INSIDE EARTHCHAPTER 1: PLATE TECTONICS

Section 1: Earths Interior

GEOLOGY

 Geology: the study of planet Earth

Geologists study the processes that create Earth’s features and search for clues about Earth’s history Geologists have to make predictions about what the Earth’s

interior is made of by making indirect observations of seismic waves

Forces beneath the Earth’s surface change the Earth’s appearance. There are two types of forces:

CONSTRUCTIVE VS. DESTRUCTIVE FORCES

Constructive: forces that build up mountains and landmasses

Destructive: forces that destroy mountains and other features of land

CONTINENTS Continents: the

seven great landmasses surrounded by oceans the seven

continents:1. North America2. South America3. Africa4. Europe5. Asia6. Australia7. Antarctica

GEOLOGISTS CANNOT OBSERVE EARTH’S INTERIOR DIRECTLY.

Use seismic waves: vibrations that travels through Earth, carrying the energy released during an earthquake

determine the speed and path of these waves to reveal the inner Earth’s structure

TEMPERATURE AND PRESSURE

As the depth of the Earth increases, so does the pressure and temperature.

Pressure: amount of force pushing on a surface (huge amount of pressure on the core)

EARTH IS MADE UP OF 3 MAIN LAYERS

1. CRUSTCrust: Layer of rock that forms Earth’s

outer skin (made of Oxygen, Silicon, Aluminum, Calcium, Iron, Sodium, Potassium and Magnesium)

Includes soil and water 8-40 km thick

Oceanic Crust: crust beneath the ocean Thin layer of crust Made of- basalt: dark dense rock with a fine

texture Continental Crust: crust that forms the

continents Thicker layer of crust Made of granite- rock that has larger

crystals basalt and is not as dense; usually light in color

2. MANTLE

Mantle: a layer of hot rock under the Earth’s crust (made of Iron, oxygen, Silicon and Magnesium)

Lithosphere: a rigid layer made up of the uppermost part of the mantle and the crust; about 100km thick- (tectonic plates) Under the Lithosphere is a layer of hot rock Temperature and pressure in the mantle increase

with depth Asthenosphere: thick, soft material that

flows in the mantle; about 3,000km thick; moves in a convection current

CORE

3. Core: innermost layer of Earth; consists of 2 parts (made of iron and nickel)

Outer Core layer of molten metal that surround the inner

core Behaves like a thick liquid Is under enormous pressure

Inner Core Dense ball of solid metal Extreme pressure makes it a solid

MAGNETIC FIELD

The Earth has a magnetic field that is caused by the inner core spinning within the outer