The stability of cratons remains a unique scientific question in the geodynamics community. Stability of Archean cratons is intriguing as any other non-cratonic parts on the earth's surface undergo recycling via the planet's tectonic processes. In this study, we simulate time dependent mantle convection models to observe the deformation of cratonic blocks since the last 410 Ma. Present day cratons' locations are reconstructed back till 409 Ma using the GPlates software (Matthews et al. 2016). Additionally, GPlates provides plate velocities since 409 Ma that are introduced as boundary condition for our mantle convection models. We use CitcomS to simulate 3-D spherical whole mantle convection models, where we initiate our model runs from 409 Ma using the location of cratons at that time. The simulations are run forward in time up to the present day (0 Ma). At every 1 Ma interval, plate velocities are updated, which drive the circulation within the mantle. We introduce different viscosity structures of cratons (10-1000 times the viscosity of lithosphere) and asthenosphere (0.01-1 times the reference viscosity of upper mantle), to see how cratonic materials deform in velocity driven whole mantle convection models. In most of the cases, the cratons undergo considerable deformation. However, cratons with high viscosity (100-1000 times the viscosity of lithosphere) remain stable without significant deformation and eventually reach to present day location. Quite similar to our earlier findings, here also we see maximum deformation in the model with weakest asthenosphere (1019 Pa-s) and cratons (10 times the viscosity of lithosphere). Deformation intensity decays as the asthenosphere and cratons become stronger. Cratons, at least 100-1000 times more viscous than the lithosphere, are potentially strong enough to be stable since the Archean.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- 7205 Continental crust;
- SEISMOLOGYDE: 8103 Continental cratons;
- TECTONOPHYSICSDE: 8110 Continental tectonics: general;
- TECTONOPHYSICSDE: 8120 Dynamics of lithosphere and mantle: general;