SciVis Contest 2021: Earth’s Mantle Convection
The 2021 IEEE SciVis Contest is dedicated to creating novel approaches and state-of-the-art visualizations to assist domain scientists to better understand the convection processes in the Earth’s mantle. Contest participants will be invited to present at the special SciVis Contest session at IEEE Vis 2021 on October 23 - 28, 2021 1. The contest is sponsored by IEEE Vis and Compute Canada.
Figure 1: Temperature and velocity over the first 200 Myrs of the simulation. Click here to watch this video directly on Vimeo.
Mid-mantle stagnation of sinking slabs is prevalent globally in seismic tomographic images. However, the existence of such high velocity anomalies at different depths in the lower mantle is not fully explained.
One possibility is that the iron spin transition (theoretically predicted by Fyfe in 1960) in the lower-mantle minerals can influence their density, thermal conductivity, thermal expansivity and bulk modulus (resistance to compression). The most abundant lower-mantle materials are aluminous silicate perovskite Al-(Mg,Fe)SiO3 and ferropericlase (Mg,Fe)O, with the respective volumetric contributions of ~62% and ~33%. Both theoretical and experimental studies in the past two decades reveal that in these two minerals iron undergoes a transition from high spin in the mid-mantle to low spin at the bottom of the mantle.
Numerical studies suggest that the overall impact of the changes in the properties of ferropericlase and perovskite can be such that a descending cold slab approaching the mid-mantle at ~1600 km depth gains positive buoyancy (decrease in density) that can slow the slab’s descent rate or cause its stagnation. A stagnated slab may eventually penetrate into the lower mantle (where it gains negative buoyancy) in the form of a sudden spin-transition induced mid-mantle avalanche (SIMMA). On the other hand, the rising hot plumes from the core-mantle boundary that are slightly lighter due to the spin-transition effects in the lower mantle become slightly heavier at the mid-mantle depths. This in turn may slow the plumes or cause their stagnation at ~1600 km depth. Stagnated plumes may merge together and eventually reach the upper levels of the lower mantle as superplumes.
- M. H. Shahnas, W. R. Peltier, Z. Wu, R. Wentzcovitch (2011): The high pressure electronic spin transition in iron: potential impacts upon mantle mixing. J. geophys. Res. 116, B08205
- M. H. Shahnas, R. N. Pysklywec, and D. A. Yuen (2016): Spawning superplumes from the mid-mantle: the impact of spin transitions in the mantle. Geochemistry, Geophysics, Geosystems 17, 4051-4063
- M. H. Shahnas, D. A. Yuen, R. N. Pysklywec (2017): Mid-mantle heterogeneities and iron spin transition in the lower mantle: Implications for mid-mantle slab stagnation. Earth and Planetary Science Letters 458, 293–304
IEEE Vis 2021 will take place either in New Orleans, Louisiana, USA or virtually (online as in 2020), depending on the developing pandemic situation. ↩︎