Daily Quiz: UPSC Prelims Marathon (Geography)| October 23rd 2020

The drainage pattern was already present before a period of uplift and folding that formed the present structure.
•As the uplift took place, the rivers were able to cut down at approximately the same rate and so maintain their courses.
•This process is called antecedence and the drainage system thus developed is called antecedent drainage.
•Many of the Himalayan Rivers have antecedent origin i.e. these rivers existed even before the Himalayan ranges were uplifted.
•These rivers originate in the Tibetan side beyond the mountain ranges of Himalayas. The Indus, Satluj, Alaknanda, Gandak, Kosi, Brahmaputra all has an antecedent origin.
•Since these rivers are antecedent, they run transverse to the mountain ranges cutting deep V-shaped, steep-sided valleys (deep gorges).
Source: NCERT & ICSE

Zoji La: Zoji La is a high mountain pass located in the Kargil district of Ladakh.
•The pass links Leh and Srinagar and provides an important link between Union Territories of Ladakh and Kashmir.
•In 2018, the Zojila tunnel project was launched.
•The tunnel is Asia’s longest and strategic bi-directional tunnel, which will provide all-weather connectivity between Srinagar, Kargil and Leh.
Banihal Pass: It is in Jammu & Kashmir. The National Highway No.1A that links Srinagar to Jammu goes through it.
NOTE: Satluj River flows through Shipki La (Pass).
Nathu La: It is in Sikkim. It gives way to Tibet from Darjeeling and Chumbi Valley. The Chumbi River flows through this pass.
Source: Oriental Black Swan

Jog Falls, also called Gersoppa Falls, cataract of the Sharavati River, western Karnataka state, southwestern India. The Jog Falls are located 18 miles (29 km) upstream from Honavar at the river’s mouth on the Arabian Sea.
Source: Majid Singh

Dharwar system is later than the Archean system but older than the other systems.
•The Dharwar period of rock formation has been largely fixed from 2500 million years ago to 1800 million years ago.
•Dharwar Rock System is special because it is the first metamorphic sedimentary rocks in India.
•They are named Dharwar system because they were first studied in Dharwar region of Karnataka.
•But they are also found in Aravallis, Tamil Nadu, Chota-nagpur plateau, Meghalaya, Delhi, and the Himalayas region.
•The Dharwar rocks are rich in iron ore, manganese, lead, zinc, gold, silver etc.
Source: NCERT

Rivers and their adjacent towns.

Source: Majid Singh

The Soils can be classified on the basis of dominating factors:
Zonal Soil – These soils occur in broad geographical areas or zones.
•They are influenced more by the climate and vegetation of the area rather than the rock-type.
•They are mature, as a result of stable conditions over a long period of time.
•For example – red soils, black soils, laterite soils, desert soils etc.
Azonal Soil – It is that soil which has been developed by the process of deposition by the agents of erosion.
•It means that it has been made by the fine rocky particles transported from the far-off regions.
•These are immature soils and lack well-developed soil profiles.
•This may be due to the non-availability of sufficient time for them to develop fully or due to the location on very steep slopes which prohibits profile development.
•For Example – alluvial and loess soils.
Intrazonal Soil – These soils occur within other zonal soils.
•It is a well-developed soil reflecting the influence of some local factor of relief, parent material, or age rather than of climate and vegetation.
•For example, calcareous soil (soils which develop from limestone), peat soil.
Source: Khullar

The Bureau of Indian Standards has classified regions in India into four seismic zones on the basis of historical seismic activity.
•These are zones II, III, IV and V. Among these, Zone V is the most seismically active region and zone II is the least active.
•According to Modified Mercalli scale, the seismic zone intensity is/are classified as zone II (low intensity zone), zone III (moderate intensity zone), zone IV (severe intensity zone) and zone V (very severe intensity zone).
According to the Ministry of Earth Sciences:
•Zone V includes entire northeastern India, parts of Jammu and Kashmir and Himachal Pradesh, Uttaranchal, Rann of Kutch in Gujarat, parts of North Bihar and Andaman & Nicobar Islands.
•Zone-IV includes the remaining parts of Jammu and Kashmir and Himachal Pradesh. Delhi-NCR region, Sikkim, northern parts of Uttar Pradesh, Bihar and West Bengal, parts of Gujarat and small portions of Maharashtra near the west coast and Rajasthan also fall in this zone.
•Regions under zone III are Goa, Kerala, Lakshadweep, and remaining parts of Uttar Pradesh, Gujarat and West Bengal, parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Maharashtra, Orissa, Andhra Pradesh, Tamilnadu and Karnataka.
•The remaining portion of the country falls under zone II.
Source: Indian Express

According to the scientists, including those from NASA’s Jet Propulsion Laboratory in the US, a sea-water current called the Beaufort Gyre keeps the polar environment in balance by storing fresh water near the surface of the Arctic Ocean.
•Wind blows the gyre in a clockwise direction around the western Arctic Ocean, north of Canada, where it naturally collects fresh water from the melting of glaciers, and river runoff.
•The researchers said this fresh water is important in the Arctic since it floats above the warmer, salty water, and helps protect the sea ice from melting – in turn regulating the Earth’s climate.
•As the fresh water is slowly released by the gyre into the Atlantic Ocean over a period of decades, it allows the Atlantic Ocean currents to carry it away in small amounts.
•However, since the 1990s, the researchers said, the gyre has accumulated a large amount of fresh water – 8,000 cubic kilometres – or almost twice the volume of Lake Michigan in the US.
•According to the new study, the cause of this gain in freshwater concentration is the loss of sea ice in summer and autumn.
•Due to this decades-long decline of the Arctic’s summertime ice cover, the Beaufort Gyre is more exposed to the wind, which has spun the gyre faster, trapping the fresh water in its current.
Source: The Hindu

The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic.
•The AMOC is a large system of ocean currents, like a conveyor belt, driven by differences in temperature and salt content – the water’s density.
•As warm water flows northwards it cools and some evaporation occurs, which increases the amount of salt.
•Low temperature and a high salt content make the water denser, and this dense water sinks deep into the ocean.
•The cold, dense water slowly spreads southwards, several kilometres below the surface (As that water cools and sinks it drives a slow circulation of the oceans that is critical to global climate, affecting the location of droughts and frequency of hurricanes).
•Eventually, it gets pulled back to the surface and warms in a process called “upwelling” and the circulation is complete.
•This global process makes sure that the world’s oceans are continually mixed, and that heat and energy are distributed around the earth. This, in turn, contributes to the climate we experience today.
•As that water cools and sinks it drives a slow circulation of the oceans that is critical to global climate, affecting the location of droughts and frequency of hurricanes.
•It also stores heat-trapping carbon dioxide deep in the ocean.
Source: The Hindu

THE KUROSHIO IS a warm northeasterly ocean current off the coast of Japan. This current is also called the gulf stream of the Pacific or Japan Current.
•Kuroshio means “the black stream” in Japanese, named after the deep ultramarine color of the high salinity water, which is found flowing north of the current’s axis.
•The system includes the following branches: Kuroshio, up to 35 degrees N; Kuroshio extension, extending eastward into two branches up to 160 degrees E longitude;
•North Pacific current, a further eastward continuation, which throws branches to the south as far as 150 degrees W;
•Tsushima current, branches of the main current that run into the Japan Sea, along the west coast of JAPAN;
•And Kuroshio counter-current, the large swirl or eddy on the east and south east of the Kuroshio.
Source: ICSE