4Lithosphere Resources

7/24/2019 4Lithosphere Resources

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200.16 Environmental Geology 7/26/20

J.M. Piwowar

Geological Resources

Bingham Copper Mine

Earths Natural Resources

Minerals, Metals and Fossil Fuels

Deposits are collectively called reserves. Reserves are

known deposits that can be mined or drilled today (Present reserves)

those that can be tapped into great expense or with new technology

and all deposits not yet discovered.

How long will the reserves last? What will happen when theyhave been exhausted? Where do we find fuels in the future,and how do they affect the environment?

Most resources are not renewable because it took millions ofyears to build them up while they are consumed within theshort period of 100 years or so.

Since the beginning of the 20th century, people have beentrying to develop substitutes for natural resources such as

synthetic minerals or alternative energy sources. Metals can be recycled

Mineral Resources

Building

Stone, Sand, Gravel,Limestone

Non-metallic Minerals

Sulfur, Gypsum, Coal,

Barite, Salt, Clay,Feldspar, GemMinerals, Abrasives,Borax, Lime,Magnesia, Potash,Phosphates, Silica,Fluorite, Asbestos,Mica

Metallic Minerals

Ferrous: Iron andSteel, Cobalt, Nickel

Metallic Minerals

Non-ferrous: Copper,Zinc, Tin, Lead,Aluminum, Titanium,Manganese,

Magnesium, Mercury,Vanadium,Molybdenum,Tungsten, Silver, Gold,Platinum

Energy Resources

Fossil Fuels: Coal, Oil,Natural Gas

Uranium

Geothermal Energy


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ROCKS AND MINERALS

A mineral is a naturally occurring,inorganic, solid element orcompound with a definite chemicalcomposition and regular internalcrystal structure.

A rock is a solid, cohesive,aggregate of one or more minerals.

Each rock has a characteristicmixture of minerals, grain sizes,and ways in which the grains areheld together.

Quartz

Rock Cycle Animation

Lava Flow Transport Settling MetamorphismCementation Melting

Lava Flow

Rock Cycle


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Sediments Transport

Rock Cycle

Sediments

Rock Cycle

Sand Grains

Rock Cycle


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Metamorphism

Rock Cycle

Melting

Rock Cycle

Rock TypesThree major rock classifications:

- Igneous- Sedimentary- Metamorphic

Igneous Rocks- Most common type of rock in earths crust.

Solidified from magma extruded onto the surface from volcanic vents. Quick cooling of magma produces fine-grained rocks. - Basalt Slow cooling of magma produces coarse-grained rocks. - Granite

Sedimentary Rocks from weathering

- Mechanical - Physical break-up of rocks into smaller particles without a change inchemical composition.

- Chemical - Selective removal or alteration of specific components that leads toweakening and disintegration of rock. -Oxidation

- Sedimentation - Deposition of loosened material.- Deposited materials that remain in place long enough, or are covered with enough

material for compaction, may again become rock. Formed from crystals that precipitate out of, or grow from, a solution.

- Shale, Sandstone, Tuff

Metamorphic Rocks

Pre-existing rocks modified by heat, pressure, and chemical agents. Chemical reactions can alter both the composition and structure of rocks as they are

metamorphosed. Marble (from limestone); Quartzite (from sandstone); Slate (from shale)


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Types of Rocks

Marble

Slate

Quartzite

Schist

Gneiss

Metamorphic rocks are produced when sedimentary or

igneous rocks are transformed by heat and/or pressure.

The word "metamorphic" comes from the Greek

language, which means "to change form."

Sandstone

Shale

Conglomerate

Limestone

Chert

Coal

Gypsum

Sedimentary rocks are made up of sediments eroded

from igneous, metamorphic, other sedimentary rocks,

and even the remains of dead plants and animals.

These materials are deposited in layers, or strata, and

then are squeezed and compressed into rock. Most

fossils are found in sedimentary rocks.

Granite

Obsidian

BasaltPumice

Andesite

Diorite

Rhyolite

Igneous rocks are created when molten material such

as magma (within the Earth) or lava (on the surface)

cools and hardens. The hot material crystallizes intodifferent minerals. The properties and sizes of the

various crystals depend on the magma's composition

and its rate of cooling.

ExamplesCharacteristicsType

Types of Rocks

Sedimentary rocks

Metamorphic rocks

Porphyritic granite: This

plutonic rock has

phenocrysts of orthoclase

set in a finer grained

matrix of orthoclase,

albite, quartz, and

biotite. These crystals are

all large enough toidentify, distinguishing it

from a volcanic rock.

Scoria: a vesicular volcanic

rock, in this case a vesicular

basalt. The crystals are too

small to identify so the basalt

rock type is inferred from its

dark color.

The vesicles (bubbles) form

as dissolved gasses come out

of solution of the originalhomogeneous silicate liquid.

Basalt: a volcanic rock

that, in this case, contains

no vesicles or

phenocrysts. The crystals

are too small to identify

and the basalt rock type is

inferred from its dark

color.

Porphyritic andesite: This

volcanic rock has a fine-

grained gray matrix

enclosing long, black

amphibole (hornblende)

phenocrysts. The matrix

grains are too small to

identify

Obsidian: volcanic glass having no crystals at all.

Gabbro: A plutonic

rock

Examples of igneous rock types

Conglomerate: a rock containing >50% clasts larger than 2 mm (the limit for

coarse sand), though conglomerates people usually think a bout usually have

pebble size grains or larger. Clasts may be any rock type, and are commonly

a mixture in any one outcrop

Arkose: a sandstone having a lot of feldspar. Grains in arkoseare usually

angular, indicating a short transport distance from the source area. This

sample happens to bee poorly sorted, though this is not a characteristic of

most arkoses.

Sandstone: grains are visible and many types can be identified with a hand

lens or low power microscope. The grains in this sample are moderately well

rounded and well sorted.

Siltstone: grains are barely visible with a hand lens or low power

microscope. Grains are too small to identify except as indicated by dark or

light color. Quartz and clays are the most common minerals.

Shale: no grains are visible, or perhaps only a few muscovite crystals are seen

on bedding surfaces. Shales are mostly made out of clay, a diverse group of

very tiny mica-like minerals. Some shalesa re very soft and fall apart in water,

others can be quite hard. Shale is the most common sedimentary rock type on

earth.

Examples of some clastic sedimentary rocks and their textures


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Gneiss = a medium- to coarse-grained rock

having a poor foliation. Minerals are easily

visible and identifiable by eye or with a hand

lens.

Schist = a medium-to coarse-grained, well

foliated rock in which the grains are easily

seen and identified by eye or with a hand

lens. Sheet silicates are abundant (typically

muscovite and biotite).

Phyllite = a fine-grained, well-foliated rock

in which the grains are barely visible with a

hand lens as shiny flakes. Sheet silicates areabundant (typically muscovite and chlorite).

Slate = a very fine-grained, well-foliated

rock in which the grains are mostly too small

to see even with a hand lens or low power

microscope. Sheet silicates are abundant

(typically muscovite and chlorite).

Typical metamorphic rock types defined by grain size and foliation quality

Folding of Rocks

A fold can be defined as a bend in rock that is the response

to compressional forces (heat & pressure). Folds are mostvisible in rocks that contain layering. Extreme deformationcan cause rocks to break

OIL Formation

organicmaterialsettles, is

buried, and istransformedby heat andpressure intooil.

In View 2 an oil trap is formed: the area folds into ananticline, and oil migrates and accumulates in theanticline crest.


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Formation of Coal

Plant materials buriedunder sediments decay toform peat, a compressedmass of plant remains.

Compaction forces waterout of the sediments toform lignite, a soft, browncoal.

Further compression andaging turn lignite intobituminous coal, a soft,black coal.

Heat and pressuremetamorphose bituminouscoal to anthracite, a hardcoal that is almost purecarbon.

Where the Oil Is

The Geography of Oil


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Hubbert Curves

In 1956, Oil geologist M. King Hubbert noted that rates ofoil production follow a bell-shaped curve.

Cumulative production follows a slanting S- curve

Production lags discovery by about ten years.

Hubberts 1956 Prediction

Where We Stand Today


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What if We Find More Oil?

Even a huge

increase in total

oil has very littleeffect on the

peak and decline

of production.

Why? We waste

most of it on

inefficient uses.

One Solution: Limit Production

Is There a Lot More Undiscovered

Oil? 80 per cent of oil being produced today is from

fields discovered before 1973.

In the 1990's oil discoveries averaged about

seven billion barrels of oil a year, only one third

of usage.

The discovery rate of multi-billion barrel fields

has been declining since the 1940's, that of giant

(500-million barrel) fields since the 1960's.

In 1938, fields with more than 10 million barrels

made up 19% of all new discoveries, but by

1948 the proportion had dropped to only 3%.


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Oil Discovery Rates

Some Relevant Quotes

... the energy-system efficiency of the motor

car with petroleum motor fuel is, thus, 5

percent ... no one is proud of this

accomplishment -- least of all the

automotive-design engineers ... The

trouble is, every time the design engineer

manages to save a few BTU it is more

than spent answering the clamor for softer

tires, for radio, for better heaters, more

lights, cigarette lighters and possibly even

air conditioning.

Petroleum is a Syllogism

There is a finite amount of it in

the world

We are using it and notreplacing it

Therefore we will eventually run

out of it

Any of this not clear?


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The End of Cheap Oil

Known petroleum can last at least a

couple of centuries more, but

It only flows through the rocks so fast. No amount of drilling will make it flow

faster, and careless drilling can shorten

the lifetime of an oil field.

Sometime in the 21st century, global

demand will outpace production capacity

and

Oil will go to the highest bidder.

Metals

Metals consumed in greatest quantity by world

industry (metric tons annually):

- Iron (740 million)

- Aluminum (40 million)

- Manganese (22.4 million)

- Copper and Chromium (8 million)

- Nickel (0.7 million)

Metals Conservation

Recycling Recycling waste aluminum consumes one-

twentieth the energy of extraction from raw ore.

Reduce metal consumption by using newmaterials or new technologies.

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