Earth Science

can be replenished over short periods of time

take millions of years to form and accumulate

any hydrocarbon that may be used as a source of energy

forms when heat and pressure transform plant and material over million of years.

partially decayed plant material

in sedimentary rock that is often called coal

continued heat and pressure

It becomes harder and releases more heat when it is burned.

Coal

form fromthe remains of plants and animals that were buried in bodies of water long ago

large amounts of plant and animals remains become buried in ocean floor sediments which protect the remains form oxidation.

Over many years the sediments build up. Mineral reactions transform the remains into liquid and gaseous hydrocarbons

some energy experts believe that fuels derived from tar sands and oil shale could become substitues for the dwindling petroleum supplies.

• mixtures of clay and sand combined with water and varing amounts of black thick tar called bitumen
• contains oil that is similar to the oil that is pumped at with anticlines but in tar sand the oilis more resisitent to flow and cannot be pumped easily.

• mined at surface
• mined material is heated wiht pressurized stream until bitimen softens and rises

• a rock that contains a waxy mixture of hydrocarbons called kerogen
• can be mined and heated to vaporize the kerogen
• kerogen vapors are processed to remove the impurities and then refined
• part of sedimentary layers that accumulated over millions of years at the bottom of 2 extremely large shallow lakes.

deposits of useful minerals that can be extracted

deposits from which minerals can be extracted profitably

a useful metallic mneral that can be mined at a profit

• the natural concentration of many minerals is rather small. If extracting a mineral costs more than a value of a mineral then it is worthless
• the occurrence of valuable mineral resources are closely related to the Earth's rock cycle.

• generate some of the best known and most important ore deposits
• usually involve minerals that are not only heavy but also durable and chemically resistant

• bends in streams
• cracks in stream bed
• best known--gold

extracted and processed either for the nonmetallic element or for their chemical and physical properties

90%

the direct use of the sun's rays to supply heat or electricity

• fuel for nuclear plants comes from radioactive materials that release energy through nuclear fission
• nuclear fission results in controlled nuclear chain reactions that release great amounts of energy

• costly, hazards associated with the disposal of nuclear wastes
• accidents are possible that allow radiactive materials to escape