Geological processes result in the formation of solids that have distinct chemical composition and have particular physical properties. These are referred to as minerals. Equally, fossil fuels form one of the most common types of minerals. Fossil fuels are fuels that contain carbon and which were formed over millions of years through decomposition, burial and compression of decaying vegetation on land and aquatic organisms on the sea bed.
Fossil fuels like coal, oil and natural gas are formed through a process that takes millions of years. These fuels are deeply embedded in the natural layers of the earth. Several methods are employed to extract the fossil fuels.
The sources of energy fall into two categories majorly renewable sources of energy and non renewable sources of energy. The term renewable implies that the energy source in consideration can be used over a long period of time without necessarily being exhausted while the non renewable sources of energy are limited, that is to say their continued use and dependence over time leads to exhaustion. The decomposition and decay of plant and animal remains trapped beneath the sedimentary rocks forms fossil fuels. The remnants are subjected to chemical and physical changes over a long period of time. Fossil fuel is a composition of hydrocarbon compounds that is formed as a result of the alteration of plant and animal remnants. It follows that the original source of energy was the sun by way of photosynthesis. The major fossil fuels are peat, oil, natural gas and oil (Camp & Daugherty, 2000, p. 349).
The type of sediment, particular type of organic matter and the post burial changes that occur determine the type of fossil fuel that is formed. Trees and bushes are the sources of organic matter found on the earth surface. They contain organic matter that tends to remain solid after burial. Remnants accumulate over time in waterlogged areas such as swamps forming peat which is the initial stage in the formation of coal. The bottom most layers are compressed and heated by the overlying layers causing water and gaseous components to escape. Subsequently, the residue formed has a higher concentration of carbon.
Minerals are classified into two categories majorly metallic, those minerals that are mined specifically for the metals that can be extracted from them, and non metallic minerals, those that are extracted for their properties as minerals. The formation of a mineral deposit is as a result of one or more processes and this will also dictate the type of mineral found in a particular rock. An insight into the mineral forming process will shed light on the type of mineral formed. The precipitation of hot water solutions forms hydrothermal deposits. Occasionally these solutions are deposited in cracks in rocks and it ends up forming a mineral vein. Under the metamorphic process very hot liquids could change the existing rocks by a process known as contact metamorphism. The liquid concentrates the minerals indistinct regions. Fractional crystallization in magmas could concentrate minerals. Mineral deposits could also be formed when a large body of water evaporates leaving behind the dissolved mineral. The resultant mineral is known as evaporate. Minerals could also be formed by a process known as chemical weathering. This is where insoluble minerals are highly concentrated in a rock after reduction in the concentration of soluble minerals (Dale and Markandya, 2001, p 187).
The formation and location of minerals is affected by a number of factors and this is explained by several theories. It could be affected by the tectonic movements of the earth crust. Another factor is the placer deposit method. This is whereby the formation of minerals takes place in a secondary location. For the greater part minerals are considered to be non renewable.
Reference
Camp, G. and Daugherty, T. (2000) Managing our natural resources. Albany, NY: Cengage publishers
Markandya, A. and Dale, N. (2001).Measuring environmental degradation: developing pressure indicators for Europe.Northampton, Massachusets: Edward Elgar Publishing