Download earth structure ppt

Earth’s Structure
Earth’s Structure
Structure of the Earth
Chemical Composition
 The chemical makeup of
Earth's materials
 Crust – average depth 30 km
outermost layer
Low density rock
Silicate minerals (silicate
and oxygen)
 Mantle – largest volume
30 m -2900 km
high density Iron and
magnesium silicate
 Core – 2900 km – 6370 km
large mass, higher density
metal, iron and nickel
Physical Composition
 How rocks respond to increased
temperature and pressure at depth
 Based on physical properties, Earth is
composed of five layers





Inner Core
Outer Core
Mesosphere
Asthenosphere
Lithosphere
Lithosphere
 Earth’s cool, rigid, outermost layer
 Extends from surface to 100 km
 Includes the crust plus the topmost
portion of the mantle
 Brittle – it will fracture when force is
applied to it
SUBDIVIDED
oceanic crust
continental crust
Oceanic Crust
 Composed of Igneous rock basalt
 Dark colored
 Relatively high density ~3.0 g/cm3
 Average thickness ~ 8 km (5 miles)
 Originates as molten magma beneath the
Earth’s crust
Continental Crust
 Composed of lower density, lighter colored igneous rock
granite
 Density ~ 2.7 g/cm3
 Originates beneath the surface as molten magma.
 Average thickness is about 35 km (22 miles)
 May reach a maximum of 60 km (37 miles)
 Highest mountain ranges
Asthenosphere
 Weak ball
 Plastic - will flow when a gradual force is
applied
 From 100 km to 700 km
 Base of upper mantle
 Hot enough to partially melt portions of
most rocks
Mesosphere
 Middle ball
 Extends to 2885 km
 Middle to lower mantle
 Deforms plastically
 Rigid due to increased pressure
Outer Core
 Liquid
 Capable of flowing
Inner Core
 Rigid
 Does not flow
 due to increased pressure
Composition of the Earth Video
 The compostion of the Earth