Lesson 1

• What does Earth appear to be, according to the study material?

  A solid, steady, and unchanging sphere of rock
• What is the truth about Earth's changes?

  Earth is constantly undergoing minor or major changes externally and internally
• What are some changes that theories have been proposed to explain?

  The formation of different landforms, separation of continents, formation of new ocean floor, and movement of lithospheric plates
• What do you call the several sections of masses that make up the Earth’s surface?

  Plates
• What does 'Pangea' mean in Greek?

  All land
• What is the name of the body of water surrounding Pangea?

  Panthalassa
• What are the two subcontinents formed after Pangea broke apart?

  Gondwana and Laurasia
• What was the sequence of how the seven continents known today were formed?

  1. 250 million years ago, continents were joined in one mass called Pangaea.
  2. 200 million years ago, Pangaea broke into Gondwana and Laurasia.
  3. Gondwana and Laurasia split into smaller land masses, forming today's continents:

  • Gondwana: Africa, Antarctica, South America, Australia, Subcontinents of India
  • Laurasia: Asia, Europe, North America
• Who hypothesized that Gondwana split into different continents in the mid-1800s?

  Eduard Suess
• Who coined that Laurasia was the precursor to the other continents in 1937?

  Alexander du Toit
• What is Plate Tectonics?


  • A scientific theory describing the large-scale motion of seven large plates and smaller plates of the Earth’s lithosphere.
  • Tectonic processes began on Earth between 3 and 3.5 billion years ago.
• Who is considered the father of the theory of Continental Drift?

  Alfred Wegener
• What is the title of Alfred Wegener's book published in 1915?

  The Origin of Continents and Oceans
• When was the theory of Continental Drift widely accepted in a refined version?

  In the 1960s
• What is seafloor spreading?


  A geologic process in which tectonic plates split apart from each other
• Who published 'The History of Ocean Basins' in 1962?

  Harry Hess
• What did Harry Hess use to map the ocean floor?

  SONAR
• Did Alfred Wegener present the Sea Floor spreading theory?

  False
• What is the scientific theory describing the large-scale motion of plates known as?

  Plate Tectonics
• What does the Continental Drift Theory describe?


  The process wherein tectonic plates move away from each other, creating the ocean floor
• Why was the Continental Drift Theory criticized?

  It cannot fully explain why continents are moving
• What did Hess discover about the oceans?

  The oceans were shallower in the middle and identified the presence of Mid Ocean Ridges
• What are the primary and secondary tectonic plates?

  Primary Plates:

  • Eurasian Plate
  • Australian Plate
  • Pacific Plate
  • North American Plate
  • South American Plate
  • African Plate
  • Antarctic Plate

  
  

  Secondary Plates:

  • Juan de Fuca Plate
  • Nazca Plate
  • Cocos Plate
  • Caribbean Plate
  • Philippine Sea Plate
  • Arabian Plate
  • Indian Plate
  • Scotia Plate
• Do you think it’s possible that the continents would converge into a single landmass or supercontinent after 250 million years? Why or why not?

  This is subjective and depends on geological predictions and theories
• How do we describe and relate the distribution of active volcanoes, earthquake epicenters, and major mountain belts to Plate Tectonic Theory?

  • Active volcanoes, earthquake epicenters, and mountain belts are often located along tectonic plate boundaries.
  • Their distribution is explained by the movement and interaction of tectonic plates.
• What happens when the Indian plate collides with the Eurasian plate?

  It creates Mount Everest, global climate change, and significant earthquakes.
• What significant earthquake occurred in Nepal in 2015?

  A magnitude 7.8 earthquake.
• How did the collision of the Indian subcontinent with Eurasia change the Earth?

  It created the Himalayas and significantly impacted global climate.
• What geological theory explains the movement of continents?

  • Plate tectonics
  • Earth's surface is made of massive plates
  • Continents move due to currents of molten earth
• How long ago did the tectonic process that formed the Himalayas begin?

  About 50 million years ago.
• What is the approximate length of the Himalayas?

  Over 1,500 miles.
• Which two religions consider the peaks of the Himalayas holy?

  Buddhism and Hinduism.
• What does the term "hot spots" refer to in the context of plate tectonics?


  Areas in the Earth's interior that create currents affecting plate movement.
• How fast did the Indian plate move compared to typical plate movement?

  Almost twenty centimeters a year.
• What was the supercontinent that included India, Africa, Australia, Antarctica, and South America called?

  Gondwanaland.
• What are the three distinct layers of the Earth's interior?

  The crust, the mantle, and the core
• How did geologists learn about the structure of the Earth's interior in the early 20th century?

  By studying the vibrations (seismic waves) generated by earthquakes
• What is the thickness of the Earth's crust under the oceans?

  Only a few miles (5 km) thick
• What is the average thickness of the Earth's crust under the continents?

  Averaging 20 miles (30 km) thick
• What happened to Gondwanaland 270 million years after its formation?

  It collided with the Euramerican continent to form Pangea.