Earth as an Evolving Planetary System

Preface1. Earth Systems Earth as a Planetary System Structure of Earth Plate Tectonics Is the Earth Unique? Interacting Earth Systems Further Reading2. The Crust Introduction Seismic Crustal Structure The Moho Crustal Layers Complexities in the Lower Continental Crust Crustal Types Oceanic Crust Transitional Crust Continental Crust Continent Size Heat Flow Heat Flow Distribution Heat Production and Heat Flow in the Continents Age Dependence of Heat Flow Exhumation and Cratonization Unraveling Pressure-Temperature-Time Histories Some Typical P-T-t Paths Cratonization Processes in the Continental Crust Rheology The Role of Fluids and Crustal Melts Crustal Composition Approaches Seismic Wave Velocities Seismic Reflections in the Lower Continental Crust Sampling of Precambrian Shields Use of Fine-Grained Detrital Sediments Exhumed Crustal Blocks Crustal Xenoliths An Estimate of Crustal Composition Crustal Provinces and Terranes Crustal Province and Terrane Boundaries The United Plates of America Further Reading3. Tectonic Settings Introduction Ocean Ridges Ocean Ridge Basalts Ophiolites Tectonic Settings Related to Mantle Plumes Large Igneous Provinces Oceanic Plateaus and Aseismic Ridges Rifted Continental Margins Continental Flood Basalts Hotspot Volcanic Islands Giant Mafic Dyke Swarms Continental Rifts General Features Rock Assemblages Rift Development and Evolution Cratons and Passive Margins Arc Systems Subduction-Related Rock Assemblages Arc Processes High-Pressure Metamorphism Igneous Rocks Compositional Variation of Arc Magmas Orogens Three Types of Orogens Orogenic Rock Assemblages Tectonic Elements of Collisional Orogens Sutures Foreland and Hinterland Basins The Himalayas Uncertain Tectonic Settings Anorogenic Granites Archean Greenstones Mineral and Energy Deposits Mineral Deposits Energy Deposits Plate Tectonics with Time Further Reading4. The Mantle Introduction Seismic Structure of the Mantle Upper Mantle Lower Mantle Mantle Upwellings and Geoid Anomalies Temperature Distribution in the Mantle The Lithosphere Oceanic Lithosphere Continental Lithosphere The Low-Velocity Zone The Transition Zone The 410-km Discontinuity The 520-km Discontinuity The 660-km Discontinuity The Lower Mantle General Features Descending Slabs The D” Layer Spin Transitions Water in the Mantle Plate Driving Forces Mantle Plumes Hotspots Plume Characteristics Tracking Plume Tails Plume Sources Mantle Geochemical Components Identifying Mantle Components Mixing Regimes in the Mantle Overview Convection in the Mantle The Nature of Convection Passive Ocean Ridges Layered Convection Model Toward a Convection Model for Earth Further Reading5. The Core Introduction Core Temperature The Inner Core Anisotropy of the Inner Core Inner Core Rotation Composition of the Core Age of the Core Generation of Earth’s Magnetic Field The Geodynamo Fluid Motions in the Outer Core Fueling the Geodynamo How the Geodynamo Works What Causes Magnetic Reversals? Origin of the Core Segregation of Iron in the Mantle Siderophile Element Distribution in the Mantle Growth and Evolution of the Core What the Future Holds Further Reading6. Earth’s Atmosphere, Hydrosphere, and Biosphere The Modern Atmosphere The Primitive Atmosphere The Post-Collision Atmosphere Composition of the Early Atmosphere Growth Rate of the Atmosphere The Faint Young Sun Paradox The Precambrian Atmosphere The Carbon Cycle The Carbon Isotope Record General Features The 2200-Ma Carbon Isotope Excursion The Sulfur Isotope Record Phanerozoic Atmospheric History The Hydrosphere Sea Level The Early Oceans Changes in the Composition of Seawater with Time The Temperature of Seawater Ocean Volume through Time Euxinia in the Proterozoic Oceans Paleoclimates Paleoclimatic Indicators Long-Term Paleoclimatic Driving Forces Glaciation Precambrian Climatic Regimes Phanerozoic Climatic Regimes The Biosphere Appearance of Eukaryotes Origin of Metazoans Stromatolites Neoproterozoic Multicellular Organisms The Cambrian Explosion Evolution of Phanerozoic Life-Forms Biological Benchmarks Mass Extinctions Episodic Distributions Glaciation and Mass Extinction Impact-Related Extinctions The Triassic Extinction Impact and a 580-Ma Extinction Epilogue Further Reading7. Crustal and Mantle Evolution Introduction The Hadean Extinct Radioactivity Hadean Zircons Origin of the First Crust Composition of the Primitive Crust Earth’s Oldest Rocks Crustal Origin How Continents Grow General Features Growth by Mafic Underplating Oceanic Plateaus and Continental Growth Growth by Plate Collisions Continental Growth Rates The Role of Recycling Juvenile Crust Freeboard Continental Growth in the Last 200 Ma Toward a Continental Growth Model The 2.4- to 2.2-Ga Crustal Age Gap Secular Changes in the Continental Crust Major Elements Rare Earth and Related Elements Nickel, Cobalt, and Chromium Oceanic Plateaus as Starters for Archean Continents Secular Changes in the Mantle Tracking Mantle Geochemical Components into the Archean Mantle Lithosphere Evolution Earth’s Thermal History Magma Oceans How Hot Was the Archean Mantle? Thermal Models Further Reading8. The Supercontinent Cycle Introduction Supercontinent Reconstruction Continental Collisions and the Assembly of Supercontinents The First Supercontinent Later Supercontinents Nuna (Columbia) Rodinia Gondwana and Pangea The Supercontinent Cycle Episodic Ages Patterns of Cyclicity Relationship to Earth History Mantle Superplume Events Superplume Events Mantle Plumes and Supercontinent Breakup Episodic LIP Events Slab Avalanches Supercontinents, Superplumes, and the Carbon Cycle Supercontinent Formation Supercontinent Breakup Mantle Superplume Events Epilogue Further Reading9. Great Events in Earth History Introduction Event 1: Origin of the Moon How Rare Is the Earth–Moon System? Constraints on Lunar Origin Early Thermal History of the Moon Event 2: Origin of Life The Role of Impacts The RNA World Hydrothermal Vents The First Life Evidence of Early Life The Origin of Photosynthesis The Tree of Life The First Fossils Possibility of Extraterrestrial Life Event 3: The Onset of Plate Tectonics Plate Tectonic Indicators Global Changes at the End of the Archean How Did Plate Tectonics Begin: Thermal Constraints When Did Plate Tectonics Begin?: The Ongoing Saga Conclusions Event 4: The Great Oxidation Event Oxygen Controls in the Atmosphere Geologic Indicators of Ancient Atmospheric Oxygen Levels Mass-Independent Sulfur Isotope Fractionation The Growth of Atmospheric Oxygen Event 5: The Snowball Earth The Observational Database The Snowball Model Event 6: Mass Extinction at the End of the Permian General Features Evidence for Impact LIP Volcanism Shallow-Water Anoxia Catastrophic Methane Release Conclusions Event 7: The Cretaceous Superplume Event Geologic Evidence The Carbon Isotope and Trace Metal Record Seeking a Cause A Possible Superchron-Superplume Connection Event 8: Mass Extinction at the end of the Cretaceous General Features Seeking a Cause Chicxulub and the K/T Impact Site Possibility of Multiple K/T Impacts Conclusions Further Reading10. Comparative Planetary Evolution Introduction Condensation and Accretion of the Planets The Solar Nebula Emergence of Planets Homogeneous Accretion Chemical Composition of the Earth and the Moon Accretion of Earth The First 700 Million Years Members of the Solar System The Planets Satellites and Planetary Rings Comets and Other Icy Bodies Asteroids Meteorites Impact Chronology of the Inner Solar System Volcanism in the Solar System Planetary Crusts Plate Tectonics Mineral Evolution Evolution of the Atmospheres of Earth, Venus, and Mars The Continuously Habitable Zone Comparative Planetary Evolution Extrasolar Planets Further ReadingReferencesIndex