Erosion.ppt

8/14/2019 Erosion.ppt

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Erosion

1. Erosion is the process by which

material is removed from a region of

the Earth surface. It can occur by

weatheringand transport of solids in

the natural environment, and leads

to the deposition of these materials

elsewhere.

2. It usually occurs due to transportby

wind, water, or ice; by down-slopecreep of soil and other material

under the force of gravity; or by living

organisms, such as burrowing

animals, in the case of bioerosion.
http://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Sediment_transporthttp://en.wikipedia.org/wiki/Downhill_creephttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Bioerosionhttp://localhost/var/www/apps/conversion/tmp/scratch_9//upload.wikimedia.org/wikipedia/commons/c/ca/Bluff_erosion_in_Pacifica_2.jpghttp://en.wikipedia.org/wiki/Bioerosionhttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Downhill_creephttp://en.wikipedia.org/wiki/Sediment_transporthttp://en.wikipedia.org/wiki/Weathering


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Although erosion is a natural process but human land usepolicies also have an effect

on erosion, especially industrial agriculture, deforestation, and urban sprawl.

Land that is used for industrial agriculture generally experiences a significantly greater

rate of erosion than that of land under natural vegetation, or land used for sustainable

agriculturalpractices.
http://en.wikipedia.org/wiki/Land_usehttp://en.wikipedia.org/wiki/Industrial_agriculturehttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Urban_sprawlhttp://en.wikipedia.org/wiki/Sustainable_agriculturehttp://en.wikipedia.org/wiki/Sustainable_agriculturehttp://en.wikipedia.org/wiki/Sustainable_agriculturehttp://en.wikipedia.org/wiki/Sustainable_agriculturehttp://en.wikipedia.org/wiki/Sustainable_agriculturehttp://en.wikipedia.org/wiki/Urban_sprawlhttp://en.wikipedia.org/wiki/Urban_sprawlhttp://en.wikipedia.org/wiki/Urban_sprawlhttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Industrial_agriculturehttp://en.wikipedia.org/wiki/Industrial_agriculturehttp://en.wikipedia.org/wiki/Industrial_agriculturehttp://en.wikipedia.org/wiki/Land_usehttp://en.wikipedia.org/wiki/Land_usehttp://en.wikipedia.org/wiki/Land_use


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Erosion Processes

Gravity

1. Mass wasting or Mass movement is the down-slope movement of rock and

sediments, mainly due to the force of gravity.

2. Mass movement is an important part of the erosional process, as it moves material

from higher elevations to lower elevations where other eroding agents such as

streams and glaciers can then pick up the material and move it to even lower

elevations.

3. Mass-movement processes are always occurring continuously on all slopes; some

mass-movement processes act very slowly; others occur very suddenly, often with

disastrous results. Any perceptible down-slope movement of rock or sediment is

often referred to in general terms as a landslide.
http://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Glacierhttp://en.wikipedia.org/wiki/Landslidehttp://en.wikipedia.org/wiki/Landslidehttp://en.wikipedia.org/wiki/Glacierhttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Mass_wastinghttp://upload.wikimedia.org/wikipedia/commons/a/a5/Mass_Waste_Palo_Duro_2002.jpg


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Example of mass wasting at Palo Duro Canyon
http://en.wikipedia.org/wiki/Palo_Duro_Canyonhttp://en.wikipedia.org/wiki/Palo_Duro_Canyonhttp://upload.wikimedia.org/wikipedia/commons/a/a5/Mass_Waste_Palo_Duro_2002.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_9//upload.wikimedia.org/wikipedia/commons/d/d5/TalusConesIsfjorden.jpg


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Talus conesproduced by mass wasting, north shore of Isfjord, Svalbard, Norway
http://en.wikipedia.org/wiki/Screehttp://en.wikipedia.org/wiki/Isfjord_(Svalbard)http://en.wikipedia.org/wiki/Svalbardhttp://en.wikipedia.org/wiki/Norwayhttp://localhost/var/www/apps/conversion/tmp/scratch_9//upload.wikimedia.org/wikipedia/commons/d/d5/TalusConesIsfjorden.jpghttp://en.wikipedia.org/wiki/Norwayhttp://en.wikipedia.org/wiki/Svalbardhttp://en.wikipedia.org/wiki/Isfjord_(Svalbard)http://en.wikipedia.org/wiki/Scree


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Water

Splash erosionis the detachment and airborne movement of small soil particles caused

by the impact of raindrops on soil. In rain splash soil particles are knocked into the air by

raindrop impact.

Sheet erosionis the detachment of soil particles by raindrop impact and their removal

down slope by water flowing overland as a sheet instead of in definite channels or rills.

the loose particles are moved down slope by broad sheets of rapidly flowing water filled

with sediment known as sheet floods. This stage of sheet erosion is generally last only

for a short time.


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Splash erosion

Sheet erosion

Splash erosion gauge


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Rill Erosion

Rill erosion refers to the development of small, ephemeral concentrated flow paths,

which function as both sediment source and sedimentdelivery systems for erosion on

hill slopes.
http://en.wikipedia.org/wiki/Rillhttp://en.wikipedia.org/wiki/Ephemeralhttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Ephemeralhttp://en.wikipedia.org/wiki/Rill


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Bank Erosion

Bank erosion is the wearing away of the

banks of a streamor river.

Erosion and changes in the form of river

banks may be measured by inserting metal

rods into the bank and marking the position

of the bank surface along the rods at different

times.
http://en.wikipedia.org/wiki/Streamhttp://en.wikipedia.org/wiki/Riverhttp://en.wikipedia.org/wiki/Riverhttp://en.wikipedia.org/wiki/Stream


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Shoreline Erosion or Coastal Erosion

Shoreline erosion or Coastal erosion primarily occurs through the action of currents and

waves but sea level (tidal) change can also play a role.


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ICE

Ice erosion can take one of two forms. It can be caused by the movement of ice,

typically as glaciers, in a process called glacial erosion.

It can also be due to freeze-thaw processes in which water inside pores and fractures in

rock may expand causing further cracking.


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Wind

1. In arid climates, the main source of erosion is wind. The general wind circulation

moves small particulates such as dust across wide oceans thousands of kilometres

downwind of their point of origin, which is known as deflation.

2. There are two main effects in wind erosion. First, wind causes small particles to be

lifted and therefore moved to another region. This is called deflation. Second, these

suspended particles may impact on solid objects causing erosion by abrasion

(ecological succession).

3. Wind erosion generally occurs in areas with little or no vegetation, often in areas

where there is insufficient rainfall to support vegetation. An example is the formation

of sand dunes, on a beach or in a desert.
http://en.wikipedia.org/wiki/Duneshttp://en.wikipedia.org/wiki/Dunes


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Erosion Measurement

Erosion is measured using tools such as the micro-erosion meter (MEM) and the

traversing micro-erosion meter(TMEM).

The MEM has proved helpful in measuring bedrock erosion in various ecosystems

around the world. It can measure both terrestrial and oceanic erosion.

On the other hand, the TMEM can be used to track the expanding and contracting of

volatile rock formations and can give a reading of how quickly a rock formation is

deteriorating.
http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Traversing_micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Micro-erosion_meter&action=edit&redlink=1

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Erosion.ppt