Structure of the Earth and Plate Tectonics

Structure of the Earth

Made up of 3 main layers

New node

Inner Core - Solid, 5000 - 6000 Celcius, 1220 km radius, contains with nickel alloy and a few unknown elements

Outer Core - Semi-solid ( viscous), 2300 km of thickness, hotter than inner core, contains with nickel iron alloy

New node

Mantle - 2900 km of thickness, 70% of earth's volume, elasticity properties,

The Crust - low temperature, contains with oxygen, silica, aluminium, iron, calcium, sodium

How do we know what the Earth is made of?

Geophysical surveys, seismic, gravity, magnetics, electrical, geodesy

PLATE TECTONICS

What lies beneath the tectonic plates?

Asthenosphere that makes up the tectonic plates

Its really hot (1-5 % liquid) (95 - 99 % solid) and had unstable properties

Plate Movement

"Plates" of lithosphere are moved around by the underlying hot mantle convection cell

What happens at tectonic plate boundries?

Three types of plate boundary

Divergent Boundries

Convergent Boundries

Continent- Continent Collision

Forming mountains, e.g. European, Alps, Himalayas

Continent - Oceanic Crust Collision

Called Subduction

Forming volcanos

Ocean- Ocean Collision

Transform Boundries

Where plates slide past each other

Volcanoes and Plate Tectonics

Pacific Ring of Fire - Volcanism is mostly focused at plate margins

Volcanoes are formed by subduction, rifting and hotspots

What are Hotspot Volcanoes?

Hot mantle plumes breaching the surface in the middle of a tectonic plate

Earthquakes and Plate Tectonics