Earth layers
Earth layers
Earth’s Layers
The Earth's rocky
outer crust solidified
billions of years ago,
soon after the Earth
formed.
This crust is not a
solid shell; it is broken
up into huge, thick
plates that drift atop
the soft, underlying
mantle.
Thickness of the layers
The Core
• Below the mantle
and to the center of
the Earth
• Believed to be mostly
Iron, smaller
amounts of Nickel,
almost no Oxygen,
Silicon, Aluminum, or
Magnesium
Inner core
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•
•
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Mostly solid iron
Hottest
Most pressure
Innermost layer
Outer core
• Above the inner core
• Liquid molten metal
The Mantle
• Layer of Earth
between the crust
and the core
• Contains most of the
Earth’s mass
• Has more
magnesium and less
aluminum and
silicon than the crust
• Is denser than the
crust
Mantle
•
•
•
•
•
Largest layer
Solid, but flows slowly like putty
Contains the most mass
Upper mantle part of lithosphere
Lower upper mantle is part of asthenosphere
Crust
•
•
•
•
•
Thinnest layer
Outermost layer
Coolest temp
Least pressure
2 types- continental crust (land) thickest
–Oceanic crust (located under ocean)
thinnest
Earth layers
Infer from the graphs about the Earth below,
what happens as the depth increases?
• The deeper inside Earth, the higher the
temperature and pressure.
• http://www.livescience.com/6959-holedrilled-bottom-earth-crust-breakthroughmantle-looms.html
Earth layers
• http://www.brainpop.com/science/earthsyste
m/earthsstructure/preview.weml
Tectonic Plates
Plate Tectonics
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•
•
•
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Greek – “tektonikos” of a builder
Pieces of the lithosphere that move around
Each plate has a name
Fit together like jigsaw puzzles
Float on top of mantle similar to ice cubes
in a bowl of water
Continental Drift
Alfred Wegener 1900’s
Continents were once a single
land mass that drifted apart.
Fossils of the same plants and
animals are found on different
continents
Called this supercontinent
Pangea, Greek for “all Earth”
245 Million years ago
Split again – Laurasia &
Gondwana 180 million years
ago
http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml
Evidence of Pangea
Lithosphere vs. asthenosphere
Lithosphere vs. asthenosphere
• What is the lithosphere?
crust and uppermost mantle
broken into 30 plates
• What is the asthenosphere?
plastic-like part of mantle under the
lithosphere
plates (lithosphere) move around on this
Lithosphere vs. asthenosphere
Lithosphere vs. asthenosphere
Plate tectonics
• BrainPOP “Plate tectonics”
• http://www.brainpop.com/science/earthsyste
m/platetectonics/