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THE EARTH AND THE UNIVERSE
- EXPLORING THE UNIVERSE
- Stars occur in clusters known as galaxies or nebulas
- Light takes 6 seconds to reach earth from moon and 8min 2 sec from sun and nearest star 4 years
- The solar system
- All planets revolve in elliptical orbit
- Surface temp of sun is 6000*C and 20 million*C in the interior
- Sun is 3 lakh times as big as earth
- Mercury is smallest planet and takes 88 day to revolve the sun
- Venus is the Earth's twin because of size, mass and density
- Mars next planet after earth to have life
- Jupiter is the largest planet
- 12 satellite
- Dark and light circular bands
- Saturn
- 3 rings and 9 satellites
- 2nd largest
- Uranus
- 50 times larger and 15 times heavier than earth
- Only clockwise orbiting planet
- Neptune
- The shape of Earth
- Geoid or earth-shaped
- Evidence of the Earth's Sphericity
- Circum-navigation of the earth
- The circular horizon
- Ship's visibility - Increasing altitude widens circular horizon and mast before ship
- Sunrise and sunset
- The lunar eclipse
- Planetary bodies are spherical
- Driving poles on level ground on a curved earth - 8 inches/mile
- Ariel photographs
- Earth's Movement
- Rotates on own axis in west to east - 24 hr
- Revolves at 18.5 miles per second 365.25 days
- Varying lengths of day and night
- 66 1/2* inclination
- In summer artic circle - Land of midnight sun - 24 hrs sunlight
- 6 months continuous daylight in poles

- The altitude of the Midday sun
- Vertically overhead at the equator called equinoxes meaning equal nights
- 21 March - spring equinox
- 21 September - autumn equinox
- Vertically overhead at the equator called equinoxes meaning equal nights
- Seasonal changes and their effects on temperature
- Summer - sun higher in the sky and days are longer so net gain
- Winter - oblique rays and net loss
- Dawn and Twilight
- Due to diffused and diffracted light
- In equator it is short because sun is sets and rise in vertical path
- In poles and temperate sun is oblique so dawn and twilight is long
- Mathematical location of places on the globe
- Intersection of latitude and longitude is the co-ordinates
- Latitude - angular distance of an point on the earth's surface, measured in degrees from the centre of the earth and is parallel to equator
- 1* , 60', 60''
- Distance between two latitude is 111Km or 60 miles
- Tropics
- Cancer - 23 1/2°N
- Capricorn - 23 1/2°S
- Antarctic circle - 66 1/2°S
- Arctic circle - 66 1/2°N
- Longitude - angular distance measure along the equator east or west of Prime meridian
- Royal astronomical observatory at Greenwich near London is Prime meridian
- 15° - 1 hour
- 1° - 4 minutes
- Indian Standard time 5 hr 30 min - 82.5°
- International date time
- East to west - gain a day
- West to east - lose a day
THE EARTH'S CRUST
- The structure of the earth
- Lithosphere
- Upper
- Granitic rocks
- Forms continental crust
- SIAL
- Density - 2.7
- Lower
- Basaltic
- Oceanic crust
- SIMA
- Density - 3
- SIAL floats on SIMA
- Upper
- Moho discontinuity
- Asthenosphere
- Mantle
- a.k.a Mesosphere
- Dense rocks rich in OLIVINE
- 2850 Km
- Gutenburg Discontinuity
- Core - 3470 Km
- Outer Core - Liquid
- 2200 Km
- Inner Core - Solid
- 1270 km
- a.k.a Barysphere
- NIFE
- Outer Core - Liquid
- Hydrosphere
- Part of crust filled with water
- Atmosphere
- Lithosphere
- The Classification of Rocks
- Igneous
- Fossil is not found
- Cooling and solidification of molten rock magma
- Crystalline structure
- Sub division based on mineral composition
- High Silica - acidic/lighter/less dense/granite
- Oxides of fe, al, mg - basic/dense/darker/
- Sub division based on origin
- Plutonic rocks
- Slowly solidified beneath so large crystal - granite, diorite, gabbro
- Volcanic
- Solidified rapidly outside so small crystal - hard and resistant/ basaltic
- Eg.antrim of northern Ireland, deccan plateau in India, Columbia-snake plateau
- Plutonic rocks
- Sedimentary
- Layer and stratified rocks
- Fossil is found
- Division based on origin
- Mechanically formed sedimentary rocks
- Sandstones by sand grains and quartz fragments
- Conglomerate - rounded pebbles
- Breccia - angular pebbles
- Shale or mudstone - clay
- Organically formed
- Remains of living organism like corals or shellfish
- Calcareous like chalk and limestone
- Carbonaceous like peat, lignite or coal
- Chemically formed
- Rock salt
- Gypsum or calcium sulphate or potash or nitrates
- Mechanically formed sedimentary rocks
- Metamorphic
- Due to heat and pressure caused by intense earth movement
- Clay into slate
- limestone into marble
- Sandstone into quartzite
- Granite into gneiss
- Shale into schist
- Coat into graphite
- Earth movements and major landforms
- Caldonian folds - oldest - scandinavia, scotland
- Hercynian folds - urals, welsh, harz, appalachians
- Young alpine - alps, himalayas, andes and rockies
- Types of mountains
- Fold mountains
- Himalayas, Rockies, Andes and Alps
- Anticline(up) & syncline(down)<overfold<recumbent fold<nappe over thrust plane or fault line
- A.k.a mountains of elevation
- Volcanic activity
- Rich minerals like tin, copper, gold and petroleum
- Block mountains
- horsts or block mountain
- Graben or rift valley
- Hunsruck mountains, vosges and black forest of rhineland, east african rift valley
- Volcanic mountains
- A.k.a mountains of accumulation
- Mt.Fuji of japan, Mt.Mayon of Phhilippines, Mt.Merapi of sumatra, Mt.Agung of Bali and Mt.catopaxi of Ecuador
- Residual mountain
- Mt.Mandnock in USA, Highlands of scotland, scandinavia and deccan plateau
- A.k.a mountain of denudation
- Fold mountains
- Types of Plateaux
- elevated uplands with extensive level surface and usually descend steeply to the surrounding lowland
- A.k.a tablelands
- Tectonic plateaux
- caused by earth movements
- Continental blocks like deccan plateau
- Tilted plateau - meseta if central Iberia
- Faulted like Harz of Germany
- Enclosed by fold mountains - intermont plateaux like Tibetan plateau between Himalayan and kunlun / Bolivian plateau between andes range - Highest and extensive
- Volcanic plateaux
- Antrim plateau of Northern Ireland and north western deccan plateau
- Columbia snake plateau
- Dissected plateaux
- Scottish highlands
- Humid highlands, glaciation, drier areas
- Mesas and buttes
- Types of plains
- Area of lowland that is either level or undulating
- Most fertile and occupied
- Indo-Gangetic plain, Mississippi plain, Yang-tze plain
- Grasslands of Russian steppers, the north american praries and argentinian pampas
- Structural Plain
- Structurally depressed
- Russian platform, great plains of USA, central lowlands of Australia
- Depositional Plain
- alluvial, flood, delta plain
- Nile delta, ganges, Hang Ho
- Outwash plain
- Not fertile
- Unsorted fluvio-glacial sands and gravels
- Till plain or drift plain
- Fertile
- Boulder clay
- Coastal plain
- Loess plain
- Aeolian deposits or very fine dust
- alluvial, flood, delta plain
- Erosional plain
- Plains of denudation
- Peneplains or almost plains
- Ice-scored plains
- Pediments or Pediplains and inselberg
- Igneous
VOLCANISM AND EARTHQUAKES
- Landforms of Igneous rocks
- Sill and Dykes
- Commonest
- Sill - horizontal - e.g Great Whin Sill
- Dykes - vertical - e.g cleveland dyke and kaula lampur
- Liths
- Larger size
- Loccolith
- Large blister or dome shaped
- Level base with pipe like conduit from below
- Henry mountain in USA
- Lopolith
- Saucer shape
- Bushveld lopolith in Transvaal
- Phacolith
- Lens shaped
- Anticline or syncline
- Fed by conduit from below
- Condon Hill in Shropshire, England
- Batholith
- Granite
- Huge
- Wicklow Mountains of Ireland, Uplands of Britanny,France and Main range of Malaysia
- Sill and Dykes
- Origin of volcanoes
- Crustal disturbances
- Basic lavas
- Hottest
- Highly fluid
- Dark coloured like Basalt
- Rich in iron and Magnesium
- Not very explosive and flows quietly
- Shield or dome volcanoes
- Acid Lava
- Highly vicious
- Light coloured
- Silica rich
- Loud explosion as rapid congealing in vents
- Forms spine or plug - Mt.Pelee in Martinique and Puy de dome of france
- Basic lavas
- Crustal disturbances
- Types of volcanoes
- Active, dormant and extinct - Mt.Vsusvius and Mt.Krakatau once thought extinct
- Extrusive landforms
- Lava plains and basalt plateaux - snake Basin, USA
- Lava domes and shield volcanoes - Hawaii Mauna Loa and Kilauea
- Caldera - eruptions weakens structure and blows of top and forms a depression
- Crater - smaller caldera
- Ash and cinder cones
- Composite cones or strato volcanoes
- Highest and most common
- Parasitic cones and subsidiary crater
- Geysers and Hot springs
- Geysers
- Volcanic region
- Upto 150 feet
- Explosive
- 3 major areas - Iceland, the rotorua district of north island and yellow stone national park
- Old faithful erupts every 63 minutes in yellow stone national park
- Hot springs
- Common
- Not explosive
- Contains minerals
- Heated by interior forces
- Iceland, hawaii, japan
- Geysers
- The distribution of earthquake
- Circum pacific areas with epicentres - 70%
- Mediterranean-Himalayan belt -20%
WEATHERING, MASS MOVEMENT AND GROUNDWATER
- Internal forces - Constructive (orogenesis)
- External forces destructive (denudation) - 4 phases
- Weathering
- Chemical - felspar(easily weathered), quartz and mica of granite
- Regolith - mineral remains of decomposed rocks
- enhanced in underlying rocks
- 3 process
- Solution - most potent
- Oxidation - iron content
- Decomposition of organic acids - acids
- Mechanical or physical
- Repeated temp changes
- Onion peeling or exfoliation of rounded boulders
- Repeated wetting and drying
- Frost action
- Frost shattered peaks
- Biotic factor
- Roots
- Chemical - felspar(easily weathered), quartz and mica of granite
- Weathering
- Mass Movement
- Weathered material due to gravity
- Soil creep
- Gradual
- Common in damp - water lubricates soil particles
- Soil flow or solifluction
- Arid region during rain
- Frozen under ground during spring
- Big-bursts in Ireland
- Landslide
- Rapid
- Steel slopes
- Earthquakes or volcanic disturbances
- Lubricating action of rain
- Slumping - permeable layer over non-permeable layer like clay
- Ground water
- Porous rocks - sand stone
- Permeable and porous - sand stone
- Non permeable but porous - clay
- Permeable and non-porous -granite
- Water table
- Permeable rock that stores water is aquifer
- Karst region - limestone - vauclusian spring
- Erosion
- Transportation
- Deposition
LANDFORMS MADE BY RUNNING WATER
- The development of a river system
- Rain fall
- Evaporated
- Seepage
- Runoff - causes denundation or general lowering of the earth's surface
- Rivulets
- Brooks
- Streams
- Tributaries
- Sources of river
- Lake
- Marsh
- Upland and catchment areas
- Crest of mountains - divide or watershed
- Initial stream consequence of slope is consequent stream
- Consequent streams are joined by tributaries either obliquely or right angles
- Homogenous beds of uniform resistance - tributaries obliquely as insequent stream
- Consequent stream + insequent stream = dendritic drainage pattern or tree-like
- Rocks with alternate hard and soft rocks - tributaries join as subsequent stream at right angle
- Consequent stream + subsequent stream = trellised or rectangular drainage
- Rain fall
- The mechanism of Humid Erosion
- Mass movement due to lubricating action and gravity
- Not Steep = slow + soil creep
- Steep = sudden + landslide
- The process of river action
- River load
- Material in solution - dissolved solution
- Material in suspension - sand, silt and mud
- The traction load - pebbles, rocks and boulders
- River load
- River erosion and Transportation
- Corrasion or abrasion - mechanical grinding of traction load on banks and beds
- Lateral corrasion - widens V-Valley
- Vertical Corrasion - deepens
- Corrosion or solution - chemical or solvent
- Calcium carbonate in limestones
- Hydraulic action - Mechanical loosening and sweeping by water itself
- Attrition - wear and tear of transported material themselves
- Corrasion or abrasion - mechanical grinding of traction load on banks and beds
- The course of a River
- The upper or mountain course or youth stage
- Predominantly erosion
- Source of river
- Swift
- Vertical corrasion
- Deep, narrow and deep V shaped valley
- Very resistant rocks - lateral corrasion is absent - gorges(indus is kashmir) and canyons(Bryce in USA)
- Features
- River capture - river piracy or river beheading
- Back cutting or headwards erosion into divide
- Elbow of capture
- Beheaded stream is called misfit
- Valley below elbow is wind gap
- E.g - Irrawaddy captured Upper sittang, Northumberland, North tyne
- Rapids, cataracts and waterfalls
- Uneven resistance - rapids or jump or fall down stream
- Cataracts - greater rapid
- Waterfall - greater cataract - forms lunge pool beneath
- River capture - river piracy or river beheading
- The middle or valley course or mature stage
- Lateral corrasion replaces vertical corrasion
- Predominantly transports sediments
- Features
- Meanders
- (concave)River cliff and (convex)slip-off slopes(shingle deposition)
- Interlocking spurs
- The lower or plain course or old age
- Vertical corrasion ceases and lateral continues
- Predominantly deposition
- Braided streams
- Features
- Flood plains
- Levees and artificial embankment
- Hwang-Ho china's sorrow
- Ox-Bow lakes or mortlake or dead lake
- cut-off or bayous in Mississippi basin
- Meander is more pronounced
- Delta
- River reaches sea and drops fine material at the mouth
- Fan-shaped alluvial area called delta
- Actually seaward extension of flood plane
- Due to obstruction caused by alluvium river discharges its water through distributaries
- Delta extends over time
- E.g - Mississippi has birds -foot delta, Nile,ganges and Mekong has fan-shaped delta
- Amazon, ob and vistula estuarine deltas, ebro of spain has tooth like projection called cuspate delta
- Conditions for delta
- Active erosion
- Tideless and sheltered coast
- No large lake to filter sediments
- no strong current perpendicular to rive mouth
- Flood plains
- River rejuvenation
- Being young again
- -ve movement -When land uplifts or sea level falls
- Active down-cutting
- Leaves behind terraces
- Knick point or rejuvenated head
- Deepening of gorges and deep valley with entrenched or incised meanders
- +ive movement - depression of land and rise in sea level -ice melting
- The upper or mountain course or youth stage
- The human aspects of rivers
- Navigation
- Boundary
LANDFORMS OF GLACIATION
- Pleistocene - 30,000 years ago ice sheets over entire temperate region
- Today only Greenland and Antarctica
- Ice shelves break into ice bergs
- Nunataks - peaks of mountain projects above surface
- Repeated melting and freezing of snow forms hard granular neve or firn
- Glacier river of ice
- Glaciers flow in tongue shape - greatest rate of movement in middle
- Glaciers converge to form an extensive ice-mass called a piedmont glacier. E.g malaspina glacier
- LANDFORMS OF HIGHLAND GLACIATION
- Glacier erodes by plucking and abrasion
- All glaciated floors have striation or scratching
- Rock flour
- Features
- Corrie, cirque or cwm
- Aretes and pyramidal peaks
- Bergschrund
- U-Shaped glacial trough
- Hanging valleys
- Rock basins and rock steps
- Moraines
- Landform of Glaciated Lowlands
- Roche Moutonnee
- Crag and Tail
- Boulder clay or glacial till
- Erratics
- Drumlins
- Eskers
- Terminal Moraines
- Outwash plains
- The Human aspects of Glaciated Landforms
ARID OR DESERT LANDFORMS
- Types
- Hamada or rocky desert
- Reg or stony desert
- Erg or sandy desert
- Badlands
- Mountain deserts
- The Mechanism of Arid Erosion
- Weathering
- Actions of wind in deserts
- Deflation
- Abrasion
- Attrition
- Landforms of Wind Erosion in Deserts
- Rock pedestals or mushroom rocks
- Zeugen
- Yardangs
- Mesas and buttes
- Inselberg
- Ventifacts or dreikanter
- Deflation hollows
- Landforms of wind Deposition in Deserts
- Dunes
- Barchan
- Seifs or longitudinal dunes
- Loess
- Dunes
- Landforms due to Water Action in deserts
LIMESTONE AND CHALK LANDFORM
- Limestone and chalk
- Characteristic Features of a Karst Region
LAKES
- THE FORMATION AND ORIGIN OF LAKES
- Lakes formed by earth movements
- Tectonic lakes
- Rift valley lakes
- Lakes formed by Glaciation
- Cirque lakes or tarns
- Kettle lakes
- Rock-hollow lakes
- Lakes due to morainic damming of valleys
- Lakes due to the deposition of glacial drifts
- Lakes formed by Volcanic Activity
- Crater and caldera lakes
- Lava-blocked lakes
- Lakes due to subsidence of a volcanic land surface
- Lakes formed by erosion
- Karst lakes
- Wind-deflated lakes
- Lakes formed by Deposition
- Lakes due to river deposits
- Lakes due to Marine deposits
- Lakes due to landslides, screes and avalanches
- Lakes formed by Human and Biological Activity
- Man-made lakes
- Lakes made by animals
- Other types of lakes
- Lakes and Man
- Communication
- Economic and industrial development
- Water storage
- Hydro-electric power generation
- Regulating river flows
- Moderation of climate
- Source of food
- Source of minerals
- Tourist attraction and health resorts
- Lakes formed by earth movements
COASTAL LANDFORMS
- The action of waves, tides and currents
- Zone of erosion - area between the low water level and high water level
- Swash and backwash
- The mechanism of Marine Erosion
- Corrasion - debris erode the base
- Attrition - against each other
- Hydraulic action - water into joints
- Solvent action - limestone coasts
- Coastal feature of Erosion
- Capes and bays
- softer rocks - inlets, coves or bays
- Harder rocks - headlands, promontories and capes
- Cliffs and wave cut platforms(eroded base) - notch becomes big and eroded material settles in off-shore terrace
- Strata dipping seaward - easily eroded
- Strata dipping landward - resistant
- Cave, arch, stack and stump
- Caves - local weakness
- Arch - two caves
- Stack - eroded arch
- Stump - further eroded stack
- Geos and gloups
- Gloups are blow-holes of caves
- Geos - enlarged gloups
- Capes and bays
- Costal feature of Deposition
- Beaches
- Spits and bars
- Marine dunes and dune Belts
- Types of coasts
- Coastlines of submergence
- Coastlines of emergence
- Ria coasts
- Fiord coasts
- Dalmatian coast
- Estuarine coast
- Coastlines of Emergence
- Uplifted lowland coast
- Emergent upland coast