The Economic Aspect of Geology

C. K. (Charles Kenneth) Leith

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• Publié par: zumuk
• Publié le: 08 décembre 2010
• Nombre de lectures: 47
• Langue: English

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The Project Gutenberg EBook of The Economic Aspect of Geology, by C. K. Leith This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: The Economic Aspect of Geology Author: C. K. Leith Release Date: January 19, 2009 [EBook #27842] Language: English *** START OF THIS PROJECT GUTENBERG EBOOK THE ECONOMIC ASPECT OF GEOLOGY *** Produced by Kevin Handy, Barbara Kosker, John Hagerson, Chrome and the Online Distributed Proofreading Team at http://www.pgdp.net THE ECONOMIC ASPECTS OF GEOLOGYC. K. LEITH UNIVERSITY OF WISCONSIN deco NEW YORK HENRY HOLT AND COMPANY COPYRIGHT, 1921 BY HENRY HOLT AND COMPANY August, 1923 PRINTED IN THE U. S. A.CONTENTS CHAPTER PAGE I. INTRODUCTION 1 Survey of Field 1 Economic applications of the several branches of geology and of other sciences 3 Mineralogy and petrology 3 Stratigraphy and paleontology 4 Structural geology 5 Physiography 6 Rock alterations or metamorphism 10 Application of other sciences 10 Treatment of the subject in this volume 11 II. THE COMMON ELEMENTS, MINERALS, AND ROCKS OF THE EARTH AND THEIR ORIGINS 13 Relative abundance of the principal elements of the lithosphere 13 Relative abundance of the principal minerals of the lithosphere 14 Relative abundance of the principal rocks of the lithosphere 16 Water (hydrosphere) 18 Soils and clays 18 Comparison of lists of most abundant rocks and minerals with commercial rocks and minerals 18 The origin of common rocks and minerals 19 Igneous processes 19 Igneous after-effects 19 Weathering of igneous rocks and veins 20 Sedimentary processes 22 Weathering of sedimentary rocks 23 Consolidation, cementation, and other sub-surface alterations of rocks 24 Cementation 24 Dynamic and contact metamorphism 25 The metamorphic cycle as an aid in studying mineral deposits 27 III. SOME SALIENT FEATURES OF THE GEOLOGY AND CLASSIFICATION OF MINERAL DEPOSITS 29 Various methods of classification 29 Names 31 Mineral deposits as magmatic segregations in igneous rocks 34 Mineral deposits within and adjacent to igneous rocks, which were formed immediately after the cooling and crystallization of the magmas through the agency of hot magmatic solutions 36 Evidence of igneous source 37 Possible influence of meteoric waters in deposition of ores of this class 41 Zonal arrangement of minerals related to igneous rocks 42 The relation of contact metamorphism to ore bodies of the foregoing class 45 Secondary concentration in place of the foregoing classes of mineral deposits through the agency of surface solutions 46 Residual mineral deposits formed by the weathering of igneous rocks in place 50 Mineral deposits formed directly as placers and sediments 51 Mechanically deposited minerals 51 Chemically and organically deposited minerals 52 Sedimentary mineral deposits which have required further concentration to make them commercially available 54 Anamorphism of mineral deposits 57 Conclusion 58 IV. MINERAL RESOURCES—SOME GENERAL QUANTITATIVE CONSIDERATIONS 60 World annual production of minerals in short tons 60 World annual production of minerals in terms of value 62 Significance of geographic distribution of mineral production 63 The increasing rate of production 63 Capital value of world mineral reserves 64 Political and commercial control of mineral resources 65 Reserves of mineral resources 65 V. WATER AS A MINERAL RESOURCE 67 General geologic relations 67 Distribution of underground water 68 Movement of underground water 71 Wells and springs 72 Composition of underground waters 73 Relation of geology to underground water supply 75 Surface water supplies 76 Underground and surface waters in relation to excavation and construction 78 VI. THE COMMON ROCKS AND SOILS AS MINERAL RESOURCES 80 Economic features of the common rocks 80 Granite 82 Basalt and related types 82 Limestone, marl, chalk 82 Marble 83 Sand, sandstone, quartzite (and quartz) 84 "Sand and gravel" 84 Clay, shale, slate 85 The feldspars 86 Hydraulic cement (including Portland, natural, and Puzzolan cements) 86 Geologic features of the common rocks 88 Building stone 88 Crushed stone 90 Stone for metallurgical purpposes 91 Clay 91 Limitations of geologic field in commercial investigation of common rocks 92 Soils as a mineral resource 94 Origin of soils 94 Composition of soils and plant growth 96 Use of geology in soil study 97 VII. THE FERTILIZER GROUP OF MINERALS 99 General comments 99 Nitrates 101 Economic features 101 Geologic features 102 Phosphates 104 Economic features 104 Geologic features 105 Pyrite 107 Economic features 107 Geologic features 108 Sulphur 109 Economic features 109 Geologic features 110 Potash 111 Economic features 111 Geologic features 112 VIII. THE ENERGY RESOURCES—COAL, OIL, GAS (AND ASPHALT) 115 Coal 115 Economic features 115 World production and trade 115 Production in the United States 117 Coke 118 Classification of coals 119 Geologic features 123 Petroleum 127 Economic ffeatures 127 Production and reserves 128 Methods of estimating reserves 134 Classes of oils 136 Conservation of oil 137 Geologic features 140 Organic theory of origin 140 Effect of differential pressures and folding on oil genesis and migration 142 Inorganic theory of origin 143 Oil exploration 144 Oil shales 150 Natural gas 151 Economic features 151 Geologic features 151 Asphalt and bitumen 151 Economic features 151 Geologic features 153 IX. MINERALS USED IN THE PRODUCTION OF IRON AND STEEL (THE FERRO-ALLOY GROUP) 154 General features 154 Iron ores 158 Economic features 158 Technical and commercial factors determining use of iron ore materials 158 Geographic distribution of iron ore production 160 World reserves and future production of iron ore 162 Geologic features 166 Sedimentary iron ores 166 Iron ores associated with igneous rocks 171 Iron ores due to weathering of igneous rocks 171 Iron ores due to weathering of sulphide ores 173 Manganese ores 173 Economic features 173 Geologic features 176 Chrome (or chromite) ores 178 Economic features 178 Geologic features 179 Nickel ores 180 Economic features 180 Geologic features 180 Tungsten (wolfram) ores 182 Economic features 182 Geologic features 184 Molybdenum ores 185 Economic features 185 Geologic features 186 Vanadium ores 187 Economic features 187 Geologic features 188 Zirconium ores 189 Economic features 189 Geologic features 189 Titanium ores 190 Economic features 190 Geologic features 190 Magnesite 191 Economic features 191 Geologic features 192 Fluorspar 193 Economic features 193 Geologic features 194 Silica 195 Economic features 195 Geologic features 196 X. COPPER, LEAD AND ZINC MINERALS 197 Copper ores 197 Economic features 197 Geologic features 199 Copper deposits associated with igneous flows 200 Copper veins in igneous rocks 201 "Porphyry coppers" 203 Copper in limestone near igneous contacts 204 Copper deposits in schists 204 Sedimentary copper deposits 205 General comments 206 Lead ores 209 Economic features 209 Geologic features 211 Zinc ores 213 Economic features 213 Geologic features 216 XI. GOLD, SILVER, AND PLATINUM MINERALS 221 Gold ores 221 Economic features 221 Geologic features 226 Silver ores 231 Economic features 231 Geologic features 234 Platinum ores 237 Economic features 237 Geologic features 239 XII. MISCELLANEOUS METALLIC MINERALS 241 Aluminum ores 241 Economic features 241 Geologic features 243 Antimony ores 246 Economic features 246 Geologic features 248 Arsenic ores 249 Economic features 249 Geologic features 251 Bismuth ores 252 Economic features 252 Geologic features 252 Cadmium ores 253 Economic features 253 Geologic features 254 Cobalt ores 254 Economic features 254 Geologic features 255 Mercury (quicksilver) ores 255 Economic features 255 Geologic features 258 Tin ores 260 Economic features 260 Geologic features 261 Uranium and radium ores 263 Economic features 263 Geologic features 264 XIII. MISCELLANEOUS NON-METALLIC MINERALS 267 Natural abrasives 267 Economic features 267 Geologic features 269 Asbestos 270 Economic features 270 Geologic features 271 Barite (barytes) 272 Economic features 272 Geologic features 273 Borax 274 Economic features 274 Geologic features 275 Bromine 277 Economic features 277 Geologic features 278 Fuller's earth 278 Economic features 278 Geologic features 279 Graphite (plumbago) 279 Economic features 279 Geologic features 282 Gypsum 283 Economic features 283 Geologic features 284 Mica 285 Economic features 285 Geologic features 287 Monazite (thorium and cerium ores) 288 Economic features 288 Geologic features 289 Precious stones 289 Economic features 289 Geologic features 291 Salt 294 Economic features 294 Geologic features 295 Talc and soapstone 299 Economic features 299 Geologic features 299 XIV. EXPLORATION AND DEVELOPMENT 301 The general relations of the geologist to exploration and development 301 Partly explored versus virgin territories 303 The use of all available information 304 Coöperation in exploration 305 Economic factors in exploration 306 Geologic factors in exploration 307 Mineral provinces and epochs 308 Classification of mineral lands 309 Outcrops of mineral deposits 311 Some illustrative cases 312 Topography and climate as aids in searching for mineral outcrops 314 Size and depth of ore bodies as determined from outcrops 315 The use of placers in tracing mineral outcrops 316 The use of magneetic surveys in tracing mineral ledges 317 The use of electrical conductivity and other qualities of rocks in exploration 319 The use of structure and metamorphism in exploration 310 Drilling in