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Mass Movement, Wind, Glaciers. Mass Movement. A down slope movement of loose sediment and weathered rocks resulting from the force of gravity.  Erosion following weathering climatic conditions determine which materials and how much  All mass movements occur on slopes

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Mass movement
Mass Movement

  • A down slope movement of loose sediment and weathered rocks resulting from the force of gravity.

  •  Erosion following weathering climatic conditions determine which materials and how much

  •  All mass movements occur on slopes

  •  Several variables influence mass movement

  • 1) Material weight result from gravity

  • 2) Materials resistance to sliding or flowing

  • 3) Trigger ie. Earthquake

  • 4) Water

  •  Movement occurs when a force works and pulls materials is the stronger than its resistance

  •  Erosion and undermining soil increases the materials pull down of the slope


Mass movement1
MaSSmOVEMENT

  • Too little H2O does not stop material’s potential mass movement.

  • Increase H2O, weight of material increases and acts like a lubricant. With the force of gravity , mudslides.

  • H2O moves with material. It is not a transport agent.


Types of movements
Types of Movements

  • 1. Creeps

  • 2. Flows

  • 3. Slides

  • 4. Slumps

  • 5. Avalanches

  • 6. Rockfalls


Creep
Creep

  • Creep - slow/steady flow of loose weathered material.

  • Noticed over a long period of time. Indication - tilt of structures.

  • The slow, downhill movement of loose, water-logged materials that occurs in regions of permafrost is called solifluction.



Flows
Flows

  • Flows - materials flow as thick liquids. Speed - few cm’s per year to 100’s km per hour.

  • Swift mixtures of mud and H2O. Trigger - earthquakes, volcanic eruptions heat the earth.

  • Common in sloped, semi arid regions - short rain storms - ex. LA Basin



Slides
Slides

  • Slides - Rapid downward movements of earth materials that

  • occur - landslides - speed 200 km per hour. Stop at the bottom of slope as debris piles. Common - steep slopes.

  • Rockslides - type that occur when a sheet of mud moves down hill on a sliding surface. Trigger - Earthquakes.



Slumps
Slumps

  • A slump is a mass of material in a landslide that rotates along a curved surface.

  • Locations of slumps are in areas of thick soil on moderate to steep slopes and highways.

  • Common after rain, reduces friction, forces between the center of the soil.

  • Slumps leave crescent shaped scars on the slope.



Avalanches
Avalanches

  • Avalanches - Landslides that occur in mountainous areas with thick accumulation of snow. - slopes 35°.

  • 10,000 avalanches occur in U.S. Sun melts the snow.

  • It reflects/ more snow added weight causing breakoff.


Alvalanche swisszerland
Alvalanche - Swisszerland


Rock falls
Rock Falls

  • Rockfalls - Occur at high elevations in step road cuts and on rocky shores.

  • Physical weathering process - breakdown - rock - rock falls straight down.

  • Human Factor - affect mass movement construction - heavy building - roads- weight helps makes slopes unstable. Leakage/septic tank seaps around.




Mass movement wind glaciers


Trenches along roads
Trenches along Roads than 25° with annual rainfall of over 90 cm.


Protective netting
Protective Netting than 25° with annual rainfall of over 90 cm.


Heavy gauged fences
Heavy Gauged Fences than 25° with annual rainfall of over 90 cm.


Retaining wall
Retaining Wall than 25° with annual rainfall of over 90 cm.


Mass movement wind glaciers
Wind than 25° with annual rainfall of over 90 cm.

  • Wind transports material up hill and down erosional agents that are modified, ie. wind changes the landscapes in arid and coastal

    regions.

  • Ability to move material as less than H2O and ice.

  • Wind transports materials causing them to move different ways.


Methods of transportation
Methods of Transportation than 25° with annual rainfall of over 90 cm.

Strong winds - carry long distance (suspension)

Saltation - Bounding motion of particles, ie. sand wind transport occurs in areas with little vegetation, ie., desserts, some arid areas, seashores and lakeshores


Mechanics of saltation
Mechanics of Saltation than 25° with annual rainfall of over 90 cm.


Dry moving sand light color is visible by streamers
Dry moving sand (light color) is visible by streamers than 25° with annual rainfall of over 90 cm.


Mass movement wind glaciers

  • Wind than 25° with annual rainfall of over 90 cm. transports material up hill and down erosional agents that are modified, ie. wind changes the landscapes in arid and coastal

  • regions.

  • Ability to move material as less than H2O and ice.

  • Wind transports materials causing them to move different ways.


Deflation
Deflation than 25° with annual rainfall of over 90 cm.

Deflation - lowering of the land’s as surface result of movement. Problem - agriculture regions: 1930’s Dust Bowl - Sever dust storms - clouds of dust blown by the wind create deflation

blowouts - shallow depressions


Deflation1
Deflation than 25° with annual rainfall of over 90 cm.


Abrasions
Abrasions than 25° with annual rainfall of over 90 cm.

  • Abrasions - when particles such as sand rub against the surface of rocks and other materials. Rocks shaped by wind blown sediments are called ventifacts.


Ventifact
Ventifact than 25° with annual rainfall of over 90 cm.


Wind deposition
Wind Deposition than 25° with annual rainfall of over 90 cm.

Occurs in arid regions of change in wind

velocity. Particles drop out of the air to the ground


Dunes
Dunes than 25° with annual rainfall of over 90 cm.

Formation of Dunes - sand accumulates from the dropping of wind. A dune is a pile of wind blown sand. Conditions necessary for

formation of dunes:

1) Availability

2) Wind velocity

3) Wind direction

4) Amount of vegetation


Types of dunes
Types of Dunes than 25° with annual rainfall of over 90 cm.


Mass movement wind glaciers

  • Desert Pavement - when finer sediments are blown away by wind and the heavier larger particles and pebbles are left behind.

  • Tallest dunes - Sands in Arabia - more than 100m in height

  • QuartzsSand - most common

  • Gypsum Dune - white sand - National Monument in New Mexico

  • Calcite Dune - Bermuda and areas of the Caribbean Sea


Desert pavement near blyth ca
Desert Pavement near Blyth CA wind and the heavier larger particles and pebbles are left behind.


Mass movement wind glaciers

  • Loess wind and the heavier larger particles and pebbles are left behind. - wind carries fine, lightweight particles, ie. Clay and silt

  • Loess deposits - Illinois, Iowa, Missouri, South Dakota, Nebraska


Mass movement wind glaciers

Glaciers wind and the heavier larger particles and pebbles are left behind.They shape the landscape by: a) eroding b) transporting c) depositing huge volumes of rock and sedimentsToday, scientists measure movements and size changes of glaciers to track climate change.


Moving masses of ice
MOVING Masses of Ice wind and the heavier larger particles and pebbles are left behind.

  • Glacier – a large moving mass of ice.

  • Formed near the earth’s poles and at high elevations in the mountains.

  • They cover only 10% of the earth.


Glacier classification
Glacier Classification wind and the heavier larger particles and pebbles are left behind.

  • Classified in two ways:

  • 1) Valley Glaciers - form in valleys in high mountainous areas, occurs when growing ice mass becomes too heavy to maintain its rigid shape and begins to flow.

  • Flow begins when the accumulation of snow and ice exceeds 20 meters in thickness.


Valley glaciers
Valley Glaciers wind and the heavier larger particles and pebbles are left behind.


Continential glaciers
Continential wind and the heavier larger particles and pebbles are left behind. Glaciers

  • 2) Continental Glaciers - cover broad, continent sized Areas.

  • They form under the same climatic conditions as valley glaciers, but move in a different way.

  • The weigh of this glacier forces it to flatten is all directions.

  • These glaciers are also called ice sheets.


Continential glacier
Continential wind and the heavier larger particles and pebbles are left behind. Glacier


Glacier erosion
Glacier Erosion wind and the heavier larger particles and pebbles are left behind.

  • Of all erosional agents, glaciers are the most powerful because of their great size, weight, and density when a valley glacier moves, it breaks off pieces of rock through a process called plucking.

  • When glaciers with embedded rocks move over bedrock valley walls, they grind out parallel scratches into the bedrock.

  • Small Scratches are called striations, larger ones are called grooves.


Glacier history
Glacier History wind and the heavier larger particles and pebbles are left behind.

  • Scratches and grooves provide evidence of a glacier’s history and establish its direction of movements.

  • Glacier features include:

  • 1) cirques - deep depressions

  • 2) arete - where two cirques on opposite sides of a valley forming a sharp, steep ridge.

  • 3) horn - glaciers on three or more sides of a mountain top, a steep, pyramid shaped peak forms. Ex. Switzerland’s Matterhorn

  • 4) hanging valley - tributary valley that enters a U-shaped valley from high up a mountain side

  • 5) waterfalls

  • 6) U-shaped valleys


Cirques
cirques wind and the heavier larger particles and pebbles are left behind.


Arete
ARETE wind and the heavier larger particles and pebbles are left behind.


Horn mt kimmel glacier national park
HORN – Mt. Kimmel Glacier National Park wind and the heavier larger particles and pebbles are left behind.


Hanging valley
HANGING VALLEY wind and the heavier larger particles and pebbles are left behind.


Waterfalls yellowstone
WATERFALLS - Yellowstone wind and the heavier larger particles and pebbles are left behind.


U shaped valleys
U SHAPED VALLEYS wind and the heavier larger particles and pebbles are left behind.


Glacier deposition
Glacier DEPOSITION wind and the heavier larger particles and pebbles are left behind.

  • Glacial till is the mixed debris that glaciers carry.

  • Moraines are ridges consisting of till deposited by glaciers.


Moraines glacier forming a cirque
Moraines glacier forming a Cirque wind and the heavier larger particles and pebbles are left behind.


Outwash
Outwash wind and the heavier larger particles and pebbles are left behind.

  • It is melt water contains gravel, sand, and fine silt formed by the grinding action of the glaciers of the glacier.

  • When this sediment is deposited by melt water, it is called out-wash.

  • The area at the leading edge of the glacier, where the melt water streams flow and deposit outwash, is called an outwash plain.


Outwash plain
Outwash Plain wind and the heavier larger particles and pebbles are left behind.


Drumlins and eskers
Drumlins and Eskers wind and the heavier larger particles and pebbles are left behind.

  • Glaciers that move over older moraines and forms the materials into elongated land forms called drumlins.


Glacier lakes
Glacier wind and the heavier larger particles and pebbles are left behind.LAKES

  • Glacial Lakes - Sometimes a large block of ice breaks off a glacier and is later covered by sediment.

  • When the ice block melts, it leaves behind a depression called a kettle hole. After the ice blocks melts, the kettle hole fills with water from rain and runoff.


Glacier lake
Glacier Lake wind and the heavier larger particles and pebbles are left behind.


Kettle lake
Kettle Lake wind and the heavier larger particles and pebbles are left behind.