Keywords:
Plate tectonics.
;
Electronic books.
Description / Table of Contents:
Mantle convection is the fundamental agent driving most geological processes. This book explains how it works, and how to quantify it in simple terms and its relevance to geological features at the Earth's surface. It is accessible to students and researchers across a variety of geoscience disciplines.
Type of Medium:
Online Resource
Pages:
1 online resource (242 pages)
Edition:
1st ed.
ISBN:
9780511989223
URL:
https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=647403
DDC:
551.1
Language:
English
Note:
Cover -- Half-title -- Title -- Copyright -- Contents -- 1 Introduction -- 2 Context -- 2.1 Crust, mantle, core -- 2.2 Lithosphere versus crust -- 2.3 Topography -- 2.4 Heat flux -- 3 Why moving plates? -- 3.1 The lead-up -- 3.2 Wilson, plumes and plates -- 3.3 Evidence for motion - magnetism -- 3.4 Evidence for motion - seismology -- 3.5 Evidence for motion - sediments -- 4 Solid, yielding mantle -- 4.1 Viscosity -- 4.2 Viscosity of the mantle -- 4.3 Dependence of viscosity on temperature -- 4.4 Inevitable convection -- 5 Convection -- 5.1 Thermal expansion -- 5.2 Buoyancy -- 5.3 Plate velocity - simple mechanical version -- 5.4 Heat conduction -- 5.5 Plate velocity - thermo-viscous version -- 5.6 The Rayleigh number and other fluid-dynamical beasts -- 6 The plate mode of convection -- 6.1 The strong lithosphere -- 6.2 The role of the lithosphere in mantle convection -- 6.3 Heat transport - the plates are mantle convection -- 6.4 The geography of topography -- 6.5 The geography of heat flow -- 6.6 Numerical model of the plate mode -- 6.7 Summary of the plate mode -- 7 The plume mode of convection -- 7.1 Inferring plumes from surface observations -- 7.2 Hotspot swells, plume flows and eruption rates -- 7.2.1 Buoyancy transported by plumes -- 7.2.2 Heat transported by plumes -- 7.2.3 Volume flow rates and eruption rates of plumes -- 7.2.4 Heat flow from the core -- 7.3 The dynamics and form of mantle plumes -- 7.3.1 Outline of plume dynamics -- 7.3.2 The Rayleigh-Taylor instability -- 7.3.3 Rate of flow up a plume tail -- 7.3.4 Rate of ascent of a plume head -- 7.3.5 Thermal entrainment into a plume head -- 7.4 Plume heads and flood basalt eruptions -- 7.5 Irregular volcanism and thermochemical plumes -- 7.6 Summary of the plume mode -- 8 Perspective -- 8.1 Separate but interacting -- 8.2 Common misconceptions.
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8.2.1 Plumes are not the return mode of plate flow -- 8.2.2 There is normally no active upwelling under mid-ocean ridges -- 8.2.3 There is no significant 'decoupling' layer -- 8.2.4 Return flow is not shallow -- 8.2.5 There is no seafloor 'flattening' -- 8.3 Layered convection? -- 8.4 Other modes and causes -- 8.4.1 Rifting model of flood basalts -- 8.4.2 Superplumes -- 8.4.3 Small-scale convection -- 8.4.4 Edge convection -- 8.4.5 Mantle wetspots -- 8.5 Pursuing implications -- 9 Evolution and tectonics -- 9.1 Parametrised thermal evolution -- 9.2 Numerical thermal evolution -- 9.3 The heat source puzzle -- 9.4 Compositional buoyancy -- 9.4.1 Four billion years of basalt subduction -- 9.4.2 Buoyancy of oceanic crust -- 9.4.3 A mid-mantle basalt barrier and early mantle overturns -- 9.4.4 Continental collision -- 9.5 Intermittent plate tectonics -- 9.6 Implications for tectonics -- 10 Mantle chemical evolution -- 10.1 Trace element and isotope observations -- 10.2 Global budgets -- 10.3 Incompatible trace elements in the mantle -- 10.4 Mantle heterogeneity -- 10.4.1 Sources of heterogeneity -- 10.4.2 Survival of heterogeneities -- 10.4.3 How much primitive mantle? -- 10.4.4 How much subducted oceanic crust? -- 10.5 Melting in a heterogeneous mantle -- 10.5.1 Melting a homogeneous source -- 10.5.2 Reaction and disequilibrium of eclogite melts -- 10.5.3 Melt trapping and recirculation -- 10.6 Previous estimates of trace element abundance -- 10.6.1 Sampling heterogeneity, not mixing reservoirs -- 10.6.2 No primitive mantle -- 10.6.3 Focus on the depleted MORB mantle -- 10.6.4 Mean compositions, not end-members -- 10.6.5 Heterogeneities from plumes -- 10.6.6 Chemical disequilibrium -- 10.6.7 Basaltic gradient through the upper mantle? -- 10.7 Dynamical modelling of refractory incompatible elements -- 10.7.1 Heterogeneity and the MORB-OIB difference.
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10.7.2 Residence times -- 10.7.3 Sampling theory -- 10.7.4 OIB ages -- 10.7.5 Heterogeneities remelted, not homogenised -- 10.8 Resolving the noble gas enigma -- 10.8.1 Noble gases in the hybrid pyroxenite -- 10.8.2 Conventional concentration estimates -- 10.8.3 New concentration estimates -- 10.8.4 Modelling evolution in the MORB and OIB sources -- 10.8.5 Application of the model -- 10.8.6 The 40Ar budget -- 10.8.7 Alternative interpretations -- 10.9 Assessment of mantle chemistry -- 11 Assimilating mantle convection into geology -- Appendix A: Exponential growth and decay -- A.1 Exponential solution -- A.2 Post-glacial rebound -- A.3 Rayleigh-Taylor instability -- Appendix B: Thermal evolution details -- B.1 Heat generation -- B.2 Parametrised thermal evolution model -- B.3 Numerical thermal evolution model -- B.4 Basalt tracers -- B.5 Models with basalt tracers -- Appendix C: Chemical evolution details -- C.1 Fraction of primitive mantle -- C.2 Fraction of crust in the mantle -- References -- Index.
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