The Earth Structure and Composition - Lec 1 part 2

Crust

Composition: high Si, Al, & O
Thickness, km: 5 to 70

Mantle

Composition: moderate Si, high Mg & Fe
Thickness, km: 2,900

Core

Composition: Fe & Ni
Thickness, km: 3,500

Oxygen

Most abundant element of the earth’s crust at 46.6%

Silicone

Second most abundant element of the earth’s crust at 27.7%

Crust

• The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.
• Chemically distinct from the underlying mantle.
• Depth: 0 - 100km silicates

Mantle

• Layer between the crust & outer core
• chemically distinct from the crust and the outer core
• not liquid, however, ductile, or plastic, which means that on very long time scales and under pressure it can flow
• mainly composed of aluminum and silicates
• Depth: 100 – 2,900 km iron and magnesium silicates

Core

• innermost layers
• chemically distinct from the mantle
• mainly composed of nickel and iron.
• Depth: 2,900-6,370 km metals

Lithosphere

• The outermost, rigid layer of the Earth.
• Made of two parts: the crust and the Moho (upper solid part of the mantle).
• Divided into pieces called tectonic plates.

Asthenosphere

• The soft layer of the mantle on which the lithospheric plates move.
• It is made of solid rock like putty that flows very slowly – about the same rate your fingernail grows.

Mesosphere

• The strong, lower part of the mantle.
• Extends to the Earth’s core.

Outer Core

• Extends from the bottom of the mantle and surrounds the inner core.
• Liquid and hot
• Composed of liquid iron and nickelI

Inner Core

• Solid (Due to pressure from upper layers.)
• Composed of iron.