Download - Frost Middle School

What are the layers of the
Earth
• Crust
• Thin layer of rock
• Surrounds Earth like a shell surrounds an egg
• Two types of crust
• Continental crust
• Makes up the continents and some major islands
• Oceanic crust
• Makes up the ocean floor
• Between 6-70 km thick (about 3.7 – 43.5 miles)
• Furthest we have ever been in 12.3 Km (7.6 miles)
Two Kinds of Crust
• Continental Crust
• Thicker of the two
• Less Dense
• Composed mostly of Granite
• Avg. of 30 – 40 Km thick (19 – 24.9 Miles)
• Oceanic Crust
• Thinner of the two
• More Dense
• Composed mostly of Basalt
• Avg. of 6 – 11 Km thick (3.7 – 6.8 Miles)
Mantle
• Thickest Layer of Earth
• Made mostly of Hot Molten Rock
• Very, Very top is cool ridged rock
• About 2900 Km (1802 miles)
• 870 – 4400 C (1598 – 7952 F)
Outer Core
• Layer of liquid metal
• Iron & Nickel
• 2300 Km (1429 Miles)
• 4400 – 6100 C (7952 – 11,012 F)
• There is more pressure than the mantle
but less pressure than the inner core
Inner Core
• Solid ball of metal
• Iron & Nickel
• 2400 Km in diameter (1491 Miles)
• 7000 – 8000 C (12,632 – 14,432 F)
• Extreme pressure keeps it solid
• Densest layer of the Earth
Lithosphere
• Made up of the crust and very top rigid part of
the mantle
• This is what the tectonic plates are made of
• Most plates have both continental and oceanic
crust
• On continents it is believed to be an average of
150 Km (93 miles)
• In ocean it is believe 50-100 Km (31 – 62 miles)
Asthenosphere
• The hot soft layer of molten rock in
the middle mantle on which the
lithosphere rests
• Flows slowly like hot tar
• Estimated to be 85- several hundred
Km thick (50 – several hundred miles)