Earth and physical Flashcards
State the zones of the earth
Frigid -66.34Temperate 23.26 Torrid 0-23.26
How does time increase in direction of earth , why
W-e Earth - west to east
How much Does time increase by 1°
15 minutes
What is the international date line
Date changes exactly by one day
Why is the international date line bent , where
Because there a small islandsBent at Bering Strait, Fiji, tonga
What is daylight saving
1 hr time ahead
What is solstice, equinox , draw diagram
Solistice - summ = @ 21 June cancer ,
winter = 22 dec Capricorn
Equinox -spring @23 sept ,
autumn @ 23march - equator
Discuss the layers of the earth and how they were discovered
Crust 1-100= sial, sima, lithosphere Aesthenosphere - brittle till 400km Mantle till 2900 km Outer core 2900-5100km Inner core = 5100-6578 km
What are the content of the crust
O>si>al>fe
What is the continental drift theory
Alfred Wegener
The earth was Pangea and Panthalassa 200m years ago
which was broken by the Tethys sea into Laurasia and Gondwana land
What is the evidence behind the continental drift theory
- S am + Africa - jigsaw
- Tillite deposits like Gondwana in south hemisphere
- Glossopterris veg @india, Australia, Antarctica
- Matching rocks 5. Gold sources
Why was the continental drift theory rejected
Could not explain why in Mesozoic era
Not consider oceans
Forces too weak
What is the convectional current theory, who coined it
Arthur Holmes 1930
Radioactive elements under the surface of the earth cause thermal differences and this heat wants to exit hence it moves upwards in conventional currents
What is palaeomagnetism
Due to convection currents and volcanic activity basaltic rocks are thrown to the seabed which have low silica but high iron
basalt is magnetic mineral which solidifies and forms rocks there a line in the direction of the magnetic field of earth at that time which is later reversed after a few years
This continued process causes stripes of alternate magnetic field rocks
What is seafloor spreading
Harry Hess
Conventional currents push the magma outside which pushes the place and hence creates a fault and spreads the ocean floor
What is evidence behind seafloor spreading theory
Paleomagnetism
Similar kind of rocks equidistant from the ridge
Deep-seated earthquakes at the Trench
Draw a diagram of the trench and the ridge
Trench where collide Ridge where separate
What is plate tectonics
The movement of plates due to the force of magma
Draw a diagram of platetectonics
Island arc @subduction plate enticing magma Ridge, trench , volcanic boundaries = mts
discuss the formation of the Himalayas
220 m yrs ago Pangea broke
india floated N - collided w asia,
submerged = Himalayas
what are the formations due to plate tectonics
island arc convergence
cordilleran
himalayan
discuss the phillipine island formation
arc = phillipine plate under sunda plate ,
ocean - ocean
Discuss the formation of Indonesian archipelago
Ocean ocean
Indo aus under sunda
Carribean island formation.
North America under Caribbean
Puerto Rico trench
Ocean ocean
Cordillerean=?
Continent- ocean
How is continental arc formed
Ocean subducts due to sediments
Discuss the formation of Andes + Rockie
Andes = continent- ocean
Nazea under S. America = Peru Chile trench
Rockies
Juan de fuca under N.Am
Discuss continent to continent convergence
Himalayan +Appalachian , Alps + Ural
What are geomorphic processes.
Relating to form of landscape.
What are the causes of geomorphic processes
Radioactive material@ Interior
Moving plates
Rotation Climate
Isostacy =Uplift due to density change
What is the main cause of endogenetic movements
Energy from the earth
What are the two kinds of Endogenetic movements
– diastrophism and sudden movements
What is the meaning of diastrophism
Slow bending or folding
What are the kinds of diastrophic movement
Orogenic = mountain building Epiorogenic = continent building Plate tectonics
What are the kinds of epiorogenic movements
Uplift = sea caves @kathiawar
Subsidence - part of rann of kachch submerged in 1819
What are the causes of exogenetic movements
Surface - sheer stress … break
Explain the types of weathering
Chemical = solution - water , carbonation - co2 from atmosphere, hydration , oxidation , reduction
Biological = burrowing
Physical = upload + expand , granular disintegration, block separation, shattering, freezing, thawing, salt@cracks expand, rolling down
Are the causes of fluvial landforms
Corrosion + abrasion Hydration Attrition-particle against each other Dam cutting Horizontal erosion
Draw a diagram of erosional fluvial landforms
River vally- gorge - canyon Meander Oxbow lake Potholes Gullies
Draw a diagram of depositional fluvial Landforms
Alluvial fans
Natural levees = embankment
Delta
Discuss the types of delta
Arcurate =fan@ Krishna
Bird@missisipi
lobate@ Godavari
Discuss Karst landforms
Sinkhole, Cavern- cave Sinking creeks Stalagmite + stalactite Column
What are marine erosional landforms
Blowhole Cave Arc Sea cliffs Stack Stump
What are depositional marine landforms
Spit Bay Barrier island Lagoon Beach tomball Island
What are erosional glacial landforms
Tarn Horn Cirque Arête = tip Glacial-trough Hanging Valley
What are depositions glacial landforms
Drumlin
Moraine
Out-wash plain
Karnes=hump
What are arid erosional landforms - water
Hill-cracks @ soil Gully= small road @mts Ravine = stream cutting Canyon Gorge Pediments- erosional delta Bajada -moderatesloping plain
What are erosional arid landforms air
Aeolian landforms Deflated basin Mushroom rock= pedestal Inselberg Demo selles = pillars with flat top Wind bridges
What are the depositional arid landforms
Ripple marks Sand dunes - longitudinal , traverse , barchans , star Loess = particles blanket land
What is the Ridge
Local folding edge
What is the range
Series of ridges
What is a system
Mountain ranges of same period
What is the chain
Mountain system of different sizes and different period
What is a cordillera
Many systems together
What is the significance of fold mountains
Tectonic
Rich in minerals
Discuss the formation of a Rift Valley
Divergens of plates and faulting due to the divergens
How are the valleys of Narmada and Tapi river is formed
Due to bending of the Indian plate due to formation of the Himalayas
How is a narrow sea formed and how does it turn into an ocean
Narrow sea is formed by the rift Valley becoming a large
and the ridges forming around it therefore it spreads
continental plate is replaced by the oceanic plate and hence a narrow sea like the red sea forms
Why are mountains concentrated at the equator
At cold places erosion takes place at lower altitudesSlow line is low
Mountains rise 1500 m above the snow line and
at equator the snow line is at 5500 m and hence the erosion is low
State the economic significance of the plateaus
Deccan and Katanga Plateau are famous for copper
Kimberly Plateau diamond
East Africa gold and diamond Iron and coal mining
and Chota Nagpur Plateau
Lava soils hence agriculture is great
Water falls hence hydroelectric power
Discuss the types of rocks and their subtypes
IGNEOUS-
1. extrusive = rapid cooling on the surface hence no crystals fine grained dense and dark in colour
2. Intrusive / plutonic = slow cooling at interior hence crystals large grains less dense and light colour
3. Basic = Poor in silica slow cooling and form Plateau heavy in minerals hence dark colour. Not hard hence not weather easily
4. Acidic = excess silicon hence cool fast form mountains not heavy hence light colour hard therefore less weathering
SEDIMENTARY
1. Mechanically formed = arenaceous - large sand particles, agricellarous - small clay particles, by ocean currents and winds
2. Chemical= stalagmites and stalactites
3. Organic= Calcerous -more calcium, carbonaceous = more carbon
METAMORPHIC
1. Orogenic = holding
2. Geodynamic = thermal , pressure
What is the significance igneous metamorphic sedimentary rocks
Igneous … Metal ores
Amy dales = air bubbles in basalt - filled with minerals
Granite - beautiful shades
Sedimentary … Building stones
Decay of mineral animals … petroleum Bauxite and manganese derived
What is Polar motion
The movement of poles when the axis of the earth moves is known as Polar motion
what are the effects of the shift in earth axis due to climate change
change the length of the day by a few milliseconds.
how does the axis of the earth shift
The location of the poles is not fixed, however, as the axis moves due to changes in how the Earth’s mass is distributed around the planet. Thus, the poles move when the axis moves, and the movement is called “polar motion”.
● According to NASA, data from the 20th century shows that the spin axis drifted about 10 centimetres per year. Meaning over a century, polar motion exceeds 10 metres.
● Generally, polar motion is caused by changes in the hydrosphere, atmosphere, oceans, or solid Earth.
discuss the timeline of the shift of earth axis
Since the 1990s, climate change has caused billions of tonnes of glacial ice to melt into oceans. This has caused the Earth’s poles to move in new directions.
● As per the study, the north pole has shifted in a new eastward direction since the 1990s, because of changes in the hydrosphere (meaning the way in which water is stored on Earth).
● From 1995 to 2020, the average speed of drift was 17 times faster than from 1981 to 1995. Also, in the last four decades, the poles moved by about 4 metres in distance.
The faster ice melting, change in non‐glacial regions due to climate change and unsustainable consumption of groundwater for irrigation and other anthropogenic activities.
● As millions of tonnes of water from below the land is pumped out every year for drinking, industries or agriculture, most of it eventually joins the sea, thus redistributing the planet’s mass.
What is the super moon
occurs when the Moon’s orbit is closest to the Earth at the same time that the Moon is full. In a typical year, there may be two to four full supermoons and two to four new supermoons in a row.
Why does the super moon appear to be red
Because of the total lunar eclipse, the moon will also appear to be red. This is because the Earth will block some of the light from the Sun from reaching the moon and as the Earth’s atmosphere filters the light, it will soften “the edge of our planet’s shadow” “giving the Moon a deep, rosy glow.”
What are the implications of this summer solstice
- All locations north of the equator have days longer than 12 hours at the June solstice. Meanwhile, all
locations south of the equator have days shorter than 12 hours. - This day is characterised by a greater amount of energy received from the sun. According to NASA, the
amount of incoming energy the Earth received from the sun on this day is 30 per cent higher at the North Pole than at the Equator.
What are the implications of the winter solistice
21st December or the Winter Solstice marks the shortest day of the year in the Northern Hemisphere.
● It is the shortest day and longest night of the year in the Northern Hemisphere and is also known as the ‘first day of winter’ in the Northern Hemisphere as well as ‘Hiemal solstice or Hibernal solstice’.
● During this, countries in the Northern Hemisphere are farthest from the Sun and the Sun shines overhead on the Tropic of Capricorn (23.5° south).
