some important points from last tuesday/thursday: soil and

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Some important points from last Tuesday/Thursday:

• Practice all definitions / Recap Japan Earthquake Movie

• 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 5 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

Marble

Gabbro

Slate

Fig. 1.11, p. 11

Resources

Perpetual Nonrenewable

Renewable

Freshair

Freshwater

Fertilesoil

Plants andanimals(biodiversity)

Directsolarenergy

Winds,tides,flowingwater

Fossilfuels

Metallicminerals

Non-Metallicminerals & rocks(iron, gold,

copper,aluminum)

(clay, sand,marble, slate)

or “Nonrenewable Mineral Resources”

These two are sometimes

Called: “Solid Nonfuel Mineral Resources”

What’s EnvironmentalDegradation?

Nonrenewable Mineral Resources: a definition

Concentrations of solid, liquid or gaseous materials in or on the earth’s crust that can be converted to useful materials at an affordable price.

Occurring in fixed quantities……..

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Part I: SoilA Renewable Resource

– Definition……..

– Most valuable natural resource after water?

– Although 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.

Factors determining type of soil and rate of development:

• Parent Material

• Slope

• Climate

• Plants & Animals

• Time

Residual and Transported Soil Soil Profile:

Mature soils have distinct layers or zones called Soil Horizons; cross-sectional views of soil horizons are called Soil Profiles.

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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

Areas of serious concern

Areas of some concern

Stable or non-vegetative areas

Estimated Rates of Soil Erosion:Before Humans: ~9 billion metric tons/yrCurrent estimates ~24 billion metric tons/yr

Lamar, Colorado1934

Soil Erosion Continues to be a ConcernREAD 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

• Estimated that ~8.1 million Km2 (12 times size of Texas) desertifiedin 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.sciencedaily.com/releases/2004/11/041103234736.htm 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.

• http://www.news.cornell.edu/stories/March06/soil.erosion.threat.ssl.html Web Link

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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: successiveplanting of different crops in the same area to improve soil fertility and help control insects, diseases and erosion.

Soil Conservation: reducing soil erosion, restoring soil fertility & producing greater yield

• Contour farming: planting crops in rows that run perpendicular to slope of land; can reduce soil erosion by 30-50% on gentle slopes.

• Strip cropping: alternating rows of two or more crops; keeps soil covered and reduces erosion, legumes restore soil fertility.

• Intercropping: planting two or more crops in an area to produce greater yield.

11:40pm?

How are Solid Non-Fuel Mineral Resources formed and concentrated?

Plate Tectonics / Rock Cycle / Hydrologic Cycle

Rock Cycle(Web Link: please read about this: http://imnh.isu.edu/digitalatlas/geo/basics/diagrams.htm)

A series of events 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.

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How are solid non-fuel mineral resources formed and concentrated?

Most of the world’s major metal deposits occur at past or present plate boundaries. Surface processes also play an important role in concentrating nonmetallic minerals and rocks.

• 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

Fig. 12-19a, p.351

Magmatic Rocks & Mineralsgranite, 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)

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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Fe

Au, CuPb, Zn, Ag, Cu

Sn

FeAu, Cu

Pb, Zn, Ag, Cu

SnIronChromiumNickel

Formation of Metals: Hydrothermal and MagmaticRead this Figure over very carefully

Know these symbols / names:Fe = IronAu = GoldNi = NickelCu = CopperPb = LeadZn = ZincAg = SilverSn = TinCr = Chromium

IronCopper Zinc Lead

DivergentPlate Boundary

Convergent Plate Boundary

Common Hydrothermal Mineral Resources & Their UseRead later

• 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 Rare Earth Elements– Hydrothermal deposits– Metamorphism


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The Rare Earth Elements“REE”

Web LinkThe 17 Rare Earth Elements

Ru Ruthenuim Os OsmiumRh Rodium Ir IridiumPd Palladium Pt Platinum

Se Selinium

Samarskite(YFe3+Fe2+U,Th,Ca)2(Nb,Ta)2O8

Most common Rare EarthElements originate in Granitic Magmas or through Hydrothermal Activity.

Some are mined out of placer deposits.

Bastnäsite: a fluorocarbonate mineral(Ce,La,Y)CO3F

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Monazite: a phosphate mineral, 4 different typesmonazite‐Ce (Ce, La, Pr, Nd, Th, Y)PO4

monazite‐La (La, Ce, Nd, Pr)PO4

monazite‐Nd (Nd, La, Ce, Pr)PO4

monazite‐Sm (Sm, Gd, Ce, Th)PO4

Wide Variety of uses: medical, military, missiles, clean energy technology, catalytic converters, magnets, transportation. Consumer Products: cell phones, computer hard drives, monitors, power tools, sun glasses, wine bottles, fluorescent light bulbs, TVs, automobiles, SUV’s

• Also used in Cell Phones

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Until the mid 1980’s, US led the world in REE production; has ~13% of world reserves.

China has ~48% of world reserves, but supplies ~97% of the world’s needs. Russia, Canada and Australia also have large deposits.

Mountain Pass Rare Earth Mine in Mountain Pass California, Mojave Desert.

Closed in 2002, re‐opened in August 2012

Web Link: The Only American Mine for Rare Earth Metals

http://www.theatlantic.com/technology/archive/2012/02/a-visit-to-the-only-american-mine-for-rare-earth-metals/253372/

Environmental Concerns• Need to excavate a lot of earth / dig huge holes / takes a lot of

energy + a lots of solid waste rock.

• Some elements associated with the REE are radioactive such as Uranium and Thorium. They end up in slurry pools and can enter groundwater.

• Toxic acids and chemicals are required during the refining process, often end up in slurry pools and can enter groundwater.

• Baotou, a city in China where ~80% of REE are mined produces ~10 million tons of wastewater/year.

• Birth defects and Leukemia have been linked to rare earth refinery in Malaysia and China

• In 2008, ~1/3 of REE in China were mined illegally by heavy polluting, violent criminal gangs.

The Lynas Plant in Malaysia is setto become the world's largestprocessing facility of rare earths.

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Metamorphism How are solid non-fuel mineral resources formed and concentrated?




Sand Mining in Monterey Bay has been occurring since 1906, ~150,000 – 250,000 cubic yards/yr, with no regulation until 1960s.

3 companies for ~80 years, only one is left.

A connection between mining and shoreline erosion

was determined in the mid

1980s, but still 1 company

mines ~235,000 cubic yards

each year.

Sand Mining in Monterey Bay (web link)

Sedimentary Deposits: Sand and gravel accumulate in river channels and bars, coastal offshore bars, sand dunes, beaches and glacial outwash plains.

After deposition sediments lithify by compaction and cementation.Materials used for: road beds, cement production, bricks, tiles, abrasives, water filtration, glass production…..

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Placer DepositsRead this slide over very carefully.

“Point Bars”

Evaporites: (Salts: halite, gypsum, borates) water evaporates from shallow inland seas or lakes in warm arid climates.

Materials used in: making glass, ceramics, metals, preservatives, cleaning agents, water softeners……..





Secondary Enrichment

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How are mineral resources found?Understand the geologic/plate tectonic history of an area

Make Maps: rock formations, faults, structure

Drill, extract and analyze rock/sediment samples

Aerial photos and satellite images,reveals outcrops and types of rock types

Seismic & gravitational surveys giveinfo about buried rock layers

Chemical analysis of water and plantsto detect minerals leached into water andabsorbed by plants

Remote sensing: (detect /analyze wavetransmitted energy) reveals outcrops andtypes of rock

Measure radiation, magnetism to detectradioactive metals, iron and other

How are Mineral Resources Extracted?

Surface Miningmachines strip away millions of tons of “Overburden” (rock/earth covering ore) and pile it up as waste material sometimes called “Spoil”

1) Open-pit mining:

commonly used surface mining technique; used for mining most major metal deposits, also sand, gravel and stone.

The Palabora open pit in NE South Africa. The hard rock allows the pit walls to be cut much steeper than is

normal in open-pit Copper mining.

More Surface Mining2) Hydraulic Mining: wash away overburden on hillsides; mine uplifted placer deposits. In CA huge volumes of sediment washed into SF-San Joaquin delta harming navigation and agriculture, ~ 1850’s – 1890’s.

~13 billion cubic yards of sediment have been washed away from the Sierra Nevada

3) Dredging: used on underwater mineral deposits; gold mining of CA riverbed sediments until 1960s; leaves great piles of spoil alongside channels called

spoil banks/dredge fields.

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How are ores processed?

• Remove undesired parts of ore (gangue)

• Smelting extracts metals from other elements

• Pure metal is then converted to desired product by manufacturing companies

Drawbacks? Results in air, water, soil pollution; solid and liquid hazardous wastes; safety and health hazards Start Here:

Surface Mining

Metal ore

Separationof ore fromgangue

Scattered in environment

Recycling

Discarding of product

Conversion to product

Melting metal

Smelting or “Extractive Metallurgy” is the practice of extracting metal from ore, purifying it, and recycling it

Why do we mine?Concerns? Environmental degradation from mining and processing, depletion

time, economic depletion, exhaustion, import dependence, high cost

Supply and Consumption of Mineral Resources

• Economic Depletion

– Costs more to find, extract, transport and process mineral than deposit is worth.

– Options: 1) recycle or reuse existing supplies, 2)waste less, 3) use less, 4) find substitute, 5) do without.

• Depletion Time:

– time it takes to use up 80% of reserves of a mineral at a given rate of use.

• US currently imports ~50% of its most important non-fuel minerals.

– Used faster than they can be produced here

– Foreign ores are higher grade and can be extracted cheaper than US reserves

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Present

Depletiontime A

Depletiontime B

Depletiontime C

Time

Pro

du

ctio

n

C

B

A

Recycle, reuse, reduceconsumption; increasereserves by improvedmining technology,higher prices, andnew discoveries

Recycle; increase reservesby improved miningtechnology, higher prices,and new discoveries

Mine, use, throw away;no new discoveries;rising prices

Mineral and Soil Resources

• Greatest concern about mining solid non-fuel mineral resources is environmental degradation caused by extracting, processing and manufacturing.

• As resources become depleted and lower grade ores are mined, environmental degradation increases.

• Soil is a renewable resource if sound, sustainable agricultural practices are used. When soil is depleted of its nutrients or topsoil erodes faster than it is replenished, soil becomes a nonrenewable resource.

• Soil loss seriously compromises our ability to grow food necessary to feed an expanding human population.

some important points from last tuesday/thursday: soil and

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