Exam 3 Flashcards
Which of the following is a non-metallic mineral?
a. Gypsum
b. Gold
c. Copper
d. Zinc
e. Aluminium
Gypsum
The process of separating a metal from its host rock is called what?
Smelting
The material produced when two metals are mixed together is called what?
An alloy
Gold is found primarily near kimberlite tubes.
False
Which type of coal is most abundant?
Bituminous
Which of the following choices is not one of the fundamental (permanent) sources of energy?
a. Fossil Fuels
b. Pull of gravity
c. Heat from the Earth’s interior
d. Fusion in the Sun
e. Radioactive Decay
Fossil Fuels
Which of the following nations gets the majority of its electricity from hydroelectric generation? Select one: a. Norway b. France c. Germany d. United States e. China
Norway
If the wind blowing through a turbine doubles in speed, how much additional energy is produced?
8x (x^3)
Which nation relies most on geothermal energy?
Iceland
Which of the following changes on Earth is cyclical? Select one: a. Differentiation b. Cooling of the mantle c. Building of supercontinents d. Evolution
Building of supercontinents
Which of the following investigative techniques would tell you most about climate 60,000 years ago?
a. Ice cores
b. rock cores
c. Dendrochronology
Ice cores
What is our current atmospheric CO2 concentration?
405 ppm
Categories of rocks and minerals
Metallic and nonmetalic
Metallic
Gold Silver Copper Lead Zinc Iron Aluminum
Non-metallic
Sand and gravel
Gypsum
Halite
Dimension stone
Types of metals mined
Precious – Rare and economically important.
Gold (Au)
Silver (Ag)
Platinum (Pt)
Base – Commonly used in industry. Iron (Fe) Lead (Pb) Zinc (Zn) Tin (Sn)
NC Gem Stones
Aquamarine, beryl, citrine, emerald, garnet, moonstone, rose quartz, ruby, sapphire, tourmaline, staurolite, topaz, and many varieties of quartz
Ores
Rock with a concentration of metal-rich minerals; present in enough abundance to be economic to mine. Metal must be readily extracted from the material
Alloys
Blending metals makes an alloys, like stainless steel or bronze.
Properties are usually superior to a standard metal
How do ores form?
Magmatic and hydrothermal activity. Ore and silicate minerals are deposited by hot magmatic fluids in cracks in surrounding rocks
Secondary Enrichment
An especially important class of residual deposit is formed by both the removal of valueless material in solution and the solution and redeposition of valuable ore minerals. Because solution and redeposition can produce highly enriched deposits, the process is known as a secondary enrichment.
Hydraulic Sorting
In high-velocity water…
Low-density minerals are suspended and washed away.
High-density grains are concentrated by settling out.
Diamonds
Diamonds originate under extremely high pressure.
~ 150 km deep – in the upper mantle.
Pure carbon is compressed into the diamond structure.
Rifting causes deep mantle rock to move upward.
Diamonds are found in kimberlite pipes.
Coal Characteristics
Black, brittle, carbonaceous sedimentary rock.
Remains of organic matter from vegetation.
Important global energy source; CO2 emitter.
Only found in rocks younger than 420 Ma.
Coal formation
Coal-forming eras. Carboniferous (354 – 286 Ma). Warm climate. Broad epicontinental seas. Tropical deltaic wetlands. Cretaceous (144 – 65 Ma).
Vegetation accumulates in an O2-free setting.
Absence of oxygen prevents organic matter decay.
Marine deltas.
Tropical coastal wetlands.
Sea level rise and fall buries wetland deposits.
Coal formation requires heat and pressure.
Compaction and decay turns plant debris into peat.
Approximately 50% carbon.
Readily cut out of a wetland deposit.
Coal Rank
Classification based on the carbon content.
Peat 50% C
Lignite 70% C
Bituminous 85% C
Anthracite 95% C
Anthracite forms by metamorphism in an orogenic belt.
Higher-rank coal yields more energy when burned.
Tunnel Mining
Underground mines – Ore obtained by tunneling.
Tunnels are linked to a vertical shaft.
Ore is removed by drilling and blasting.
Excavated ore is hauled to the surface for processing.
Expensive and dangerous.
Coal Mining
Underground mining – Coal removed by tunneling.
For coal deeper than 100 m, shafts are advanced to seam.
Tunnels excavated along the seam remove the coal.
Coal mining is specialized, expensive, and dangerous.
Tunnels can collapse.
Methane gas.
Asphyxiation.
Explosions.
Black lung disease.
Strip Mining
Strip mining – Landscape destroyed to reach coal.
A large drag line bucket is used to scrape off overburden.
Spoil is stockpiled nearby for later use during reclamation.
Exposed coal is removed and the excavation is reclaimed.
Excavation is backfilled with spoil and soil, then planted.
Mountain-Top Removal
Removal of 100s of meters of elevation Deforestation Destroy ecosystems Pollute headwaters Increased flooding
Effects of Coal on Environment
Smog Acid rain Acid mine drainage Waste 5-20% original volume Composed of non-combustible silicate minerals + toxic metals.
Fundamental Sources of Energy
Nuclear fusion in the Sun.
The pull of gravity.
Nuclear fission reactions.
Energy in the interior of the Earth.
Solar Energy Source
Energy directly from the Sun’s nuclear fusion reactor.
Heat and light radiate outward from the Sun.
A tiny portion of the solar output strikes Earth.
Direct solar energy can be used by humans.
Conversion into electricity by photovoltaic cells.
Conversion into heat.
Controlled fusion is currently beyond human technology.
Energy via Photosynthesis
Chlorophyll stores solar energy in H-C bonds.
Water and carbon dioxide react to form sugar and oxygen.
6CO2 + 12H2O + light > C6H12O6 + 6O2 + 6H2O
H-C bonds release stored energy when broken (oxidized).
Gravity-driven energy sources
Energy directly from gravity.
Falling water for Hydroelectric is most common, but tidal energy is also related to gravity.
Energy from nuclear fission
Certain radioactive atoms can be fragmented.
This process, called fission, yields tremendous energy.
Fission energy is used to run nuclear power plants.
Energy from Earth’s internal heat
Earth’s internal (geothermal) energy has 2 sources.
Residual heat from planet formation.
Heat from radioactivity.
Geothermal energy drives tectonic plates.
Heat lost through the crust can be harnessed.
Oil and Gas Genesis
Oil and gas hail from plankton and marine algae.
Dead plankton and algae sink in quiet water.
This organic material accumulates with fine mud.
Under anoxic conditions, organic matter is preserved.
Lithification forms a black shale petroleum source rock.
Burial to depths of 2 to 4 km heats the black shale.
Heating breaks the organics down into waxy kerogen.
Kerogen-rich source rocks are called oil shales.
Continued heating breaks
down kerogen.
Oil and gas form in
specific T ranges.
Oil and gas – 90o to 160oC.
Gas only – 160o to 250oC.
Graphite – >250oC.
Shale Gas
100 Year supply of natural gas
New technology makes reserves economically viable
- Horizontal drilling techniques
- Hydraulic Fracking
Getting oil out of the ground
Primary recovery.
Uses reservoir pressure and pumping to extract oil.
Inefficient; only able to recover about 30% of the oil.
Secondary recovery.
Fluids (steam, CO2) are injected to heat and push oil.
Hydrofracturing – Artificially increases permeability.
Tar Sands
Tar sands – Deposits of residual petroleum in sand.
Heavy oil, or bitumen, is residue of a former oil field.
Lighter hydrocarbons are removed by bacterial digestion.
The remaining hydrocarbon is too viscous to be pumped.
Tar sands must be mined
and processed.
Extensive deposits in
Alberta and
in Venezuela.
Nuclear Energy
Fissionable U-235 is bombarded with neutrons to begin a chain reaction. Plants are cheaper to run and less fuel-intensive than coal plants of similar output
U235 is a limited resource, just like fossil fuels.
Little inexpensive U235 remains.
Attempts at recycling or using other fissionable materials
Nuclear Accidents
Plant safety is a major concern.
Extensive efforts applied to thwart terrorism.
Nuclear accidents are rare but have occurred.
1986 – Chernobyl (Ukraine) spread radioactivity globally.
1979 – Three Mile Island (Pennsylvania, U.S.).
2011 – Fukushima Daiichi (Japan)
Solar Energy
By far the most abundant source of energy
Solar energy dwarfs that of hydrocarbon resources.
But solar energy is hard to utilize because it is…
Diffuse.
Highly variable on a seasonal and daily basis.
Difficult to convert into more usable forms of energy
Issues in Solar scalability
100-Megawatt Solar Array:
30-40,000 tons steel
5000 tons glass
200,000 tons concrete
Nuclear Power Plant:
500 tons steel
50,000 tons concrete
Waste
Wind Energy
Winds are powered by the sun: so more solar energy.
Wind has been used historically for grain milling and pumping of water.
Requires consistent, strong winds to be most efficient
Issues with Wind Energy
Intermittent wind means it is not a dependable source of energy: Primarily used as a supplement. Improved tech has resulted in energy production ~95%
Space: You’d need 100 sq. miles of turbines to equal one large coal or nuclear plant in energy output
Require energy storage mechanism like solar energy
Higher winds at higher elevations – Mile high wind vanes.
Place wind farms on grazing or agricultural lands
Offshore wind farms: 1st by Denmark in 1991
Many 1-200 MW wind farms in Europe with 1000-9000 MW farms planned in UK.
Geothermal Energy
Energy from rising magma
Most abundant near plate boundaries
Can be used for direct thermal heating for homes or for electricity generation
Hydrothermal Heating
Water cycles through warm subsurface or steam is transported directly to buildings for heat
Drawbacks of Geothermal
Lots of dissolved minerals Subsidence Not universally available Output can vary – Decreases over time Long transmission distances Not useful for transportation
Hydroelectric
Energy derived from the kinetic motion of falling water
Positive aspects. Reduces the risk of floods. Impounds water for drinking, irrigation, and recreation. 3. Provides renewable energy without creating wastes.
Negatives of Hydroelectric
Dams destroy valued landscapes and alter ecosystems.
Reservoirs accumulate the sediment load of the river.
Sediments added to reservoirs require expensive dredging.
Erosion is accelerated downstream of dams.
Unidirectional Changes
Differentiation - At first, Earth was fairly homogeneous, but during core formation, iron sank to the center
Evolution
Building of continental crust, which DOES NOT SUBDUCT
Cyclic Changes
Supercontinent cycle
Sea Level - Has oscillated all throughout history, and usually coincides with glacial cycles
Carbon Cycle
Seeing what the Earth used to look like
Ice and Sediment Cores
Pollen Records
Dendrochronology (Only reaches hundreds of years)
Albedo
The ability to reflect
Milkankovitch Cycles
The shape of Earth’s orbit varies (~ 100,000 year cyclicity).
Tilt of Earth’s axis varies from 22.5o to 24.5o (~41,000 years).
Precession – Earth’s axis wobbles like a top (23,000 years).
Asteroid
A relatively large rocky body that is orbiting the sun. Up to 1000km diameter.
Meteoroid
Relatively small rocky body moving through interplanetary space. Up to 1m diameter
Meteor
A rocky body from space that enters earth atmosphere appearing as a streak of light (Shooting Star)
Meteorite
A meteor that survives passage through the atmosphere such that part of it strikes the ground
Types of Meteorites
Iron -------- Core material from destroyed planets or asteroids Extremely Dense Magnetic 90-95% iron
Stone Meteorites -------------------------- Most common Crustal material from planet or asteroid May contain chondrules Can be from Moon or Mars
Stony-Iron Meteorites -------------------------------- Very Rare (2%) Formed at core-mantle boundary Large olivine crystals Pallasites Mesosiderites (equal Ni-Fe and Si)
Cosmic collisions in evolution of Solar System
Early phase (4.5 billion yrs ago): planet formation Planetesimals collided or accreted to form larger pieces
Formation of Moon by glancing collision with Earth
Collision made Venus rotate backwards
Collision tipped Uranus onto its side (now rotates at 90 deg to rotation axes of all other planets)
“Late Heavy Bombardment” (~3.9 billion years ago) from Lunar record
First signs of life on Earth immediately followed “Late Heavy Bombardment” period. Is there some sort of connection?
Evidence that moon formed as a result of a collision
Differentiation: Earth has Iron core, Moon does not
Composition: Moon is similar to Earth’s Mantle
Density: Moon (3.3 grams/cm3) is much less than Earth (5.5 grams/cm3)
Carbonaceous Chrondrites
Contain amino acids, fatty acids, other so-called “building blocks of life”
Did building blocks of life come to Earth from space?
Did life itself come to Earth from space?
“Panspermia” theory
Meteorites… as rare as we think?
About 25 million collisions occur every day totaling around 100 tons new material
10-50 impacts on the Earth’s surface a day
incomplete reporting
What are the odds of a catastrophic meteorite impact?
20,500 near-Earth asteroids larger than 330 feet
Large enough to survive entry and cause regional or greater damage
Occur approximately once every 1000 years
“Global Consequence” impacts occur every 100ka
Asteroid deflection techniques
Nuclear detonation
Gravitational pull from satellite
Collision with spacecraft (Don Quijote)
Using solar energy (Yarkovsky effect)
Solar sails
The key is having enough time
Meteorite impacts and extincitons
K-T boundary extinction event
Dated at 65 Ma
Marine Organism Losses
planktonic foraminifera -83%
ammonites -100%
marine reptiles -93 %
Continental Organism Losses
Reptiles in general: -56%
Non-avian dinosaurs and pterosaurs: -100%
Some did alright… Higher Plants -10% Dinoflagellates – 5% MAMMALS - +120% Everything that survived on land was small (<25kg)
Largest meteorite recovered
Named: Hoba
Found: 1920
Location: Namibia
Impacted: < 80ka
Weight: 60 Tons
Ice in the solar system
Mercury, comets, mars, europa
Titan
Methane Lakes are found around Titan’s Surface
Largest moon of Saturn
Thick atmosphere: 98% Nitrogen
We landed a probe on Titan’s surface in 2005
