Flashcards in Surface/Exterior Processes Deck (39)
What are Alluvial fans and how do they form?
Form when a steep mountain stream reaches dry level land at the base. Dry level land slows down the stream's velocity and much of the sediment load is dropped.
What is an aquifer?
Layer of rock and sediment that carries water which can supply wells
What are Carol attols and how do they form?
Ring-shaped island of coral. Formed when:
Fringing reef of coral surrounds volcanic island
Fringing reef becomes barrier reef as it grows above sea level. Volcanic island will sink and barrier reef will contain a lagoon.
Island eventually be completely submerged. Barrier reef surrounding lagoon without volcanic island called Carol atoll.
What is calving?
Process of glaciers reaching sea and large chunks fall to form icebergs
What is a channel?
The path which water flows in a river or stream
What is the Coriolis effect? What are it's affects and where is it the greatest?
(Hint: There are 5)
Tendency of an object moving over Earth's surface having a curved trajectory.
Char of Coriolis Effect:
Weakest at equators and strongest at the poles
Effect increases as objects speed increases
Large distances are required for effect to be noticable
N. Hemi. objects deflect to the right S.Hemi. to the left
N.Hemi. high pressure systems spin clockwise and low spinnig counter clockwise. Opposite in S. Hemi
Causes hurricanes to spin counterclockwise in N. Hem and clockwise in S.Hem
What are Crevasses and where are they found?
Cracks or fissures near surface of a glacier. Form across width of the glacier
What are drumlins?
Long, smooth canoe-shaped hills. Formed when advancing glacier moves over earlier glacier moraine. Point in the direction of glacier advancement
What is the Ekman Transport and how does it work?
Effect of net water movement being perpendicular to the wind direction.
Note: For N.Hemi: Upwelling winds cause E.T to be away from land.
Downwelling winds cause E.T to be towards land
Index Finger: Points in wind
Middle Finger: Points up away from water
Thumb: Points to direction of E.T
What is Erosion and give examples of it
Removal and transport of rocks or soil by the action of water, ice or wind.
What is an Esker?
A long winding ridge of glacier deposit formed as glacier melts
What is Fetch and how does it affect the size of lakes?
Length of open water that winds constantly blows over
Larger fetch = Larger height of waves
What is a firn?
A rough granular ice material that forms as buried snow becomes thicker and is compressed that it recrystallizes.
Can be turned into solid ice from weight above it. Once it starts flowing outward or downward it's a glacier
What is a fjord?
A deep, long, steep-sided bay made from the sea flooding a glacier trough
What are geysers?
Hot spring that shoots out hot water into the air. Caused by superheated water quickly expanding producing burst of steam
What is hardwater and what causes it?
Water that has large amounts of ions from dissolved minerals such as Calcium, iron and magnesium
What is a floodplain?
The valley floor where the river travels
How do levees form?
Thick deposits which have built up along the stream banks
Embankment built to prevent overflow of a river
What are meanders and how do they form?
A back and forth sharp board curve in a river.
Due to the fast moving water at the outside of the river bend which causes rapid erosion
What are oxbow lakes and how do they form?
A lake that is formed as meanders are cut off during floods as the river drops mud and silt at the ends of the meander
Meander is eventually separated from the river and an oxbow lake is formed
What are Kames?
A steep-sided mound of sand and gravel deposited by a melting ice sheet
What is Mass Movement?
The down slope movement of weathered earth materials under the influence of gravity
List and describe the various conditions that cause mass movement
Volcanic Activity: Repeatded leads to huge mudflows when icy cover of a volcano melts and mixes with the soil to form mud as the magma in the volcano stirs
Mudslides: Develops when water rapidly accumulates in the ground, changing the Earth into a flowing river of mud and "slurry"
Earthquake Shocks: Cause sections of mountains and hills to break off and slide down
Human Modification: Of the land or weathering and erosion help loosen large chunks of Earth and start sliding downhill
Human Caused Vibrations: From machinery, traffic, weight loading for accumulation of snow e.t.c
Types of Mass Movement:
Erosion: Removal and transport of rocks or soil by the action of water, ice or wind
Landslide: Movement of bedrock, soil and rock down a slope of a cliff, hill or mountain
Creep: Slow movement of rock debris and soil down a weathered slope. (Causes poles to lean downhill)
Slump: Occurs as the bottom of the slope can not support the top of the slope which becomes unstable
Earthflow: Water saturated weathered material flows downhill. Very slow can take days or years
Mudflows: Fast movements of water containing much clay and silt. Can travel upp to 100 km/h.
What are moraines?
Deposit of till left behind when glacier retreats
What is a delta and how does it form?
A triangular-like shape deposited at the mouth of a river.
Forms when: velocity greatly slows down at the river's mouth and the sediments are deposited. Sediments build up and form the delta
What are the diff. between alluvial fans and deltas?
Alluvial fans have deposits form on land, delta has water
Alluvial fans have coarse sands and gravels instead of fine silt and clay
Alluvial fans have a sloping surface instead of flat
What are potholes and how do they form?
Produced from sand, pebbles and/or small boulders churning in the rocky riverbed from whirlpool action
What causes can increase water density in seawater?
Water density increases as salinity increases. Caused by evaporation of water and salt left behind