Science, Plate Tectonics Flashcards
Four layers of the earth:
Crust: Solid
Mantle: Hot and dense
Inner Core: Liquid
Outer Core: Solid
Why do plates move?
Convection currents in the mantle cause the solid rock to circulate, pushing and pulling on the crust, causing plate movement.
What causes convection currents?
Heat from earth’s core causes material to rise and heat, then sink and cool in a continuous cycle. This ultimately drives movement of the crust
What is a convergent boundary?
When two tectonic plates collide with one another
What are the different types of convergent boundaries and what are their effects?
- Subduction zone
- Island arc
- Collision zone
Convergent boundary: Subduction zone
- Oceanic plate sinks below continental plate
- Volcanoes, mountains, earthquakes, ocean trenches
Convergent boundary: Island arc
- Two oceanic plates, older plate sinks below younger plate
- Volcanoes, earthquakes, ocean trenches
Convergent boundary: Collision zone (or uplifting)
- Two continental plates, same density: both rise upwards
- Earthquakes, mountains
What are the different types of divergent boundaries and what are their effects?
- Rift zone
- Mid-ocean trench
- Continental rift
Divergent boundary: Rift zone
- Two continental plates
- Rifts / valleys, earthquakes, volcanoes
Divergent boundary: Mid-ocean ridge
- Two oceanic plates
- New seafloor, mountains, volcanoes, earthquakes
Other key words:
Seafloor magnetism
Seafloor spreading
Divergent boundary: Continental rift
- Continental and oceanic plate
- New seafloor, rift / valley (underwater), volcanoes, earthquakes
What are volcanic hotspots?
Volcanic hotspots are when there is a mantle plume inside of the mantle, from which magma erupts. The mantle plume, although stationery, the plates above it move along it. This creates volcano chains over millions of years, with the most active volcano being the one right above the hotspot.
Transform boundary
- Plates slide past each other
- The friction generated through the sliding creates earthquakes
