Influence of dynamic topography on sea level and its rate of change

Mantle fl ow likely supports up to 2 km of long-wavelength topographic relief over Earth’s surface. Although the average of this dynamic support must be zero, a net defl ection of the ocean basins can change their volume and induce sea-level change. By calculating dynamic topography using a global mantle fl ow model, we fithat continents preferentially conceal depressed topography associated with mantle downwelling, leading to net seafl oor uplift and ~90 ± 20 m of positive sea-level offset. Upwelling mantle fl ow is currently amplifying positive dynamic topography and causing up to 1.0 m/Ma of sea-level rise, depending on mantle viscosity. Continental motions across dynamic topography gradients also affect sea level, but uncertainty over the plate motion reference frame permits sea-level rise or fall by ±0.3 m/Ma, depending on net lithosphere rotation. During a complete Wilson cycle, sea level should fall during supercontinent stability and rise during periods of dispersal as mantle fl ow pushes continents down dynamic topography gradients toward areas of mantle downwelling. We estimate that a maximum of ~1 m/Ma of sea-level rise may have occurred during the most recent continental dispersal. Because this rate is comparable in magnitude to other primary sea-level change mechanisms, dynamic offset of sea level by mantle fl ow should be considered a potentially signifi cant contributor to long-term sea-level change.

[1]  Gabi Laske,et al.  The Relative Behavior of Shear Velocity, Bulk Sound Speed, and Compressional Velocity in the Mantle: Implications for Chemical and Thermal Structure , 2013 .

[2]  R. Müller,et al.  Subsidence in intracontinental basins due to dynamic topography , 2008 .

[3]  Lijun Liu,et al.  Reconstructing Farallon Plate Subduction Beneath North America Back to the Late Cretaceous , 2008, Science.

[4]  Louis Moresi,et al.  A benchmark study on mantle convection in a 3‐D spherical shell using CitcomS , 2008 .

[5]  E. Humler,et al.  Global scale patterns of continental fragmentation: Wilson's cycles as a constraint for long-term sea-level changes , 2008 .

[6]  R. Müller,et al.  Global plate motion frames: Toward a unified model , 2008 .

[7]  N. Simmons,et al.  Dynamic topography and long-term sea-level variations: There is no such thing as a stable continental platform , 2008 .

[8]  C. Conrad,et al.  Tethyan closure, Andean orogeny, and westward drift of the Pacific Basin , 2008 .

[9]  P. Tackley,et al.  Buoyant melting instabilities beneath extending lithosphere: 1. Numerical models , 2008 .

[10]  R. Müller,et al.  The case for dynamic subsidence of the U.S. east coast since the Eocene , 2008 .

[11]  R. Müller,et al.  Long-Term Sea-Level Fluctuations Driven by Ocean Basin Dynamics , 2008, Science.

[12]  T. Becker,et al.  Azimuthal seismic anisotropy constrains net rotation of the lithosphere , 2008 .

[13]  James H. Roberts,et al.  Supercontinent cycles, true polar wander, and very long-wavelength mantle convection , 2007 .

[14]  Clinton P. Conrad,et al.  Global mantle flow and the development of seismic anisotropy: Differences between the oceanic and continental upper mantle , 2007 .

[15]  J. Mitrovica,et al.  Lateral variations in mantle rheology: implications for convection related surface observables and inferred viscosity models , 2007 .

[16]  T. Becker.  On the effect of temperature and strain-rate dependent viscosity on global mantle flow, net rotation, and plate-driving forces , 2006 .

[17]  C. Conrad,et al.  Tectonic velocities, dynamic topography, and relative sea level , 2006 .

[18]  L. Husson.  Dynamic topography above retreating subduction zones , 2006 .

[19]  Eh Tan,et al.  GeoFramework: Coupling multiple models of mantle convection within a computational framework , 2006 .

[20]  V. Courtillot,et al.  Mean age of oceanic lithosphere drives eustatic sea-level change since Pangea breakup , 2006 .

[21]  R. Müller,et al.  Controls on back‐arc basin formation , 2006 .

[22]  C. Conrad,et al.  Global reconstructions of Cenozoic seafloor ages: Implications for bathymetry and sea level , 2006 .

[23]  C. Conrad,et al.  Influence of continental roots and asthenosphere on plate‐mantle coupling , 2006 .

[24]  K. Miller,et al.  The Phanerozoic Record of Global Sea-Level Change , 2005, Science.

[25]  Archie Paulson,et al.  Modelling post-glacial rebound with lateral viscosity variations , 2005 .

[26]  H. Bunge,et al.  Heterogeneity and time dependence in 3D spherical mantle convection models with continental drift , 2005 .

[27]  C. Conrad,et al.  Iceland, the Farallon slab, and dynamic topography of the North Atlantic , 2004 .

[28]  Hendrik Jan van Heijst,et al.  Global transition zone tomography , 2004 .

[29]  L. Fleitout,et al.  Effect of lateral viscosity variations in the top 300 km on the geoid and dynamic topography , 2003 .

[30]  M. Gurnis,et al.  Seismic tomography, surface uplift, and the breakup of Gondwanaland: Integrating mantle convection backwards in time , 2003 .

[31]  W. Collins.  Slab pull, mantle convection, and Pangaean assembly and dispersal , 2003 .

[32]  G. Bokelmann.  Which forces drive North America , 2002 .

[33]  Richard G. Gordon,et al.  Young tracks of hotspots and current plate velocities , 2002 .

[34]  W. Spakman,et al.  Subducted slabs beneath the eastern Indonesia–Tonga region: insights from tomography , 2002 .

[35]  Bijaya B. Karki,et al.  Origin of lateral variation of seismic wave velocities and density in the deep mantle , 2001 .

[36]  M. Gurnis,et al.  Constraining mantle density structure using geological evidence of surface uplift rates: The case of the African Superplume , 2000 .

[37]  Hans-Peter Bunge,et al.  Mesozoic plate-motion history below the northeast Pacific Ocean from seismic images of the subducted Farallon slab , 2000, Nature.

[38]  Louis Moresi,et al.  Role of temperature‐dependent viscosity and surface plates in spherical shell models of mantle convection , 2000 .

[39]  Shijie Zhong,et al.  Effects of plate and slab viscosities on the geoid , 1999 .

[40]  G. Jarvis,et al.  Effects of mantle heat source distribution on supercontinent stability , 1999 .

[41]  P. Silver,et al.  Dynamic topography, plate driving forces and the African superswell , 1998, Nature.

[42]  M. Richards,et al.  The dynamics of Cenozoic and Mesozoic plate motions , 1998 .

[43]  Y. L. Stunff,et al.  Partial advection of equidensity surfaces: A solution for the dynamic topography problem? , 1997 .

[44]  M. Richards,et al.  The geoid constraint in global geodynamics: viscosity structure, mantle heterogeneity models and boundary conditions , 1997 .

[45]  M. Gurnis,et al.  Cenozoic subsidence and uplift of continents from time-varying dynamic topography , 1997 .

[46]  J. Mitrovica,et al.  Haskell [1935] revisited , 1996 .

[47]  R. V. D. Hilst.  Complex morphology of subducted lithosphere in the mantle beneath the Tonga trench , 1995, Nature.

[48]  Richard G. Gordon,et al.  Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions , 1994 .

[49]  M. Gurnis.  Phanerozoic marine inundation of continents driven by dynamic topography above subducting slabs , 1993, Nature.

[50]  P. Hoffman.  Did the Breakout of Laurentia Turn Gondwanaland Inside-Out? , 1991, Science.

[51]  M. Gurnis.  Ridge Spreading, Subduction, and Sea Level Fluctuations , 1990, Science.

[52]  L. Fleitout,et al.  Topography of the ocean floor: Thermal evolution of the lithosphere and interaction of deep mantle heterogeneities with the lithosphere , 1990 .

[53]  C. Beaumont,et al.  Tilting of continental interiors by the dynamical effects of subduction: Tectonics , 1989 .

[54]  Michael Gurnis,et al.  Large-scale mantle convection and the aggregation and dispersal of supercontinents , 1988, Nature.

[55]  B. Haq,et al.  Chronology of Fluctuating Sea Levels Since the Triassic , 1987, Science.

[56]  Robert W. Clayton,et al.  Lower mantle heterogeneity, dynamic topography and the geoid , 1985, Nature.

[57]  B. Hager.  Subducted slabs and the geoid: Constraints on mantle rheology and flow , 1983 .

[58]  W. C. Pitman.  Relationship between eustacy and stratigraphic sequences of passive margins , 1978 .

[59]  G. Bond.  Evidence for continental subsidence in North America during the Late Cretaceous global submergence , 1976 .

[60]  T. Jordan.  The continental tectosphere , 1975 .

[61]  J. Wilson,et al.  Did the Atlantic Close and then Re-Open? , 1966, Nature.

[62]  Archie Paulson,et al.  FAST TRACK PAPER: Inference of mantle viscosity from GRACE and relative sea level data , 2007 .

[63]  Michelle A. Kominz,et al.  Oceanic Ridge Volumes and Sea-Level Change - An Error Analysis , 1984 .