| Jul 2012| © 2012 UPES
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| Jul 2012| © 2012 UPES
© 2012 UPESJul 2012Jul 2012
© 2012 UPESJul 2012Jul 2012
Mineral
A Mineral is a natural occurring substance of definite chemical
composition with identifiable physical properties eg Aluminium
Or
Are naturally occurring ,inorganic ,crystalline solids having a
definite chemical composition and characteristics physical
and chemical properties.
Ore
An ore is a mineral or composition of minerals from which a
useful substance like metal can be extracted and then used to
manufacture useful products eg. Bauxite
© 2012 UPESJul 2012Jul 2012
Metallic mineral sources (def. discussed in lecture 1)
Like iron, aluminium, zinc, copper, cobalt, nickel are raw
material for industries
Non metallic mineral sources (def. discussed in lecture 1)
Like salt, clay silica, phosphorus, carbon
Stones like granite, marble, limestone is another category of
minerals
Gems like diamond, emeralds, ruby have ornamental and
aesthetic value
Minerals like oil, gas and coal form the fossil fuels .
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Is the process of extraction of useful products from minerals
and other ores
Minning involves four stages
Prospecting: searching for mineral
Exploration : assessing size, shape, location and economic
value of mienral deposit
Development: preparing for access to deposit for extraction of
mineral
Exploitation: extracting the minerals from the mines
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Mining is of two types
Surface mining
Extraction of minerals from shallow deposit is known as surface
mining.
Is done in open pit, open cast, strip mines
Sub surface mining
Is done to extract minerals ( or fossil fuels ) from deep deposit in
soil by using sub surface mining .
Is done in deep or shaft mines
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De-vegetation and defacing of landscape
Subsidence of land
Groundwater contamination
Surface water contamination
Air pollution
Occupational health hazards
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De-vegetation and defacing of landscape
Topsoil and vegetation is removed from mining area to get
assess of minerals
Large scale deforestation or Devegetation leads to ecological
loss
Landscape get badly affected
Huge quantities of debris and alongwith big scar and disruption
of spoil aesthetic value
Make more prone to soil erosion.
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Subsidence of land
Associated with underground mining
It results in –
Tilting of buildings
Cracks in houses
Buckling of roads
Bending of rail tracks
Leaking of gas from cracked gas pipelines
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Groundwater contamination
Mining pollutes groundwater
Affects hydrological cycle
Sulphur normally present as impurity in ore get converted
into sulphuric acid through microbial action
Some heavy metals leached into groundwater
contaminated it
Posing health hazards
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Surface water contamination
Acid mine drainage often contaminates the nearby
streams and lakes.
The acidic water detrimental to aquatic life
Radioactive material affects the aquatic life
Heavy metals contaminates the water body and affects
the aquatic life
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Air pollution
Smelting is done to purify the metals from other impurities
During smelting enormous quantites of air pollutant
released affects
Vegetation
Serious environmental impacts
Eg SPM, soot, lead ,cadmium shoot up in smelter
atmosphere causes health problems
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Occupational health hazards
Miners suffers from respiratory and skin problems due to
constant exposure to SPM and other toxic
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Hazards of mining are
Underground mining is more hazardous than surface mining
Rock falls, roof falls can kill miners
Inadequate ventilation and floods
Explosions have killed many miners
Fumes from incomplete dynamite explosions are extremely
poisonous
Methane gas is a health hazard
Mines dust causes lung fibrosis called black lung or
pneumoconiosis
Radiations cause cancer or life threatening diseases.
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Indispensable resource
70% of the earth’s surface is covered by water but only
3% of total water is fresh water ( 2% in polar ice caps and
1% is usable water in rivers, lakes, subsoil aquifers)
60-65% of animal and plant is made up of water
Water usage
Use At Global Level In India
Irrigation 70% 90%
Industry 25% 7%
Domestic 5% 3%
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© 2012 UPESJul 2012Jul 2012
Water which percolates down the soil and is not picked by the
roots, moves downward slowly until it reaches an impervious
layer of rocks.When the water get accumulated/trapped in the
porous strata of rocks it forms aquifers
Types
Confined aquifers
When water gets accumulated between two layers of rocks in both
layers are impervious
Unconfined aquifers
When water gets accumulated between two layers of rocks in
which lower layers is impervious and upper layer is pervious.
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Discussed earlier in lecture 1 of Unit 2
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A flood is an overflow of water that submerges land.
The European Union (EU) Floods Directive defines a flood
as a covering by water of land not normally covered by water
According to geosciences Australia
A general and temporary condition of partial or complete
inundation of normally dry land areas from overflow of
inland or tidal waters from the unusual and rapid
accumulation or runoff of surface waters from any source.
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Natural
Heavy rainfall
Snow melting
In coastal regions, high tides, storms, cyclones, hurricanes, or
tsunamis
Manmade
Global warming
Deforestation
Poor dams
Heavy rainfall
Mining
Overgrazing
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© 2012 UPESJul 2012Jul 2012
Primary effects
Physical damage – damage to structures, including bridges, buildings,
sewerage systems, roadways, and canals.
Secondary effects
Water supplies – Contamination of water. Clean drinking water will
become scarce.
Diseases – Unhygienic conditions. Spread of water-borne diseases.
Crops and food supplies – Shortage of food crops can be caused due to
loss of entire harvest.However, lowlands near rivers depend upon
river silt deposited by floods in order to add nutrients to the local soil.
Trees – Non-tolerant species can die from suffocation.
Transport – Transport links destroyed, so hard to get emergency aid to
those who need it.
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Tertiary and long-term effects
Economic – economic hardship due to temporary decline in tourism,
rebuilding costs, food shortage leading to price increase, etc.
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Restoration and development of a dense plant cover on hill
slopes and land surface in the catchment area of rivers.
Straightening the course of river channels to hasten the
discharge of the flood flow
Reduction in volume of flood flow by constructing huge
storage reservoirs
Diversion of flood water to other channels to reduce its
volume
Reduction in impact of floods
Awareness among masses, living in flood prone areas.
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Most arid and semi arid regions areas of the world are drought
prone due to unpredictable rain in certain years leading to
serious scarcity of water to drink, to use in agriculture or to
provide for urban and industrial use.
In these drought prone areas agriculturists have no steady
income.
For such areas, India has ‘Drought Prone Areas Development
Programmes’, under which people are given wages in drought
years to build roads, minor irrigation programs and plantation
program.
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It is a natural meteorological phenomena in the arid and the semi
arid regions of the world
Possible anthropogenic causes could be
Global warming
Climate changes
Deforestation
Industrialization
Overgrazing
Intensive cropping pattern, overexploitation of water resources
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It destroys top soil making it prone to wind erosion
It causes desertification
Acute shortage of food, fodder and water to living organisms
Causes ailments and death due to starvation of animal and
man
Decreases economic growth and causes unemployment
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Rain water harvesting
Canal irrigation
Improvement of agricultural practices like dryland farming to
conserve water in drought prone areas
Stopping paddy cultivation in areas of water scarcity and
growing drought resistant variety of crops
Promoting social forestry and waste land reclamation, growing
species according to the ecological requirement of the area
Supplying food, fodder and water to drought-hit people and
their rehabilitation with all essential requirements.
© 2012 UPESJul 2012Jul 2012
Cyclones are huge revolving storms caused by winds blowing around
a central area of low atmospheric pressure.
In the northern hemisphere, cyclones are called hurricanes or
typhoons and their winds blow in an anti-clockwise circle.
In the southern hemisphere, these tropical storms are known as
cyclones, whose winds blow in a clockwise circle.
It moves like spinning top at the speed of 10-20 km /hr.
For a cyclone to develop, the sea surface must have a temperature of
at least 26ºC.
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Tropical cyclones are called
hurricanes in the Atlantic, Caribbean and north eastern pacific .
Typhoons in western pacific
Cyclones in Indian Ocean.
Willy willies in the sea around Australia .
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Cyclones create several dangers for people living around tropical
areas.
The most destructive force of a cyclone comes from the fierce winds.
These winds are strong enough to easily topple fences, sheds, trees,
power poles and caravans, while hurling helpless people through the
air.
Many people are killed when the cyclone's winds cause buildings to
collapse and houses to completely blow away.
A cyclone typically churns up the sea, causing giant waves and
surges of water known as storm surges. The water of a storm surge
rushes inland with deadly power, flooding low-lying coastal areas. The
rains from cyclones are also heavy enough to cause serious flooding,
especially along river areas.
© 2012 UPESJul 2012Jul 2012
The rains from cyclones are also heavy enough to cause serious
flooding, especially along river areas.
Long after a cyclone has passed, road and rail transport can still be
blocked by floodwaters.
Safe lighting of homes and proper refrigeration of food may be
impossible because of failing power supplies.
Water often becomes contaminated from dead animals or rotting food,
and people are threatened with diseases like gastroenteritis.
© 2012 UPESJul 2012Jul 2012
Planting more trees on the coastal belt
Construction of dams, dykes, embankments, storm shelter, wind
breaks
Proper drainage
Wide roads for quick evacuation
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A tsunami is often misnamed a tidal wave, but in fact a
tsunami is not just one wave but usually a series of seven or
eight, that have nothing to do with the tide.
In the open ocean, tsunamis are only about one metre high,
but as they approach shallower waters and the shore, they
grow to heights as high as eighty-five meters.
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The most common causes of tsunamis are volcanoes,
earthquakes and earthslides - mostly undersea.
Volcanoes that have been erupting continuously for a long time
have empty magma chambers. The roof then collapses forming
a crater sometimes upto one kilometre in diameter. Water
gushes into this crater in a very short amount of time, causing a
tsunami.
Earthquake originated tsunamis occur when portions of the
Earth's crust on either side of a fault jolt past each other. For a
tsunami to occur however, there must be some kind of vertical
movement along the fault. This vertical movement must be
capable of displacing huge amounts of water, thus causing
waves.
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Tsunamis can also be caused by land sliding in to the sea with
such great force that it creates a wave. Similar to the effect of
throwing a pebble into a puddle of water.
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The effects of the tsunami on the country during this period
range from
destruction and damage,
death, injury,
millions of dollars in financial loss, and
long lasting psychological problems for the inhabitants
of the region.
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Erosion is the process by which soil and rock are removed
from the Earth's surface by natural processes such as wind or
water flow, and then transported and deposited in other
locations.
© 2012 UPESJul 2012Jul 2012
Physical Processes
Water erosion-
Rainfall-There are three primary types of erosion that occur as a direct
result of rainfall—sheet erosion, rill erosion, and gully erosion.
Rivers and streams-
Coastal erosion-Shoreline erosion, which occurs on both exposed and
sheltered coasts, primarily occurs through the action of currents and
waves but sea level (tidal) change can also play a role.
Glaciers- Glaciers erode predominantly by three different processes:
abrasion/scouring, plucking, and ice thrusting
Floods
Freezing and thawing
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Physical Processes
Wind erosion
Wind erosion is a major geomorphological force, especially in arid and
semi-arid regions. It is also a major source of land degradation,
evaporation, desertification, harmful airborne dust, and crop
damage—especially after being increased far above natural rates by
human activities such as deforestation, urbanization, and agriculture.
Gravitational erosion
Mass movement is the downward and outward movement of rock and
sediments on a sloped surface, mainly due to the force of gravity
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Factors affecting erosion rates
Precipitation and wind speed
Soil structure and composition
Topography
Vegetation cover
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Human activities that increase erosion rates
Agricultural practices
Unsustainable agricultural practices are the single greatest contributor
to the global increase in erosion rates
Deforestation
Roads and urbanization
Urbanization has major effects on erosion processes—first by denuding
the land of vegetative cover, altering drainage patterns, and
compacting the soil during construction; and next by covering the land
in an impermeable layer of asphalt or concrete that increases the
amount of surface runoff and increases surface wind speeds
Climate change
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Land degradation
Sedimentation of aquatic ecosystems
Airborne dust pollution
Tectonic effects
The removal by erosion of large amounts of rock from a particular
region, and its deposition elsewhere, can result in a lightening
of the load on the lower crust and mantle. This can cause
tectonic or isostatic uplift in the region
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The most effective known method for erosion prevention is to
increase vegetative cover on the land, which helps prevent both
wind and water erosion.
Terracing is an extremely effective means of erosion control,
which has been practiced for thousands of years by people all
over the world.
Windbreaks (also called shelterbelts) are rows of trees and
shrubs that are planted along the edges of agricultural fields, to
shield the fields against winds. In addition to significantly
reducing wind erosion, windbreaks provide many other benefits
such as improved microclimates for crops (which are sheltered
from the dehydrating and otherwise damaging effects of wind),
habitat for beneficial bird species, carbon sequestration,and
aesthetic improvements to the agricultural landscape.
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In addition to significantly reducing wind erosion, windbreaks
provide many other benefits such as improved microclimates
for crops (which are sheltered from the dehydrating and
otherwise damaging effects of wind), habitat for beneficial bird
species, carbon sequestration,and aesthetic improvements to
the agricultural landscape.
Traditional planting methods, such as mixed-cropping (instead
of monocropping) and crop rotation have also been shown to
significantly reduce erosion rates.
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Man was a just hunter or gatherer quiet like an animal.
10,000-12,000 years back he took agriculture by
cultivating plant of his own choice.
Traditional agriculture used
Simple tools
Small plot
Naturally available water
Organic fertilizer
Mix crop
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Impact of Traditional agriculture
Deforestation
Soil erosion
Depletion of nutrients
Modern agriculture uses
Hybrid seeds of selected and single crop varities.
High tech equipments
Lots of energy subsides in the form of fertilizers, pesticides,
and irrigation water
Output being increased food production is increased evidenced
by green revolution.
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Impact of high yielding varieties
Encourages monoculture
Incase attack by some pathogens, there is total devastation of crop
by diseases due to exactly uniform condition, which help in the
spread of the disease.
Fertilizer related diseases
Micronutrient imbalance : e.g. excessive use fertilizer lead to
deficiency of zinc in the soil of Punjab and Haryana which is affecting
the productivity of soil.
Nitrate pollution : nitrogenous fertilizers applied in the field often
leaches to the and ultimately contaminate the groundwater. When the
concentration exceeds beyond 25mg/l they become serious health
hazard called blue baby syndrome.
More prevalent in England, Demark ,Netherland, Germany and in
some parts of India .
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Eutrophication
Pesticides related problems
Creating super pest
Death of non target organisms
Biological magnification.
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Benefits
Provide employment
Raising the standard and quality of life
Check in flood
Generates electricity
Reduce water shortage problem
Provide irrigation water to low lying areas
Promote navigation and fisheries
Provide drinking water to lower areas.
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Upstream
Downstream
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Displacement of tribal people
Loss of flora, fauna and forest.
Changes in fisheries and spawning ground
Siltation and sedimentation of reservior
Loss of non forest land
Stagnation and water logging near reservoir
Breeding of vector borne diseases
Reservoir induced seismicity causing earthquakes.
Growth of aquatic weeds
Microclimate changes.
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Water logging and Salinity due to over irrigation.
Microclimate change
Reduced water and silt deposition .
Flash floods
Salt water intrusion at river mouth.
Loss of land fertility along the river since sediments carrying
nutrients get deposited in the reservoir.
Outbreak of vector borne diseases like malaria.
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