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Table 2 Rheological parameters of rocks

From: A possible mechanism for spontaneous cyclic back-arc spreading

  Viscous flow Frictional stress*1
  Activation energy Activation volume Cohesion Effective frictional coefficient
AN EN VN c ϕ
/s/MPa kJ/mol cm3/mol MPa  
Continental upper crust 10–11 54*2 0 30 (1) 0.4 (ϕ AL)
Continental lower crust 10–7 118*3 0 30 (1) 0.4 (ϕ AL)
Oceanic crust 10–7 118*3 0 1 0.005
Mantle wedge 2 × 10–8 150 4 1 ϕ AL
Upper mantle 5 × 10–7 215*4 4 30 (1) 0.4 (ϕ AL)
Upper mantle for SP*5 5 × 10–7 215*4 4 30 (1) 0.4 (0.1)
Transition zone 5 × 10–7 215*4 4 30 (1) 0.6 (0.4)
Lower mantle 6 × 10–10 200 2.5–1.3*6 30 (1) 0.6 (0.4)
  1. *1 Values in brackets denote friction coefficient and cohesion in weakened state for strain larger than 0.5 (cweakened, ϕ weakened)
  2. *2 Dislocation creep of wet quartz (n = 4, Edis = 135 kJ/mol, Hirth et al. 2001)
  3. *3 Dislocation creep of wet plagioclase (n = 3, Edis = 235 kJ/mol, Rybacki and Dresen 2004)
  4. *4 Dislocation creep of wet olivine (n = 3, Edis = 430 kJ/mol, Karato and Wu 1993)
  5. *5 Upper mantle for subducting plate (purple in Figs. 1b and 2)
  6. *6 Linearly decrease with the depth of 660–2900 km