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GeographyMediumAsked in: RRB NTPC · 13 June 2022, Shift 1

The metallic minerals that occur as alluvial deposits in flood plains or valleys are known as _______.

  1. A.metallic nodules
  2. B.bulk deposits
  3. C.vein deposits
  4. D.placer deposits

Correct answer

D. placer deposits

Explanation

The correct answer is D, placer deposits. Minerals that are washed out of their parent rock and settle in the sand and gravel of a river bed, flood plain or valley floor are called placer deposits. Running water carries the lighter material away and drops the heavy, non-corrodible grains, so placers are rich in gold, platinum, tin and tungsten. Panning for gold in the sands of the Subarnarekha river, and the monazite-bearing beach sands of Kerala, are Indian examples. Option A is wrong because manganese nodules are potato-sized lumps lying on the deep ocean floor, not in valleys. Option B is wrong because a bulk deposit only means ore mined in large tonnages and says nothing about how it formed. Option C is wrong because vein deposits are minerals that fill cracks and fissures inside solid rock, which is exactly the source a placer is eroded from. Exam tip: placer = heavy minerals in river or beach sand; veins = cracks in rock; nodules = ocean floor.

Practice Questions

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Q2.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.

  1. A.2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: C. 2 and 3 only

Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.

Q3.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.

  1. A.1 and 2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.

Q4.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.

  1. A.1 only
  2. B.2 and 3
  3. C.1, 2 and 4
  4. D.2 and 4 only
Show answer
Correct answer: C. 1, 2 and 4

Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.