Download and at the subduction zones Lesser Antilles Subduction Zone

Notes= Yellow
 There
are two ways that scientists label
the layers of the Earth.
• Composition layers
• Physical layers
 These
are the more familiar layers. They are:
• Crust
 Ranges from 5 to 100 km in thickness
 Thinnest layer of the Earth
 Split into two types: Continental and Oceanic
• Mantle
 Roughly 2900 km thick
 No one has ever drilled to the mantle. It is also very hot
• Core
 Mostly made of iron and nickel
 The core’s diameter is roughly 6856 km (about the size of
Mars)
 The
less familiar layers are the physical layers.
They are based on how the layer looks or acts.
• Lithosphere “rock sphere” (15-300 km)
 The tectonic Plates
 A combination of crust and the upper region of the mantle
 Cold and brittle (easily broken)
• Asthenosphere “weak sphere” (250 km)
 Hard rock that acts like warm tar or honey
• Mesosphere “middle sphere” (2550 km)
 Rest of the mantle
 Much stronger and hotter than the Asthenosphere
• Outer Core (2200 km)
 Liquid layer
• Inner Core (diameter= 2456 km)
 Solid, dense core of the planet
 Did
you know?...
• The center of the Earth’s core is hotter than the
surface of the sun. The temperature of Earth’s
inner core reaches 6000 °C whereas the surface
of the sun is roughly 5500 °C.
 The sun’s core, however, is 15,000,000 °C
Crust
Mantle
Lithosphere
Asthenosphere
Mesosphere
Core
Outer Core
Inner Core
 Theory
by Alfred Wegener
 Continental
drift is the theory that continents
can drift apart from one another and have done
so in the past.
• Puzzling observations that could be explained by
continental drift:
 Puzzle-like fit of the continents
 Fossils of the same plants and animals found on both sides of
the Atlantic Ocean
 Strange grooves cut by ancient glaciers that line up
 With
the idea that continents can drift
apart, scientists felt that some force had
to be making these continents move.
 The
theory of plate tectonics developed
as a way to explain continental drift
 Tectonic
plates are large pieces of the
lithosphere that move around on top of
the asthenosphere like icebergs in the
ocean.
 There are 10 major plates
The Core
•solid inner
•liquid outer
•density of 10-13 gm/cm³
The Mantle
•surrounds the core
•density of 3.3-5.7gm/cm³
•three distinct zones
The Crust
•oceanic - 3 gm/cm³
•continental - 2.7 gm/cm³
Plate Tectonic Theory explains
the interactions of these zones
 Plate
tectonics is the theory that the
Earth’s lithosphere is divided into large
tectonic plates that move around on top
of the asthenosphere.
• All plates share boundaries with other plates,
just like states share borders.
 There are three main types of boundaries
• Convergent
 When plates push against each other
• Divergent
 When plates move away from each other
• Transform
 When plates slide against each other
 Online
animations
crust
mantle
Outer core
Inner core
Inner core is solid and
made of iron and nickel
Outer core is liquid and
made of Fe, N, and
lighter elements
Mantle is largest layer
and is plastic-like
(asthenosphere)
Two (2) types of crust—
continental (made of
silicon and oxygen) and
oceanic (made of iron
and magnesium)
Joshua and Jennifer Mosser, Briar Woods High School
 This
movement of
heat energy causes
the tectonic plates to
move.
 When
oceanic plates
collide with another
oceanic plate or a
continental plate, one
may be pushed
under the other
causing magma to
rise thus forming
volcanoes.
 This
movement of
heat energy causes
the tectonic plates to
move.
S-wave shadow zone
P-wave shadow zone
Mantle
INNER CORE
How the Earth’s Core affects the travel of seismic
waves. (After C.F. Richter (1985) Elementary Seismology, W.H. Freeman)
Volcanoes form at the ridge(s) and at
the subduction zones
Lesser Antilles Subduction Zone
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