SYNOPSIS: IASbaba’s TLP – 2018: UPSC Mains General Studies Questions [7th December 2017]- Day 14
1. What are cratons? How do they differ from shields? Discuss the distribution of major shields of the world. Also comment on their geological significance.
- This question is simple and direct. You needs to write asked aspects directly.
- You should write in points for better presentation and use diagrams for better illustration.
- What are cratons?
A craton is an old and stable part of the continental lithosphere, where the lithosphere consists of the Earth’s two topmost layers, the crustand the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep lithospheric roots that extend as much as several hundred kilometres into the Earth’s mantle.
How do they differ from shields?
The term craton is used to distinguish the stable portion of the continental crust from regions that are more geologically active and unstable. Cratons can be described as shields, in which the basement rock crops out at the surface, and platforms, in which the basement is overlaid by sediments and sedimentary rock.
Cratons whose ancient rocks are widely exposed at the surface, often with relatively subdued relief, are known as shields. If the ancient rocks are largely overlain by a cover of younger rocks then the ‘hidden’ craton may be referred to as a platform.
The distribution of major shields of the world
- The Canadian Shieldforms the nucleus of North America and extends from Lake Superior on the south to the Arctic Islands on the north, and from western Canada eastward across to include most of Greenland.
- The Amazonian (Brazilian) Shieldon the eastern bulge portion of South America. Bordering this is the Guiana Shield to the north, and the Platian Shield to the south.
- The Baltic (Fennoscandian) Shieldis located in eastern Norway, Finland and Sweden.
- The African (Ethiopian) Shieldis located in Africa.
- The Australian Shieldoccupies most of the western half of Australia.
- The Arabian-Nubian Shieldon the western edge of Arabia.
- The Antarctic Shield.
- In Asia, an area in China and North Korea is sometimes referred to as the China-Korean Shield.
- The Angaran Shield, as it is sometimes called, is bounded by the Yenisey River on the west, the Lena River on the east, the Arctic Ocean on the north, and Lake Baikal on the south.
- The Indian Shieldoccupies two-thirds of the southern Indian peninsula.
Shields are normally the nucleus of continents and most are bordered by belts of folded Cambrian rocks.
These Shields is rich in natural resources, including minerals, forests and freshwater.
Best Answer: Neverquit1234
2. What is a coastline? How do coastlines get their shape? Are coastlines transforming due to climate change? Examine. What will be its consequence for the low lying coastal regions? Discuss.
In introduction, define what is coastline. Then in body part, start with how coastline get their shape. 2nd part, mention how due to climate change coastlines are getting transformed. Then final part, write what are the consequences for low lying regions.
Note: Don’t use too much of technical words, this is GS answer. Use words from basic NCERT.
A coastline also called as seashore is the area where land meets the sea or ocean, or a line that forms the boundary between the land and the ocean or a lake. India has a coastline of 7516.6km covering Main land and Islands.
Points to be covered:
How coastline get their shape:
- Waves: Wave erosion and wave deposition help in formation of coastlines.
- Sedimentation: Brought by rivers, streams, flood water, eroded cliffs.
- Currents: Ocean currents also help in formation.
- Upliftment and depression: Of land.
- Ports and Island: Construction of ports and artificial islands.
- Dredging: Activities involving dredging along seashore.
Coastlines are transforming due to climate change:
- Sea level increase: Due to increase in activities like Tsunami, Cyclones, precipitation, storm surge leading to sea level increase which in turn leads to coastline changes.
- Increased erosion and deposition: Due to increased phenomena like precipitation, floods, tidal currents etc.
Consequences of low lying coastal areas:
- Flooding: Frequent flooding will take place.
- Submergence: In near future.
- Acidification: Of shoreline due to constant mixing of land based minerals brought in by human activities.
- Damages: To human environment, ecosystem, coastal resources like coral reefs, mangroves etc.
- Economic loses: Many metropolitan cities of world are located along coastal areas like California, New York, Mumbai, Hong kong, Singapore etc. will need to be relocated.
Climate change is a manmade disaster waiting to happen. Necessary steps have to be taken to reverse climate change. World countries should come forward to limit the climate change as agreed upon in Paris climate conference to create a sustainable future.
Connecting the dots:
- Disaster management.
- Impacts of climate change.
Best Answer: Ramyaa Invincible
3. What is calving? What are the factors that cause calving? How does calving affect the glaciers? Also examine the effects of glacier retreat on the climate.
It is a pretty straight forward question. The points to are to be noted while answering this question is that, this question has got 4 parts. The answer for all parts is to be written distinctly so that the examiner can make out that no aspect is left.
Since each of these sub questions will be carrying individual marks, writing too much detail for one part and ignoring other will not help.
Calving process by which ice breaks off a glacier’s terminus; usually the term is reserved for tidewater glaciers or glaciers that end in lakes, but it can refer to ice that falls from hanging glaciers.
It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse. The ice that breaks away can be classified as an iceberg, but may also be a growler, bergy bit, or a crevasse wall breakaway
Watch this amazing video of calving. This is the largest calving ever recorded in history:
Factors causing Calving:
Calving is the natural process through which glaciers lose mass. The calving process begins when a rift opens in the edge of a glacier, caused by wind or water erosion, melting ice, or other events that cause the glacier to become unstable.
This crack in the ice ultimately causes a block to break away from the land and form an iceberg, which falls into the ocean. More ice from the land flows in behind it and breaks off next.
Some of the processes through which calving occurs are:
Longitudinal stretching of glaciers – When glaciers extend in ocean or lake water, the crevasse/rift increases in the ice because of pressure and it breaks from several joints.
Melting at waterline – melting at waterline undercuts the sub – aerial ice, leading to collapse of a big ice chunk.
Tidal and seismic activities – the daily rise and fall of sea water because of tides and seismicity of a region can also trigger calving.
Buoyant Force – Buoyant force of sea water cause the submerged foot of ice to break. Sometimes these events can be very violent as ice is forced to move up.
Affect on Glaciers:
Calving is a natural part of a glacier’s life cycle to a certain extent, but the extreme rate at which these glaciers are calving is what’s incredible and worrying: between 2000 and 2010, this glacier retreated nine miles – further than it had retreated in the previous 100 years combined. Scientists say its current flow rate, the rate at which the glacier drops ice into the ocean, is three times what it was in the 1990s.
As the ice is weakened, the glaciers starts to move quickly and are prone to melting and ablation. Calving cause receding glaciers.
- Calving at polar ice caps increase the number of ice bergs in the ocean.
- Some icebergs can flow in cold ocean currents and can be brought down to lower latitudes causing sudden drop in temperatures.
- Melting of icebergs cause salinity change in ocean water which affects biodiversity in ocean.
- It eventually will lead to sea level rise.
- Loss of habitation of polar land dwelling animals like Polar bears, Penguins etc.
Note: You can add more points in this section. Keep in mind that only climatic impact is asked. Do not write impact on economy, society etc.
Best Answer: Ankita Pathak
4. A recent research finding has suggested that the Arctic sea ice may be thinning faster than predicted. That means Arctic Ocean could be ice free much sooner than predicted. What would be the harmful consequences of ice-free summers in the Arctic Ocean? Examine.
Arctic sea ice is declining rapidly, with the seasonal low in summer shrinking particularly quickly. Scientists have different ways to predict Arctic sea ice decline. If melting continues as it has in recent years, it could be as soon as 2020, but climate models suggest it won’t happen until 2040 or later.
- Introduce with the reasons and the present situation in arctic sea
- Please mention about the studies
- Then mention the harmful consequences of it.
A stunning decline in the sea ice covering the northern polar regions — a more than 50 percent drop in extent in summer, and an even steeper reduction in ice volume. Just a few decades ago, ice 10 to 12 feet thick covered the North Pole, with sub-surface ice ridges in some parts of the Arctic extending down to 150 feet. In 2017, that ice is long gone, while the total volume of Arctic sea ice in late summer has declined, according to two estimates, by 75 percent in half a century.
Consequences of Arctic sea ice melt:
- Few scientists understand that the Arctic sea ice “death spiral” represents more than just a major ecological upheaval in the world’s Far North.
- The decline of Arctic sea ice also has profound global climatic effects, or feedbacks, that are already intensifying global warming and have the potential to destabilize the climate system.
- Sea ice, in summer, reflects roughly 50 percent of incoming radiation back into space.
- Its replacement with open water — which reflects roughly 10 percent of incoming solar radiation — is causing a high albedo-driven warming across the Arctic.
- As ocean and air temperatures in the Arctic rise, this adds more water vapor to the atmosphere, since warmer air holds more moisture. Water vapor is itself a greenhouse gas, trapping outgoing long-wave radiation and holding heat closer to the surface of the earth.
- Melting Greenland ice sheet raises sea levels- In fact, the loss of reflective sea ice is part of the reason Arctic temperature has risen three times faster than the global average in recent decades.
- Thawing permafrost amplifies warming- Scientists are concerned carbon dioxide and methane released from the carbon-rich permafrost could cause additional warming by adding to greenhouse gases already in the atmosphere.
- Ocean circulations could change- Another impact of Arctic and Greenland ice melt could be that the freshwater runoff into the ocean disrupts part of a major circulation system known as the Atlantic Meridional Overturning Circulation (AMOC). The AMOC carries warm surface water northward, giving Europe its mild climate.
- Melting sea ice can influence winter weather- As temperatures rise faster in the Arctic than at lower latitudes, this changes large-scale temperature and pressure gradients.
- Sea-level rise is projected to have serious implications for coastal communities and industries, islands, river deltas, harbors, and the large fraction of humanity living in coastal areas worldwide.
- Sea-level rise will increase the salinity of bays and estuaries. It will increase coastal erosion, especially where coastal lands are soft rather than rocky.
- In Southeast Asia, many very large cities including Bangkok, Bombay, Calcutta, Dhaka, and Manila are located on coastal lowlands or on river deltas.
The top of the world is turning from white to blue in summer as the ice that has long covered the north polar seas melts away. This monumental change is triggering a cascade of effects that will amplify global warming and could destabilize the global climate system.
Best Answer: no best answer For this question.
5. What is Bitcoin? Why has Bitcoin’s value risen so high? Are concerns about its volatility justified? Discuss.
- Introduction- Explaining what bitcoin is, how it originated etc.
- Reasons behind rise in its value
- Concerns about volatility
- Are the concerns justified or not?
Bitcoin is a cryptocurrency or digital currency based on Block Chain technology. It was first started by an anonymous person Sakoshi Nakomoto in 2006.
Other crypto currencies are Ethereum, IOTA etc. They all are ‘mined’ using complex algorithms in high speed computers.
Reasons behind rise in its value:
The value of Bitcoin has risen by about 900% in 2017 alone. The reasons for it’s this are-
- Demand-supply mismatch: Limited supply of currency but increasing demand.
- Fear of Missing out: Investors feel they are being left out of golden opportunity so they started investing in Bitcoins.
- Speculation by investors.
- Fast-growing user base. Significant rise in the number of people using Bitcoin grows with each passing day.
- Can be used for money laundering and tax Evasion as it records only digital adresses of and not the individuals involved.
- There is growing acceptance of Bitcoins as some central banks like the Japanese legalising it. Growing number of businesses are accepting Bitcoins also as mode of payment.
- Theoretically it can’t be stolen
Concerns about volatility:
All these risks involved make the cryptocurrency highly susceptible to volatility the RBI has also warned investor about investing in virtual currencies
- Volatility is because Bitcoin’s price today is not based on any fundamental value.
- These are not backed by any statutory body unlike fiat currencies, these are less trust worthy and thus prone to volatility. It is not Legal Tender. Not printed by government or traditional banks.
- No tracing mechanism to check the pathway of money.
- Massive Crypto Currency theft could mark a new security threat.
- Misuse of Cryto Currency by Cyber Criminals-FBI hunt on Dark Net.
- Virtual currency denominated IPOs have been launched by many dubious startups who seek to bypass market regulation.
- The concerns have been raised by stalwarts like the CEO of JP Morgan, that Bitcoin is in a bubble. No value stability i.e. can go down sharply with any unexpected event.
The volatility can erode people’s hard earned savings and governments should thus bring up regulations.
Even as the price of Bitcoins rise higher, opinion on Crypto Currency remains divided, for some it seems to be a boon and for rest it is fraud.
Despite its concerns, Bitcoins have a potential place in the digital economy. IT is high time that governments clarify its position on Bitcoins. This will end the policy uncertainty which is in part responsible for the bubble in Bitcoin. The recent RBI study on blockchain technology is a step in the right direction.
Connecting the dots:
- Blockchain technology
- Bitcoins regulation in India
Best answer: Shobhit
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