EARTH SCIENCE

What to expect  Earth  Its layers  How they behave  How new mantel is created

Layers  2 types  Compositional  Mechanical

Compositional  Crust  Mantel  Core

Crust  Low density  Between 5-70 km thick  2 different types of crust  Continental Under continents Varies in composition Varies in thickness  Oceanic Under oceans Usually thinner (5-6 km) Mafic Uniform

Mantel  High density  Ultramafic silicate rock  Over 2900 km thick and makes up over 80% of the volume of the Earth.  The mantle is not molten!

Core  Iron and nickel  Liquid outer region  Solid center  The core is just over half the diameter of the Earth.

IMPORTANT  These compositional layers have sharp or abrupt boundaries between them.

Mechanical layers  Lithosphere  Asthenosphere  Mesosphere (lower mantel)  Outer core  Inner core

Lithosphere  Most ridged layer of the earth  About 100 km thick  Really thin in mid ocean ridges  Thicker under continents

Asthenosphere  Plastic (kind of solid but it moves)  About 100 km thick

Mesosphere  Ridged (still can move, but less than asthenosphere)  Takes up the rest of the mantel

Outer core  Liquid  Mostly iron and some other elements  Actually a liquid (ONLY LAYER THAT IS TRUELLY A LIQUID)  km thick

Inner core  Ridged/solid  Same composition as the outer core, just in solid form  About ½ the size of the overall core  km thick