Some important points from last Monday:
• Practice all definitions
• List / discuss examples of all internal & external processes
• Understand general concepts of Plate Tectonics: SFS, plate
boundaries, locations, examples, associated geologic hazards and
resources
• Discuss / describe common Geologic Hazards (focus on E-quakes,
Tsunamis and Mass Wasting)
• What can we do to reduce damage? Make a list here for each one.
• Describe all types of E-Quake Waves: how are they useful?
• Damage from E-Quakes, a function of what?
• What causes Tsunamis? Where most likely to occur?
• Main causes of Mass Movement? How do humans make things
worse? Why Santa Cruz Mountains so susceptible?
• Also look over Volcanoes and Coastal Processes
SOIL AND SOLID NON-FUEL MINERAL RESOURCES
Au
Cu
SnO2
Gabbro
Slate
Marble
Part I: Soil
Resources
A Potentially Renewable Resource
Renewable
Direct
solar
energy
Nonrenewable
Winds,
tides,
flowing
water
Fossil
fuels
Fresh
air
Fresh
water
NonMetallic
minerals
& rocks
Metallic
minerals
(iron, gold,
copper,
aluminum)
Potentially
Renewable
Fertile
soil
or “Nonrenewable
Mineral Resources”
(clay, sand,
marble, slate)
These two are
sometimes
Called: “Solid
Nonfuel
Mineral
Resources”
What’s Environmental
Degradation?
Plants and
animals
(biodiversity)
– Definition……..
– Most valuable natural resource after water?
– Although potentially renewable, it is produced very
slowly, if topsoil erodes faster than it is renewed, soil
becomes a nonrenewable resource.
– Most of the world’s crops are grown on cleared grassland
(e.g. US Midwest) and deciduous forest soils.
Fig. 1.11, p. 11
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Factors determining type of soil and rate
of development:
•
•
•
•
•
Residual and Transported Soil
Parent Material
Slope
Climate
Plants & Animals
Time
Soil Profile:
Soil Erosion
– Natural process/rock cycle that occurs to all soils
– Causes (human activities)?
farming, logging, mining, construction, overgrazing,
urbanization, clear-cutting, fires, off-road vehicles
Mature soils have
distinct layers or zones
called Soil Horizons;
cross-sectional views of
soil horizons are called
Soil Profiles.
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Lamar, Colorado
1934
Areas of serious concern
Areas of some concern
Stable or non-vegetative areas
Estimated Rates of Soil Erosion:
Before Humans: ~9 billion metric tons/yr
Current estimates ~24 billion metric tons/yr
Soil Erosion Continues to be a Concern
READ this page on your own
• The US is losing soil 10 times faster -- and China and India are
losing soil 30 to 40 times faster -- than the natural replenishment rate.
Source: Cornell University
Km2
• Estimated that ~8.1 million
(12 times size of Texas) desertified
in the last 50 years. Each year an area the size of ~Greece.
• Human activity causes 10 times more erosion of continental surfaces
than all natural processes combined.
•
•
http://www.huffingtonpost.com/2011/04/12/soil-erosion-ewg-losing-groundreport_n_848096.html Web Link
The economic impact of soil erosion in the United States costs the nation about
$37.6 billion each year in productivity losses. Damage from soil erosion
worldwide is estimated to be $400 billion per year.
•
Soil Conservation: reducing soil erosion, restoring soil
fertility & producing greater yield
• Conservation tillage
farming: disturb soil as little as
possible; machines till subsurface
soil w/out breaking up topsoil or
inject seeds into unplowed soil. As
of 2004 used on ~38% of US
cropland. (USDA)
• Terracing: converting a slope
into a series of step-like platforms;
retains water and reduces erosion.
• Crop Rotation: successive
planting of different crops in the
same area to improve soil fertility
and help control insects, diseases
and erosion.
http://www.reuters.com/article/2012/02/13/us-unep-soil-idUSTRE81C13J20120213 Web Link
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Soil Conservation: reducing soil erosion,
restoring soil fertility & producing greater yield
• Contour farming: planting
crops in rows that run
perpendicular to slope of land,
plow along the contour of the
slope; can reduce soil erosion by
30-50% on gentle slopes.
Resources
Renewable
Direct
solar
energy
Nonrenewable
Winds,
tides,
flowing
water
Fossil
fuels
rows of two or more crops; keeps
soil covered and reduces erosion,
legumes restore soil fertility.
Potentially
Renewable
How are solid non-fuel mineral resources
formed and concentrated?
Fresh
air
Fresh
water
Fertile
soil
(clay, sand,
marble, slate)
These two are
sometimes
Called: “Solid
Nonfuel
Mineral
Resources”
What’s Environmental
Degradation?
• Wind Breaks: planting trees
or large shrubs along the margins
of the field
NonMetallic
minerals
& rocks
Metallic
minerals
(iron, gold,
copper,
aluminum)
• Strip cropping: alternating
or “Nonrenewable
Mineral Resources”
Plants and
animals
(biodiversity)
Fig. 1.11, p. 11
How are solid non-fuel mineral resources formed and concentrated?
• Rock Cycle
Web Links: please read about this:
http://imnh.isu.edu/digitalatlas/geo/basics/diagrams.htm
http://www.usgs.gov/science/instance.php?term=8
A series of events / processes, both internal and external,
through which a rock changes between igneous, sedimentary
and metamorphic forms. Cycle takes millions of years and is
responsible for concentrating Earth’s Nonrenewable
Mineral Resources.
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits: wind, water, placers
– Evaporites
– Secondary Enrichment
• + Plate Tectonics / Hydrologic Cycle……
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Magmatic Rocks & Minerals
granite, diorite, quartz, feldspar, chromite,
Common Magmatic Rock / Mineral Resources
& Their Use (Read later)
• Granite / Diorite / Gabbro: building materials, dimension stone,
roads, shoulders, furniture, counter tops, interior/exterior surfaces
• (FeMg)Cr2O4 Chromite: important ore of chromium, used to
harden and manufacture steel, coloring agent, making bricks,
tanning leather, dyes, also used in common materials such as cars,
planes, engines, satellites, weapons, home appliances (form from
basaltic magmas)
• Opal (Quartz): gems, abrasives, mortar, glass, silica brick,
porcelain, paints, sandpaper, scouring soaps, wood filler, radios,
watchesl
• Platinum, Magnetite, Cobalt and Manganese: also used in
manufacturing cars, planes, engines, satellites, weapons, home
appliances (form from basaltic magmas)
Fig. 12-19a, p.351
Hydrothermal Deposits
Metallic chemical elements, Sulfides and Oxides form
in association with magma and water.
Hydrothermal deposits often occur in “veins”
Disseminated deposits / gangue
e.g. Au rich deposits of CA Sierra Nevada.
Black Smokers (undersea hot springs) form at Oceanic
Ridges (divergent plate boundaries) and at undersea hot
spots.
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Formation of Metals: Hydrothermal and Magmatic
Read this Figure over very carefully
Know these symbols / names:
Fe = Iron
Divergent
Au = Gold
Plate Boundary
Ni = Nickel
Cu = Copper
Pb = Lead
Zn = Zinc
Ag = Silver
Sn = Tin
Cr = Chromium
Iron
Copper
Zinc
Lead
Hydrothermal Activity
Black smokers (undersea hot
springs) form at mid-ocean
ridge/divergent boundaries.
Convergent
Plate Boundary
Au, Cu
Pb, Zn, Ag, Cu
Fe
Sn, Mo
Fe
Hydrothermal vein deposits. e.g.
rich Au deposits of CA Sierra
Nevada.
Pb, Zn,
Au, Ag, Cu
Sn
Cu
Iron
Chromium
Nickel
Common Hydrothermal Mineral Resources & Their Use
Read later
How are solid non-fuel mineral resources formed and concentrated?
• Fe / Iron: bikes, cars, bridges, magnets, machines, nails, tools, food
supplements
• Fe / Hematite (Fe2O3 ): ore of iron, pigments, polishing powder, jewelry
• Au / Gold: circuit boards, electronics, jewelry, planes, space shuttles, compact
discs, cameras, telephones
• Cu / Copper: electrical purposes, circuit boards, wire, sculpture,
brass = Cu and Zn, bronze = Cu + Sn and some Zn, German silver
• Pb / Galena (PbS): lead sulfide, major source of lead, used in making
metals, pipe, sheets, solder, glass
• Zn / Sphalerite (ZnS): ore of zinc, important metal alloy used in making
brass, paint, zinc oxide, batteries
• Ag / Silver: photographic film and paper, photosensitive glass, mirrors,
batteries, silverware
• Sn / Tin: metals, coins, cups, plates, cans, solder, opalescent glass, enamel,
weather resistant vinyl siding
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
Rare Earth Elements
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits: wind, water, placers
– Evaporites
– Secondary Enrichment
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