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WEATHERING AND FOSSILS-III. BY: MS. SAWERA FARRUKH. Contents. Rocks Sedimentary, Igneous, Metamorphic Rock Cycle Transportation, Deposition, Sedimentation Weathering Physical, Chemical, Biological Fossil formation and Quarrying Fossil fuels and their use. What are Fossil Fuels?.
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WEATHERING AND FOSSILS-III BY: MS. SAWERA FARRUKH
Contents • Rocks • Sedimentary, Igneous, Metamorphic • Rock Cycle • Transportation, Deposition, Sedimentation • Weathering • Physical, Chemical, Biological • Fossil formation and Quarrying • Fossil fuels and their use
What are Fossil Fuels? • Fossil fuels are the carbon rich fuels produced from the prehistoric, fossilized organic remains of vegetation and other organisms that have endured intense heat and pressureinside the earth over a long period of time (millions of years). • These are found within the top layer of the earth's crust. • Fossil fuels are capable of producing tremendous amount of energy to meet our energy needs that are increased since the Industrial Revolution.
How were Fossil Fuels formed? Fossil fuels are all formed in the same way. Depending on their chemical composition, these fossilized remains formed coal, oil or natural gas. • Oil and natural gas • They were created from organisms that lived in the water and were buried under ocean or river sediments. • Long after these seas and rivers vanished, heat, pressure and bacteria combined to compress and "cook" the organic material under layers of silt.
How were Fossil Fuels formed? • In most areas, thick liquid called oil is formed first. But in deeper, hot regions underground, the cooking process continued until natural gas was formed. • Over time, some of this oil and natural gas began working its way upward through the earth's crust until they ran into rock formations called "cap rocks" that are dense enough to prevent them from seeping to the surface.
How were Fossil Fuels formed? • Coal • It is formed from the dead remains of trees, ferns and other plants that lived 300 to 400 million years ago. • In some areas coal was formed from swamps covered by sea water. The sea water contained a large amount of sulphur, and as the seas dried up, the sulphur was left behind in the coal. • Some coal deposits, however, were formed from freshwaterswamps which had very littlesulphur in them.
Types of Fossil Fuels The three types of fossil fuelsare coal, oil and natural gas. gas oil coal • Some also include oil shale and bituminous sands, although current commercial production is minor. • TheAsphalt recently has beenrecognized as the fourth fossil fuel.
Crude Oil Oil is a dark liquid composed of diatoms, or tiny photosynthetic algae and other marine microorganisms deposited on the sea floor. • It is not found everywhere on the earth. • It is mainly used to fuel jets and automobiles. It also is used to generate electricity, and its derivatives are utilized in the medicine and plastic industries, applied in roads and roofs. • The widespread use of petroleum also has contributed to air and water pollution.
Crude Oil • The hydrocarbons in it are separated into many products by refining impurities from oxygen, nitrogen and sulphur. • petroleum gases such as propane and butane, • petrochemicals for manufacturing purposes, • gasoline, • kerosene, • diesel fuel, • lubricants, • waxes and, • asphalt.
Natural Gas • It is a colourless and odourless gaseous fossil fuel which is highly compressed in small volumes and is found at large depths in pockets underneath the earth's surface. It is formed from the remains of marine microorganisms. • Natural gas reserves are more evenly distributed around the globe than oil supplies. • The major consumers of natural gas are the residential, commercial and industrial sectors. It is also used to generate electricity.
Natural Gas • Unlikeother, fossil fuels natural gas is cleanerand causes less pollution. • Natural gas is comprised mostly of methane. • It also contains: • ethane, • propane and • butane.
Coal • Coal is a black, solid fossil fuel found as a sedimentary rock throughout the world. • This substance, made primarily of carbon, was formed over millions of years by decay of land vegetation. When layers were compacted and heated over time, deposits were turned into coal. • The electricity generated worldwide is powered by coal. The steel industry also is greatly dependent upon this fossil fuel.
Coal • Coal is a greenhouse gas nightmare. When coal burns, the sulphur can become an air pollutant. • It can be gasified or liquefied to create synthetic fuels similar to gas or crude oil.
Why are Fossil Fuels Non-Renewable Humans needenergyfor just about any type of function they perform. Energy generation can be performed using various different sources. These sources can be eitherrenewableor non-renewable. • Renewable energy sources are replaced in time and will therefore not run out easily. However, non-renewable energy sources are threatening to run out if our standard of usage becomes too high.
Why are Fossil Fuels Non-Renewable • Fossil fuels are considered a finite resource, or non-renewable because of the sheer length of time required to make them. Although their known reserves are vast, but they will eventually run out. • Nowadays many renewable energy sources (like solar energy, wind energy and water power)are also being used to overcome the future crises that can happen due to unavailability of fossil fuels. But ironically, we still gain mostof our energy from fossil fuels.
Damage to the Environment • Fossil fuels principally consist of carbon and hydrogen bonds. When fossil fuels areburned, carbon andhydrogenreact withoxygenin air to form carbon dioxide(CO2) and water (H2O). • Coal may result in underground fires that are virtually impossible to extinguish. • The Oil spills in soil or water in raw form has caused many natural disasters in the past.
Damage to the Environment • The Burning of fossil fuels is responsible for many environmental problems as: • greenhouse gas accumulation, • acidification, • air pollution, • water pollution, • damage to land surface and • ground-level ozone.
Future Fossil Fuels Fossil fuels are non-renewable sources of energy. The non-renewability of these sources will probably cause prices to rise up to a point where they are no longer economically feasible. • Also as we are excessively dependent on these, alternativeformsof energy need to be developed in order to deal with the imminent energy scarcity.
Asphalt/Bitumen Naturally occurring or crude bitumen is a sticky, tar-like form of petroleum which can be upgraded to synthetic crude oil. It is so thickandheavythat it must be heatedor dilutedbefore it will flow. • It became the "fourth fossil fuel" in the mid-1980s. It is derived from the naturally occurring large reserves in theOrinoco oil belt, Venezuela and in theoil sandsofAlberta, Canada.
Asphalt/Bitumen • Most bitumen contain sulphur and several heavy metals such as Nickle, Vanadium, Lead, Chromium, Mercury and also other toxic elements like Arsenic, Selenium, etc. • The primary use of bitumen is in road construction. Its other main uses are for bituminous waterproofing products, production of roofing felt and for sealing flat roofs. • It is also an economically viable fuel for power generation to be used as a commercial boiler fuel in power plants.
Methane Hydrates It is an ice-like combination of natural gas and wateroccurring in the pore spaces of sediments, either hundreds of feet below the sea floor or a few feet under the frozen tundra in the Northern Hemisphere. • It was discovered only a few decadesago. • This crystalline combination, formed under low temperatures and high pressures, looks remarkably like ice but burns if it meets a lit match. • As methane is a greenhouse gas, so it’s release can affect the Earth's atmosphere.
