Upper mantle electrical resistivity structure beneath the central Mariana subduction system

This paper reports on a magnetotelluric (MT) survey across the central Mariana subduction system, providing a comprehensive electrical resistivity image of the upper mantle to address issues of mantle dynamics in the mantle wedge and beneath the slow back-arc spreading ridge. After calculation of MT response functions and their correction for topographic distortion, two-dimensional electrical resistivity structures were generated using an inversion algorithm with a smoothness constraint and with additional restrictions imposed by the subducting slab. The resultant isotropic electrical resistivity structure contains several key features. There is an uppermost resistive layer with a thickness of up to 150 km beneath the Pacific Ocean Basin, 80–100 km beneath the Mariana Trough, and 60 km beneath the Parece Vela Basin along with a conductive mantle beneath the resistive layer. A resistive region down to 60 km depth and a conductive region at greater depth are inferred beneath the volcanic arc in the mantle wedge. There is no evidence for a conductive feature beneath the back-arc spreading center. Sensitivity tests were applied to these features through inversion of synthetic data. The uppermost resistive layer is the cool, dry residual from the plate accretion process. Its thickness beneath the Pacific Ocean Basin is controlled mainly by temperature, whereas the roughly constant thickness beneath the Mariana Trough and beneath the Parece Vela Basin regardless of seafloor age is controlled by composition. The conductive mantle beneath the uppermost resistive layer requires hydration of olivine and/or melting of the mantle. The resistive region beneath the volcanic arc down to 60 km suggests that fluids such as melt or free water are not well connected or are highly three-dimensional and of limited size. In contrast, the conductive region beneath the volcanic arc below 60 km depth reflects melting and hydration driven by water release from the subducting slab. The resistive region beneath the back-arc spreading center can be explained by dry mantle with typical temperatures, suggesting that any melt present is either poorly connected or distributed discontinuously along the strike of the ridge. Evidence for electrical anisotropy in the central Mariana upper mantle is weak.

[1]  S. Karato,et al.  Water, partial melting and the origin of the seismic low velocity and high attenuation zone in the upper mantle , 1998 .

[2]  D. Wiens,et al.  Seismic attenuation tomography of the Mariana subduction system: Implications for thermal structure, volatile distribution, and slow spreading dynamics , 2009 .

[3]  S. Peacock.  Fluid Processes in Subduction Zones , 1990, Science.

[4]  S. Newman,et al.  Chemical and Isotopic Composition of Lavas from the Northern Mariana Trough: Implications for Magmagenesis in Back-arc Basins , 1998 .

[5]  P. Tackley,et al.  Intraplate volcanism with complex age‐distance patterns: A case for small‐scale sublithospheric convection , 2009 .

[6]  A. Schultz,et al.  Northeastern Pacific mantle conductivity profile from long-period magnetotelluric sounding using Hawaii-to-California submarine cable data , 1995 .

[7]  P. V. Keken,et al.  The structure and dynamics of the mantle wedge , 2003 .

[8]  Masayuki Obayashi,et al.  Stagnant slabs in the upper and lower mantle transition region , 2001 .

[9]  J. Hunen,et al.  Controls on sublithospheric small-scale convection , 2003 .

[10]  Jie Guo,et al.  Elastic and electrical properties of serpentinite dehydration at high temperature and high pressure , 2002 .

[11]  M. C. Pomposiello,et al.  Low electrical resistivity associated with plunging of the Nazca flat slab beneath Argentina , 2004, Nature.

[12]  A. Chave,et al.  Correction of seafloor magnetotelluric data for topographic effects during inversion , 2005 .

[13]  Greg Hirth,et al.  Water in the oceanic upper mantle: implications for rheology , 1996 .

[14]  Katherine A. Kelley,et al.  Mantle melting as a function of water content beneath back-arc basins , 2006 .

[15]  Alan D. Chave,et al.  Bounded influence magnetotelluric response function estimation , 2004 .

[16]  R. Stern,et al.  Geochemical mapping of the Mariana arc‐basin system: Implications for the nature and distribution of subduction components , 2005 .

[17]  Simon M. Peacock,et al.  Subduction factory 1. Theoretical mineralogy, densities, seismic wave speeds, and H 2 O contents , 2003 .

[18]  J. A. Tyburczy,et al.  GEOPHYSICAL SIGNIFICANCE AND IMPLICATIONS FOR CHARGE TRANSPORT AND MELT STRUCTURE , 1983 .

[19]  J. Gerald,et al.  Grain boundary melt films in an experimentally deformed olivine‐orthopyroxene rock: Implications for melt distribution in upper mantle rocks , 1996 .

[20]  S. Newman,et al.  MORB mantle and subduction components interact to generate basalts in the southern Mariana Trough back-arc basin , 1996 .

[21]  P. Fryer.  Evolution of the Mariana Convergent Plate Margin System , 1996 .

[22]  K. Okino,et al.  The Philippine Sea: New survey results reveal the structure and the history of the marginal basins , 1999 .

[23]  Robert L. Parker,et al.  Optimal one-dimensional inversion and bounding of magnetotelluric apparent resistivity and phase measurements , 1996 .

[24]  Douglas R. Toomey,et al.  Crustal magma plumbing within a segment of the Mid-Atlantic Ridge, 35°N , 2000 .

[25]  Walter H. F. Smith,et al.  New, improved version of generic mapping tools released , 1998 .

[26]  B. Parsons,et al.  An analysis of the variation of ocean floor bathymetry and heat flow with age , 1977 .

[27]  Eugene I. Smith,et al.  Shear-driven upwelling induced by lateral viscosity variations and asthenospheric shear: A mechanism for intraplate volcanism , 2009 .

[28]  P. Kaikkonen,et al.  Local 1-D interpretation of magnetotelluric B-polarization impedances , 1994 .

[29]  Laura S. Magde,et al.  Three‐dimensional mantle upwelling, melt generation, and melt migration beneath segment slow spreading ridges , 1997 .

[30]  E. Flueh,et al.  Upper lithospheric structure of the subduction zone offshore of southern Arauco peninsula, Chile, at ∼38°S , 2008 .

[31]  Shear-wave splitting in the Mariana trough—a relation between back-arc spreading and mantle flow? , 2006 .

[32]  S. Constable.  FAST TRACK PAPER: SEO3: A new model of olivine electrical conductivity , 2006 .

[33]  F. Gaillard,et al.  Carbonatite Melts and Electrical Conductivity in the Asthenosphere , 2008, Science.

[34]  F. Gaillard,et al.  Electrical conductivity of magma in the course of crystallization controlled by their residual liquid composition , 2005 .

[35]  S. Newman,et al.  H2O and CO2 in magmas from the Mariana arc and back arc systems , 2000 .

[36]  K. Suyehiro,et al.  Distinct regional differences in crustal thickness along the axis of the Mariana Trough, inferred from gravity anomalies , 2006 .

[37]  S. Peacock.  Are the lower planes of double seismic zones caused by serpentine dehydration in subducting oceanic mantle , 2001 .

[38]  H. Utada,et al.  3-D modelling and analysis of Dst C-responses in the North Pacific Ocean region, revisited , 2005 .

[39]  Kiyoshi Baba,et al.  Electrical Structure in Marine Tectonic Settings , 2005 .

[40]  T. Yoshino,et al.  Hydrous olivine unable to account for conductivity anomaly at the top of the asthenosphere , 2006, Nature.

[41]  S. Newman,et al.  The role of water in the petrogenesis of Mariana trough magmas , 1994 .

[42]  M. Hirschmann,et al.  Water follows carbon: CO2 incites deep silicate melting and dehydration beneath mid-ocean ridges , 2007 .

[43]  B. Taylor,et al.  Back-arc basin basalt systematics , 2003 .

[44]  S. Karato,et al.  Comments on “Electrical conductivity of wadsleyite as a function of temperature and water content” by Manthilake et al. , 2009 .

[45]  D. Forsyth,et al.  Geophysical evidence from the MELT area for compositional controls on oceanic plates , 2005, Nature.

[46]  S. Peacock.  Thermal Structure and Metamorphic Evolution of Subducting Slabs , 2013 .

[47]  S. Karato,et al.  The role of hydrogen in the electrical conductivity of the upper mantle , 1990, Nature.

[48]  S. Karato,et al.  The effect of water on the electrical conductivity of olivine , 2005, Nature.

[49]  Robert J. Stern,et al.  SUBDUCTION ZONES , 2002 .

[50]  C. Wolfe,et al.  Shear-wave splitting and implications for mantle flow beneath the MELT region of the east pacific rise , 1998, Science.

[51]  H. Utada,et al.  1-D electrical conductivity structure beneath the Philippine Sea: Results from an ocean bottom magnetotelluric survey , 2007 .

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

[53]  J. Roberts,et al.  Partial‐melt electrical conductivity: Influence of melt composition , 1999 .

[54]  Per Christian Hansen,et al.  Analysis of Discrete Ill-Posed Problems by Means of the L-Curve , 1992, SIAM Rev..

[55]  A. Chave,et al.  Mantle dynamics beneath the East Pacific Rise at 17°S : insights from the Mantle Electromagnetic and Tomography (MELT) experiment , 2006 .

[56]  H. Kern,et al.  Thermal dehydration reactions characterised by combined measurements of electrical conductivity and elastic wave velocities , 1993 .

[57]  T. Yoshino,et al.  Reply to Comments on “Electrical conductivity of wadsleyite as a function of temperature and water content” by Manthilake et al. , 2009 .

[58]  G. Abers,et al.  Reply to comment by R. Bousquet et al. on ''Subduction factory: 1. Theoretical mineralogy, densities, seismic wave speeds and H 2 O contents'' , 2005 .

[59]  D. Kohlstedt,et al.  Diffusion of Hydrogen and Intrinsic Point Defects in Olivine , 1998 .

[60]  J. Morgan,et al.  Bending-related faulting and mantle serpentinization at the Middle America trench , 2003, Nature.

[61]  S. Poli,et al.  Experimentally based water budgets for dehydrating slabs and consequences for arc magma generation , 1998 .

[62]  William Rodi,et al.  Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion , 2001 .

[63]  Teruyuki Kato,et al.  Geodetic evidence of back‐arc spreading in the Mariana Trough , 2003 .

[64]  J. Gerald,et al.  Shear wave attenuation and dispersion in melt-bearing olivine polycrystals: 2. Microstructural interpretation and seismological implications , 2004 .

[65]  H. Utada,et al.  ON EARTH EVOLUTION , VOL . 2 Electrical structure of the upper mantle in the Mariana subduction system , 2005 .

[66]  D. Hussong,et al.  Origin and emplacement of Mariana forearc seamounts , 1985 .

[67]  A. Pommier,et al.  Laboratory measurements of electrical conductivities of hydrous and dry Mount Vesuvius melts under pressure , 2008 .

[68]  Katherine A. Kelley,et al.  Mantle temperature variations beneath back-arc spreading centers inferred from seismology, petrology, and bathymetry , 2006 .

[69]  A. Chave,et al.  A bounded influence regression estimator based on the statistics of the hat matrix , 2003 .

[70]  D. L. Anderson,et al.  Edge-driven convection , 1998 .

[71]  K. Baba,et al.  A study on correction equations for the effect of seafloor topography on ocean bottom magnetotelluric data , 2007 .

[72]  D. Wiens,et al.  Complex mantle flow in the Mariana subduction system: evidence from shear wave splitting , 2007 .

[73]  Gerald W. Hohmann,et al.  Magnetotelluric responses of three-dimensional bodies in layered earths , 1984 .

[74]  E. Parmentier,et al.  The effects of deep damp melting on mantle flow and melt generation beneath mid-ocean ridges , 2000 .

[75]  G. W. Hohmann.  Three-Dimensional Induced Polarization and Electromagnetic Modeling , 1975 .

[76]  M. Hirschmann,et al.  Storage capacity of H2O in nominally anhydrous minerals in the upper mantle , 2005 .

[77]  K. Priestley,et al.  The thermal structure of the lithosphere from shear wave velocities , 2006 .

[78]  R. Hékinian,et al.  Spreading-rate dependence of the extent of mantle melting beneath ocean ridges , 1997, Nature.

[79]  Alan D. Chave,et al.  Magnetotelluric imaging of the Society Islands hotspot , 1998 .

[80]  H. Utada,et al.  A semi‐global reference model for electrical conductivity in the mid‐mantle beneath the north Pacific region , 2003 .

[81]  E. Parmentier,et al.  Effect of solid flow above a subducting slab on water distribution and melting at convergent plate boundaries , 2007 .

[82]  K. Baba,et al.  A new technique for the incorporation of seafloor topography in electromagnetic modelling , 2002 .

[83]  A. Deschamps,et al.  Faulting and volcanism in the axial valley of the slow‐spreading center of the Mariana back arc basin from Wadatsumi side‐scan sonar images , 2005 .

[84]  C. Peach,et al.  Melt distribution in olivine rocks based on electrical conductivity measurements , 2005 .

[85]  Xu,et al.  Electrical conductivity of olivine, wadsleyite, and ringwoodite under upper-mantle conditions , 1998, Science.

[86]  K. Suyehiro,et al.  Structure and growth of the Izu‐Bonin‐Mariana arc crust: 1. Seismic constraint on crust and mantle structure of the Mariana arc–back‐arc system , 2008 .

[87]  B. Kennett,et al.  Spatial and temporal evolution of the subducting Pacific plate structure along the western Pacific margin , 2006 .

[88]  T. Yoshino,et al.  Electrical conductivity of wadsleyite as a function of temperature and water content , 2009 .

[89]  Alan G. Jones,et al.  Two-dimensional interpretation of three-dimensional magnetotelluric data: an example of limitations and resolution , 2002 .

[90]  T. Kanazawa,et al.  Seismic Evidence for Sharp Lithosphere-Asthenosphere Boundaries of Oceanic Plates , 2009, Science.

[91]  Tomoo Katsura,et al.  The effect of water on the electrical conductivity of olivine aggregates and its implications for the electrical structure of the upper mantle , 2009 .

[92]  S. Uyeda,et al.  Tectonic Processes and the History of the Mariana Arc: A Synthesis of the Results of Deep Sea Drilli , 1982 .

[93]  T. Grove,et al.  Kinematic variables and water transport control the formation and location of arc volcanoes , 2009, Nature.