Download Chapter 3 Geosphere

Chapter 3
The Dynamic Earth
The Earth as a System
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Earth is an integrated system that
consists of 4 parts.
– Rock, air, water, living things
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Four interactive parts
– Geosphere (rock)
– Atmosphere (air)
– Hydrosphere (water)
– Biosphere (living things)
Geosphere
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Solid part of the earth (rock, soils, and
sediments)
Most of geosphere located in earth’s
interior.
The Atmosphere
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Mixture of gases that makes up all of
the air we breathe.
The Hydrosphere
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Makes up all of the water on or near
the earth’s surface.
Much of the water is in the oceans.
Water is also found in atmosphere, on
land, and in soil.
The Biosphere
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Made up of parts of the
geosphere, atmosphere
and hydrosphere.
Part of the earth where
life exists.
Extends from 9km
above the earth’s
surface down to the
bottom of the ocean.
Discovering Earth’s
Interior
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Scientists use seismic waves to learn
about Earth’s interior.
Seismic Waves: same waves that
travel through earth’s interior during
an earthquake.
The Composition of the Earth
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Earth: divided into 3 layers based on the
composition on each layer
– Crust, Mantle, Core

Made of progressively denser materials
toward the center of the earth.
The Crust
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Made almost entirely of light elements.
Makes up less than 1% of the planet’s
mass.
Thinnest layer.
5km to 70km thick
The Mantle
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Layer beneath crust.
Makes up 64% of the mass of earth.
Approx. 2,900 km thick. (1,802 miles)
Made of rocks of medium density.
The Core
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Composed of the densest elements.
Radius of approx. 3400 km.
The Structure of the Earth

Earth can be divided into five layers
based on physical properties of each
layer.
1. Lithosphere: outer layer; cool, rigid,
15km-300km thick. Includes crust and
uppermost layer of mantle. Divided into
tectonic plates.
2. Asthenosphere: beneath the lithosphere. Made
of rock that flows very slowly and allows tectonic
plates to move on top of it.
3. Mesosphere: lower part of the mantle.
4. Outer core: made of liquid nickel and iron.
5. Inner core: sphere of solid nickel and iron.
Plate Tectonics
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Lithosphere is divided into tectonic
plates.
Plates glide across the underlying
asthenosphere.
Major tectonic plates: Pacific, North
American, Cocos, Nazca, South
American, Eurasian, Indian, Australian,
Antarctic
Plate Boundaries

Much of the geologic activity at surface of earth
takes place at boundaries between tectonic
plates.
Plate Tectonics and
Mountain Building

When tectonic
plates collide, crust
becomes thicker
and eventually
forms mountain
ranges.
Earthquakes

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Fault: break in earth’s crust along which
blocks of the crust slide relative to one
another.
Majority of earthquakes take place at or
near tectonic plate boundaries.
When rocks that are under stress break
along a fault, ground vibrations are set off.
-Richter scale: used to quantify the amount
of energy released by a earthquake.
Volcanoes
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Mountain built from magma.
Often located near tectonic boundaries
where plates are either colliding or
separating from one another.
May occur on land or under sea.
Local Effects of Volcanic
Eruptions
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Volcanic ash can
mix with water and
cause mudflows.
Entire cities can be
engulfed.
Global Effects of Volcanic
Eruptions
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Can change earth’s climate.
Can reduce sunlight exposure.
Can reduce global temperature.
Erosion
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Removal and
transport of surface
material.
Can be either
caused by water or
wind