Inevitability of Plate Tectonics on Super-Earths

Valencia, Diana; O’Connell, Richard J.; Sasselov, Dimitar

doi:10.1086/524012

Cited by 255 publications

(197 citation statements)

References 27 publications

(22 reference statements)

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“…It is nonetheless worthwhile considering because it does not require plate tectonics; a carbon dioxide source and the existence of some sort of hydrothermal activity in basalt, which is a widespread rock type on other terrestrial planets without plate tectonics, should be sufficient. For instance, van Berk et al (2012) modelled Mg-Fe-rich carbonates in the Comanche outcrop in Gusev crater on Mars, which was analysed by the Mars Exploration Rover Spirit, and found that one possible scenario for their formation involves a waterrich environment at temperatures around 280 K and 0.5-2 bar P CO 2 , as may have prevailed during the Noachian. Alt & Teagle (1999) analysed borehole cores from various ocean drilling sites that probed young oceanic crust and observed a decrease of bound carbon with depth into the extrusive rock; most of the CO 2 is stored in the upper 600 m. They found an average content of 0.214 wt.% CO 2 in the bulk rock, while Staudigel (2014) arrived at a total carbonate uptake of 0.355 wt.% and an uptake of 0.45 wt.% of crystal-bound water.…”

Section: Influence Of Surface Processesmentioning

confidence: 99%

“…Batalha 2014), it has proven difficult to establish only on the basis of mass and radius whether plate tectonics is more or less likely to occur than on Earth. While some authors argue for a reduced tendency for plate tectonics to take place on these bodies (O'Neill & Lenardic 2007;Kite et al 2009;Stamenković et al 2012;Stein et al 2013), others favour an increased tendency (Valencia et al 2007;van Heck & Tackley 2011;O'Rourke & Korenaga 2012) or suggest that the tectonic behaviour of a rocky body can be strongly affected by the specific thermal conditions present after planetary formation and by the particular thermochemical history experienced by the interior (e.g. Noack & Breuer 2014;O'Neill et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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The habitability of a stagnant-lid Earth

Tosi

Godolt

Stracke

et al. 2017

A&A

128

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Context. Plate tectonics is considered a fundamental component for the habitability of the Earth. Yet whether it is a recurrent feature of terrestrial bodies orbiting other stars or unique to the Earth is unknown. The stagnant lid may rather be the most common tectonic expression on such bodies. Aims. To understand whether a stagnant-lid planet can be habitable, i.e. host liquid water at its surface, we model the thermal evolution of the mantle, volcanic outgassing of H 2 O and CO 2 , and resulting climate of an Earth-like planet lacking plate tectonics. Methods. We used a 1D model of parameterized convection to simulate the evolution of melt generation and the build-up of an atmosphere of H 2 O and CO 2 over 4.5 Gyr. We then employed a 1D radiative-convective atmosphere model to calculate the global mean atmospheric temperature and the boundaries of the habitable zone (HZ).Results. The evolution of the interior is characterized by the initial production of a large amount of partial melt accompanied by a rapid outgassing of H 2 O and CO 2 . The maximal partial pressure of H 2 O is limited to a few tens of bars by the high solubility of water in basaltic melts. The low solubility of CO 2 instead causes most of the carbon to be outgassed, with partial pressures that vary from 1 bar or less if reducing conditions are assumed for the mantle to 100-200 bar for oxidizing conditions. At 1 au, the obtained temperatures generally allow for liquid water on the surface nearly over the entire evolution. While the outer edge of the HZ is mostly influenced by the amount of outgassed CO 2 , the inner edge presents a more complex behaviour that is dependent on the partial pressures of both gases. Conclusions. At 1 au, the stagnant-lid planet considered would be regarded as habitable. The width of the HZ at the end of the evolution, albeit influenced by the amount of outgassed CO 2 , can vary in a non-monotonic way depending on the extent of the outgassed H 2 O reservoir. Our results suggest that stagnant-lid planets can be habitable over geological timescales and that joint modelling of interior evolution, volcanic outgassing, and accompanying climate is necessary to robustly characterize planetary habitability.

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Section: Influence Of Surface Processesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The habitability of a stagnant-lid Earth

Tosi

Godolt

Stracke

et al. 2017

A&A

128

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“…In the following, we focus on a model with a constant Λ (hence, = 0), which is often assumed [e.g., Foley and Bercovici, 2014;Foley et al, 2012;O'Rourke and Korenaga, 2012;Solomatov, 2004;Valencia et al, 2007]. To illustrate our results, we choose the parameters = 1∕3 and = 2∕3 for the scaling of the heat flux and convective velocity with Rayleigh number (equations (A2) and (A5)).…”

Section: Implications Of a Normal Stress Worldmentioning

confidence: 99%

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

2016

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We use 1‐D thermal history models and 3‐D numerical experiments to study the impact of dynamic thermal disequilibrium and large temporal variations of normal and shear stresses on the initiation of plate tectonics. Previous models that explored plate tectonics initiation from a steady state, single plate mode of convection concluded that normal stresses govern the initiation of plate tectonics, which based on our 1‐D model leads to plate yielding being more likely with increasing interior heat and planet mass for a depth‐dependent Byerlee yield stress. Using 3‐D spherical shell mantle convection models in an episodic regime allows us to explore larger temporal stress variations than can be addressed by considering plate failure from a steady state stagnant lid configuration. The episodic models show that an increase in convective mantle shear stress at the lithospheric base initiates plate failure, which leads with our 1‐D model to plate yielding being less likely with increasing interior heat and planet mass. In this out‐of‐equilibrium and strongly time‐dependent stress scenario, the onset of lithospheric overturn events cannot be explained by boundary layer thickening and normal stresses alone. Our results indicate that in order to understand the initiation of plate tectonics, one should consider the temporal variation of stresses and dynamic disequilibrium.

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“…If the increase of mean density with planet size is additionally taken into account, plate tectonics becomes more likely for all combinations, as in the studies of Valencia et al (2007) and Valencia & O'Connell (2009). These results are show in Fig.…”

Section: Scaling Of Yielding-induced Plate Tectonicsmentioning

confidence: 71%

“…Higher gravitational acceleration results in a more rapid increase of pressure with depth, implying stronger plates ) but acting in the opposite sense, a larger planet also has a higher heat flux hence thinner plates and more vigorous convection. Valencia et al (2007) and Valencia & O'Connell (2009) used parameterized models of a compressible planet to study the combination of the various factors on the likelihood of plate tectonics, finding that for plate tectonics is favored at larger planet size. van Heck & Tackley (2011) studied both numerical and parameterized models of incompressible planets, studying two possible types of yield stress function (linearly increasing with pressure and constant with pressure) and two modes of heating (basal or internal) finding that for all combinations of these, plate tectonics is either equally likely or more likely on at https:/www.cambridge.org/core/terms.…”

Section: Scaling Of Yielding-induced Plate Tectonicsmentioning

confidence: 99%

Habitable Planets: Interior Dynamics and Long-Term Evolution

et al. 2012

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Abstract.Here, the state of our knowledge regarding the interior dynamics and evolution of habitable terrestrial planets including Earth and super-Earths is reviewed, and illustrated using state-of-the-art numerical models. Convection of the rocky mantle is the key process that drives the evolution of the interior: it causes plate tectonics, controls heat loss from the metallic core (which generates the magnetic field) and drives long-term volatile cycling between the atmosphere/ocean and interior. Geoscientists have been studying the dynamics and evolution of Earth's interior since the discovery of plate tectonics in the late 1960s and on many topics our understanding is very good, yet many first-order questions remain. It is commonly thought that plate tectonics is necessary for planetary habitability because of its role in long-term volatile cycles that regulate the surface environment. Plate tectonics is the surface manifestation of convection in the 2900-km deep rocky mantle, yet exactly how plate tectonics arises is still quite uncertain; other terrestrial planets like Venus and Mars instead have a stagnant lithosphereessentially a single plate covering the entire planet. Nevertheless, simple scalings as well as more complex models indicate that plate tectonics should be easier on larger planets (super-Earths), other things being equal. The dynamics of terrestrial planets, both their surface tectonics and deep mantle dynamics, change over billions of years as a planet cools. Partial melting is a key process influencing solid planet evolution. Due to the very high pressure inside super-Earths' mantles the viscosity would normally be expected to be very high, as is also indicated by our density function theory (DFT) calculations. Feedback between internal heating, temperature and viscosity leads to a superadiabatic temperature profile and self-regulation of the mantle viscosity such that sluggish convection still occurs.

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Inevitability of Plate Tectonics on Super-Earths

Cited by 255 publications

References 27 publications

The habitability of a stagnant-lid Earth

The habitability of a stagnant-lid Earth

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

Habitable Planets: Interior Dynamics and Long-Term Evolution

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