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