Unit 4 Earth Systems and Resources - Weeblyambermillerscience.weebly.com/uploads/2/2/6/7/22677146/...South Asia and Africa Detection of tsunamis Buoys in open ocean Tsunami Rock cycle-

Unit 4

Earth Systems and Resources

The Earth’s resources were determined when the planet

formed.

Core- the innermost zone of the planet made of nickel and iron. Inner core (soild) & outer core (liquid)

Mantle- above the core containing magma (thickest layer)

Crust- the outermost layer of the planet. Continental (granite) and oceanic

(basalt)

The Earth’s Layers

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Asthenosphere- the outer part of the mantle, composed of semi-molten rock.

Lithosphere- the brittle outermost layer of the planet that is approximately 100 km thick.

The Earth’s Layers

Major Features of the Earth’s

Crust and Upper Mantle

Fig. 14-2, p. 348

The Earth is very hot at the center.

This heat causes plumes of hot magma to well upward from the mantle.

Hotspots- places where molten material from the mantle reach the lithosphere.

Convection and Hot Spots

Plate tectonics- the theory that states that Earth’s lithosphere is divided into plates, most of which are in constant motion.

Theory of Plate Tectonics

Tectonic Plates

Pangaea

http://pubs.usgs.gov/gip/dynamic/dynamic.html

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Volcanoes- as a plate moves over a hot spot, rising magma forms a volcano.

Consequences of Plate Movement

Divergent plate boundaries- when plates move apart from one another.

Convergent plate boundaries- when plates move toward one another and collide.

Transform fault boundaries- then plates move sideways past each other.

Types of Plate Contact

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Faults- a fracture in rock across which there is movement.

Earthquakes- occur when the rocks of the lithosphere rupture unexpectedly along a fault.

Faults and Earthquakes

Fault zone- large expanses of rock where movement has occurred.

Epicenter- the exact point on the surface of Earth directly above the location where the rock ruptures.

Richter scale- a measure of the largest ground movement that occurs during an earthquake. The scale increases by a factor of 10, so an earthquake of 7 is 10 times greater than an earthquake of 6.

Faults and Earthquakes

Fig. 14-7a, p. 351

Liquefaction of recent

sediments causes

buildings to sink

Two adjoining plates

move laterally along

the fault line

Earth movements

cause flooding in

low-lying areas Landslides

may occur on

hilly ground

Shock

waves

Focus Epicenter

Giant undersea wave caused by an earthquake,

volcanic eruption or landslide

Travel > 450 mph

Tsunami wave may be 1m deep in ocean

Becomes 30.5m high on shore

Magnitude 9.3 earthquake in Indian Ocean

Triggered tsunami that killed over 230,000 people in

South Asia and Africa

Detection of tsunamis

Buoys in open ocean

Tsunami

Rock cycle- the constant formation and destruction of rock.

The Rock Cycle

Igneous rocks- rocks that form directly from magma. Intrusive igneous- form from within Earth as magma

cools.

Extrusive igneous- from when magma cools above Earth. (ex. A volcano that ejects magma out will form this)

Sedimentary rocks- form when sediment such as mud, sands, or gravels are compressed by overlying sediments.

Metamorphic rocks- form when sedimentary, igneous or other metamorphic rocks are subjected to

high temperatures and pressures.

The Rock Cycle

Sedimentary

Sediments from eroded rocks or plant/animal remains

Transported by water, wind, gravity

Deposited in layers and compacted

Sandstone

Shale

Dolomite

Limestone

Lignite

Bituminous coal

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Igneous Forms below or at earth’s surface from magma Granite Lava rocks

Metamorphic Preexisting rock subjected to high pressures, high temperatures, and/or chemically active fluids Anthracite Slate Marble

Weathering- when rocks are exposed to air, water, certain chemicals or biological agents that degrade the rock.

Physical weathering- the mechanical breakdown of rocks and minerals.

Weathering and Erosion

Chemical weathering- the breakdown of rocks and minerals by chemical reactions.

Weathering and Erosion

Erosion- the physical removal of rock fragments from a landscape or ecosystem. Wind, water, ice transport and living organisms can erode materials.

Deposition- the accumulation or depositing of eroded material such as sediment, rock fragments or soil.

Erosion

Soil is important because it

Is a medium for plant growth

Serves as a filter for water

A habitat for living organisms

Serves as a filter for pollutants

Soil

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Factors that determine the formation of soil:

Parent material- what the soil is made from influences soil formation

Climate- what type of climate influences soil formation

Topography- the surface and slope can influence soil formation

Organisms- plants and animals can have an effect on soil formation

Time- the amount of time a soil has spent developing can determine soil properties.

The Formation of Soil

Parent Material- the rock material from which soil is derived.

The Formation of Soil

Soil Composition

Mineral Particles

(45%)

Weathered rock

Organic Material (5%)

Litter, animal dung,

dead remains of plants

and animals

Water (25%)

Air (25%)

Soil Properties

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As soils form, they develop characteristics layers.

Soil Horizons

E Horizon

Is heavily

Leeched

Soil

O horizon- (organic layer) composed of the leaves, needles, twigs and animal bodies on the surface.

A horizon- (topsoil) the zone of organic material and minerals mixed together.

B horizon- (subsoil) composed primarily of mineral material with very little organic matter

C horizon- (parent material) the least weathered horizon and is similar to the parent material.

Soil Horizons

Texture- the percentage of sand, silt and clay the soil contains.

Physical Properties of Soil

Soil Properties

Soil texture affects soil properties

Coarse textured soil (sandy)

Excellent drainage

Fine textured soil (high in clay)

Poor drainage

Low oxygen levels in soil

Due to negatively charged surface, able to hold onto

important plant nutrients (K+, Ca2+, NO2-)

Soil Properties Affected by Soil

Texture

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Porosity- how quickly the soil drains (which depends on its texture)

Physical Properties of Soil

Soil Properties

Soil Acidity

Measured using pH scale

pH of most soils range from 4–8

Affects solubility of certain plant nutrients

Optimum soil pH is 6–7, because nutrients are most

available to plants at this pH

Chemical Properties of Soil

Cation exchange capacity- the ability of a soil to adsorb and release cations, positively charged mineral ions. Soil bases- calcium, magnesium, potassium and sodium Soil Acids- aluminum and hydrogen Base saturation- the proportion of soil bases to soil acids

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Biological Properties of Soil

Many organisms are found in the soil including fungi, bacteria, protozoans, rodents and earthworms.

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Soil Organisms

Soil organisms provide ecosystem services

Def: Important environmental benefits that

ecosystems provide

Examples

Decaying and cycling organic material

Breaking down toxic materials

Cleansing water

Soil aeration

Major Soil Groups

Variations in soil forming factors cause variation

in soils around globe

Soil Taxonomy

Separates soils into 12 orders

Subdivided into more than 19,000 soil series that

vary by locality

Five common soil orders

Spodosols, alfisols, mollisols, aridosols, oxisols

Major Soil Groups

Spodosols

Form under

coniferous forests

O-horizon composed

of decaying needles

E-horizon is ash -

gray under A-horizon

Not good farmland -

too acidic

Major Soil Groups

Alfisols

Brown to gray-

brown A-horizon

Precipitation high

enough to leach

most organics and

nutrients out of O-,

A- and B-horizons

Soil fertility

maintained by leaf

litter

Major Soil Groups Mollisols

Found in temperate,

semi-arid grassland

Very fertile soil

Thick, dark brown/

black A-horizon

Soluble nutrients stay

in A-horizon due to

low leaching

Major Soil Groups

Aridosols

Found in arid regions

of all continents

Low precipitation

preclude leaching

and growth of lush

vegetation

Development of salic

horizon possible

Major Soil Groups Oxisols

Found in tropical and

subtropical areas with

high precipitation

Very little organic

material accumulation

due to fast decay rate

B-horizon is highly

leached and nutrient

poor

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Elemental Composition of the Earth’s Crust

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The Life Cycle of a Metal

Resource

Fig. 14-11, p. 355

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Reserves

Reserves- the known quantity of a resource that can be economically recovered.

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Important Minerals and Their

Uses

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Types of Mining

Surface mining- removing minerals that are close to Earth’s surface.

Strip mining- removing strips of soil and rock to expose ore.

Open pit mining- the creation of a large pit or hole in the ground that is visible from the surface.

Mountain top removal- removing the entire top of a mountain with explosives.

Placer mining- looking for metals and stones in river sediments.

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Types of Mining

Subsurface mining- mining for resources that are 100 m below Earth’s surface.

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Surface Mining

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See the Trailer on The Last

Mountain Standing

http://thelastmountainmovie.com/

54

Formation of Mineral Deposits

Result of natural processes

Magmatic concentration

As magma cools heavier elements (Fe and Mg) settle

Responsible for deposits of Fe, Cu, Ni, Cr

Hydrothermal processes

Minerals are carried and deposited by water heated deep in earth’s crust

Sedimentation

Weathered particles are transported by water and deposited as sediment on sea floor or shore

Evaporation

Salts are left behind after water body dries up

Negative Effects of Mining

80% or more of mined ore consists of impurities

- called tailings

Contain toxic materials

Smelting plants emit large amounts of air

pollutants

Requires a lot of energy (fossil fuels

combustion)

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Fig. 14-12, p. 356

Natural Capital Degradation

Extracting, Processing, and Using

Nonrenewable Mineral and Energy Resources

Steps Environmental Effects

Mining Disturbed land; mining

accidents; health

hazards; mine waste

dumping; oil spills and

blowouts; noise;

ugliness; heat

Exploration,

extraction

Processing

Solid wastes; radioactive

material; air, water, and

soil pollution; noise;

safety and health

hazards; ugliness; heat

Transportation,

purification,

manufacturing

Use Noise; ugliness; thermal

water pollution; pollution

of air, water, and soil;

solid and radioactive

wastes; safety and health

hazards; heat

Transportation or

transmission to

individual user,

eventual use, and

discarding

Environmental Impacts of

Mining

Disturbs large area

Prone to erosion

Uses large quantities of water

Must pump water out of mine to keep it dry

Acid Mine Drainage (AMD)

Pollution caused when sulfuric acid and dissolved

lead, arsenic or cadmium wash out of mines into

nearby waterways

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Mine Tailings

Acid Mine Drainage

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How to mitigate the issues with

mining

Remediation of lands

Prevention is less costly than cleaning pollution

Use Phytoremediation by using plants to trap

pollutants

Trap pollutants before get into streams and

wetlands

Recycle and reduce use of minerals that are in

short suppy

Invent new substances to replace minerals

Change “throw away” attitude 62

Aluminum Cans Ready for

Recycling

Fig. 14-22, p. 366

Solutions: Sustainable Use of

Nonrenewable Minerals

Fig. 14-23, p. 366