The planet we live on: The beginnings of the Earth Sciences

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Figure 5.16: <strong>The</strong> sources of fuel used in current world energy consumption.it can to reduce the effects of climate change. One of the main causes seems to be theincreasing amount of carbon dioxide (and other ‘greenhouse gases’) in the atmosphere andtheir ‘greenhouse effect’. Even though enormous amounts of carbon are cycled throughthe carbon cycle and the Earth’s atmosphere each year, through such processes as photosynthesisin plants and respiration in all organisms, the amount of carbon dioxide in theatmosphere in the recent geological past had stayed fairly stable until the beginning ofthe Industrial Revolution. As more and more fossil fuel has been burnt since this time,the carbon dioxide content of the atmosphere has increased, so that now about 100 timesmore carbon dioxide is released into the atmosphere each year by burning fossil fuels thanis released by natural volcanic emissions.<strong>The</strong> fossil fuels, coal, oil and natural gas, together are called hydrocarbons. When thecarbon in them burns, it combines with oxygen from the atmosphere to form carbondioxide. As the atomic mass of oxygen (16) is greater than that of carbon (12), andeach carbon atom combines with two oxygen atoms to make CO 2 , the mass of the carbondioxide produced by burning is greater than the mass of the original carbon. Even naturalgas, the most efficient of the fossil fuels, emits more than its <strong>we</strong>ight of carbon dioxide onburning.Currently more than 80% of the po<strong>we</strong>r used on Earth comes from the burning of fossilfuels (Figure 5.16), so there will be no easy way to reduce carbon emissions. Neverthelessthree different methods are being used to reduce the amount of carbon dioxide beingreleased to the atmosphere:• generate more po<strong>we</strong>r from non-hydrocarbon fuel sources, to reduce the burning ofhydrocarbons;• reduce the amount of po<strong>we</strong>r needed, by using fuel more efficiently;123
Figure 5.17: A windfarm in Ireland. Figure 5.18: Solar panels being used inMallorca.• burn hydrocarbons, but then trap the carbon dioxide formed and store it in oldexhausted oil and gas fields.Figure 5.16 shows how difficult it is going to be to generate a lot more energy fromnon-hydrocarbon sources. We can’t easily increase biofuel production, as this wouldmean growing and burning more trees; biofuels are usually grown on land used to growcrops for human consumption, so production from these is not likely to increase greatly.Increasing po<strong>we</strong>r production from hydroelectricity would mean building more dams andreservoirs, which is not possible in dryer or low-lying countries. For these reasons, mosteffort is being focused on nuclear, solar and wind po<strong>we</strong>r generation. Nuclear po<strong>we</strong>r isbeing strongly developed in some countries and being considered by others, despite theproblems of nuclear waste disposal and potential large scale nuclear disaster. Wind, solarand geothermal po<strong>we</strong>r supplies are also being developed, but these are starting from suchlow percentages that they won’t make a great impact on global po<strong>we</strong>r supplies for sometime.Many countries are developing onshore and offshore windfarms of clusters of windturbines. Meanwhile buildings in some regions are being fitted with solar panels to contributeto the energy needed by the building, whilst other building projects are using the‘geothermal energy’ supplied by ‘heat engines’. <strong>The</strong>se draw in heat from the surroundingground (ground-source heat engines) or air (air-source heat engines) which is thenused for heating the building. In warm summers, heat can be returned to the ground byreversing the heat engines to provide air conditioning. Most of the ‘geothermal energy’used by ground-source heat engines, and all the air-source heat engine energy, is actuallysolar energy from the sun, and so is not ‘geothermal’ at all. Proper ‘geothermal energy’is only available in ‘hot spot’ areas of the Earth, like Iceland or New Zealand, or where ithas been trapped in deep underground water supplies over many thousands of years, asin parts of France.One of the factors likely to be contributing to the increase of carbon dioxide in theatmosphere is the cutting down of forests, particularly in equatorial regions. Trees absorband store carbon dioxide through photosynthesis, but can no longer do this if they havebeen felled. This is why there are global concerns over deforestation, particularly of the124
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Basic Books in ScienceBook 6<strong
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BASIC BOOKS IN SCIENCE- a Series of
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BASIC BOOKS IN SCIENCE- a Series of
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Looking ahead - If you came across
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3.2 Plate tectonics (20th Century)
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1.30 Coal seams in an opencast coal
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3.4 Alfred Wegener, the polar explo
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5.14 A GPS remote volcano monitorin
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Figure 1.2:minerals.A sandstone roc
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Even diamond can have different col
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Figure 1.8: A red garnet crystal in
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Figure 1.12: Crystals of minerals i
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Hematite, Fe 2 O 3 - earthy red, me
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Figure 1.17: Sedimentary rocks show
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Figure 1.20: A close up view of a p
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Figure 1.26: Ancient wave ripple ma
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Figure 1.30: Coal seams in an openc
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Figure 1.32: Close up view of a pie
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Figure 1.35: A fossil colonial cora
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Figure 1.38: Fossil ammonites, indi
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Figure 1.39: ‘Massive’ igneous
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Figure 1.41: A close up view of a p
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Figure 1.44: A basalt flow that coo
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Figure 1.47: Deposit of volcanic as
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Figure 1.49: An old slate quarry, s
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Figure 1.51: Slate, a low-grade met
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Figure 1.53: Schist, a medium-grade
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Figure 1.56: Metaquartzite, produce
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Figure 1.58: A region of folded roc
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Figure 1.61: A normal fault. This s
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Figure 1.64: An unconformity. Older
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proper geological maps. Fossils hav
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Cephalopods are not extinct, but th
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Figure 1.68: A shelled cephalopod f
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You can try the rock sequencing pri
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Chapter 2Reading landscapes: how la
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Figure 2.3: Rock fragments loosened
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Figure 2.6: The jo
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Figure 2.10: The m
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are forming them. Similarly the sha
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Figure 2.19: This photo was taken f
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Figure 2.25: Dinosaur tracks conser
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• On coastal sections, whenever p
Page 87 and 88: found evidence that the Earth was a
Page 89 and 90: Figure 3.3: James Hutton, the ‘Fo
Page 91 and 92: Figure 3.5: A page of Wegener’s 1
Page 93 and 94: Figure 3.7: The st
Page 95 and 96: Figure 3.10: The r
Page 97 and 98: Figure 3.13: The m
Page 99 and 100: Figure 3.15: The S
Page 101 and 102: Figure 3.19: An ocean versus contin
Page 103 and 104: Figure 3.23: Map of the major tecto
Page 105 and 106: Figure 3.26: Global temperature cha
Page 107 and 108: Figure 3.29: A computer generated p
Page 109 and 110: Figure 3.31: The
Page 111 and 112: planet extended th
Page 113 and 114: Figure 4.1: William Smith’s geolo
Page 115 and 116: Millionsof yearsago (Ma)01000Some M
Page 117 and 118: ocks whilst the first definite plan
Page 119 and 120: Figure 4.9: The ch
Page 121 and 122: Figure 4.12: The 4
Page 123 and 124: Millionsof years Some Major Earth E
Page 125 and 126: Figure 5.2: Strike-slip movement (r
Page 127 and 128: Figure 5.4: The So
Page 129 and 130: Figure 5.6: An ash eruption rising
Page 131 and 132: Figure 5.10: A hazard zone map of t
Page 133 and 134: isk to humans. The
Page 135 and 136: Figure 5.14: A GPS (global satellit
Page 137: None of these methods has yet prove
Page 141 and 142: Figure 5.19: A beautifully preserve
Page 143 and 144: Another ‘missing link’ find has
Page 145 and 146: Figure 5.22: A dinosaur reconstruct
Page 147 and 148: Figure 5.25: A working aggregate-pr
Page 149 and 150: Figure 5.26: The E
Page 151 and 152: Chapter 6Understanding what geologi
Page 153 and 154: Figure 6.2: A drilling rig used for
Page 155 and 156: When an oil/gas field has been foun
Page 157 and 158: Figure 6.6: Groundwater flowing out
Page 159 and 160: Dam disaster in Italy, when the wav
Page 161 and 162: Figure 6.10: A slab foundation, bui
Page 163 and 164: An example of this is investigation
Page 165 and 166: GlossaryAbsolute age The</s
Page 167 and 168: Carbon capture The
Page 169 and 170: Crustal shortening This results of
Page 171 and 172: Evaporite deposits (or evaporites)
Page 173 and 174: Geophysical survey Using the method
Page 175 and 176: “Integrated waste management” <
Page 177 and 178: Metamorphism The r
Page 179 and 180: Pore spaces (or pores) Gaps bet<str
Page 181 and 182: Saltation Sediment movement by flui
Page 183 and 184: Suspension Sediment movement by flu
Page 185 and 186: AcknowledgementsPermission to repri
Page 187 and 188: Figure 2.3 A scree slope. Photo ID:
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Figure 1.15a Hematite.Figure 1.15b
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Figure 1.28 Dune cross bedding in s
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Figure 3.18 An island arc volcano,
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Figure 5.21 Excavations at the dino
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