The Indian desert also known as Marusthali is believed to be under the sea during which one of the following eras?
- A.Cenozoic era
- B.Palaeozoic era
- C.Mesozoic era
- D.Archaean and Pre-Cambrian era
Correct answer
Explanation
The correct answer is C, Mesozoic era. The Great Indian Desert, or Marusthali, lies to the north-west of the Aravalli hills in western Rajasthan. It is believed that during the Mesozoic era, the age of the dinosaurs some 250 to 66 million years ago, this region lay under the sea. The proof comes from marine fossils and fossilised wood found at Akal near Jaisalmer, where the Akal Wood Fossil Park now preserves tree trunks about 180 million years old, and from the marine sedimentary rocks of the area. Today the desert has sand dunes, barchans and salt lakes such as Sambhar, with the Luni as its main river. Option A is wrong because by the Cenozoic era the region had already risen above the sea. Option B is wrong because the Palaeozoic is older than the period of the marine deposits seen here. Option D is wrong because Archaean and Pre-Cambrian rocks form the old shield of the peninsula, such as the Aravallis, not the seabed of the desert. Exam tip: Marusthali under the sea in the Mesozoic; fossil park at Akal, Jaisalmer.
Practice Questions
View allLoktak lake is situated in the State of
- A.Sikkim
- B.Manipur
- C.Odisha
- D.Mizoram
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Loktak Lake lies south of Imphal in Manipur and is the largest freshwater lake in North-East India. Loktak is famous for its phumdis, floating masses of soil, vegetation and decaying organic matter that drift on the water.
Read the full explanation →The formation of 'tors' on small rocky hills is associated with which among the following?
- A.Granite
- B.Limestone
- C.Alluvial
- D.Dolomite
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Tors are piles of rounded, weathered blocks standing on hilltops, and they form typically in granite. Granite cools deep underground and develops a network of joints, or cracks.
Read the full explanation →Which one of the following statements is NOT correct ?
- A.Bokaro steel plant is located in Damodar river basin
- B.Jamshedpur steel plant is located on the confluence of Damodar and Barakar
- C.Salem steel plant is located on the bank of Kaveri River
- D.Bhilai steel plant obtains water from Tandula reservoir
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Jamshedpur stands at the meeting point of the Subarnarekha and Kharkai rivers, not the Damodar and Barakar. Jamsetji Tata chose Sakchi, later named Jamshedpur, and the Tata Iron and Steel Company began production there in 1912.
Read the full explanation →Which of the following is/are warm ocean current(s) ? 1. Alaska Current 2. Agulhas Current 3. Falkland Current 4. West Australian Current Select the answer using the code given below :
- A.1 only
- B.1 and 2
- C.3 and 4
- D.4 only
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The Alaska Current and the Agulhas Current carry warm water, while the Falkland and West Australian currents are cold. A useful rule is that currents flowing from the tropics towards the poles are warm and those flowing from high latitudes towards the equator are cold.
Read the full explanation →Consider the following statements regarding the nature of rocks : I. Rocks are aggregates of one or more minerals. II. Granite is softer than soapstone. III. Gabbro is black and quartzite can be milky white. IV. Sedimentary rocks are related to foliation. Which of the statements given above are not correct ?
- A.I and II
- B.I and III
- C.II and IV
- D.II and III
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Granite is far harder than soapstone, and foliation is a feature of metamorphic rocks, not sedimentary ones, so these two statements are wrong.
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