PLATE BOUNDARIES

🌍 Plate boundaries: locations, causes, features & characteristics

1. Constructive boundaries

Movement: Plates move apart
Cause: Convection currents bring magma up, creating new crust

Locations:

  • Mid-Atlantic Ridge

  • East African Rift

Features & characteristics:

  • Mid-ocean ridges / rift valleys

  • Gentle volcanic activity

  • Shallow earthquakes

  • New crust formed

  1. Destructive boundaries

a) Oceanic + continental

Movement: Plates move together; oceanic plate subducts
Cause: Oceanic plate is denser

Location:

  • Andes Mountains

Features:

  • Fold mountains

  • Explosive volcanoes

  • Deep ocean trenches

  • Strong earthquakes

b) Oceanic + oceanic

Movement: One oceanic plate subducts beneath the other

Location:

  • Mariana Trench

Features:

  • Island arcs

  • Volcanoes

  • Deep-sea trenches

  • Earthquakes

  1. Collision (continental + continental)

Movement: Plates collide, no subduction
Cause: Both plates are too buoyant to sink

Location:

  • Himalayas

Features:

  • Fold mountains

  • No volcanoes

  • Strong earthquakes

  • Thickened crust

4. Conservative boundaries

Movement: Plates slide past each other
Cause: Plates moving in different directions/speeds

Location:

  • San Andreas Fault

Features & characteristics:

  • No crust created or destroyed

  • Frequent earthquakes

  • No volcanoes

  • Fault lines