Oceanic Hotspots: Intraplate Submarine Magmatism and Tectonism 2004 edition

Marc Notes: Includes bibliographical references and index. Table of Contents: References.- 1 Sea-Floor Topography and Morphology of the Superswell Region.- 1.1 Introduction.- 1.2 Data Sources and Methods.- 1.3 Sea-floor Morphology in French Polynesia.- 1.3.1 Bathymetric Expression of the Superswell.- 1.3.2 Midplate Swells.- 1.3.3 Plate Boundary Features.- 1.3.4 Off-Ridge Features.- 1.4 Conclusions.- Acknowledgements.- References.- 2 Seismicity of the Society and Austral Hotspots in the South Pacific: Seismic Detection, Monitoring and Interpretation of Underwater Volcanism.- 2.1 Introduction.- 2.2 Seismic Waves Used.- 2.2.1 Seismic Tremors.- 2.2.2 T Waves.- 2.3 Volcano-Seismic Activities on the Society Hotspot.- 2.3.1 Generalities and Chronological Events.- 2.3.2 The Over-All Seismicity of the Society Hotspot.- 2.3.3 Seismic Detection, Magnitude and Seismic Moment.- 2.3.4 Overview of the Swarms.- 2.3.5 Evolution of the Swarms and Nature of the Recorded Events.- 2.3.6 Frequency-Magnitude Relationship.- 2.3.7 Seismic and Magmatic Activity in the Society Hotspot Volcanoes.- 2.4 Volcano-Seismic Activity of the Austral Hotspot: Macdonald Seamount.- 2.4.1 Seismic Swarms.- 2.4.2 Bathymetric Surveys of the Macdonald Seamount.- 2.5 Summary and Conclusions.- 2.5.1 Society Hotspot.- 2.5.2 Austral Hotspot.- 2.5.3 General Conclusions.- Acknowledgements.- References.- 3 A Global Isostatic Load Model and its Application to Determine the Lithospheric Density Structure of Hotspot Swells.- 3.1 Introduction.- 3.2 Isostasy of the Lithospheric Plate.- 3.2.1 Lithostatic Load.- 3.2.2 The Generalized Equation of Isostatic Load.- 3.3 Reference Model.- 3.3.1 Compensation Depth.- 3.3.2 Lithospheric Density.- 3.3.3 Location of the Reference Column.- 3.4 Lithospheric Density Structure of Hotspot Swells.- 3.4.1 Introduction.- 3.4.2 French Polynesia, South Pacific Super Swell.- 3.4.3 Hawaiian-Emperor Island Chain.- 3.4.4 Mascarene-Reunion Hotspot Track.- 3.4.5 Ascension Island.- 3.4.6 The Great Meteor and Josephine Seamounts.- 3.4.7 Iceland.- 3.5 Subsidence of Hotspot Structures.- 3.6 Conclusions.- Acknowledgements.- References.- 4 Origin of the 43 Ma Bend Along the Hawaiian-Emperor Seamount Chain.- 4.1 Introduction.- 4.2 The Emperor Seamount Chain Paradox.- 4.2.1 Paleomagnetic Interpretations.- 4.2.2 A Simple Test.- 4.2.3 The E-SMC Paradox and Solution.- 4.3 The Origin of the 43Ma Bend.- 4.3.1 Reasoning Towards a Preferred Model.- 4.3.2 Trench Jam at 43Ma Caused by the Arrival of Hawaiian Plume Head/Oceanic Plateau.- 4.3.3 Evidence Versus Coincidence.- 4.4 Summary and Conclusion.- Acknowledgements.- References.- 5 South Pacific Intraplate Volcanism: Structure, Morphology and Style of Eruption.- 5.1 Introduction.- 5.2 Society Hotspot.- 5.2.1 Abyssal Hill Region and Limits of Hotspot Vo1canism.- 5.2.2 The Sea Floor ( Bulge ) Around the Hotspot Edifices.- 5.2.3 The Volcanic Edifices of the Society Hotspot.- 5.3 Austral Hotspot.- 5.3.1 The Submarine Edifices of the Austral Hotspot.- 5.4 Pitcairn Hotspot.- 5.4.1 Volcanic Edifices of the Pitcairn Hotspot.- 5.4.2 The Distribution and Extent of Hotspot Volcanism.- 5.5 Hotspot Versus Non-Hotspot Volcanoes.- 5.5.1 Sea-Floor Lineation and Seamount Distribution.- 5.5.2 Morphological Classification of Intraplate Volcanoes.- 5.6 Style of Eruption and Formation of Hotspot Edifices.- 5.6.1 Types of Eruption.- 5.6.2 The Formation of a Volcanic Edifice.- 5.6.3 Relationship Between Hotspot Volcanic Edifices.- 5.7 Summary and Conclusions.- Acknowledgements.- References.- 6 Submarine Landslides in French Polynesia.- 6.1 Introduction.- 6.2 Geological Setting.- 6.2.1 Data.- 6.2.2 Landslide Characterization.- 6.3 Landslides of the Society Islands.- 6.3.1 Mehetia.- 6.3.2 Moua Pihaa Seamount.- 6.3.3 Tahiti.- 6.3.4 Moorea.- 6.3.5 Huahine.- 6.3.6 Raiatea-Tahaa.- 6.3.7 Bora Bora.- 6.3.8 Tupai.- 6.4 Austral Island Landslides.- 6.4.1 Macdonald.- 6.4.2 Rapa.- 6.4.3 Raivavae.- 6.4.4 Tubuai.- 6.4.5 Arago.- 6.4.6 Rurutu.- 6.4.7 Rimatara.- 6.5 Classification of the Society and Austral Landslides.- 6.5.1 Geometric Characteristics.- 6.5.2 Seismic Velocity.- 6.6 Evolution of the Mass Wasting with the Age of the Edifices.- 6.6.1 Landslide Related to Submarine Active Volcanoes.- 6.6.2 Landslide Related to Young Oceanic Islands (4 Ma).- 6.6.4 Landslide Related to Tectonic Events.- 6.7 Conclusion.- Acknowledgements.- References.- 7 Mantle Plumes are NOT From Ancient Oceanic Crust.- 7.1 Introduction.- 7.2 Petrological Arguments.- 7.2.1 Melting of Oceanic Crust Cannot Produce the High Magnesian Melts Parental to Many OIB Suites.- 7.3 Geochemical Arguments.- 7.3.1 Melting of Subduction-Zone Dehydrated Residual Oceanic Crusts Cannot Yield the Trace Element Systematics in OIE.- 7.3.2 OIB Sr-Nd-Hf Isotopes Record no Subduction-Zone Dehydration Signatures.- 7.4 Mineral Physics Arguments.- 7.4.1 Subducted Oceanic Crusts are too Dense to Rise to the Upper Mantle.- 7.4.2 Basaltic Melts in the Lower Mantle Conditions are Denser than Ambient Solid Peridotites.- 7.5 Summary.- Acknowledgements.- References.- 8 The Sources for Hotspot Volcanism in the South Pacific Ocean.- 8.1 Introduction.- 8.2 The Hotspot Chains of the South East Pacific.- 8.2.1 Cook-Australs.- 8.2.2 Society Islands.- 8.2.3 Pitcairn-Gambier Chain.- 8.2.4 Marquesas Islands.- 8.2.5 Juan Fernandez Chain.- 8.2.6 Foundation Seamounts.- 8.2.7 Easter/Sala y Gomez-Nazca Chain.- 8.3 Discussion: Petrogenesis of South East Pacific Hotspots.- 8.3.1 Location of Magma Sources: Plume, Asthenosphere or Lithosphere?.- 8.3.2 Superswell How Geochemically Different is It?.- Acknowledgements.- References.- 9 Plume-Ridge Interactions: New Perspectives.- 9.1 Introduction.- 9.2 Concepts.- 9.2.1 Mantle Plumes: Deep-Rooted Hot Materials or Wet Shallow Mantle Melting Anomalies?.- 9.2.2 Nature of Plume Materials.- 9.2.3 Ocean Ridges: Ridge Suction The Active Driving Force for Plume-Ridge Interactions.- 9.2.4 Ridge Suction Increase with Increasing Spreading Rate.- 9.2.5 The Effect of Plume-Ridge Distance.- 9.3 Examples.- 9.3.1 Proximal Versus Distal Plume-Ridge Interactions.- 9.3.2 Spreading Rate Directs Plume Flows.- 9.4 Summary and Conclusion.- Acknowledgements.- References.- 10 Intraplate Gabbroic Rock Debris Ejected from the Magma Chamber of the Macdonald Seamount (Austral Hotspot): Comparison with Other Provinces.- 10.1 Introduction.- 10.2 The Macdonald Seamount.- 10.2.1 Eruptive Activity.- 10.2.2 Morphology and Structure.- 10.2.3 Sampling and Observations.- 10.2.4 Volcanic Terrains.- 10.3 Petrology.- 10.3.1 Analytical Techniques.- 10.3.2 Rock Descriptions.- 10.4 Geochemistry.- 10.5 Discussion.- 10.5.1 Comparison with Gabbros Recovered from Mid-Ocean Ridges.- 10.5.2 Comparison with Gabbroic Ejecta from Other Intraplate Regions.- 10.5.3 Origin of the Macdonald Seamount Gabbroic Clasts.- 10.6 Summary and Conclusions.- Acknowledgements.- References.- 11 The Foundation Chain: Inferring Hotspot-Plate Interaction from a Weak Seamount Trail.- 11.1 Introduction.- 11.2 Sample Preparation and Analytical Procedure.- 11.2.1 Sample Selection and Preparation.- 11.2.2 Dating Technique.- 11.2.3 Irradiation and Analysis.- 11.2.4 Data Reduction.- 11.3 Results.- 11.3.1 Migration of Volcanism Along the Foundation Chain.- 11.3.2 Hotspot-Spreading Center / Microplate Interaction.- 11.3.3 Volcanic Elongated Ridges (VERs).- 11.4 Discussion.- 11.4.1 VERs and the Pacific-Antarctic Spreading Axis.- 11.4.2 Foundation VERs and the Selkirk Microplate.- 11.4.3 Pacific Plate Motion.- 11.4.4 Implications for Plume-Hotspot Theory.- 11.5 Conclusions.- Acknowledgements.- References.- 12 Hydrothermal Iron and Manganese Crusts from the Pitcairn Hotspot Region.- 12.1 Introduction.- 12.2 Geological Setting.- 12.3 Sample Description.- 12.3.1 Mineralogy.- 12.3.2 Age Dating.- 12.3.3 Biomineralization.- 12.4 Chemical Composition.- 12.4.1 Fe Crusts.- 12.4.2 Mn Crusts.- 12.4.3 Rare Earth Elements (REE).- 12.5 Formation of Fe and Mn Crusts.- 12.6 Conclusions.- Acknowledgements.- References.- 13 Methane Venting into the Water Column Above the Pitcairn and the Society-Austral Seamounts, South Pacific.- 13.1 Introduction.- 13.2 Geological Setting.- 13.3 Methods.- 13.4 Results and Discussion.- 13.4.1 Water Column Characteristics and Methane Distribution.- 13.4.2 Origin of Hydrothermal Methane.- 13.5 Conclusions.- Acknowledgements.- References.- 14 Petrology of Young Submarine Hotspot Lava: Composition and Classification.- 14.1 Introduction.- 14.2 Composition and Description of Oceanic Rocks.- 14.2.1 Common Mineral Constituents.- 14.2.2 Rock Types.- 14.3 Relationship Between Intraplate-Hotspot and Spreading-Ridge Magmatism.- 14.4 Compositional Differences Among Hotspots.- 14.4.1 Relationship between Large and Small Hotspot Edifices.- 14.4.2 Volcanic Stratigraphy.- 14.5 Summary and Conclusions.- Acknowledgements.- References."