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GEOLOGICAL AGENTS & THEIR
ACTION
Kaustubh J. Sane
HJD Institute of Technical
Education and Research, Kera
Geological agents
GEOLOGICAL
AGENTS
WIND
RIVER SEA
GROUNDWATER GLACIERS
WORK OF WIND
• The wind acts in three different ways viz.
Erosion, Transportation, Deposition.
• Erosive work of wind:
– T...
Deflation
• The removal of sand particles and dust by strong wind
is called deflation.
• This is observed mainly in desert...
Wind Abrasion
• Wind when consist of sand and dust particles
it becomes powerful agent.
• These type of erosion evolves ru...
• Yardangs:
• These are elongated, low- lying ridges forming
overhangs above depression.
• These are formed in areas where...
• Ventifacts:
• These are small size rock fragments having
one, two three or more polished surfaces.
• The polishing of su...
Transportation
Most Effective in Moving Loose Material
• Suspension (Silt)
– Light silt grade particles are lifted up in t...
Depositional features
• Dunes:
– It is a broadly conical heap of sand characterized
with two slope either side of a medial...
Verhar (Pakistan)
Loess
• Term is used for wind blown deposits of silt
and clay.
• Loess is an aeolian sediment formed by the
accumulation o...
Engineering consideration
• Dunes and loess offer complicated problem in construction.
• As dunes & loess are migrating th...
Weathering agents
Weathering agents
Weathering agents
Weathering agents
Weathering agents
Weathering agents
Weathering agents
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Weathering agents

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Transcript of "Weathering agents"

  1. 1. GEOLOGICAL AGENTS & THEIR ACTION Kaustubh J. Sane HJD Institute of Technical Education and Research, Kera
  2. 2. Geological agents GEOLOGICAL AGENTS WIND RIVER SEA GROUNDWATER GLACIERS
  3. 3. WORK OF WIND • The wind acts in three different ways viz. Erosion, Transportation, Deposition. • Erosive work of wind: – Three types • Deflation • Abrasion • Attrition
  4. 4. Deflation • The removal of sand particles and dust by strong wind is called deflation. • This is observed mainly in desert regions. • In some deserts deflation may remove the sand from a particular location and create a depressions. • These depressions some times reaches the ground water table. These deeper water filled depressions are called as OASES. • Wind deflation also produces another feature like HAMMADA. It is bare rock surface which is called as desert pavement.
  5. 5. Wind Abrasion • Wind when consist of sand and dust particles it becomes powerful agent. • These type of erosion evolves rubbing, grinding, polishing and abrading of rock surface by wind is called wind abrasion. • These type of process itself is responsible for formation of various landforms viz. Yardangs, pedestal rocks, ventifacts.
  6. 6. • Yardangs: • These are elongated, low- lying ridges forming overhangs above depression. • These are formed in areas where rocks of alternate hard and soft characters are lying above one another with gentle slope. • Pedestal rocks: • These are also called as mashroom rocks. • These are flat topped rock masses with narrow bottom.
  7. 7. • Ventifacts: • These are small size rock fragments having one, two three or more polished surfaces. • The polishing of surface is carried out by prolonged action of wind. • As soon as polishing of one surface is achieved the rock is overturned by strong wind and again second face gets under action of wind. • These wind polished and facetted fragments are called ventifacts.
  8. 8. Transportation Most Effective in Moving Loose Material • Suspension (Silt) – Light silt grade particles are lifted up in to upper layer and moves along with it. • Saltation (Sand) • Rolling
  9. 9. Depositional features • Dunes: – It is a broadly conical heap of sand characterized with two slope either side of a medial ridge or crest.
  10. 10. Verhar (Pakistan)
  11. 11. Loess • Term is used for wind blown deposits of silt and clay. • Loess is an aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20–50 micro-metre size range. • It is usually homogeneous and highly porous and is traversed by vertical capillaries.
  12. 12. Engineering consideration • Dunes and loess offer complicated problem in construction. • As dunes & loess are migrating they are moving structures. • Methods applied in such conditions are; – Establishing frontal belts of vegetation that can resist the advancing of sand dunes. – Construction of wind breakers around the area. These walls check the velocities of approaching wind. – Treating the sands locally with crude oil. – In loess soil engineering problems is to deal with hydro consolidation characteristics of soil. – As loess soil gets settle down quickly in moisture, which is dangerous foundation soil.
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