Contents. Acknowledgments INTRODUCTION 3 HOW ARE MINERALS IDENTIFIED? 39 MATERIALS OF THE SOLID EARTH 15 FUNDAMENTALS OF CRYSTAL STRUCTURES 63

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1 Table of Preface Acknowledgments 1 2 xiii xv INTRODUCTION Formation of Earth s chemical elements in supernovae Birth of the solar system and Earth Accretion and early history of the Earth Internal structure of the Earth Cooling of the planet and plate tectonics Plate tectonics and the formation of rocks Divergent plate boundaries Convergent plate boundaries Transform boundaries Mantle plumes and hot spots Outline of subsequent chapters 11 Summary 12 Review questions 13 Online resources 13 Further reading 13 MATERIALS OF THE SOLID EARTH Definition of a mineral Examples of some familiar minerals How are minerals classified? How are minerals named? What is a crystal, and what is the crystalline state? What is a rock? How do rocks form? Classification into igneous, sedimentary, and metamorphic Examples of some familiar rocks Plate tectonics and the generation of rocks Midocean-ridge rock factory Convergent-plate-boundary rock factory Continental divergent-plate-boundary rock factory ( rift valley ) Mantle plume hot-spot rock factory Passive-margin rock factories Epeiric-sea rock factories Metamorphic rock factories Summary 35 Review questions 35 Online resources 36 Further reading 36 HOW ARE MINERALS IDENTIFIED? Habit State of aggregation Color and luster Reasons for color Cleavage Hardness Specific gravity (relative density) Specific gravity and atomic structure Magnetism, solubility in acid, and radioactivity Instrumental methods for the quantitative characterization of minerals X-ray powder diffraction Electron beam techniques : scanning electron microscopy, electron microprobe analysis, and transmission electron microscopy 57 Summary 60 Review questions 61 Further reading 61 FUNDAMENTALS OF CRYSTAL STRUCTURES Naturally occurring chemical elements Atomic and ionic radii What factors control the packing of ions (and atoms) in mineral structures? Pauling s rules What forces hold crystal structures together? Electronic configuration of atoms and ions Chemical bonding Atomic substitutions Factors responsible for the extent of atomic substitution ( solid solution ) Types of solid solution 83 vii

2 Table of viii 5 6 Summary 84 Review questions 85 Further reading 85 INTRODUCTION TO CRYSTALLOGRAPHY Symmetry elements and operations Combinations of symmetry elements The six crystal systems Crystallographic axes Hermann-Mauguin symmetry notation Crystallographic notation for planes in crystals Definition of crystal form Crystallographic notation for directions in crystals Crystal projections Seven of the thirty-two point groups Twins Some aspects of space groups Space groups Polymorphism 126 Summary 131 Review questions 132 Further reading 133 MINERALS AND ROCKS OBSERVED UNDER THE POLARIZING OPTICAL MICROSCOPE Light and the polarizing microscope Passage of light through a crystal: refractive index and angle of refraction Passage of polarized light through minerals Accessory plates and determination of fast and slow vibration directions Extinction positions and the sign of elongation Anomalous interference colors, pleochroism, and absorption Mineral identification chart Uniaxial optical indicatrix Biaxial optical indicatrix Uniaxial interference figures Determination of optic sign from uniaxial optic axis figure Biaxial interference figures, optic sign, and optic angle (2V) Modal analysis Summary 153 Review questions 155 Online resources 155 Further reading 155 IGNEOUS ROCK-FORMING MINERALS Common chemical elements in the Earth s crust and in mineral and rock analyses Calculation of mineral formulas Triangular diagrams Systematic mineralogical descriptions of common igneous minerals Plagioclase feldspar K-feldspar Quartz and silica polymorphs Nepheline Leucite Sodalite Enstatite Pigeonite Augite Aegirine Hornblende Muscovite Phlogopite Biotite Olivine Zircon Tourmaline Allanite Melilite Magnetite Chromite Hematite Ilmenite Rutile Uraninite Pyrite Pyrrhotite Chalcopyrite Apatite 189 Summary 189 Review questions 190 Further reading 191 HOW DO IGNEOUS ROCKS FORM? Why, and how, does solid rock become molten? 195

3 Table of ix Composition of the upper mantle Melting range of upper-mantle peridotite Geothermal gradient and the geotherm Three primary causes of melting and their plate tectonic settings Raising the temperature of mantle peridotite to the melting range over hot spots Decompression melting at divergent plate boundaries Fluxing with water at convergent plate boundaries ( subduction zones ) Melting processes in rocks Melting of a mixture of minerals Melting of a pair of minerals : the eutectic Congruent melting and the granite and nepheline syenite eutectics Incongruent melting and the peritectic Melting relations of solid solutions Effect of pressure on melting Effect of pressure on the anhydrous melting of rock Hydrous melting of rock and the solubility of water in magma Solubility of other gases in magma Exsolution of magmatic gases and explosive volcanism Physical properties of magma Magma density Magma viscosity Diffusion in magma, crystal growth, and grain size of igneous rocks Magma ascent Buoyancy Buoyant rise of magma Processes associated with the solidification of magma in the crust Cooling of bodies of magma by heat conduction Cooling of bodies of magma by convection and radiation Magmatic differentiation by crystal settling Compaction of crystal mush Assimilation and fractional crystallization Liquid immiscibility 231 Summary 232 Review questions Online resources 234 Further reading 235 IGNEOUS ROCKS: THEIR MODE OF OCCURRENCE, CLASSIFICATION, AND PLATE TECTONIC SETTING Why an igneous rock classification is necessary Mode of occurrence of igneous rocks Shallow intrusive igneous bodies : dikes, sills, laccoliths, cone sheets, ring dikes, and diatremes Plutonic igneous bodies : lopoliths, batholiths, and stocks Extrusive igneous bodies : flood basalts, shield volcanoes, composite volcanoes, domes, calderas, ash-fall and ash-flow deposits International Union of Geological Sciences classification of igneous rocks Mode and norm IUGS classification of igneous rocks Composition of common plutonic igneous rocks IUGS classification of volcanic igneous rocks Irvine-Baragar classification of volcanic rocks Igneous rocks and their plate tectonic setting Igneous rocks formed at midocean-ridge divergent plate boundaries Igneous rocks of oceanic islands formed above hot spots Continental flood basalts and large igneous provinces Alkaline igneous rocks associated with continental rift valleys Igneous rocks formed near convergent plate boundaries Special Precambrian associations Komatiites Massif-type anorthosites Rocks associated with large meteorite impacts 283 Summary 285 Review questions 286 Online resources 287 Further reading 287

4 Table of x SEDIMENTARY ROCK-FORMING MINERALS AND MATERIALS The interaction of the Earth s atmosphere with minerals Ice Goethite Kaolinite Calcite Aragonite Dolomite Magnesite Siderite Rhodochrosite Halite Sylvite Gypsum Anhydrite Chert and agate Phosphorite Soil 305 Summary 306 Review questions 307 Further reading 307 FORMATION, TRANSPORT, AND LITHIFICATION OF SEDIMENT Importance of sediments in understanding the history of the Earth Sediment formed from weathering of rock Role of carbon dioxide in weathering Weathering products of rock Detrital grain size Detrital grain roundness and resistance to abrasion Organically produced sediment Formation of carbonate and siliceous sediment Formation of hydrocarbons in sediment Chemically produced sediment Sediment produced by glacial erosion Transport of sediment Laminar and turbulent flow Movement of particles by fluid flow Movement of particles in turbidity currents Movement of sediment in debris flows Layering in sediments and sedimentary rocks Law of superposition Milankovitch cycles Sediments related to tectonic processes Sites of deposition and tectonic significance Convergent plate boundaries Passive continental margins Rift and pull-apart basins Conversion of unconsolidated sediment to sedimentary rock: lithification Porosity and compaction Cementation of sediment Pressure solution Recrystallization, replacement, dolomitization 334 Summary 335 Review questions 336 Online resources 337 Further reading 337 SEDIMENTARY ROCK CLASSIFICATION, OCCURRENCE, AND PLATE TECTONIC SIGNIFICANCE Siliciclastic sedimentary rocks Mudrocks ( includes shales ) Sandstones Conglomerates and breccias Carbonate sedimentary rocks Limestones Dolostones Tectonic settings of carbonate rocks Coals Oil and natural gas Evaporites Phosphorites Iron-formations 363 Summary 363 Review questions 364 Online resources 365 Further reading 365 METAMORPHIC ROCK-FORMING MINERALS Systematic mineralogical descriptions of common metamorphic minerals Garnet Andalusite 370

5 Table of xi Sillimanite Kyanite Staurolite Diopside Anthophyllite Cummingtonite-grunerite Tremolite-ferroactinolite Glaucophane Wollastonite Rhodonite Talc Chlorite Antigorite Chrysotile Epidote and clinozoisite Cordierite Vesuvianite Titanite (sphene) Scapolite Lawsonite Pumpellyite Topaz Corundum Chabazite 386 Summary 388 Review questions 389 Further reading 389 METAMORPHIC ROCKS What changes occur during metamorphism? Why do rocks change? Thermodynamics and the reason for change Rates of metamorphic reactions Gibbs phase rule and the number of minerals a metamorphic rock can contain Metamorphic grade and facies Textures of metamorphic rocks Textures of contact metamorphic rocks Deformation and textures of regional metamorphic rocks Simple descriptive classification of metamorphic rocks Metamorphism of mudrock Graphical representation of a simple metamorphic reaction A simple pressure-temperature petrogenetic grid Metamorphic field gradients Graphical representation of mineral assemblages in metapelites Mineral assemblages in Barrow s metamorphic zones and part of the petrogenetic grid for metapelites Metamorphism of impure dolomitic limestone Metamorphism and partial melting: migmatites Geothermometers and geobarometers Plate tectonic significance of metamorphism Pressure-temperature-time ( P-T-t ) paths Plate tectonic setting of metamorphic facies 424 Summary 425 Review questions 427 Further reading 428 SOME ECONOMIC MINERALS, MAINLY FROM VEINS AND PEGMATITES Gold Silver Copper Diamond Sulfur Galena Sphalerite Bornite Chalcocite Marcasite Molybdenite Arsenopyrite Bauxite Fluorite Barite Spodumene Lepidolite Several gem minerals 444 Summary 448 Review questions 449 Further reading 449 SOME SELECTED EARTH MATERIALS RESOURCES Construction materials Building stones Bricks, cement, and concrete Crushed stone, sand, and gravel 455

6 Table of xii Iron ore Clay minerals Copper ore Lithium ore Rare earth elements Zeolites Energy resources Oil, natural gas, and coal reserves Nuclear energy Geothermal energy 464 Summary 465 Review questions 466 Online resources 467 Further reading 467 EARTH MATERIALS AND HUMAN HEALTH The human body s need for Earth materials Soils and human health What constitutes a fertile soil? Increasing crop production from agricultural land and soil depletion The need for fertilizers Carcinogenic and chemical hazards posed by Earth materials Erionite Asbestos minerals Silica minerals Arsenic, an example of a chemically hazardous Earth material Health hazards due to radioactivity Carbon sequestration to mitigate climate change Hazards from volcanic eruptions Monitoring active volcanoes Lahars Tsunamis Ejecta from meteorite impacts 483 Summary 484 Review questions 486 Online resources 486 Further reading 487 Glossary 489 Minerals and varieties 515 Common igneous, sedimentary, and metamorphic rocks 517 Index 519