Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
Collection
For ¥0.57 per day, unlimited downloads CREATE MEMBERSHIP Download

toTop

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

home > search >

Evolution of the slab bending radius and the bending dissipation in three-dimensional subduction models with a variable slab to upper mantle viscosity ratio

Author:
W.P. Schellart  


Journal:
Earth and Planetary Science Letters


Issue Date:
2009


Abstract(summary):

Three-dimensional laboratory subduction models are presented investigating the influence of the slab/upper mantle viscosity ratio (eta SP/eta UM) on the slab bending radius (R B), with eta SP/eta UM = 66-1375. Here, R B is non-dimensionalized by dividing it by the upper mantle thickness (T UM). The results show that R B/T UM varies with time, reaching a maximum when the subduction velocity is maximum. Furthermore, R B/T UM increases approximately linearly with increasing eta SP/eta UM for the investigated viscosity range. The model results show that the slab bending force (F Be) and the energy dissipation during bending (thetas Be) are small compared to the negative buoyancy force of the slab (F Bu) and the potential energy release during sinking (thetas Bu). Maxima in thetas Be/thetas Bu (apFBe/FBu) are reached in the early stage of subduction when RB/TUM is minimum and the slab tip is at 220-440 km depth. Maximum thetas Be/thetas Bu increases with increasing eta SP/eta UM, with thetas Be/thetas Bu(max) = 0.06, 0.11, 0.18 and 0.22 for eta SP/eta UM=66, 217, 709 and 1375, respectively. For subduction depths >220-440km, thetas Be/thetas Bu = 0.02-0.11 for all viscosity ratios. Assuming that in nature eta SP/eta UM<1000, and that viscous dissipation during plan view curvature of the slab is les1%, the models predict that in nature most of the slab's potential energy is used to drive mantle flow (on average 88%-97% and minimally 81%), whilst only a small component is used to bend the subducting plate at the hinge (on average 2-11% and maximally 18%). Applying the model predictions for RB/TUM and thetas Be/thetas Bu to natural subduction zones implies that in nature eta SP/eta UM = 1-7 times 10 2 and eta UM = 0.8-2.7 times 10 20Pamiddots. Finally, the laboratory models, which use glucose syrup and silicone oil as modelling materials, highlight the importance of accurate control on temperature during an experiment. New material investigations show that the viscosity of these two materials decreases exponentially with temperature in the range 3-33degC, their density decreases approximately linearly with temperature, and their coefficient of thermal volumetric expansion is 3.8-4.2 times 10 -4 C -1 (glucose syrup) and 9.2 times 10 -4 C -1 (silicone oil). [All rights reserved Elsevier].


Page:
0-319


VIEW PDF

The preview is over

If you wish to continue, please create your membership or download this.

Create Membership

Similar Literature

Submit Feedback

This function is a member function, members do not limit the number of downloads