Crust
Composition: Silicon, Oxygen, and Aluminum
Types: › Continental Crust: solid & rocky outer layer› Oceanic Crust: thin & dense material
Lithosphere
Includes the Earth’s Crust & Upper Mantle
Divided into small and large tectonic plates that help move the continental and oceanic crust
Mantle
Composition: Silicon, Oxygen, and Magnesium
Thickest layer Convection currents are located here
Outer Core
Composition: Molten (liquid) Iron & Nickle
Inner Core
Composition: Solid Iron & Nickle Solid because of the pressure from the
layers above Solid inner core spins in the molten
(liquid) outer core› Creates the Earth’s Magnetic Field
Hottest layer
Convection Currents
Happens in the Middle Mantle› Has hot, dense rock that slowly flows
Movement created moves the tectonic plates in the Lithosphere
Caused by hot material, deep in the Mantle, being heated by the Core to rise then cool and sink again
Magma
Molten rock found beneath the Earth’s surface
Lava
Molten rock found on the Earth’s surface
Tectonic Plates Large pieces of Earth’s crust
(lithosphere) that can move, collide, or slide past each other
Causes:› Continental drifting› Earthquakes› Volcanoes› Mountains› Ocean trenches
Theory of Plate Tectonics States pieces of Earth’s lithosphere are in constant, slow motion, driven by convection currents in the Mantle
Explains: › Plate formation› Plate movement› Subduction of plates
Convergent Plate Boundary
Two tectonic plates moving toward each other and collide
Types = Creates: › Continental-continental = Mountains & their
ranges› Oceanic-oceanic = Island Arcs› Continental-oceanic = Subduction Zone &
Trenches
Divergent Plate Boundary
Two tectonic plates moving away from each other
Creates: › Volcanoes› Mid-Ocean Ridge› New Ocean Floor› Rift Valley
Transform Plate Boundary
Two tectonic plates that move or slide past one another› Opposite or same direction at different rates
Creates: › Earthquakes› Fault lines
Continental Drift Theory
Continents have shifted their position over geologic time
One time, all land masses were connected to form Pangaea
Evidence: › Continents look to fit together› Minerals, fossils, and mountains now on
different continents would match if they were together
Evidence from Minerals, Fossils, and Mountains
Sea-Floor Spreading Theory
Magma and molten material rises from the convection currents to create a divergent boundary, separating plates
Helps move the continents Oceans are spreading ~2 cm per year Creates:
› New Ocean Floor Crust› Mid-Ocean Ridges
Subduction Process where the ocean floor sinks
beneath an ocean trench and melts back into the Mantle
Subduction