Transcript Document

Geology and Nonrenewable Minerals
Chapter 14
PART 1
GEOLOGIC TIMESCALE
 Geologists have divided Earth's history into a series of
time intervals.
 The geologic time scale was constructed to visually show
the duration of each time unit.
 The Earth is 4.6 billion
years old.
• The geologic processes
have been happening for
a very long time.
• Humans just showed up
at the end.
GEOLOGIC TIMESCALE
 The time intervals are
variable in length. This is
because geologic time is
divided using significant
events in the history of
the Earth.
• New biological
developments
• Mass extinctions
14-1 What Are the Earth’s Major Geological
Processes and Hazards?
 Concept 14-1A Gigantic plates in the earth’s
crust move very slowly atop the planet’s mantle,
and wind and water move the matter from place
to place across the earth’s surface.
 Concept 14-1B Natural geological hazards
such as earthquakes, tsunamis, volcanoes, and
landslides can cause considerable damage.
The Earth Is a Dynamic Planet
 The earth’s interior consists of:
• Core: innermost zone with solid inner core and molten
outer core that is extremely hot
• Mantle: liquid rock with a rigid outer part (asthenosphere)
that is melted pliable rock
• Crust: layer of solid rock (lithosphere) which underlies the
continents and the oceans
• Continental crust
• Oceanic crust
The Earth Beneath Your Feet is Moving
 Plate Tectonics
• The theory that Earth’s crust is divided into huge
tectonic plates that float on magma or molten rock.
• Convection currents within the mantle move the
plates around.
• Evidence:
• Puzzle-like fit of the continents
• Matching plant/animal fossils on
opposite sides of oceans
• Matching rock layers on opposite
sides of oceans
• Evidence of past climates
The Earth’s Major Tectonic Plates
Major Features of the Earth’s Crust
and Upper Mantle
 Major features of the earth’s crust and upper mantle.
Tectonic Plate Boundaries
 Plates move apart at
divergent plate
boundaries.
 Mid-ocean ridge – the site of sea-floor spreading
Tectonic Plate Boundaries
 Plates grind into one
another at convergent
plate boundaries.
• Folded mountains
• Volcanic mountains
Tectonic Plate Boundaries
 Plates slide past one another at transform
plate boundaries.
Some Parts of the Earth’s Surface Build Up
and Some Wear Down
 Internal geologic processes
• Generally build up the earth’s surface
• Result from the heat generated by the Earth’s interior
 External geologic processes
• Wear down the Earth’s surface and move it around
• Result from solar energy and gravity (wind, flowing water)
• Weathering – Processes that break
rocks down into smaller pieces
• Plays key role in soil formation
• Different kinds of rock will result in
different soil properties
Volcanoes Release Molten Rock
from the Earth’s Interior
 Volcanoes are simply vents in the
earth's surface through which lava
and other volcanic products erupt.
Earthquakes Are Geological
Rock-and-Roll Events
 The sudden release of energy stored up by the
movement of tectonic plates
 Energy travels as seismic
waves, each with own type
of movement and speed.
• P-wave
• S-wave
• Surface
waves
14-2 How Are the Earth’s Rocks Recycled?
 Concept 14-2 The three major types of rocks
found in the earth’s crust—sedimentary, igneous,
and metamorphic—are recycled very slowly by the
process of erosion, melting, and metamorphism.
There Are Three Major Types of Rocks
 A very slow geochemical cycle involves three types
of rock found in the earth’s crust:
• Igneous rock (granite, pumice, basalt)
• Solidified lava or magma
• Sedimentary rock (sandstone, limestone, shale)
• Fusion of eroded sediments
• Metamorphic rock (slate, marble, quartzite)
• Application of heat / pressure
Natural Capital: The Rock Cycle Is the Slowest
of the Earth’s Cyclic Processes
14-3 What Are Mineral Resources, and what
are their Environmental Effects?
 Concept 14-3A Some naturally occurring
materials in the earth’s crust can be extracted
and made into useful products in processes that
provide economic benefits and jobs.
 Concept 14-3B Extracting and using mineral
resources can disturb the land, erode soils,
produce large amounts of solid waste, and
pollute the air, water, and soil.
We Use a Variety of
Nonrenewable Mineral Resources
 Mineral – naturally occurring, inorganic, solid
element or compound with a definite chemical
composition and a regular internal crystal structure.
 Mineral resource (Ore) – a deposit of minerals that
can be extracted and processed into useful
materials at an affordable cost.
• Deposits of nonrenewable mineral resources in the
earth’s crust vary in their abundance and distribution.
• High Grade Ore – high percentage of desired mineral
• Low Grade Ore – low percentage of desired mineral
We Use a Variety of
Nonrenewable Mineral Resources
 Examples of nonrenewable metal and nonmetal
mineral resources:
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Aluminum – beverage cans, motor vehicles, aircraft
Steel (alloy of iron and other elements) – buildings
Copper – electrical and communications wiring
Platinum – electrical equipment, industrial catalyst
Gold – electrical equipment, jewelry, medical implants
Sand – glass, bricks, concrete
Limestone, - road rock, concrete, cement
Manganese, Cobalt, Chromium – light bulbs, computers,
automobiles, aircraft, etc.
Concentration of Minerals in Earth’s Crust
Aluminum ~8%
Iron
~5.8%
most Fe and Al is in silicate minerals (like sand) and is,
therefore, not used as an ore
Titanium
Nickel
Zinc
Copper
Lead
Uranium
Silver
Gold
0.82%
0.0075%
0.0082%
0.0058%
0.0013%
0.00016%
0.000008%
0.0000004%
Classification of
Nonrenewable Mineral Resources
 The U.S. Geological Survey classifies mineral
resources into four major categories:
• Identified: location, quantity, and quality or existence
known based on direct evidence and measurements.
• Undiscovered: potential supplies that are assumed
to exist.
• Reserves: identified resources that can be extracted
profitably.
• Other: undiscovered or identified resources not
classified as reserves
The Life Cycle of a Metal Resource
 The extraction, processing, and use of mineral
resources has a large environmental impact.
• Mining of low grade ore requires more energy, water,
and produces more waste.
Extracting, Processing, Using Nonrenewable
Mineral and Energy Resources