Chapter 04: Earth's Structure & Plate Tectonics Flashcards
Earth’s structure/layers
Lithosphere (crust)
Made up of lithospheric plates
Asthenosphere
“Silly putty” layer on which lithospheric plates move, part of mantle
Mantle
Where convection cells are; flows of melted rock
Outer core
Liquid iron and nickel
Inner core
Solid iron and nickel (solid because of pressure)
Deduction of Earth’s interior
Layers identified by studying seismic waves
Waves refract, reflect, and change velocity as they encounter different material
Earth’s magnetic field
Created by core
Inner core is solid, rotates faster than outer core
Earth’s internal heat
Heat is slowly being lost (net loss is greater than net gain of heat)
Heat formed from:
- friction & pressure
- radioactive decay of Uranium, Thorium, and Potassium
Convection cells
Less dense rock rises, cools, becomes more dense and descends back down to hotter portion of mantle to repeat cycle
These cells are the mechanism for the movement of lithospheric plates
Divergent plate boundary
Associated with:
tensional stress
normal faulting (rock dropping down)
ocean ridges
rift valleys
enlarging oceans
earthquakes, volcanoes
Convergent plate boundary
Associated with:
compressional stress
reverse faulting (rock being pushed up)
subduction or folding
mountains
volcanoes, earthquakes
trenches (of subduction)
Transform plate boundary
Associated with:
shearing stress
strike-slip or lateral faulting
Lithospheric plates (8)
North American (moving W, NW)
Pacific (moving N, NW)
Juan de Fuca (moving E)
Eurasian + Indian (converging)
African + Arabian (diverging)
Arabian + Eurasian (converging)
Indo-Australian + Eurasian (converging)
Plate boundaries and people (4 points)
Natural hazards (earthquakes, volcanic eruptions, landslides)
Natural resources
Climate
Development of life
How do we know core’s composition?
Seismic waves have been observed to travel in a way that indicates iron and nickel
Asteroids are predominantly iron
