NCERT Class 11 Geography Fundamental of Physical Geography: Chapter 4 — C H A P T E R
This chapter from NCERT's Fundamental of Physical Geography, Class 11, delves into the distribution of oceans and continents. It introduces Alfred Wegener's Continental Drift Theory, proposed in 1912, which suggested that continents were once joined as a supercontinent called Pangaea, surrounded by the mega-ocean Panthalassa. The chapter explores the evidence supporting this theory, including the matching coastlines of continents (Jig-Saw-Fit), the presence of rocks of the same age across oceans, tillite deposits indicating ancient glaciation in different Southern Hemisphere landmasses, and the distribution of fossils like Lemurs and Mesosaurus. It also discusses the forces Wegener proposed for drifting (pole-fleeing and tidal forces) and later theories like Arthur Holmes' Convectional Current Theory. The chapter highlights how post-WWII ocean floor mapping provided new insights into this geological phenomenon, crucial for understanding Earth's dynamic surface.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Geography |
| Book | Fundamental of Physical Geography |
| Chapter | Chapter 4 — C H A P T E R |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 6 minutes |
| Word count | 1119 |
Learning outcomes
- Understand Alfred Wegener's Continental Drift Theory.
- Identify and explain the evidence supporting continental drift.
- Recognize the historical development of theories on Earth's continental distribution.
- Appreciate the role of post-WWII research in understanding ocean floor features.
Vocabulary
| Word | Meaning |
|---|---|
| Pangaea | The supercontinent that existed during the late Paleozoic and early Mesozoic eras, comprising all the landmasses of the Earth. |
| Panthalassa | The vast global ocean that surrounded Pangaea. |
| Continental Drift | The theory that Earth's continents have moved over geologic time relative to each other, thus appearing to have 'drifted' across the ocean bed. |
| Laurasia | The northern component of Pangaea, which later split into North America, Europe, and Asia. |
| Gondwanaland | The southern component of Pangaea, which later split into South America, Africa, Antarctica, Australia, and India. |
| Tillite | A sedimentary rock formed from glacial deposits. |
| Radiometric dating | A method of determining the age of rocks and minerals by measuring the rate of decay of radioactive isotopes. |
| Placer deposits | Deposits of valuable minerals, such as gold or platinum, found in stream beds or other alluvial deposits. |
| Convection currents | Circulation of material in the Earth's mantle caused by differences in temperature and density. |
| Fossils | The preserved remains or traces of ancient organisms. |
The complete chapter text is read in the official NCERT PDF viewer below (streamed from ncert.nic.in). This page provides NCERT Help study material — summary, vocabulary, practice questions, and FAQs — not a full reproduction of the textbook.
Read chapter online
This PDF is loaded from the official NCERT website (ncert.nic.in). Use the page buttons below to read — download is disabled on NCERT Help.
Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.
Practice questions
- Who proposed the Continental Drift Theory and in which year? Answer: Alfred Wegener proposed the Continental Drift Theory in 1912.
- What were the names of the supercontinent and the mega-ocean proposed by Wegener? Answer: The supercontinent was named Pangaea, and the mega-ocean was called Panthalassa.
- Name two pieces of evidence that support the Continental Drift Theory. Answer: Two pieces of evidence are the matching of continents (Jig-Saw-Fit) and rocks of the same age across oceans.
- What is tillite and what does it indicate? Answer: Tillite is a sedimentary rock formed from glacial deposits, indicating extensive and prolonged glaciation.
- What forces did Wegener suggest were responsible for continental drift? Answer: Wegener suggested the pole-fleeing force and tidal force.
Practice MCQs
Q1. According to Wegener, the supercontinent was named:
Explanation: Wegener proposed that all continents formed a single supercontinent named Pangaea.
Q2. The mega-ocean surrounding Pangaea was called:
Explanation: Panthalassa was the name given to the vast global ocean that surrounded the supercontinent Pangaea.
Q3. Which of the following is NOT considered evidence for continental drift?
Explanation: While volcanic activity is related to plate tectonics, it was not a primary piece of evidence used by Wegener for continental drift. The other options are direct evidence cited in the chapter.
Q4. Tillite deposits are evidence of:
Explanation: Tillite is a sedimentary rock formed from glacial deposits, indicating past periods of extensive glaciation.
Q5. The radiometric dating of rocks from Brazil's coast matched with those from:
Explanation: The chapter mentions that the radiometric dating of ancient rocks from the Brazil coast matches those from the western coast of Africa.
Q6. Arthur Holmes proposed which theory to explain the forces behind continental movement?
Explanation: Arthur Holmes, in the 1930s, discussed the possibility of convection currents operating in the mantle portion to explain the forces behind continental drift.
Frequently asked questions
What is the main idea of the Continental Drift Theory?
The Continental Drift Theory, proposed by Alfred Wegener, suggests that Earth's continents were once joined together in a single supercontinent called Pangaea and have since drifted apart to their current positions.
What evidence did Wegener use to support his theory?
Wegener used evidence such as the matching shapes of continental coastlines (Jig-Saw-Fit), similar rock formations and ages across oceans, distribution of fossils, and tillite deposits indicating ancient glaciation.
What were the proposed forces for continental drift?
Wegener suggested that the rotation of the Earth (pole-fleeing force) and the gravitational pull of the moon and sun (tidal force) were responsible for continental drift.
What is Pangaea and Panthalassa?
Pangaea was the name given to the supercontinent, and Panthalassa was the name of the vast ocean that surrounded it.
How did post-World War II research contribute to understanding continental distribution?
Detailed mapping of the ocean floor after WWII revealed its complex relief and provided new data that supported and expanded upon the ideas of continental movement and plate tectonics.
What is tillite and why is it significant?
Tillite is a sedimentary rock formed from glacial deposits. Its presence in continents now in tropical or temperate zones (like India, Africa, South America) provides strong evidence for past glaciation and continental drift.
Related resources
Important topics
Topics covered
NCERT Class 11 Geography — Fundamental of Physical Geography — Chapter 4 — C H A P T E R. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.