge between two different cirques. A sharpened interfluve.
Hanging Valley
When a stream has to become a waterfall in order to reach the bottom of the riverbed.
The Matterhorn. A mountain peak glaciated on three sides, eroded to a sharp peak.
Continental Glacier
Exist away from the equator in cooler summer areas.
How does sea level change in an ice age?
Sea level goes down in an ice age because the glaciers don’t melt and return to the ocean.
Effects of Ice Age
Creation of landforms through glacial erosion and deposition.
Creates numerous lakes – Great Lakes
Migration and selective extinction of plant and animal species (Canadian treeline)
Effects of ice ages on the lithosphere
As the glaciers melt off the land, the ground will rebound from the removal of weight. Finland is rising about a centimeter each year.
An elongated hill or ridge of glacial drift. Tall at one end, tapers off at the end. Lies parallel to flow of glacier. Occurs as a result of the glaciers retreat. As the glaciers readvances, it will bulldoze over the hill.
A long, narrow ridge of coarse gravel deposited by a stream flowing in or under a decaying glacial ice sheet.
Depositional. Former meltwater stream under a glacier.
Glacial erratic
Huge boulders left as deposits as the glacier melts.
Kettle Lake
A shallow, sediment-filled body of water formed by retreating glaciers or draining floodwaters. Formed as large blocks of ice that were covered in dirt melted and left a depression on the earth. Lots in Minnesota.
Outwash plain
Looks like a braided stream, but it is created by a glacier. Glacial sediments deposited by meltwater outwash at the terminus of a glacier.
Any glacially formed accumulation of unconsolidated glacial debris. Debris left behind from a glacier (?)
End Moraine
End moraines, or terminal moraines, are ridges of unconsolidated debris deposited at the snout or end of the glacier. They usually reflect the shape of the glacier’s terminus. Glaciers act much like a conveyor belt, carrying debris from the top of the glacier to the bottom where it deposits it in end moraines.
Ground Moraine
Ground moraines are till covered areas with irregular topography and no ridges, often forming gently rolling hills or plains.
Recessional Moraine
Recessional moraines are often observed as a series of transverse ridges running across a valley behind a terminal moraine. They form perpendicular to the lateral moraines that they reside between and are composed of unconsolidated debris deposited by the glacier.
Lateral Moraines
Parallel ridges of debris deposited along the sides of a glacier.
Till/Glacial Till
Till or glacial till is unsorted glacial sediment.
Equilibrium Line
The amount of snow that falls in the winter is equal to the amount that melts in the summer.
Accumulation Zone
More snow accumulates that than melts.
Ablation Zone
Below the Equilibrium Line. Snow/Glacier continues to advance, even though it is not growing, it takes time to melt.
Pluvial Lakes (paleolakes)
Formed during ice ages, nothing to do with glaciers. Cooler temps and lots of precipitation filled valleys with water. Left shorelines on mountains. 10,000 years ago, temps warmed up. Great Salt Lake is former pluvial lake.
Evidences of ice ages
pluvial lakes
Fremont island
Stansbury Mountains
Pleistocene Epoch
Occured two million years ago.
One third of Earth’s land area was covered in ice.
Glaciers advanced and retreated numerous times.
Little ice age
Cold phases of the Pleistocene. They still happen today.
Medieval warm period
First around 900 AD. Greenland colonized during this period. As the temperature got colder, the Europeans couldn’t handle the cold and died out.
Ice Shelf
A sheet of ice on the continent produced by a melting glacier. As the glacier melts, it pushes the ice out over the ocean.
Alpine glacier
Form on the crests and slopes of mountains and are also known as Mountain Glaciers.
Continental glaciers
Also called ice sheets. Antarctica and Greenland.
Milutin Milakovitch’s suggestion of a possible climate change.
Change in earth’s orbit results in time periods that are colder or warmer, which will affect climate change.
Sea Level changes during ice age
The sea level is lower in an ice age because the glaciers retain the water.
Spit and hook
Sand that builds up from the movement of waves and extends across a bay, sometimes curls into a hook.
Baymouth bar
A spit becomes a baymouth bar when it connects two points.
A sand bar that sticks out from the coast. Small island out from the coast, waves break on the island and sediment drops and builds land that connects the shore to the island/rock.
Barrier islands

Low, flat, sandy islands. Storm waves move into shallow water and then slow down due to friction. As they slow down, they deposit their sediment.


Barrier islands can help protect the shore in a hurricane because they absorb the force of the sea waves.

The enclosed area, formerly a bay, created by a baymouth bar.
A hole at the inland end of a cave. Looks like a geyser. Occurs in uplifted coastal areas.
A partly enclosed coastal body of water with one or more rivers or streams flowing into it and with a free connection to the open sea.
Marine cliff
Bedrock that has been lifted up and the sea waves eroded it. White Cliffs of Dover
Sea arch
opening in a sea cliff where the waves have eroded it.
Sea stack
A rock or portion of an uplifted coastline that remains after the sea cliff has retreated inland. Twelve Apostles in Australia
Coral Reefs
Corals are delicate marine animals that live in dense colonies. They extract calcium carbonate from the seawater and secrete lime to form an exoskeleton.
Environmental Requirements for Coral Reefs:
1. Warm seawater
2. Lots of sunlight
3. A stable foundation

a coral island (or islands) that encircles a lagoon partially or completely.

Almost Atoll
Part of the island remain above sea level. There is less land than water inside the reef.

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