The feedback between surface mobility and mantle compositional heterogeneity: Implications for the Earth and other terrestrial planets

Trim, S. J.; Heron, Philip J.; Stein, Claudia; Lowman, J. P.

doi:10.1016/j.epsl.2014.08.019

Cited by 21 publications

(30 citation statements)

References 62 publications

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“…Our present finding on the spatial correlation between the surface motion and chemical heterogeneity in the lowermost mantle is not in good agreement with that of the series of papers by Trim and coworkers [44,48], who indicated no clear correlation between the two. The difference of our finding from theirs is probably due to the difference in the assumed dependence of viscosity on temperature and that in the geometries of convecting vessels.…”

Section: Discussion and Concluding Remarkscontrasting

confidence: 76%

“…The difference of our finding from theirs is probably due to the difference in the assumed dependence of viscosity on temperature and that in the geometries of convecting vessels. In the works by Trim and coworkers [44,48], the viscosity is assumed to be dependent on the geotherm (horizontally-averaged temperature) and, hence, is taken to be laterally unchanged regardless of variations in local temperature. That is, the cold descending flows in their works are not likely to be so "stiff" compared to ours where the viscosity locally depends on temperature.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

“…In addition, in contrast to our use of (2D) spherical geometry, their use of 2D Cartesian geometry does not allow one to incorporate the effect of the decrease with depth in the areas of horizontal planes. Considering these two influences, the models by Trim and coworkers [44,48] are most likely underestimating the roles of cold descending flows in deforming and/or sweeping of the chemically-dense materials in the lowermost mantle. In other words, the difference between our results and those of earlier works may indicate the importance of fully-temperature-dependent viscosity and model geometries in the studies of the relation between the surface motions and the thermochemical state in the lowermost mantle.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

“…Note that ∆b is similar to the residual buoyancy used in [48] and is a measure of the convective vigor of ascending and descending plumes at given depths. The snapshot of Case 2 clearly shows that the distribution of ∆b is quite similar to that of temperature T, because the distribution of c is almost uniform in the entire mantle.…”

Section: Effects Of the Density Difference Of Chemical Heterogeneitymentioning

confidence: 99%

See 3 more Smart Citations

Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection

Kameyama

Harada

2017

Geosciences

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Abstract:In this study, we conduct numerical simulations of thermochemical mantle convection in a 2D spherical annulus with a highly viscous lid drifting along the top surface, in order to investigate the interrelation between the motion of the surface (super)continent and the behavior of chemical heterogeneities imposed in the lowermost mantle. Our calculations show that assembly and dispersal of supercontinents occur in a cyclic manner when a sufficient amount of chemically-distinct dense material resides in the base of the mantle against the convective mixing. The motion of surface continents is significantly driven by strong ascending plumes originating around the dense materials in the lowermost mantle. The hot dense materials horizontally move in response to the motion of continents at the top surface, which in turn horizontally move the ascending plumes leading to the breakup of newly-formed supercontinents. We also found that the motion of dense materials in the base of the mantle is driven toward the region beneath a newly-formed supercontinent largely by the horizontal flow induced by cold descending flows from the top surface occurring away from the (super)continent. Our findings imply that the dynamic behavior of cold descending plumes is the key to the understanding of the relationship between the supercontinent cycle on the Earth's surface and the thermochemical structures in the lowermost mantle, through modulating not only the positions of chemically-dense materials, but also the occurrence of ascending plumes around them.

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Section: Discussion and Concluding Remarkscontrasting

confidence: 76%

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Section: Effects Of the Density Difference Of Chemical Heterogeneitymentioning

confidence: 99%

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Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection

Kameyama

Harada

2017

Geosciences

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“…McNamara and Zhong, 2004;Nakagawa and Tackley, 2008;Deschamps et al, 2011;Stamenković et al, 2012;Trim et al, 2014). The community is currently divided about the existence of dense material at the base of the mantle and estimates of the lifespan, stability and origin of such material vary wildly.…”

Section: Discussionmentioning

confidence: 99%

Using pattern recognition to infer parameters governing mantle convection

Atkins

Valentine

Tackley

et al. 2016

Physics of the Earth and Planetary Interiors

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a b s t r a c tThe results of mantle convection simulations are fully determined by the input parameters and boundary conditions used. These input parameters can be for initialisation, such as initial mantle temperature, or can be constant values, such as viscosity exponents. However, knowledge of Earth-like values for many input parameters are very poorly constrained, introducing large uncertainties into the simulation of mantle flow. Convection is highly non-linear, therefore linearised inversion methods cannot be used to recover past configurations over more than very short periods of time, which makes finding both initial and constant simulation input parameters very difficult. In this paper, we demonstrate a new method for making inferences about simulation input parameters from observations of the mantle temperature field after billions of years of convection. The method is fully probabilistic. We use prior sampling to construct probability density functions for convection simulation input parameters, which are represented using neural networks. Assuming smoothness, we need relatively few samples to make inferences, making this approach much more computationally tractable than other probabilistic inversion methods. As a proof of concept, we show that our method can invert the amplitude spectra of temperature fields from 2D convection simulations, to constrain yield stress, surface reference viscosity and the initial thickness of primordial material at the CMB, for our synthetic test cases. The best constrained parameter is yield stress. The reference viscosity and initial thickness of primordial material can also be inferred reasonably well after several billion years of convection.

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Effects of Earth's rotation on the early differentiation of a terrestrial magma ocean

Maas

Hansen

2015

JGR Solid Earth

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Similar to other terrestrial planets like Moon and Mars, Earth experienced a magma ocean period about 4.5 billion years ago. On Earth differentiation processes in the magma ocean set the initial conditions for core formation and mantle evolution. During the magma ocean period Earth was rotating significantly faster than today. Further, the viscosity of the magma was low, thus that planetary rotation potentially played an important role for differentiation. However, nearly all previous studies neglect rotational effects. All in all, our results suggest that planetary rotation plays an important role for magma ocean crystallization. We employ a 3‐D numerical model to study crystal settling in a rotating and vigorously convecting early magma ocean. We show that crystal settling in a terrestrial magma ocean is crucially affected by latitude as well as by rotational strength and crystal density. Due to rotation an inhomogeneous accumulation of crystals during magma ocean solidification with a distinct crystal settling between pole and equator could occur. One could speculate that this may have potentially strong effects on the magma ocean solidification time and the early mantle composition. It could support the development of a basal magma ocean and the formation of anomalies at the core‐mantle boundary in the equatorial region, reaching back to the time of magma ocean solidification.

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The feedback between surface mobility and mantle compositional heterogeneity: Implications for the Earth and other terrestrial planets

Cited by 21 publications

References 62 publications

Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection

Supercontinent Cycle and Thermochemical Structure in the Mantle: Inference from Two-Dimensional Numerical Simulations of Mantle Convection

Using pattern recognition to infer parameters governing mantle convection

Effects of Earth's rotation on the early differentiation of a terrestrial magma ocean

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