Geology and Earth ResourcesBotkin Ch 27 Raven, p110-116, Ch 16

Warmup (Hwcheck) 8/21/13Of the 1498 contaminated sites on the US Superfund National Priorities list in 2002, 846 sites were cleaned up by 2006. What percent remains to be cleaned up?A.44%B.56%C.77%D.82%

Key Terms• Convection• Converge• Deposition• Diverge• Geologic time• Organic• Pangaea• Precipitate• Richter scale• Ring of Fire• Social Responsibility• Subduction

Objectives - KWL• Explain basic geologic principles, including how tectonic plate

movements affect conditions for life on earth

• Explain how the three major rock types are formed and how the rock cycle works

• Summarize economic mineralogy and strategic minerals

• Discuss the environmental effects of mining and mineral processing

• Recognize the geologic hazards of earthquakes, volcanoes, and tsunamis

Outline• Dynamic Planet• Rocks and Minerals • Categories of Minerals• Environmental Effects of Resource Extraction• Conserving Geologic Resources• Geologic Hazards

A Dynamic Planet

The Earth consists of four layers• Inner core – dense very hot iron• Outer core – plastic consistency• Mantle – pliable and less dense

• Lighter elements include oxygen, silicon, magnesium• Convection currents occur due to heat from the core

• Crust – lighter, brittle, and broken into pieces called plates, which move

• Contain calcium, potassium, sodium, aluminum• Divergent boundaries – where plates separatae• Convergent boundaries – where plates come together• Transverse boundaries – where plates slide past each other

The inner and outer core form Earth’s magnetic field

Earth’s formation - Theory

Formation of solar system bodies occurred with the SunEARTH’s FORMATION• 4.54 billion years ago (bya) Solar nebula begins to collapse• Partitions into separate volumes over 10 million years

Crust Dynamics

• Divergent boundaries are driven apart by convection in the mantle• Magma is iron-rich (basalt)• New crust is formed as it cools• Plates push away from each other

• Convergent Boundaries: Subduction occurs as one plate collides into its neighboring plate and slides downward into the mantle• Deep ocean trenches at subduction zone• Volcanoes arise as gases bubble up from the mantle• Magma is silica-rich (granite)

• “Ring of Fire” – subduction zones in the Pacific Ocean Rim, where most of the world’s earthquakes and volcanoes occur

• “Hot Spots” – continual stream of magma in one area, crust moves over it creating a chain of volcanic mountains. Ex: Hawaii

Rocks and Minerals

• Minerals: compounds of elements that occur in crystalline structure• Rocks: aggregates of one or more minerals• Rock Cycle: rocks form and are destroyed in a continual cycle of

crystallization, breaking down, heating, pressure, cooling • Three types of rocks:• Igneous – “formed of fire”, when magma rises to earth’s surface• Metamorphic – modified by heat and pressure• Sedimentary – formed by the “weathering” of other rock types that are

carried by wind and water, deposited, and compacted

Agenda: Monday, Aug 26I. Discuss: How should government respond to Hazards? Write a summary

sentence based on your reading, then pass the paper on to each team member.

II. Demonstrations : Density and Viscosity

III. Video Questions: Hot Spots – 1:28 start https://www.youtube.com/watch?v=07b6ijzbT6A

1. How do volcanoes affect the atmosphere? biosphere?2.What is a hot spot? What do Hawaii and Yellowstone have in common? Video Question: How are the Himalayas formed?https://www.youtube.com/watch?v=goszsQl0Bc0

QUIZ FRIDAY!!! OOPS! I forgot there is no school. What shall we do? I want to test what you’ve learned so far. OK Quiz next Wednesday!!!! STUDY!!

DEMONSTRATIONS • How is density measured?• How does silica affect viscosity?

DEFINITIONS:Density – mass per unit volume (g / m3)Silica – the mineral present in sand that is found in magma at

convergent boundariesViscosity – the property of a fluid that causes it to resist

movement, generally understood as thickness.

Should we revise mining laws?

20 minutes CLOSE READING / DISCUSS:1. Underline any words you do not know or cannot figure out.2. Use context clues to guess at the meaning. (note in the

margin)3. Look them up in the dictionary if you need to.4. How many acres could I buy for $100 if I wanted to start a

business on public land when I retire?5. What kind of profits are being made through the General

Mining Law? Provide examples. 6. List the pros and cons of this law.7. What do you think?

Elements present in Earth’s structure

Whole Earth (core, mantle, crust)

Crust only

Iron 33.3 Oxygen 45.1

Oxygen 29.8 Silicon 27.2

Silicon 15.6 Aluminum 8.2

Magnesium 13.9 Iron 5.8

Nickel 2.0 Calcium 5.1

Aluminum 1.5 Sodium 2.3

Sodium 0.2 Potassium 1.7

Total 100% Total 100%

Create two different graphs, one for each set of percentages of elements in the different parts of Earth’s structures. What processes account for the differences?

Categories of Minerals

• Minerals, especially metals, are important to industry• Mining, processing, and distribution are commercial activities• Minerals found in abundance are worth extraction costs• Besides metals, sand, and gravel, minerals deposited through

evaporation can be mined and refined commercially

Metals Non-metals Evaporates

Aluminum, iron, lead, nickel, gold, platinum, silver copper, chromium

Sand, gravel - constructionSilicates – high silica sand for glass; gemstones, mica, talc, asbestos Soil

Limestone - constructionHalite - saltsGypsum – plasterPotash – fertilizerSulfur – batteries, medicine

Important Metals and primary sources

AluminumLeadZincIron ore

Aluminum ,Tin, Mercury, Zinc, Lead, Iron ore,

Nickel, Zinc, Copper

Copper, Lead

Nickel

Copper, Tin, Zinc, Iron Ore

Aluminum, Nickel, Tin

AluminumMercury

Metals and their usesMetal Use

Aluminum

Chromium

Copper

Iron

Manganese

Nickel

Platinum

Gold

Silver

Environmental Effects of Resource Extraction

• Mining disturbs the surface of the land (see next page)• Air is polluted with dust and chemicals• Smelting is the process of roasting ore to release metals; this

releases sulfur emissions• Water is polluted by chemical and sediment runoff• Piles of crushed ore are sprayed with alkaline-cyanide solution • Chemicals leak into groundwater, surface waters are

contaminated

The 1977 Surface Mining Control and Reclamation Act requires restoration of mined lands.

Mining

• Placer mining – water is used to disturb the surface; streams fill with sediment• Open pit mining – upper layers removed, polluted water accumulates in pits• Strip mining – layers are systematically removed and the spoils are dumped• Shaft mining – methane accumulates in tunnels; explosions and collapses occur• Mountaintop removal – tops of mountains are blasted away and the spoils

tumble into river valleys

Conserving Geologic Resources• Recycling metals (aluminum, platinum) costs less than mining

for the metal ore• Using new materials, new technologies helps reduce our need

for mining and extraction• Polymers• Alloys• glass

Geologic Hazards• Geologic forces have shaped the Earth for millions of years• Massive events happen rarely and are called natural disasters• Floods – take the most human lives• Hurricanes and tornadoes cause greatest property damage• Earthquakes cause the most damage in areas with poorly

constructed buildings• Tsunamis, generated by earthquakes or volcanoes, cause flooding

in coastal areas• Volcanoes release huge amounts of dust and gases into the

atmosphere blocks sunlight, reduce temperature, produce sulfuric acid rain, reduces stratospheric ozone

• Landslides cause property damage when people build homes and roads on unstable ground