Chapter 7, Section 1 - Mineral Resources
Ore - A natural mineral deposit from which metals and nonmetals may be profitably removed.
- Can be found either as native elements or in compounds.
- Formed in various ways...
- By Cooling Magma
By Contact Metamorphism
- Dense metallic minerals sink as magma cools => form a layer at the bottom of the magma chamber.
- ex. - ores of Cr, Ni, Pb
By Moving Water
- Heat & chemical reactions can change rock to form ores.
- Hot fluids flowing through cracks (hydrothermal solutions) can dissolve away some minerals and leave others to form veins (narrow zones) of ores.
- Lode - An ore deposit where many thick veins form in a relatively small area.
- ex. - ores of Au, Ag, Sn, Pb, Cu
- As rock is weathered, small fragments of native elements can be released.
- The fragments are carried by water until the current grows too weak, and they are deposited.
- Placer Deposit - A deposit that contains a valuable mineral that has been concentrated by mechanical sorting.
- ex. - Au
Uses of Mineral Resources
- Gemstone - A mineral, rock or organic material that can be cut and polished for use as jewelry.
- Examples of common mineral uses...
| Metallic Minerals|| Uses|
| Hematite & Magnetite (iron)|| for making steel|
| Galena (lead)|| in car batteries, in solder |
| Gold, Silver, Platinum || in electronics and dental work; as coins, jewelry, eating utensils and bowls|
| Chalcopyrite (copper)|| as wiring; in coins and jewelry; as building ornaments |
| Sphalerite (zinc)|| for making brass and galvanized steel |
| Nonmetallic Minerals||Uses |
| Diamond (carbon)|| in drill bits and saws (industrial grade); in jewelry (gemstone quality)|
| Graphite (carbon)|| in pencils, paint, lubricants, and batteries|
| Calcite|| in cement; as building stone |
| Halite (salt)|| for food preparation and preservation |
| Kaolinite (clay)|| in ceramics, paper, cement and bricks |
| Quartz (sand)|| in glass and computer chips |
| Sulfur || in gunpowder, medicines and rubber |
| Gypsum|| in plaster and wallboard |
Mineral Exploration & Mining
- An area is considered for mining if it contains 100 to 1000 times the concentration of desired minerals found elsewhere.
- Mineral deposits are located and identified by...
- Studying local geology: patterns in magnetism, gravity, radioactivity, and rock color.
- Testing rock samples for composition.
- Types of Mining...
- Subsurface Mining [video]
- Miners work underground to locate and recover minerals.
- Surface Mining
- Overlying material is stripped away to reveal mineral deposits.
- Placer Mining
- Floating barges dredge up sediments and separate out the denser minerals.
- Remaining sediment is released into the water.
- Undersea Mining
- Nodules (lumps of Fe, Mn, Ni) form on the ocean floor.
- Difficult to mine due to location. (Minerals on land are less expensive to mine.)
Chapter 7, Section 2 - Nonrenewable Energy
Nonrenewable Resource - A resource that forms at a rate much slower than the rate at which it is consumed.
Fossil Fuel - A nonrenewable energy source formed from the remains of organisms that lived long ago.
- Composed mainly of hydrocarbons (compounds of H and C), which store energy converted from sunlight.
- Petroleum (Oil)
- Natural Gas
- The remains of ancient plants that undergo the process of carbonization to form coal.
- Partially decomposed plant matter is buried and compressed to form peat.
- Methane (CH4) and carbon dioxide (CO2) are released until mainly carbon remains. (In the absence of oxygen.)
- As sediments are added on top, water and gases are squeezed out, peat is converted into lignite (brown coal).
- With more heat and pressure, lignite changes into bituminous coal (soft coal), which is 80% carbon.
- Folding of the crust creates enough heat and pressure to convert bituminous coal into anthracite coal (hard coal), which is 90% carbon.
- All of these can be used as energy sources.
- Bituminous is the most abundant.
- Anthracite releases the most energy.
Petroleum & Natural Gas
- Made up of hydrocarbons; petroleum (a.k.a.: oil) is in liquid form, natural gas is in gaseous form.
- Formed from dead plants and microorganisms that were buried by sediments in oceans, lakes and seas. Heat and pressure converted the remains into petroleum and natural gas.
- Usually mined from permeable sedimentary rocks. (Rock with spaces for fluids to flow through.)
Pg. 190-191 #5-24, 34-36.