GEOGRAPHY PAPER 1 PLATE TECTONICS

• What does the theory of plate tectonics describe?

  The movement of Earth's crust
• The Earth's crust is composed of a single, continuous plate.

  False
• Plate boundaries where plates move apart are called divergent
• What is formed at divergent plate boundaries in the ocean?

  Mid-ocean ridges
• Steps in the formation of a mid-ocean ridge

  1️⃣ Molten rock rises from the mantle

  2️⃣ Rock cools and solidifies

  3️⃣ New crust is added to the plate
• Subduction occurs at convergent plate boundaries.
• When two continental plates collide, they form mountains
• What is the Ring of Fire known for?

  Volcanic activity
• Match the type of plate boundary with its characteristic feature:

  Divergent ↔️ Mid-ocean ridge

  Convergent ↔️ Deep ocean trench

  Transform ↔️ Earthquakes
• The San Andreas Fault is an example of a transform
• Earthquakes occur only at transform plate boundaries.

  False
• What are the primary causes of plate movement?

  Convection currents in the mantle
• Steps in the process of convection currents in the mantle

  1️⃣ Heated mantle rock rises

  2️⃣ Rock cools and sinks

  3️⃣ Circular motion drives plate movement
• Volcanoes can only occur at plate boundaries.

  False
• Volcanoes that are not associated with plate boundaries are called hotspots
• What is the process by which molten rock escapes the Earth's surface?

  Volcanic eruption
• What is the diameter of the Earth's inner core?

  About 1400km
• The outer core is a semi-molten metal layer with temperatures between about 5000-5500°C
• What is the approximate thickness of the Earth's mantle?

  2900km
• The Earth's crust is made up of two types: continental and oceanic.
• The oceanic crust is thinner but heavier and denser than the continental crust.
• What is the typical thickness of the oceanic crust?

  5-10km
• Continental crust is much older than oceanic crust because it is continually created and destroyed by plate movement.

  False
• Stages in the process of ridge push and slab pull

  1️⃣ New crust forms at constructive boundary

  2️⃣ Older crust is pushed away

  3️⃣ Denser oceanic plate subducts

  4️⃣ Weight of subducting plate drags the rest of the plate
• At a ridge push boundary, new crust forms and pushes the older crust away
• What causes the weight of the denser oceanic plates to subduct in slab pull theory?

  Gravity
• Earthquakes most commonly occur along the Pacific 'Ring of Fire'.
• What percentage of active volcanoes are located around the Pacific 'Ring of Fire'?

  75%
• The Mid-Atlantic Ridge is an example of a constructive plate boundary.
• Both volcanic eruptions and earthquakes can occur at a constructive plate boundary.
• What type of plate boundary is formed when the Nazca plate subducts under the South American plate?

  Destructive
• At a collision boundary, two continental plates collide, forming fold mountains such as the Himalayas.
• Earthquakes are the only hazard at a conservative plate boundary.