EGU2020-704
https://doi.org/10.5194/egusphere-egu2020-704
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Understanding deformation of cratons in presence of mid-lithospheric discontinuity

Jyotirmoy Paul and Attreyee Ghosh
Jyotirmoy Paul and Attreyee Ghosh
  • Indian Institute of Science, Centre for Earth Sciences, Bangalore, India (jyotirmoyp@iisc.ac.in)

The recent discovery of mid-lithospheric discontinuity (MLD) within most cratons has added a new dimension in the understanding of cratonic survival. The MLD shows up as a seismic discontinuity at ~80-160 km depth. However, there is controversy regarding the strength of this layer. While some studies suggest that this layer is as strong as the craton itself, others advocate that under some special conditions (e.g. metasomatism) MLD can become weak and aid in the delamination of cratons. In this study, we develop 3-D full spherical mantle convection models to understand the effect of MLD in the survival of cratons. In our models, we incorporate MLDs of variable strength, depth and thickness. Along with varying the strength of MLDs, we use different combinations of craton and asthenosphere viscosity to quantitatively estimate how deformation pattern varies. Results obtained from the models suggest that in the presence of a weak MLD stress magnitudes decrease but strain-rates increase  ~2-3 times. This could potentially lead to delamination of cratons. To constrain the present-day strength of MLDs, we predict deviatoric stresses from these different models and compare them to the observed SHmax directions obtained from the World Stress Map. The deviatoric stress pattern changes as the viscosity, depth and thickness of MLD changes.

How to cite: Paul, J. and Ghosh, A.: Understanding deformation of cratons in presence of mid-lithospheric discontinuity , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-704, https://doi.org/10.5194/egusphere-egu2020-704, 2019

Display materials

Display file

Comments on the display material

AC: Author Comment | CC: Community Comment | Report abuse

Display material version 2 – uploaded on 03 May 2020, no comments
One type error is corrected. In slide 5, "SMEAN 2" is replaced by "SMEAN2".
Display material version 1 – uploaded on 01 May 2020, no comments