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Chapter 8
Earth Systems and Resources
The Earth’s resources were
determined when the planet
formed.
The Earth’s resources were
determined when the planet
formed.
•Earth was formed roughyly 4.6 billion years
ago.
•Molten material slowly cooled, separated
into layers based on mass.
The Earth’s Layers
Core- the innermost zone of the
planet made of nickel and iron.
 Mantle- above the core containing
magma
 Crust- the outermost layer of the
planet.

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The Earth’s Layers
Asthenosphere- the outer part of
the mantle, composed of semimolten rock.
 Lithosphere- the brittle
outermost layer of the planet
that is approximately 100 km
thick. (smaller plates)

Checkpoint…



How did Earth form?
What is the composition of each of Earth’s
layers?
What is the practical significance today of the
way Earth’s resources were distributed when
the planted formed and cooled?
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Earth is dynamic and constantly
changing…

Earth’s geologic cycle consists of 3 major
prcesses:
 Tectonic cycle
 Rock cycle
 Soil formation
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Convection and Hot Spots




The Earth is very hot at the center.
This heat causes plumes of hot magma to well
upward from the mantle. (convection)
High temp. of mantle and outer core – due to
radioactive decay.
Hotspots- places where molten material from the
mantle reach the lithosphere.
Theory of Plate Tectonics





Plate tectonics- the theory that states that Earth’s
lithosphere is divided into plates, most of which are in
constant motion.
Alfred Wegener – German
meteorologist – 1912.
Pangea
Tectonic cycle – sum of the
Processes that build up and
Break down the lithosphere.
Continental vs Oceanic plates
Theory of Plate Tectonics
Tectonic Plates


Sea floor spreading – slow drifting of plates,
rising magma forming new crust on seafloor.
Subduction – heavier oceanic plate sliding
below lighter continental plate
13
Consequences of Plate
Movement
Consequences of Plate
Movement

Volcanoes- as a plate moves over
a hot spot, rising magma forms a
volcano.
Types of Plate Contact

Divergent plate boundaries- when plates move
apart from one another. (sea-floor spreading)
 OCEAN ----------------- OCEAN

Convergent plate boundaries- when plates move
toward one another and collide. (subduction)
 OCEAN---OCEAN

OCEAN--CONTINENTAL
Transform fault boundaries- then plates move
sideways past each other.
 CONTINENTCONTINENT
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Faults and Earthquakes




Faults- a fracture in rock across which
there is movement.
Earthquakes- occur when the rocks of
the lithosphere rupture unexpectedly
along a fault.
(transform fault
boundary )
Faults and Earthquakes




Fault zone- large expanses of rock where
movement has occurred.
Fault – fracture in rock where there is
movement.
Epicenter- the exact point on the surface
of Earth directly above the location
where the rock ruptures.
Seismic activity occurs at fault zones or
areas where earthquakes are common.
Environmental and Human Toll
of Earthquakes and Volcanoes



Richter scale- a measure of the largest ground
movement that occurs during an earthquake.
The scale increases by a factor of 10, so an
earthquake of 7 is 10 times greater than an
earthquake of 6. (logarithmic)
Bill nye – Earthquakes!
http://www.bing.com/videos/search?q=bill+nye
%2c+earthquakes&view=detail&mid=9024D15
A0C1A5F56168C9024D15A0C1A5F56168C&fi
rst=0&FORM=NVPFVR
22
Check point…

What is the theory of plate tectonics?

What are some environmental
consequences of the tectonic cycle?

How do earthquakes and volcanoes occur?
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The Rock Cycle

Rock cycle- the constant formation
and destruction of rock.
The Rock Cycle
(Constant formation and destruction of rock)

Rocks are the substance of the lithosphere

Rocks are composed of minerals


Minerals – solid chemical substances with uniform
(often crystalline) structures that form under specific
pressure and temp.
Can be made of compounds or one single element.
The Rock Cycle

Igneous rocks- rocks that form directly from magma.
 Intrusive igneous- form from within Earth as magma
cools.
 Extrusive igneous- from when magma cools above Earth.
(ex. A volcano that ejects magma out will form this)


Sedimentary rocks- form when sediment such as
mud, sands, or gravels are compressed by overlying
sediments.
Metamorphic rocks- form when sedimentary,
igneous or other metamorphic rocks are subjected to
high temperatures and pressures.
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Weathering and Erosion

Weathering- when rocks are exposed to
air, water, certain chemicals or biological
agents that degrade the rock.
 Physical weathering- the mechanical
breakdown of rocks and minerals.
Weathering and Erosion

Chemical weathering- the breakdown
of rocks and minerals by chemical
reactions.

Acid rain
Erosion


Erosion- the physical removal of rock
fragments from a landscape or ecosystem.
Wind, water, ice transport and living
organisms can erode materials.
Deposition- the accumulation or depositing
of eroded material such as sediment, rock
fragments or soil.
Check point…

What is the rock cycle?

What re the 3 basic rock pes, and how is each
formed?

What is the difference between weathering and
erosion? Why are both important?
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Soil


Mix of geologic and organic components.
Soil is important because it
 Is a medium for plant growth
 Serves as a filter for water
 A habitat for living organisms
 Serves as a filter for pollutants
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The Formation of Soil

Factors that determine the formation of soil:
 Parent material- what the soil is made from
influences soil formation
 Climate- what type of climate influences soil
formation
 Topography- the surface and slope can
influence soil formation
 Organisms- plants and animals can have an
effect on soil formation
 Time- the amount of time a soil has spent
developing can determine soil properties.
The Formation of Soil

Parent Material- the rock material
from which soil is derived.
Soil Horizons

As soils form, they develop
characteristics layers.
Soil Horizons




O horizon- (organic layer) composed of the
leaves, needles, twigs and animal bodies on
the surface.
A horizon- (topsoil) the zone of organic
material and minerals mixed together.
B horizon- (subsoil) composed primarily of
mineral material with very little organic
matter
C horizon- (parent material) the least
weathered horizon and is similar to the
parent material.
Physical Properties of Soil

Texture- the percentage of sand, silt
and clay the soil contains.
Physical Properties of Soil

Porosity- how quickly the soil drains
(which depends on its texture)
Chemical Properties of Soil
Cation exchange capacity (CEC)- the
ability of a soil to adsorb and release
cations, positively charged mineral ions.
Soil bases- calcium, magnesium,
potassium and sodium
Soil Acids- aluminum and hydrogen
Base saturation- the proportion of soil
bases (Calcium, magnesium, potassium
and sodium) to soil acids
Chemical properties of soil…

With the exception of sodium, all bases are
essential for plant growth
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Biological Properties of Soil

Many organisms are found in the soil
including fungi, bacteria, protozoans,
rodents and earthworms.
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Check point…

How do soils form?

What are the roles of soils in ecosystems?

How do a soil’s physical and chemical
properties influence its role as a medium for
plant growth?
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Elemental Composition of
the Earth’s Crust
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Reserves

Reserves- the known quantity of a
resource that can be economically
recovered.
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Types of Mining

Surface mining- removing minerals that are
close to Earth’s surface.
 Strip mining- removing strips of soil and
rock to expose ore.
 Open pit mining- the creation of a large
pit or hole in the ground that is visible
from the surface.
 Mountain top removal- removing the entire
top of a mountain with explosives.
 Placer mining- looking for metals and
stones in river sediments.
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Types of Mining

Subsurface mining- mining for resources
that are 100 m below Earth’s surface.
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SURFACE MINING
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Strip mining
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Open pit mining
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Mountain top removal
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Placer mining
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SUBSURFACE MINING
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Reclamation
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Checkpoint…

Why are economiocally valuable mineral
resources distributed unevenly on the planet?

Describe the various types of surface mining.

What are the consequences of surface mining
versus subsurface mining, and how has mining
legislation tried to reduce those impacts?
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