Daily Quiz: UPSC Prelims Marathon (Geography) – September 4, 2020

A variety of evidence was offered in support of the continental drift. Some of these are given below.

The Matching of Continents (Jig-Saw-Fit): The shorelines of Africa and South America facing each other have a remarkable and unmistakable match.

• It may be noted that a map produced using a computer programme to find the best fit of the Atlantic margin was presented by Bullard in 1964.
• It proved to be quite perfect. The match was tried at 1,000- fathom line instead of the present shoreline.

Tillite: It is the sedimentary rock formed out of deposits of glaciers.

• The Gondawana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere.
• At the base, the system has thick tillite indicating extensive and prolonged glaciation.
• The glacial tillite provides unambiguous evidence of palaeo-climates and also of drifting of continents.

Placer Deposits: The occurrence of rich placer deposits of gold in the Ghana coast and the absolute absence of source rock in the region is an amazing fact.

The gold bearing veins are in Brazil and it is obvious that the gold deposits of the Ghana are derived from the Brazil plateau when the two continents lay side by side.

An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3,000 metres (9,800 ft) and 6,000 metres (20,000 ft). Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface.

Mid – Oceanic Ridges: This forms an interconnected chain of mountain system within the ocean.

• It is the longest mountain-chain on the surface of the earth though submerged under the oceanic waters.
• It is characterised by a central rift system at the crest, a fractionated plateau and flank zone all along its length.
• The rift system at the crest is the zone of intense volcanic activity.

Some important minor plates are listed below:

• Cocos plate: Between Central America and Pacific plate
• Nazca plate: Between South America and Pacific plate
• Arabian plate: Mostly the Saudi Arabian landmass
• Philippine plate: Between the Asiatic and Pacific plate
• Caroline plate: Between the Philippine and Indian plate (North of New Guinea)
• Fuji plate: North-east of Australia.

These are deep valleys, some comparable to the Grand Canyon of the Colorado River.

• They are sometimes found cutting across the continental shelves and slopes, often extending from the mouths of large rivers.
• The Hudson Canyon is the best known submarine canyon in the world.

The Kuroshio, also known as the Black or Japan Current or the Black Stream, is a north-flowing, warm ocean current on the west side of the North Pacific Ocean.

Movement in search of pastures is undertaken either over vast horizontal distances or vertically from one elevation to another in the mountainous regions.

• The process of migration from plain areas to pastures on mountains during summers and again from mountain pastures to plain areas during winters is known as transhumance.
• In mountain regions, such as Himalayas, Gujjars, Bakarwals, Gaddis and Bhotiyas migrate from plains to the mountains in summers and to the plains from the high altitude pastures in winters.

Iron & Steel Industry: The industry is one of the most complex and capital-intensive industries and is concentrated in the advanced countries of North America, Europe and Asia.

• Pittsburg area is now losing ground. It has now become the “rust bowl” of U.S.A.
• In Europe, U.K., Germany, France, Belgium, Luxembourgh, the Netherlands and Russia are the leading producers.
• The important steel centres are Scun Thorpe, Port Talbot, Birmingham and Sheffield in the U.K.;
• Duisburg, Dortmund, Dusseldorf and Essen in Germany; Le Creusot and St. Ettienne in France;
• And Moscow, St. Petersburgh, Lipetsk, Tula, in Russia and Krivoi Rog, and Donetsk in Ukraine.

Digboi Refinery is India’s oldest refinery. It was established in 1901. It gets crude oil from Moran and Naharkatiya fields.

• Barauni petrochemicals plant is in the country the second oil refinery in the public sector and forms an important part of theIndian petrochemical industry.
• It belongs to theIndian oil corporation limited (IOCL). It was built in partnership with Romania and USSR.
• The plant of Barauni petrochemicals is located from Patna at a distance of 125 kilometers. In 1964 it was commissioned and had a 1 mmtpa refining capacity.

In a lake in Brazil, researchers have discovered a virus that they find unusual and intriguing called Yaravirus, it has a “puzzling origin and phylogeny”, they report in a study on the pre-print server bioRxiv.

• The Yaravirus infects amoeba and has genes that have not been described before, something that could challenge how DNA viruses are classified.
• The researchers found the Yaravirus while looking in the lake for giant viruses that infect amoeba.
• Because of the Yaravirus’s small size, it was unlike other viruses that infect amoeba and they named it as a tribute to Yara, the “mother of waters” in the mythological stories of the Tupi-Guarani indigenous tribes.