Chapter 5.1 Notes Earth’s Interior

Exploring the Earth Geologists use two types of evidence to learn about the Earth’s interior: -direct evidence from rock samples -indirect evidence from seismic wavesseismic waves *the deeper into the Earth you go, the greater the temperature and pressure

Layers of the Earth The Earth is divided into four layers: -crust -mantle -outer core -inner core

Layers of the Earth The crust: definition – a layer of solid rock that includes both dry land (continental crust) and the ocean floor (oceanic crust)

Layers of the Earth The crust:

Layers of the Earth The crust: definition – a layer of solid rock that includes both dry land (continental crust) and the ocean floor (oceanic crust) thickness - the crust can range between 5 and 70 kilometers thick -thickest under mountain ranges -thinnest under the ocean composition – -continental crust mainly made of granite -oceanic crust mainly made of basalt

Layers of the Earth The crust:

Layers of the Earth The mantle: definition – The mantle is made of solid rock that is very hot. It is separated into 3 layers. The lithosphere, the asthenosphere and lower mantle. thickness – almost 3,000 kilometers composition – silicon, magnesium and iron

Layers of the Earth The mantle: -lithosphere – solid rock, similar to the crust - temperature is between 1400°C and 3000°C -the deeper you go, the rock begins to become “softer”

Layers of the Earth The mantle: -athenosphere – increased temperature and pressure continue to soften the rock -temperature is at or above 3000°C -convection currents occur in this section -hotter rock rises and cooler rock sinks

Layers of the Earth The mantle: -lower mantle – solid layer of rock that surrounds the outer core -temperature reaches almost 4000°C

Layers of the Earth Outer core: definition – the outer core is a layer of liquid rock the moves around the inner core thickness – almost 2,300 kilometers composition – mainly iron and nickel, some sulfur, oxygen and silicon temperature – between 4000°C – 5000°C

Layers of the Earth Inner core: definition – The inner core is a solid ball of metal, due to the extreme temperature and pressure. thickness – over 1,200 kilometers composition – mainly iron and nickel, some sulfur, oxygen, carbon and silicon temperature – between 5000°C – 6000°C