Inside the Earth : Inside the Earth Layers of Earth
According to composition Earth is divided into : According to composition Earth is divided into Crust
Mantle
Core
Slide 3 : Layers of the EARTH CRUST MANTLE OUTER CORE INNER CORE
Composition (What it is made of) : Composition (What it is made of) Crust
Mantle
Core
The Crust : The Crust Outer thinnest layer
5-100 km thick
The layer we live on
2 types of crust
Oceanic (very dense, made of basalt, 5-8 km thick)
Continental (less dense, made of granite, around 30 km thick)
Oceanic and Continental Crust : Oceanic and Continental Crust
The Mantle : The Mantle Thicker than crust
Between crust & core
2,900 km thick No one sees it, too far to drill down to it
Seen only when molten rock comes out from mantle (volcanoes/vents)
Similar to olivine
Much iron/magnesium
The Core : The Core Made mostly of iron,some nickel, sulfur and oxygen
Extends from bottom of mantle to the center of Earth
1/3 of the earth’s mass (33% of the mass)
6,856 km in diameter
Very hot
Earth’s Layers : Earth’s Layers How are the earth’s layers similar to an egg?
Shell=?
Egg white=?
Yolk=?
According to it’s physical structure Earth is divided in to 5 Layers : According to it’s physical structure Earth is divided in to 5 Layers Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
Lithosphere : Lithosphere Outermost layer
Rigid like rock
Made of crust and rigid outer part of mantle
Divided into large pieces called tectonic plates
Asthenosphere : Asthenosphere Under lithosphere
Weak
Made of soft layer of mantle (hot) on which pieces of lithosphere float
(it’s solid but acts like putty that flows slowly)
Mesosphere : Mesosphere Below the asthenosphere
Made of strong lower part of mantle (due to pressure)
“middle sphere”
Extends from the asthenosphere to the Earth’s core
Outer Core : Outer Core Liquid layer of the Earth’s core
(lies beneath the mantle and surrounds the inner core)
Inner Core : Inner Core Solid, dense center of the core
Extends from bottom of outer core to the center of Earth
Tectonic Plates : Tectonic Plates These are pieces of the lithosphere that move around on top of the asthenosphere
(think of the lithosphere as a giant jigsaw puzzle)
Tectonic Plates : Tectonic Plates Tectonic plates have names
(Pacific plate, North American Plate, African plate etc.)
Notice that the plates lie under oceans as well
The plates fit together like a jigsaw puzzle
Plates differ in size
Some plates have both continental crust on them, while others only have oceanic crust
Which plates have continental and oceanic crust and which only have oceanic crust? : Which plates have continental and oceanic crust and which only have oceanic crust?
A tectonic plate close upPage 171 : A tectonic plate close upPage 171
Tip of the Icebergpg 171 : Tip of the Icebergpg 171
Difference between Crusts : Difference between Crusts Continental Crust
Similar to granite
Average thickness 30 km
Thicker
Less dense Oceanic Crust
Similar to basalt
Average thickness 5-8 km
Thinner
denser