Some important points from last Tuesday/Thursdaydschwartz/documents/RockMinSoil... · 2015-02-18 · 1 Some important points from last Tuesday/Thursday: • Practice all definitions

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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 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

Types of “Natural Resources”?

Renewable aka “Perpetual”

Nonrenewable

Potentially Renewable

Fig. 1.11, p. 11

Resources

Renewable Nonrenewable

PotentiallyRenewable

Fresh

air

Fresh

waterFertilesoil

Plants and

animals

(biodiversity)

Direct

solar

energy

Winds,

tides,

flowing

water

Fossil

fuelsMetallic

minerals

Non-Metallic

minerals & rocks(iron, gold,

copper,

aluminum)(clay, sand,

marble, slate)

or “Nonrenewable

Mineral Resources”

These two are

sometimes

Called: “Solid

Nonfuel

Mineral

Resources”

What’s Environmental

Degradation?

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Part I: SoilA Potentially Renewable Resource

– 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.

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/yr

Current estimates ~24 billion metric tons/yr

Colorado Kansas

“Dust

Bowl”

Oklahoma

New Mexico

Texas

MEXICO

Case Study: 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

• Estimated that ~8.1 million Km2 (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-ground-

report_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.

• 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

• 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.

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.

• Strip cropping: alternating

rows of two or more crops; keeps

soil covered and reduces erosion,

legumes restore soil fertility.

• Wind Breaks: planting trees

or large shrubs along the margins

of the field

11:40?

Fig. 1.11, p. 11

Resources

Renewable Nonrenewable

PotentiallyRenewable

Fresh

air

Fresh

waterFertilesoil

Plants and

animals

(biodiversity)

Direct

solar

energy

Winds,

tides,

flowing

water

Fossil

fuelsMetallic

minerals

Non-Metallic

minerals & rocks(iron, gold,

copper,

aluminum)(clay, sand,

marble, slate)

or “Nonrenewable

Mineral Resources”

These two are

sometimes

Called: “Solid

Nonfuel

Mineral

Resources”

What’s Environmental

Degradation?

How are solid non-fuel mineral resources

formed and concentrated?

• Rock Cycle(Web Link: please read about this:

http://imnh.isu.edu/digitalatlas/geo/basics/diagrams.htm)

A series of events / processes, both internal and extrenal,

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?

• 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 & 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)

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, Cu

Pb, Zn, Ag, CuSn

FeAu,

Cu

Pb, Zn,

Ag, Cu

SnIron

ChromiumNickel

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

Know these symbols / names:

Fe = Iron

Au = Gold

Ni = Nickel

Cu = Copper

Pb = Lead

Zn = Zinc

Ag = Silver

Sn = Tin

Cr = Chromium

Iron

Copper

Zinc

Lead

Divergent

Plate BoundaryConvergent

Plate Boundary

Hydrothermal Activity

Black smokers (undersea hot

springs) form at mid-ocean

ridge/divergent boundaries.

Hydrothermal vein deposits. e.g. rich Au deposits of CA Sierra

Nevada.

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

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– Magmatic deposits Rare Earth Elements– Hydrothermal deposits

– Metamorphism



– Evaporites


The Rare Earth Elements

“REE”

Web Link

The 17 Rare Earth Elementshttp://en.wikipedia.org/wiki/Rare_earth

_element

Ru Ruthenuim Os Osmium

Rh Rodium Ir Iridium

Pd Palladium Pt Platinum

Se Selinium

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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.

In 2015, global industry forecast is to consume 185,000 tons of rare earth’s

Over 3 Square miles

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/

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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.


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.




– Metamorphism


– Sedimentary deposits

– Evaporites

– Water / Placer deposits


Metamorphism

• 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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– Metamorphism



– Evaporites


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……..








– Metamorphism



– Evaporites


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 give

info about buried rock layers

Chemical analysis of water and plants

to detect minerals leached into water and

absorbed by plants

Remote sensing: (detect /analyze wave

transmitted energy) reveals outcrops and

types of rock

Measure radiation, magnetism to detect

radioactive metals, iron and other

How are Mineral Resources Extracted?

Surface Mining

machines 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.

Bingham Copper Mine, Utah>4km wide, 1.2 km deep, >6 billion tons of rock mined since 1906

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

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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.

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

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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 Present

Depletiontime A

Depletion

time BDepletion

time C

Time

Pro

du

cti

on

C

B

A

Recycle, reuse, reduceconsumption; increase

reserves by improvedmining technology,

higher prices, andnew discoveries

Recycle; increase reservesby improved mining

technology, 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.

Documents

Some important points from last Tuesday/Thursdaydschwartz/documents/RockMinSoil... · 2015-02-18 · 1 Some important points from last Tuesday/Thursday: • Practice all definitions