Home › Subjects › O-Level Geography › Plate Tectonics (Topic 4.1)

O-Level Plate Tectonics (Topic 4.1)

the theory, its supporting evidence and what happens at plate boundaries

What the syllabus expects

• Plate tectonic theory holds that Earth's interior is made of core, mantle and crust, the crust being continental and oceanic, and explains how internal forces drive global plate movement.
  Scope: What the plate tectonic theory is
• Convection currents within the hot, softened mantle beneath the crust act as the driving force for the plates above.
  Scope: What the plate tectonic theory is
• The slab-pull force is the gravity-driven subduction of a denser oceanic plate that drags the rest of the plate along with it.
  Scope: What the plate tectonic theory is
• Seafloor spreading happens as magma rises through mid-ocean ridges and forms new oceanic crust.
  Scope: How seafloor spreading supports the plate tectonic theory
• Rock age offers evidence, with younger rocks lying nearer the crest of mid-ocean ridges and progressively older rocks found further from them.
  Scope: How seafloor spreading supports the plate tectonic theory
• Limited sediment build-up is further evidence, reflecting the destruction of older oceanic crust at trenches and oceanic crust being younger than continental crust.
  Scope: How seafloor spreading supports the plate tectonic theory
• Magnetic striping consists of normal and reversed polarity, appearing as bands of seafloor rock with alternating magnetic properties.
  Scope: How magnetic striping supports the plate tectonic theory
• Rock composition provides evidence, since basalt is a volcanic rock forming the oceanic crust and holds minerals that Earth's magnetic field can influence.
  Scope: How magnetic striping supports the plate tectonic theory
• Rock patterns show that alternating polarity produces a striped arrangement rather than random or isolated occurrences.
  Scope: How magnetic striping supports the plate tectonic theory
• At divergent boundaries the plates pull apart, producing earthquakes, rift systems, mid-ocean ridges and volcanoes such as volcanic islands and submarine volcanoes.
  Scope: What occurs at plate boundaries as plates move
• At convergent boundaries the plates push together, producing earthquakes, oceanic trenches, fold mountains and volcanoes such as submarine volcanoes.
  Scope: What occurs at plate boundaries as plates move
• At transform boundaries plates slide past one another, producing faults and earthquakes.
  Scope: What occurs at plate boundaries as plates move

How it's examined

About 2% of the past-paper style questions in Rae's bank for this subject sit in this topic.

More O-Level Geography topics

Thinking Geographically (Topic 1.1) · Sustainable Development (Topic 1.2) · Geographical Methods (Topic 1.3) · Tourism Activity (Topic 2.1) · Tourism Development (Topic 2.2) · Sustainable Tourism Development (Topic 2.3) · all of O-Level Geography