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Chapter 4: Distribution Of Oceans And Continents MCQs

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Class 11 • Geography

Chapter 4: Distribution Of Oceans And Continents

Source: NCERT Official Textbook

This chapter explores the dynamic nature of Earth’s surface, focusing on the theories that explain the distribution and movement of oceans and continents. It begins with Alfred Wegener’s Continental Drift Theory (1912), which proposed that all continents were once joined in a supercontinent called Pangaea, surrounded by a mega-ocean, Panthalassa.

The chapter details the evidence Wegener used, including the jigsaw-fit of continents, matching rock ages and glacial deposits (tillite) across oceans, and the distribution of fossils like Mesosaurus. The theory initially faced rejection due to its inadequate explanation for the driving force. However, post-World War II discoveries, especially the mapping of the ocean floor, revealed crucial new evidence: the existence of mid-ocean ridges, young oceanic crust, and magnetic stripes.

This led to Harry Hess’s Sea Floor Spreading hypothesis (1961), which explained how new crust forms at ridges and is consumed at trenches. These ideas culminated in the Theory of Plate Tectonics. The chapter explains that the Earth’s lithosphere is divided into major and minor plates that move over the asthenosphere. It describes the three types of plate boundaries—divergent, convergent, and transform—and attributes plate movement to convection currents in the mantle.

Finally, it applies this theory to explain the northward journey of the Indian plate, its collision with Eurasia to form the Himalayas, and the concurrent formation of the Deccan Traps.

Topics Covered:

Section A: Descriptive Questions

  1. What observation about the Atlantic coastline first suggested to scientists that continents might have moved? (Pg. 1) Page 27
  2. Name and describe the two large continental masses that initially formed when Pangaea broke apart. (Pg. 1) Page 27
  3. Explain how the distribution of the fossil reptile *Mesosaurus* supports the continental drift theory. (Pg. 2) Page 28
  4. What major discovery from post-World War II ocean floor mapping revitalized the study of continent distribution? (Pg. 2-3) Page 28-29
  5. Describe the distribution pattern of earthquake foci (shallow vs. deep) in relation to mid-ocean ridges and the Pacific Rim. (Pg. 3) Page 29
  6. What is the basic concept of “sea floor spreading” as proposed by Harry Hess? (Pg. 4-5) Page 30-31
  7. What are the three main types of plate boundaries? Define each briefly. (Pg. 7) Page 33
  8. Explain the convection cell model as the driving force for plate tectonics. (Pg. 7-8) Page 33-34

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Section B1: Objective MCQs

Page 27

Who first proposed the comprehensive theory of ‘continental drift’? (Pg. 1)

A) Abraham OrteliusB) Antonio PellegriniC) Alfred WegenerD) Arthur Holmes
View Answer
Correct Answer: C
Reference: NCERT Page 27
Page 27-28

What evidence for continental drift is provided by the matching rock formations of 2,000 million years between Brazil and West Africa? (Pg. 1-2)

A) Matching Continents (Jig-Saw-Fit)B) Rocks of Same Age Across OceansC) Tillite DepositsD) Placer Deposits
View Answer
Correct Answer: B
Reference: NCERT Page 27-28
Page 28

What was the key problem with the forces (pole-fleeing and tidal) suggested by Wegener to move the continents? (Pg. 2)

A) They were too strong.B) They were seasonal.C) They were considered totally inadequate.D) They only worked in oceans.
View Answer
Correct Answer: C
Reference: NCERT Page 28
Page 29

Which of the following is NOT one of the three major divisions of the ocean floor? (Pg. 3)

A) Continental MarginsB) Abyssal PlainsC) Mid-Ocean RidgesD) Oceanic Trenches
View Answer
Correct Answer: D
Reference: NCERT Page 29
Page 30

According to sea floor spreading, where is the youngest oceanic crust found? (Pg. 4)

A) At the deep-sea trenchesB) Farthest from the mid-ocean ridgeC) Closest to the continentsD) At the crest of the mid-ocean ridge
View Answer
Correct Answer: D
Reference: NCERT Page 30
Page 32

A tectonic plate is composed of: (Pg. 6)

A) Only continental crust.B) Only oceanic crust.C) Both continental and oceanic lithosphere.D) Only the asthenosphere.
View Answer
Correct Answer: C
Reference: NCERT Page 32
Page 33

At which type of boundary is new crust generated? (Pg. 7)

A) Convergent BoundaryB) Divergent BoundaryC) Transform BoundaryD) Subduction Zone
View Answer
Correct Answer: B
Reference: NCERT Page 33
Page 33

How do scientists determine the rate of plate movement? (Pg. 7)

A) By measuring earthquake depthB) Using strips of normal and reverse magnetic field parallel to ridgesC) By dating continental rocksD) By satellite imagery only
View Answer
Correct Answer: B
Reference: NCERT Page 33
Page 34

What major geological formation in India is linked to the outpouring of lava during the northward movement of the Indian plate? (Pg. 8)

A) The Eastern GhatsB) The Deccan TrapsC) The Aravalli RangeD) The Satpura Range
View Answer
Correct Answer: B
Reference: NCERT Page 34
Page 35

(Exercise) Who amongst the following was the first to consider the possibility of Europe, Africa and America having been located side by side? (Pg. 9)

A) Alfred WegenerB) Antonio PellegriniC) Abraham OrteliusD) Edmond Hess
View Answer
Correct Answer: C
Reference: NCERT Page 35
Page 35

(Exercise) Polar fleeing force relates to: (Pg. 9)

A) Revolution of the EarthB) GravitationC) Rotation of the earthD) Tides
View Answer
Correct Answer: C
Reference: NCERT Page 35
Page 35

(Exercise) Which one of the following is not a minor plate? (Pg. 9)

A) NazcaB) ArabiaC) PhilippinesD) Antarctica
View Answer
Correct Answer: D
Reference: NCERT Page 35
Page 35

(Exercise) Which fact was NOT considered in discussions of sea floor spreading? (Pg. 9)

A) Volcanic activity along ridges.B) Magnetic stripes on the ocean floor.C) Distribution of fossils.D) Age of rocks from the ocean floor.
View Answer
Correct Answer: C
Reference: NCERT Page 35
Page 35

(Exercise) What is the type of plate boundary of the Indian plate along the Himalayas? (Pg. 9)

A) Ocean-continent convergenceB) Divergent boundaryC) Transform boundaryD) Continent-continent convergence
View Answer
Correct Answer: D
Reference: NCERT Page 35

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Section B2: Factual One-Liners

Alfred Wegener named the single supercontinent ______. (Pg. 1) Page 27

Reveal Answer
Pangaea (Page 27)

______ is the sedimentary rock formed from glacier deposits, used as evidence for continental drift. (Pg. 2) Page 28

Reveal Answer
Tillite (Page 28)

Arthur Holmes proposed that ______ currents in the mantle could be the driving force for continental movement. (Pg. 2) Page 28

Reveal Answer
convection(al) (Page 28)

The longest mountain chain on Earth, submerged under ocean waters, is the ______. (Pg. 3) Page 29

Reveal Answer
mid-oceanic ridge (Page 29)

A key observation for sea floor spreading was that sediments on the ocean floor are unexpectedly ______. (Pg. 4) Page 30

Reveal Answer
thin (Page 30)

The Pacific plate is largely an ______ plate. (Pg. 6) Page 32

Reveal Answer
oceanic (Page 32)

The location where one plate sinks under another is called a ______ zone. (Pg. 7) Page 33

Reveal Answer
subduction (Page 33)

The movement of the Indian plate caused the uplift of the ______. (Pg. 8) Page 34

Reveal Answer
Himalayas (Page 34)

(Exercise) What were the two forces suggested by Wegener for continental movement? (Pg. 9) Page 35

Reveal Answer
Pole-fleeing force and Tidal force (Page 35)

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