Rheologic controls on the dynamics of slab detachment

Abstract The detachment of subducted lithosphere (slabs) has been proposed in a number of locations as the cause for observed volcanism and regional tectonic evolution. For example, along-strike progression of uplift in the Adriatic Sea and west-to-east progression of volcanism in the Trans-Mexican Volcanic Belt may be caused by propagating detachment of subducted slabs. An understanding of the dynamics of slab detachment is necessary to relate the timing of detachment to surface observations. We demonstrate using two-dimensional (2D) numerical models that the timing, occurrence, and surface effects resulting from the detachment of subducted lithosphere are strongly dependent upon the stiffness (i.e. stress supported viscously) of the lithosphere and rheology of the upper mantle. In particular, in models with a Newtonian upper mantle where plastic yielding is the only weakening process within the slab, detachment does not occur. Models accounting for non-Newtonian upper mantle deformation demonstrate two modes of detachment: (1) slow and deep detachment of strong slabs (500 MPa or greater maximum yield strength) controlled by heating of the slab, and (2) fast and shallow detachment of weaker slabs (300 MPa) controlled by yielding within the slab interior. For slabs with a maximum yield strength of 500 MPa, the time to detachment increases with slab age (for ages ranging from 40 to 120 My), indicating that detachment time is controlled by the integrated stiffness of the slab, which limits the sinking rate. However, the detachment time for weaker slabs (300 MPa) is independent of age because weaker slabs sink rapidly, and the time to detachment is limited by the rate of flow of the surrounding mantle.

[1]  P. Montone,et al.  State of stress in southern Italy from borehole breakout and focal mechanism data , 1995 .

[2]  Robert D. van der Hilst,et al.  Travel-time tomography of the European-Mediterranean mantle down to 1400 km , 1993 .

[3]  M. Mattauer,et al.  Evolutionary model of the Himalaya–Tibet system: geopoem: based on new modelling, geological and geophysical data , 2000 .

[4]  H. Bellon,et al.  La Purísima volcanic field, Baja California Sur (Mexico): Miocene to Quaternary volcanism related to subduction and opening of an asthenospheric window , 2006 .

[5]  K. Furlong,et al.  Three-dimensional thermal modeling of the California upper mantle: a slab window vs. stalled slab , 2001 .

[6]  J. Stock,et al.  Pacific-North America Plate Tectonics of the Neogene Southwestern United States: An Update , 1998 .

[7]  W. Spakman,et al.  Subduction and slab detachment in the Mediterranean-Carpathian region. , 2000, Science.

[8]  B. Simoneit,et al.  The gulf and peninsular province of the Californias , 1991 .

[9]  R. Hilst,et al.  Epeirogenic uplift above a detached slab in northern Central America , 2002 .

[10]  X. Liao,et al.  Slab breakoff depth: A slowdown subduction model , 2002 .

[11]  H. Kanamori,et al.  Source process and tectonic implications of the Spanish deep-focus earthquake of March 29, 1954☆ , 1976 .

[12]  Mark D. Zoback,et al.  Implications of hydrostatic pore pressures and high crustal strength for the deformation of intraplate lithosphere , 2001 .

[13]  A. Pêcher,et al.  A slab breakoff model for the Neogene thermal evolution of South Karakorum and South Tibet , 2002 .

[14]  Bradford H. Hager,et al.  Mantle Viscosity: A Comparison of Models from Postglacial Rebound and from the Geoid, Plate Driving Forces, and Advected Heat Flux , 1991 .

[15]  H. Schmeling,et al.  Delamination and detachment of a lithospheric root , 1998 .

[16]  D. Yuen,et al.  Thermomechanical modelling of slab detachment , 2004 .

[17]  Gregory M. Hulbert,et al.  Accurate determination of surface normal stress in viscous flow from a consistent boundary flux method , 1993 .

[18]  F. Blanckenburg,et al.  Slab breakoff: A model of lithosphere detachment and its test in the magmatism and deformation of collisional orogens , 1995 .

[19]  T. Becker,et al.  The dynamics of subduction and trench migration for viscosity stratification , 2005 .

[20]  A. Tommasi,et al.  Anisotropy of thermal diffusivity in the upper mantle , 2001, Nature.

[21]  J. Eiler.  Inside the subduction factory , 2003 .

[22]  Patrick Wu,et al.  Rheology of the Upper Mantle: A Synthesis , 1993, Science.

[23]  L. Ferrari.  Slab detachment control on mafic volcanic pulse and mantle heterogeneity in central Mexico , 2004 .

[24]  F. Blanckenburg,et al.  Slab breakoff: A model for syncollisional magmatism and tectonics in the Alps , 1995 .

[25]  Shijie Zhong,et al.  Interaction of weak faults and non-newtonian rheology produces plate tectonics in a 3D model of mantle flow , 1996, Nature.

[26]  G. Hirth,et al.  Rheologic controls on slab dynamics , 2007 .

[27]  B. Evans,et al.  Strength of the lithosphere: Constraints imposed by laboratory experiments , 1995 .

[28]  Passive Seismology and Deep Structure in Central Italy , 1998 .

[29]  Harmen Bijwaard,et al.  Tethyan subducted slabs under India , 1999 .

[30]  U. Christensen.  The influence of trench migration on slab penetration into the lower mantle , 1996 .

[31]  B. Hager,et al.  Controls of the structure of subducted slabs , 1988, Nature.

[32]  C. Faccenna,et al.  Slab detachment beneath eastern Anatolia: A possible cause for the formation of the North Anatolian fault , 2006 .

[33]  M. Wortel,et al.  Late Miocene uplift in the Romagnan Apennines and the detachment of subducted lithosphere , 1999 .

[34]  Giorgio Ranalli,et al.  Rheology of the earth , 1987 .

[35]  R. J. Lillie,et al.  Slab behaviour and its surface expression: new insights from gravity modelling in the SE-Carpathians , 2004 .

[36]  K. Fuchs,et al.  The Romanian earthquake of March 4, 1977 ii. Aftershocks and migration of seismic activity + , 1979 .

[37]  G. Hirth.  Laboratory Constraints on the Rheology of the Upper Mantle , 2002 .

[38]  J. Oliver,et al.  Seismic velocity anomalies beneath the New Hebrides Island Arc: Evidence for a detached slab in the upper mantle , 1973 .

[39]  J. Chatelain,et al.  Detachment of part of the downgoing slab and uplift of the New Hebrides (Vanuatu) Islands , 1992 .

[40]  E. Möbius,et al.  Charge states of energetic (≈0.5 MeV/n) ions in corotating interaction regions at 1 AU and implications on source populations , 2002 .

[41]  W. Spakman,et al.  Structure and dynamics of subducted lithosphere in the Mediterranean region , 1992 .

[42]  Arie P. van den Berg,et al.  The influence of rheological weakening and yield stress on the interaction of slabs with the 670 km discontinuity , 2002 .

[43]  Louis Moresi,et al.  Role of faults, nonlinear rheology, and viscosity structure in generating plates from instantaneous mantle flow models , 1998 .

[44]  D. May,et al.  Evolution and diversity of subduction zones controlled by slab width , 2007, Nature.

[45]  S. Buiter,et al.  Two-dimensional simulations of surface deformation caused by slab detachment , 2002 .

[46]  A. Peccerillo,et al.  Trace element and isotopic variations from Mt. Vulture to Campanian volcanoes: constraints for slab detachment and mantle inflow beneath southern Italy , 2006 .

[47]  J. Royer,et al.  Slab-tearing following ridge-trench collision: Evidence from Miocene volcanism in Baja California, México , 2007 .

[48]  H. Wenk,et al.  Plastic deformation of minerals and rocks , 2002 .

[49]  G. Hirth,et al.  Newtonian versus non‐Newtonian upper mantle viscosity: Implications for subduction initiation , 2005 .

[50]  B. Sichler,et al.  Oceanic-ridge subduction vs. slab break off: Plate tectonic evolution along the Baja California Sur continental margin since 15 Ma , 2006 .

[51]  M. Wortel,et al.  Shallow slab detachment as a transient source of heat at midlithospheric depths , 2001 .

[52]  S. Poli,et al.  Petrology of subducted slabs , 2002 .

[53]  H. C. Heard,et al.  The Brittle-ductile transition in rocks : the Heard volume , 1990 .

[54]  W. Spakman,et al.  Late Cenozoic mineralization, orogenic collapse and slab detachment in the European Alpine Belt , 1998 .

[55]  J. Oliver,et al.  Descent of Lithosphere beneath New Hebrides, Tonga-Fiji and New Zealand: Evidence for Detached Slabs , 1973, Nature.

[56]  M. Benoit,et al.  Spatial and temporal evolution of basalts and magnesian andesites (''bajaites'') from Baja California, Mexico: the role of slab melts , 2003 .

[57]  Magali I. Billen,et al.  Multiscale dynamics of the Tonga—Kermadec subduction zone , 2003 .

[58]  M. Wortel,et al.  Slab detachment in continental collision zones: An analysis of controlling parameters , 1997 .

[59]  L. Ferrari,et al.  Ignimbrite flare‐up and deformation in the southern Sierra Madre Occidental, western Mexico: Implications for the late subduction history of the Farallon plate , 2002 .

[60]  Donald L. Turcotte,et al.  Geodynamics - 2nd Edition , 2002 .

[61]  M. Brudzinski,et al.  Evidence for a large-scale remnant of subducted lithosphere beneath Fiji. , 2001, Science.