Geochemistry

Preface Chapter 1 Introduction 1.1 Introduction 1.2 Beginnings 1.3 Geochemistry in the 21st Century 1.4 The Philosophy of Science 1.4.1 Building scientific understanding 1.4.2 The scientist as skeptic 1.5 Elements, Atoms, crystals and Chemical Bonds: Some Chemical Fundamentals 1.5.1 The periodic table 1.5.2 Electrons and orbits 1.5.3 Some chemical properties of the elements 1.5.4 Chemical bonding 1.5.5 Molecules, crystals, and minerals 1.6 A Brief Look at the Earth 1.6.1 Structure of the Earth 1.6.2 Plate tectonics and the hydrologic cycle 1.7 A Look Ahead Chapter 2 Energy, entropy and fundamental thermodynamic concepts 2.1 The Thermodynamic Perspective 2.2 Thermodynamic Systems And Equilibrium 2.2.1 Fundamental thermodynamic variables 2.2.2 Properties of state 2.3 Equations Of State 2.3.1 Ideal gas law 2.3.2 Equations of state for real gases 2.4 Temperature, Absolute Zero, And The Zeroth Law Of Thermodynamics 2.5 Energy And The First Law Of Thermodynamics 2.5.1 Energy 2.5.2 Work 2.6 The Second Law And Entropy 2.6.1 Statement 2.6.2 Statistical mechanics: a microscopic perspective of entropy 2.6.3 Integrating factors and exact differentials 2.7 Enthalpy 2.8 Heat Capacity 2.8.1 Constant volume heat capacity 2.8.2 Constant pressure heat capacity 2.8.3 Energy associated with volume and the relationship between Cv and Cp 2.8.4 Heat capacity of solids: a problem in quantum physics 2.8.5 Relationship of entropy to other state variables 2.8.6 Additive nature of silicate heat capacities 2.9 The Third Law And Absolute Entropy 2.9.1 Statement of the third law 2.9.2 Absolute entropy 2.9 Calculating Enthalpy And Entropy Changes 2.9.1 Enthalpy changes due to changes in temperature and pressure 2.9.2 Changes in enthalpy due to reactions and change of state 2.9.3 Entropies of reaction 2.10 Free Energy 2.10.1 Helmholtz free energy 2.10.2 Gibbs free energy 2.10.3 Criteria for equilibrium and spontaneity 2.10.4 Temperature and pressure dependence of the Gibbs free energy 2.11 The Maxwell Relations 2.12 Summary Chapter 3 Solutions and Thermodynamics of Multicomponent Systems 3.1 Introduction 3.2 Phase Equilibria 3.2.1 Some definitions 3.2.2 The Gibbs phase rule 3.2.3 The Clapeyron equation 3.3 Solutions 3.3.1 Raoult's Law 3.3.2 Henry's Law 3.4 Chemical Potential 3.4.1 Partial molar quantities 3.4.2 Definition of chemical potential and relationship to Gibbs free energy 3.4.3 Properties of the chemical potential 3.4.4 The Gibbs-Duhem relation 3.4.5 Derivation of the phase rule 3.5 Ideal Solutions 3.5.1 Chemical potential in ideal solutions 3.5.2 Volume, enthalpy, entropy, and free energy changes in ideal solutions 3.6 Real solutions 3.6.1 Chemical potential in real solutions 3.6.2 Fugacities 3.6.3 Activities and activity coefficients 3.6.4 Excess functions 3.7 Electrolyte Solutions 3.7.1 The nature of water and water-electrolyte interaction 3.7.2 Some definitions and conventions 3.7.3 Activities in electrolytes 3.8 Ideal Solutions in Crystalline Solids and Their Activities 3.8.1 Mixing-on-site model 3.8.2 Local charge balance model 3.9 Equilibrium Constants 3.9.1 Derivation and definition 3.9.2 The Law of mass action 3.9.3 KD values, apparent equilibrium constants, and the solubility product 3.9.4 Henry's Law and gas solubilities 3.9.5 Temperature dependence of equilibrium constant 3.9.6 Pressure dependence of equilibrium constant 3.10 Practical Approach to Electrolyte Equilibrium 3.10.1 Choosing components and species 3.10.2 Mass balance 3.10.3 Electrical neutrality 3.10.4 Equilibrium constant expressions 3.11 Oxidation and Reduction 3.11.1 Redox in aqueous solutions 3.11.2 Redox in magmatic systems 3.12 Summary Chapter 4 Applications of thermodynamics to the Earth 4.1 Introduction 4.2 Activities in Non-Ideal Solid Solutions 4.2.1 Mathematical models of real solutions: Margules equations 4.3 Exsolution Phenomena 4.4 Thermodynamics and Phase Diagrams 4.4.1 The thermodynamics of melting 4.4.2 Thermodynamics of phase diagrams for binary systems 4.4.3 Phase diagrams for multi-component systems 4.5 Geothermometry and Geobarometry 4.5.1 Theoretical considerations 4.5.2 Practical thermobarometers 4.6 Thermodynamic models of magmas 4.6.1 Structure of silicate melts 4.6.2 Magma solution models 4.7 Reprise: Thermodynamics of Electrolyte Solutions 4.7.1 The Equation of state for water 4.7.2 Activities and mean ionic and single ion quantities 4.7.3 Activities in high ionic strength solutions 4.7.4 Electrolyte Solutions at elevated temperature and pressure 4.8 Summary Chapter 5 Kinetics: The Pace of Things 5.1 Introduction 5.2 Reaction Kinetics 5.2.1 Elementary and overall reactions 5.2.2 Reaction mechanisms 5.2.3 Reaction rates 5.2.4 Rates of complex reactions 5.2.5 Steady state and equilibrium 5.3 Relationships between Kinetics and Thermodynamics 5.3.1 Principle of detailed balancing 5.3.2 Enthalpy and activation energy 5.3.3 Aspects of transition state theory 5.4 Diffusion 5.4.1 Diffusion flux and Fick's Laws 5.4.2 Diffusion in multicomponent systems 5.4.3 Driving force and mechanism of diffusion 5.4.4 Diffusion in solids and the temperature dependence of the diffusion coefficient 5.4.5 Diffusion in liquids 5.4.6 Diffusion in porous media 5.5 Surfaces, Interfaces, and Interface Processes 5.5.1 The surface free energy 5.5.2 The Kelvin effect 5.5.3 Nucleation and crystal growth 5.5.4 Adsorption 5.5.5 Catalysis 5.6 Kinetics of Dissolution 5.6.1 Simple oxides 5.6.2 Silicates 5.6.3 Non-silicates 5.7 Diagenesis 5.7.1 Compositional gradients in accumulating sediment 5.7.2 Reduction of sulfate in accumulating sediment 5.8 summary Chapter 6 Aquatic Chemistry 6.1 Introduction 6.2 Acid-Base Reactions 6.2.1 Proton accounting, charge balance, and conservation equations 6.2.2 The carbonate system 6.2.3 Conservative and non-conservative ions 6.2.4 Total alkalinity and carbonate alkalinity 6.2.5 Buffer intensity 6.3 Complexation 6.3.1 Stability constants 6.3.2 Water-related complexes 6.3.3 Other complexes 6.3.4 Complexation in fresh waters 6.4 Dissolution And Precipitation Reactions 6.4.1 Calcium carbonate in ground and surface waters 6.4.2 Solubility of Mg 6.4.3 Solubility of SiO2 6.4.4 Solubility of Al(OH)3 and other hydroxides 6.4.5 Dissolution of silicates and related minerals 6.5 Clays And Their Properties 6.5.1 Clay mineralogy 6.5.2 Ion-exchange properties of clays 6.6 Mineral Surfaces And Their Interaction With Solutions 6.6.1 Adsorption 6.6.2 Development of surface charge and the electric double layer 6.7 Summary Chapter 7 Trace Elements in Igneous Processes 7.1 Introduction 7.1.1 Why care about trace elements? 7.1.2 What is a trace element? 7.2 Behavior of the Elements 7.2.1 Goldschmidt's classification 7.2.2 The geochemical periodic table 7.3 Distribution of Trace Elements Between Coexisting Phases 7.3.1 The partition coefficient 7.4 Factors Governing the Value of Partition Coefficients 7.4.1 Temperature and pressure dependence of the partition coefficient 7.4.2 Ionic size and charge 7.4.3 Compositional dependency 7.4.4 Mineral-liquid partition coefficients for mafic and ultramafic systems 7.5 Crystal-Field Effects 7.5.1 Crystal field theory 7.5.2 Crystal field influences on transition metal partitioning 7.6 Trace Element Distribution During Partial Melting 7.6.1 Equilibrium or batch melting 7.6.2 Fractional melting 7.6.3 Zone refining 7.6.4 Multiphase solids 7.6.5 Continuous melting 7.6.6 Constraints on melting models 7.7 Trace Element Distribution during Crystallization 7.7.1 Equilibrium crystallization 7.7.2 Fractional crystallization 7.7.3 In situ crystallization 7.7.4 Crystallization in open system magma chambers 7.7.5 Comparing Partial Melting and Crystallization 7.8 Summary Of Trace Element Variations During Melting And Crystallization Chapter 8 Radiogenic Isotope Geochemistry 8.1 Introduction 8.2 Physics of the Nucleus and the Structure of Nuclei 8.2.1 Nuclear structure and energetics 8.2.2 The decay of excited and unstable nuclei 8.3 Basics of Radiogenic Isotope Geochemistry and Geochronology 8.4 Decay Systems and Their Applications 8.4.1 Rb-Sr 8.4.2 Sm-Nd 8.4.3 Lu-Hf 8.4.4 Re-Os 8.4.5 La-Ce 8.4.6 U-Th-Pb 8.4.7 U and Th decay series isotopes 8.4.8 Isotopes of He and other rare gases 8.5 "Extinct" And Cosmogenic Nuclides 8.5.1 "Extinct" radionuclides and their daughters 8.5.2 Cosmogenic Nuclides 8.5.3 Cosmic-ray exposure ages of meteorites 8.7 Summary Chapter 9 Stable Isotope Geochemistry 9.1 Introduction 9.1.1 Scope of stable isotope geochemistry 9.1.2 Some definitions 9.2 Theoretical Considerations 9.2.1 Equilibrium isotope fractionations 9.2.2 Kinetic isotope fractionations 9.2.3 Mass-dependent and mass-independent fractionations 9.2.4 Isotopic "Clumping" 9.3 Isotope Geothermometry 9.4 Isotopic Fractionation in the Hydrologic System 9.5 Isotopic Fractionation in Biological Systems 9.5.1 Carbon isotope fractionation during photosynthesis 9.5.2 Nitrogen isotope fractionation in biological processes 9.5.3 Oxygen and hydrogen isotope fractionation by plants 9.5.4 Biological fractionation of sulfur isotopes 9.5.5 Isotopes and diet: you are what you eat 9.5.6 Isotopic "fossils" and the earliest life 9.6 Paleoclimatology 9.6.1 The marine Quaternary 18O record and Milankovitch cycles 9.6.2 The record in glacial ice 9.6.3 Soils and paleosols 9.7 Hydrothermal Systems and Ore Deposits 9.7.1 Water in Hydrothermal Systems 9.7.2 Water-rock ratios 9.7.3 Sulfur isotopes and ore deposits 9.8 Mass-Independent Sulfur Isotope Fractionation and the Rise of Atmospheric Oxygen 9.9 Stable Isotopes in the Mantle and Magmatic Systems 9.9.1 Stable isotopic composition of the mantle 9.9.2 Stable isotopes in crystallizing magmas 9.9.3 Combined fractional crystallization and assimilation 9.10 Non-Traditional Stable Isotopes 9.10.1 Boron isotopes 9.10.2 Li isotopes 9.10.3 Calcium isotopes 9.10.4 Silicon isotopes 9.10.5 Iron isotopes 9.10.6 Mercury isotopes 9.11 Summary Chapter 10 The Big Picture: Cosmochemistry 10.1 Introduction 10.2 In the Beginning ... Nucleosynthesis 10.2.1 Astronomical background 10.2.2 The polygenetic hypothesis of Burbidge, Burbidge, Fowler and Hoyle 10.2.3 Cosmological nucleosynthesis 10.2.4 Nucleosynthesis in stellar interiors 10.2.5 Explosive nucleosynthesis 10.2.6 Nucleosynthesis in interstellar space 10.2.7 Summary 10.3 Meteorites: Essential Clues to the Beginning 10.3.1 Chondrites: the most primitive objects 10.3.2 Differentiated meteorites 10.4 Time and the Isotopic Composition of the Solar System 10.4.1 Meteorite ages 10.4.2 Cosmic ray exposure ages and meteorite parent-bodies 10.4.3 Asteroids as meteorite parent-bodies 10.4.3 Isotopic anomalies in meteorites 10.5 Astronomical and Theoretical Constraints on Solar System Formation 10.5.1 Evolution of young stellar objects 10.5.2 The condensation sequence 10.5.3 The solar system 10.5.4 Other solar systems 10.6 Building a Habitable Solar System 10.6.1 Summary of observations 10.6.2 Formation of the planets 10.6.3 Chemistry and history of the Moon 10.6.4 The giant impact hypothesis and formation of the Earth and the Moon 10.6.5 Tungsten isotopes and the age of the Earth 10.7 Summary Chapter 11 Geochemistry Of The Solid Earth 11.1 Introduction 11.2 The Earth's Mantle 11.2.1 Structure of the mantle and geophysical constraints on mantle composition 11.2.2 Cosmochemical constraints on mantle composition 11.2.3 Observational constraints on mantle composition 11.2.4 Mantle mineralogy and phase transitions 11.3 Estimating Mantle and Bulk Earth Composition 11.3.1 Major element composition 11.3.2 Trace Element composition 11.3.3 Composition of the bulk silicate Earth 11.4 The Earth's Core and Its Composition 11.4.1 Geophysical constraints 11.4.2 Cosmochemical constraints 11.4.3 Experimental constraints 11.5 Mantle Geochemical Reservoirs 11.5.1 Evidence from oceanic basalts 11.5.2 Evolution of the depleted MORB mantle 11.5.3 Evolution of mantle plume reservoirs 11.5.4 The subcontinental lithospheric mantle 11.6 The Crust 11.6.1 The oceanic crust 11.6.2 The continental crust 11.6.3 Growth of the continental crust 11.7 Subduction zone Processes 11.7.1 Major element composition 11.7.2 Trace element composition 11.7.3 Isotopic composition and sediment subduction 11.7.4 Magma genesis in subduction zones 11.8 Summary Chapter 12 Organic Geochemistry, The Carbon Cycle, And Climate 12.1 Introduction 12.2 A Brief Biological Background 12.3 Organic Compounds and Their Nomenclature 12.3.1 Hydrocarbons 12.3.2 Functional groups 12.3.3 Short-hand notations of organic molecules 12.3.4 Biologically important organic compounds 12.4 The Chemistry of Life: Important Biochemical Processes 12.4.1 Photosynthesis 12.4.2 Respiration 12.4.3 The stoichiometry of life 12.5 Organic Matter in Natural Waters and Soils 12.5.1 Organic matter in soils 12.5.2 Dissolved organic matter in aquatic and marine environments 12.6 Chemical Properties of Organic Molecules 12.6.1 Acid-base properties 12.6.2 Complexation 12.6.3 Adsorption phenomena 12.7 Sedimentary Organic Matter 12.7.1 Preservation of organic matter 12.7.2 Diagenesis of marine sediments 12.7.3 Diagenesis of aquatic sediments 12.7.4 Summary of diagenetic changes 12.7.5 Biomarkers 12.7.6 Kerogen and bitumen 12.7.7 Isotope composition of sedimentary organic matter 12.8 Petroleum and Coal Formation 12.8.1 Petroleum 12.8.2 Compositional evolution of coal 12.9 The Carbon Cycle and Climate 12.9.1 Greenhouse energy balance 12.9.2 The exogenous carbon cycle 12.9.3 The deep carbon cycle 12.9.4 Evolutionary changes affecting the carbon cycle 12.9.5 The carbon cycle and climate through time 12.9.6 Fossil fuels and anthropogenic climate change 12.10 Summary Chapter 13 The Land Surface: Weathering, Soils, and Streams 13.1 Introduction 13.2 Redox in Natural Waters 13.2.1 Biogeochemical redox reactions 13.2.2 Eutrophication 13.2.3 Redox buffers and transition metal chemistry 13.3 Weathering, Soils, and Biogeochemical Cycling 13.3.1. Soil profiles 13.3.2 Chemical cycling in soils 13.3.3 Biogeochemical cycling 13.4 Weathering Rates 13.4.1 The in situ approach 13.4.2 The watershed approach 13.4.3 Factors controlling weathering rates 13.5 The Composition of Rivers 13.6 Continental Saline Waters 13.7 Summary Chapter 14 The Ocean as a Chemical System 14.1 Introduction 14.2 Some Background Oceanographic Concepts 14.2.1 Salinity, chlorinity, temperature and density 14.2.2 Circulation of the ocean and the structure of ocean water 14.3 The Composition of Seawater 14.3.1 Speciation in seawater 14.3.2 Conservative elements 14.3.3 Dissolved gases 14.3.4 Seawater pH and alkalinity 14.3.5 Carbonate dissolution and precipitation 14.3.5 Nutrient elements 14.3.6 Particle-reactive elements 14.3.7 The one-dimensional advection-diffusion model 14.4 Sources and Sinks of Dissolved Matter in Seawater 14.4.1 Residence time 14.4.2 The river and groundwater flux to the oceans 14.4.3 The hydrothermal flux 14.4.4 The atmospheric source 14.4.5 Sedimentary sinks and sources 14.5 Summary Chapter 15 Applied Geochemistry 15.1 Introduction 15.2 Mineral Resources 15.2.1 Ore deposits: definitions and classification 15.2.2 Orthomagmatic ore deposits 15.2.3 Hydromagmatic ore deposits 15.2.4 Hydrothermal ore deposits 15.2.5 Sedimentary ore deposits 15.2.6 Weathering-related ore deposits 15.2.7 Rare Earth Ore Deposits 15.2.8 Geochemical exploration: finding future resources 15.3 Environmental Geochemistry 15.3.1 Eutrophication redux 15.3.2 Toxic metals in the environment 15.3.3 Acid deposition 15.4 Summary Appendix Index