Geology

GEOLOGY Geology = The study of Earth DEFINITION Greek Earth

INNER CORE HOT!!!! – Thought to be as hot as the surface of the Sun! Solid Composed of Iron and Nickel

OUTER CORE HOT! (but not as hot as the inner core) Liquid Composed of Iron and Nickel

MANTLE Still hot! – but not as hot as the core! Largest layer Composed of various materials Solid and liquid

CRUST Cool What we live on Composed of rocks, various materials make up the crust Solid or Liquid?

SOLID!!!! Even though 70% of the Earth’s surface is water, there is crust under the water. The water sits on top of the crust!

The Earth’s crust moves!!!!! The continents have not always been arranged like they are today. - The Earth’s crust is divided into segments called plates.

Pangaea Supercontinent that existed 250 million years ago All the land made up 1 continent until its split into the modern day configuration of the continents. Discovered by Alfred Wegner in 1912, but not accepted by the public until after his death in the 1950’s.

Earth’s internal heat engine 3 reasons for internal heat: from impact during Earth formation 2) radioactive decay of uranium, thorium, potassium 3) heat released as inner core forms Ways to transfer heat: 1) conduction - motion of atoms 2) convection - mass movement of material

Convection in the Mantle Drives Plate Tectonics! But how?

Earth’s dynamic interior and crust Prelude: Plate Tectonics Earth’s dynamic interior and crust Heat loss drives plate tectonics Three types of plate boundaries

material, per unit volume. Usually given in grams per Density: Defined as the mass of a material, per unit volume. Usually given in grams per cubic centimeter (g/cm3). For comparison, the density of water is 1.0 g /cm3.

Earth’s internal heat engine Cooler materials are denser and sink. Hot materials are less dense and rise. Cooler materials are denser and sink.

Convecting materials in the Earth’s mantle originate deep, near the core-mantle boundary

Most heat from the deep interior is transferred to the shallow mantle by buoyant masses of hot, low density material called “plumes”.

Heat of the upper mantle sets up shallow convection cells that drive plate motions.

Plumes Create Volcanic Hotspots Hawaiian Islands

Earth’s internal heat engine See: MantleConvection.MOV

Consequences of Plate Motions: Mountain Building

Volcanic Activity Mt. Mayon, Philippines

Consequences of Plate Motions: Earthquakes!