T247 Lithospheric Structure and Evolution of Cratons

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

THE EFFECT OF MID-LITHOSPHERIC DISCONTINUITY ON THE STABILITY OF CRATON

Paper number: T247-15
Program: Technical Sessions
Time: 1:00 PM – 1:10 PM

Authors

Abstract

The long-term survival of craton has always been an important research topic of geodynamics. Although in a few cases, cratons might have been destroyed (e.g., North China craton), most of cratons remain stable through long-time plate tectonics. Recent studies found a gradient zone with significantly reduced velocity in the mantle lithosphere beneath craton, named mid-lithospheric discontinuity (MLD). Some studies suggest that MLD is a weak-coupling layer, which may accommodate some displacements between the upper and lower lithosphere. In this study, we construct 2-D numerical models to investigate the influence of the MLD’s viscosity and plate velocity on the stability of craton. The results show that the viscosity of MLD in stable craton is greater than 5´1020 Pa s. When MLD’s viscosity is less than 5´1019 Pa s, no/little craton root can survive through plate tectonics. Our results show that the mechanical properties of MLD may play a fundamental role in craton stability. Even seismic velcosities reduce in MLD, the visocisty of MLD may be still higher than 5´1020 Pa s.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-356967

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