Layers of the Earth Geosphere
The Earth as a System • Integrated system of rock, air, water, and living things. • This system is divided into four parts: • atmosphere (air) • hydrosphere (water) • biosphere (living things) • geosphere (rock)
Geosphere • Solid part of the Earth’s crust that consists of all rock, and the soils and sediments on Earth’s surface. • Most located in Earth’s interior
Earth’s Interior • Seismic Waves: the waves that travel through the Earth’s interior during an earthquake. • Altered by the type of material that it travels through.
Seismologists • Scientists who measure changes in these waves to determine that the earth’s interior is made in layers.
Composition of the Earth • Three layers: • crust • mantle • core • Density increases towards the center of the Earth
Crust • Thin, outer layer. • Made up of light elements • less than 1% of Earth’s mass • 5-70km thick
Mantle • Layer beneath the crust • 64% of mass of Earth • 2,900 km thick • Made of • lithosphere • asthenosphere • mesosphere
Lithosphere • Outer layer • cool, rigid • divided up into huge tectonic plates
Asthenosphere • 250 km thick • solid, plastic layer made of rock • flows very slowly and allows tectonic plates to move across
Mesosphere • 2,250 km thick • “middle” sphere • lower part of mantle
Core • 3,248 km radius • sphere of hot, dense nickel and iron • 4,000 - 5,000 °C • 1/3 of the Earth’s mass • Made of • Outer Core • Inner Core
Outer Core; 2,200 km thick, outer shell, made of liquid nickel and iron • Inner Core: 1,228 km radius; a sphere of solid iron and nickel
First Life??? • First life may have first evolved deep in the crust and then migrated to the surface when conditions became favorable. • “extremophiles” • Hypothesized that the biomass below the surface far exceeds the biomass at the surface.
Be able to draw and label the three layers of the earth (crust, mantle, and core) as well as the 5 layers based on physical properties (lithosphere, asthenosphere, mesosphere, outer and inner core).