Articles | Volume 12, issue 2
22 Feb 2021
Research article | 22 Feb 2021
Timescales of chemical equilibrium between the convecting solid mantle and over- and underlying magma oceans
Daniela Paz Bolrão et al.
No articles found.
Antonio Manjón-Cabeza Córdoba and Maxim D. Ballmer
The origin of many volcanic archipelagos on the Earth remains uncertain. By using 3D modelling of mantle flow and melting, we investigate the interaction between the convective mantle near the continental-oceanic transition and rising hot plumes. We believe that this phenomenon is the origin behind some archipelagos, in particular the Canary Islands. Analysing our results, we reconcile observations that were previously enigmatic, such as the complex patterns of volcanism in the Canaries.
Fengping Pang, Jie Liao, Maxim Ballmer, and Lun Li
Solid Earth Discuss.,
Preprint under review for SEShort summary
Plume-ridge interaction is an intriguing geological process in plate tectonics. In this manuscript, we address the respective role of ridge suction vs plate drag in 2D thermomechanical models and compares the results with a compilation of observations on Earth. From a geophysical and geochemical analysis of Earth plumes and in combination with the model results, we propose that the absence of plumes interacting with ridges in the Pacific is largely caused by the presence of plate drag.
Anna Johanna Pia Gülcher, Maxim Dionys Ballmer, and Paul James Tackley
Solid Earth, 12, 2087–2107,Short summary
The lower mantle extends from 660–2890 km depth, making up > 50 % of the Earth’s volume. Its composition and structure, however, remain poorly understood. In this study, we investigate several hypotheses with computer simulations of mantle convection that include different materials: recycled, dense rocks and ancient, strong rocks. We propose a new integrated style of mantle convection including
streaksthat agrees with various observations of the deep Earth.
Antonio Manjón-Cabeza Córdoba and Maxim D. Ballmer
Solid Earth, 12, 613–632,Short summary
The study of intraplate volcanism can inform us about underlying mantle dynamic processes and thermal and/or compositional anomalies. Here, we investigated numerical models of mantle flow and melting of edge-driven convection (EDC), a potential origin for intraplate volcanism. Our most important conclusion is that EDC can only produce moderate amounts of mantle melting. By itself, EDC is insufficient to support the formation of voluminous island-building volcanism over several millions of years.
Patrick Sanan, Dave A. May, Matthias Bollhöfer, and Olaf Schenk
Solid Earth, 11, 2031–2045,Short summary
Mantle and lithospheric dynamics, elasticity, subsurface flow, and other fields involve solving indefinite linear systems. Tools include direct solvers (robust, easy to use, expensive) and advanced iterative solvers (complex, problem-sensitive). We show that a third option, ILDL preconditioners, requires less memory than direct solvers but is easy to use, as applied to 3D problems with parameter jumps. With included software, we hope to allow researchers to solve previously infeasible problems.
Jana Schierjott, Antoine Rozel, and Paul Tackley
Solid Earth, 11, 959–982,Short summary
We investigate the size of mineral grains of Earth's rocks in computer models of the whole Earth. This is relevant because grain size affects the stiffness (large grains are stiffer) and deformation of the Earth's mantle. We see that mineral grains grow inside stable non-deforming regions of the Earth. However, these regions are less stiff than expected. On the other hand, we find that grain size diminishes during deformation events such as when surface material comes down into the Earth.
Robert I. Petersen, Dave R. Stegman, and Paul J. Tackley
Solid Earth, 8, 339–350,Short summary
In this study we propose a dichotomy in the strength profile of tectonic plates. This apparent dichotomy suggests that plates at the Earth's surface are significantly stronger, by orders of magnitude, than the subducted slabs in the Earth's interior. Strong plates promote single-sided, Earth-like subduction. Once subducted, strong slabs transmit dynamic stresses and disrupt subduction. Slabs which are weakened do not disrupt subduction and furthermore exhibit a variety of observed morphologies.
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We use numerical models to investigate the thermo-chemical evolution of a solid mantle during a magma ocean stage. When applied to the Earth, our study shows that the solid mantle and a magma ocean tend toward chemical equilibration before crystallisation of this magma ocean. Our findings suggest that a very strong chemical stratification of the solid mantle is unlikely to occur (as predicted by previous studies), which may explain why the Earth’s mantle is rather homogeneous in composition.
We use numerical models to investigate the thermo-chemical evolution of a solid mantle during a...