Tidally-induced melting events as the origin of south-pole activity on Enceladus

Běhounková, M.; Tobie, G.; Choblet, G.; Čadek, O.

doi:10.1016/j.icarus.2012.03.024

Cited by 70 publications

(104 citation statements)

References 41 publications

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“…Using 3D simulations of thermal convection and tidal dissipation, we showed in our previous study (Běhounková et al, 2012) that periods with enhanced eccentricity can lead to tidallyinduced melting events in the ice shell, potentially resulting in enhanced surface activities. However, we showed that such enhanced activity periods associated with thermal convection and internal melting should be brief ($1-10 Myr) followed by relatively long periods of inactivity ($100 Myr) during which the cessation of thermal convection is likely.…”

Section: Introductionmentioning

confidence: 98%

“…The abnormal endogenic power is most likely the consequence of strong tidal dissipation along the ridges and within the ice shell (Nimmo et al, 2007;Tobie et al, 2008). However, as tidal friction should result in a rapid damping of the orbital eccentricity, maintaining a highly dissipative state on geological timescales is challenging (Meyer and Wisdom, 2007;Zhang and Nimmo, 2009;Běhounková et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, for the present-day value of eccentricity, the power generated by tidal friction in the ice shell is modeled to be much smaller than heat loss by thermal convection (Roberts and Nimmo, 2008;Běhounková et al, 2012), suggesting that Enceladus may have experienced a recent period of enhanced eccentricity and dissipation. Using 3D simulations of thermal convection and tidal dissipation, we showed in our previous study (Běhounková et al, 2012) that periods with enhanced eccentricity can lead to tidallyinduced melting events in the ice shell, potentially resulting in enhanced surface activities.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, our goal is to understand how tidal heating, especially during periods of elevated eccentricity, may influence the onset of convection. To answer this question, we performed 3D simulations of thermal convection including a self-consistent computation of tidal dissipation using the code ANTIGONE previously described in Běhounková et al (2010Běhounková et al ( , 2012. To better simulate the mechanical properties of the ice shell, we considered a composite non-Newtonian rheology including three creep mechanisms following Durham et al (2001) and Goldsby and Kohlstedt (2001), and we defined an effective tidal viscosity reproducing the dissipation function of the Andrade model (Castillo-Rogez et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…To better simulate the mechanical properties of the ice shell, we considered a composite non-Newtonian rheology including three creep mechanisms following Durham et al (2001) and Goldsby and Kohlstedt (2001), and we defined an effective tidal viscosity reproducing the dissipation function of the Andrade model (Castillo-Rogez et al, 2011). Section 2 provides a brief description of the numerical model and describes the new implementation in addition to Běhounková et al (2012). The onset of convection in a heterogeneously heated shell is discussed in Section 3.…”

Section: Introductionmentioning

confidence: 99%

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Impact of tidal heating on the onset of convection in Enceladus’s ice shell

Běhounková

Tobie

Choblet

et al. 2013

Icarus

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impact of tidal heating on the onset of convection in Enceladus’s ice shell

Běhounková

Tobie

Choblet

et al. 2013

Icarus

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The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux

Showman

Han

Hubbard

2013

Geophysical Research Letters

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[1] Enceladus exhibits a strong tectonic contrast between its south polar terrain (SPT), which is young and geologically active, and its northern hemisphere, which is relatively ancient and stable. Previous global three-dimensional (3-D) spherical models of convection exhibit patterns that are symmetrical around the equator and fail to explain the formation of a hemispheric dichotomy. Here we present global 3-D spherical models of convection in Enceladus' ice shell to show that convection in Enceladus' ice shell with plasticity and irregular core geometry can self-consistently generate a hemispheric dichotomy in tectonics and heat flux. With a spherical core, convection produces global overturning, which cannot explain the regional confinement of Enceladus' current tectonic activity to the SPT. Models with appropriate nonspherical core geometry and plasticity tend to produce overturning confined to the SPT or regional overturning in different regions at different times, which can explain the tectonic dichotomy and local age differences on Enceladus. Our models predict heat flows up to 5-10 gigawattts (GW) during active episodes, consistent with Cassini observations. Citation: Showman, A. P., L. Han, and W. B. Hubbard (2013), The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux, Geophys. Res. Lett., 40,[5610][5611][5612][5613][5614]

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Self‐consistent generation of single‐plume state for Enceladus using non‐Newtonian rheology

et al. 2014

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The thermal dichotomy of Enceladus suggests an asymmetrical structure in its global heat transfer. So far, most of the models proposed that obtained such a distribution have prescribed an a priori asymmetry, i.e., some anomaly in or below the south polar ice shell. We present here the first set of numerical models of convection that yield a stable single-plume state for Enceladus without prescribed mechanical asymmetry. Using the convection code StagYY in a 2-D spherical annulus geometry, we show that a non-Newtonian ice rheology is sufficient to create a localized, single hot plume surrounded by a conductive ice mantle. We obtain a self-sustained state in which a region of small angular extent has a sufficiently low viscosity to allow subcritical to weak convection to occur due to the stress-dependent part of the rheological law. We find that the single-plume state is very unlikely to remain stable if the rheology is Newtonian, confirming what has been found by previous studies. In a second set of numerical simulations, we also investigate the first-order effect of tidal heating on the stability of the single-plume state. Tidal heating reinforces the stability of the single-plume state if it is generated in the plume itself. Lastly, we show that the likelihood of a stable single-plume state does not depend on the thickness of the ice shell.

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Tidally-induced melting events as the origin of south-pole activity on Enceladus

Cited by 70 publications

References 41 publications

Impact of tidal heating on the onset of convection in Enceladus’s ice shell

Impact of tidal heating on the onset of convection in Enceladus’s ice shell

The effect of an asymmetric core on convection in Enceladus' ice shell: Implications for south polar tectonics and heat flux

Self‐consistent generation of single‐plume state for Enceladus using non‐Newtonian rheology

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