Download CH. 12 Notes

Geology and Nonrenewable Minerals
Geology
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Geology – science devoted to study of dynamic
processes occurring on earth's surface and interior
Three major concentric zones
Earth's Dynamics
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Core – earth's inner most zone
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Mantle – surrounds the core, thick zone of solid rock
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Asthenosphere – located right above mantle, partly
melted rock
Crust – continental / oceanic crust, thinnest zone of
earth
Lithosphere – outermost part of mantle
Earth's Movement
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Convection cells – move large volumes of rock and
heat in loops within the mantle
Continent formation
Tectonic Plates – move extremely slowly atop the
asthenosphere
Plate Boundaries
Plate Movement
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Speed of plates – rate at which fingernails grow
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Seperate – Collide – Slide Past
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Mountain formation, earthquakes, volcanoes
Seperation
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Magma (molten rock) flows up through resulting
cracks
Creates Ocean Ridges, high peeks and deep canyons
Collision
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Continental plate rides up over the denser oceanic
plate
Subduction – the denser plate gets pushed down into
the mantle
Subduction Zone
Continental plate collision causes mountain ranges to
be created
Slide and Grind
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Plates can also grind past one another
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Usually occurs at transform faults
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Most of these are located on ocean floor, but few are
found on land
i.e. North American Plate and Pacific Plate slide past
each other near the San Andreas Fault
Volcanos
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Volcano – occurs where magma reaches the earth's
surface through a central vent / long crack
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Fissure
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Occurs near tectonic plate movement
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Lava – magma which reaches the earth's surface
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Volcanic activity can release : lava rock, hot ash, liquid
lava and gases
Provide some benefits : formation of mountains, soil
fertilization
Earthquakes
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Transform fault – fracture in earth's crust
Seismic Waves – energy accumulate is released in
form of vibrations
Most earthquakes occur at boundaries of tectonic
plates
Scientists measure the the magnitude of seismic
waves
Magnitude – measure of ground motion caused by
earthquake as indicated by the amplitude
Measuring Earthquakes
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Seismograph – measures the amplitude of an
earthquake
Richter Scale – each unit has an amplitude of 10 times
greater than the next smaller unit
i.e. 5.0 is 10 times more ground shaking than 4.0
Largest earthquake : Chile, May 22, 1960 measured
9.5 on Richter Scale
Tsunami
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Tsunami – a series of large waves generated when
part of the ocean floor suddenly rises or drops
Usually result of an underwater earthquake or volcanic
eruption
Travel across the ocean at the speed of a jet plane
Waves are far apart, crests not very high at first, yet
when approaching coast it slows and waves squeeze
together
Tsunami Detection
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Can be detected through network or ocean buoys or
pressure recorders located on ocean floor
Between 1900 and 2008, tsunamis killed an estimated
278,000 people in regions of Pacific Ocean
Earth's Crust
• Minerals: an solid element that has
a regular internal
crystalline structure.
• Rocks: solid combinations of
minerals.
Rock Types
• Sedimentary: Dead plant and
animal remains
• Igneous: Cooled and pressurized
magma
• Metamorphic: Rocks that are
subject to high temperature and
pressures
Rock Recycling
• Changes rocks from one type to
another
• Concentrates the planet's non
renewable recousrces
Mineral Resources
• Fossil Fuels
• Metallic Minerals
• Known collectively as "nonrenewable resources"
Ore
• Low-grade: Small Concentration
• High-grade: High Concentration
Mining Types
• Surface Mining
oOpen Pit Mining
oStrip Mining
oMountaintop Removal Mining
• Subsurface Mining
Harmful Affects of Mining
• Scarring and Disruption to Surface
• Chemical Spillage
• Prohibits Vegetation
• Subsidence (collapse of land)
Removing Metals from Ore
• Smelting:Heating Ore to extract
desired metals
• Pollution
• Ore Mineral
• "Gangue"
12-4 Nonrenewable Resources
The earths crusts contains many important resources that
cannot be replenished
Some of these resources are very common like iron while
others like platinum are very scarce
Five countries, the United States, Russia, Canada, South
Africa, and Australia supply most of the earths
nonrenewable resources
United States Nonrenewable
Resource Use
Between the years of 1900 and 1950 the United States
greatly increased its resource use.
This lead to the depletion of its large supplies of
resources like lead, iron, and aluminum
Due to the shortage of resources, the United States
import over 50% of its nonrenewable resources
Important Resources
Minerals are very important to a countries economic
status, for instance South Africa bases its economy off
the mining of Gold, Chromium, and Platinum
Experts believe that four metal resources are very
important to a countries economic and military
strength: Manganese, Cobalt, Chromium, and Platinum
Overuse of Nonrenewable Resources
Thomas Graedel at Yale University did a study that
stated that if every country in the world used
nonrenewable resources like developed countries, than
there would not be enough metal resources meet the
demand of the people.
Economic Depletion of Resources
If we use a resource so much, until the point that its price
drops lower than the cost of actually extracting and
transporting the resource, than the resource will be
economically depleted.
Dealing With Economic Depletion
When a resource becomes economically depleted than
there are five ways to increase the price of the product
1. Recycle or reuse existing supplies
2. Waste less
3. Use less
4. Find a substitute
5. Or do without the resource
The Cost of A Resource
The cost of a resource is based off of the supply and demand of the
product.
In general, in a competitive market, if the supply is greater than the
demand, than the market will be considered cheap
On the other hand if the supply is less than the demand than the
good will be considered scarce and thus will be more expensive
Most mineral prices are kept artificially low to help promote
economic growth
Lower Grade Mining
One of the ways to limit the loss of nonrenewable metals
is to have lower grade mining ores, which are ores that
produce less in order to increase the cost of the metal
There are limiting factors however like water shortages,
increased cost, and increased environmental disruption
Ocean Minerals
Most minerals in the ocean are not concentrated enough
to be industrialized.
Only Bromine, Magnesium, and Sodium Chloride are
found in high enough concentrations
Hydrothermal deposits may in the future become a good
source of minerals from the ocean but it is currently to
expensive
Case Study- The U.S. General Mining
Law of 1872
The law stated that a person or corporation that claims
that a piece of land contains valuable minerals can
assume legal ownership of the land. You must spend
$500 on improvements and $120 a year for every 20
acres
This applied for all lands that were not National Parks or
Wilderness Areas
Case Study- Cont.
The impacts of this law was that people abused the law
and began to build essentially whatever they wanted
on the land.
Also because of this law, mining companies have to pay
very small taxes, around2.3% of their royalties
The law has been tightened up over the last couple of
decades
12-5 How Can we Use Mineral
Resource More Sustainably
Many scientists believe that in the future many key
minerals will be able to be replaced by technology in
the future
Still some minerals like Platinum will probably never be
replaced.
Because of this we need to limit the overuse of scarce
resources
Recycling and Reusing
The easiest way to not lose scarce resources is to
recycle and reuse
Recycling has a much lower environmental cost than
mining. For example recycling cans and scrap
aluminum has 95% less air pollution, 97% less water
pollution, and uses 95% less energy
Case Study-Copying Ecosystems
One way to increase sustainability is to recycle and reuse
minerals and chemicals similar to what is found in
nature. In nature the outputs of one organism become
the inputs of another
This biomimicry is being tried in Kalundborg, Denmark.