Resorption process in Astypalaea Linea extensive region (Europa)

Mével, Loı̈c; Mercier, Éric

doi:10.1016/j.pss.2004.12.005

Cited by 8 publications

(13 citation statements)

References 26 publications

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“…However, Voyager and more recently Galileo's images reveal a surface widely disturbed by "geological" features (Lucchitta and Soderblom, 1982;Greeley et al, 2000;Figueredo and Greeley, 2000). These observations suggest that processes have driven movements in the icy crust in the past and possibly recently and have refreshed the surface 1999;Mével and Mercier, 2005). This last point is supported by the lack of impact craters compared to Ganymede and Callisto implying a young mean surface age ranging from 30 to 70 Myr (Zahnle et al, 2003).…”

Section: Introductionmentioning

confidence: 93%

Large-scale doming on Europa: A model of formation of Thera Macula

Mével

Mercier

2007

Planetary and Space Science

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To cite this version:Loïc Mével, Eric Mercier. Large-scale doming on Europa: A model of formation of Thera Macula.. Planetary and Space Science, Elsevier, 2007, pp.915-927 AbstractSince Galileo spacecraft reveals Europa's surface at high and medium resolution, deformation and processes affecting the relatively young surface have been more accurately defined. This work reports the observations carried out on a large-scale feature of the south hemisphere, Thera Macula. It is shown that Thera presents common points with many other features including small-scale domes, lenticulae and large-scale chaotic area (disrupted ancient surfaces lying on a dark matrix), but remains singular through its asymmetric morphology. On the basis of observations, we propose a scenario for the setting of Thera Macula. It involves a large-scale doming (40-70 km in radius) of the pre-existing surface associated to ductile deformations, and the consecutive collapse of the created megadome associated to brittle disruption of blocks and flow of low viscosity material over the surrounding ridged plains. The processes responsible for each stage of the proposed scenario have been investigated. Both cryomagmatic and diapiric origins are discussed and confronted to observations. Finally, comparison of similar features at various scales suggests that Thera Macula by its originalities (asymmetry, rounding bulge) may have preserved the intermediate stages of the formation of subcircular chaos at least up to about 50 km in radius. A common evolution and endogenic origin for multi-scale hot spot features is proposed: 1) the doming stage, 2) the collapse and extrusion stage, and 3) the relaxation stage.

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Section: Introductionmentioning

confidence: 93%

Large-scale doming on Europa: A model of formation of Thera Macula

Mével

Mercier

2007

Planetary and Space Science

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“…For a viscosity contrast in the range

1 0^{2}

–

1 0^{4}

, sluggish‐convection operates and produces a relatively fast resurfacing. While ongoing global‐scale surface mobility is reported in the case of Europa (Howell & Pappalardo, ; Kattenhorn & Prockter, ; Mével & Mercier, ), it has been argued that convective processes might not be responsible for this mobility (Howell & Pappalardo, ). Sluggish‐lid regime is therefore probably not pertinent for ice shells.…”

Section: Ice Layer As a Tidally Heated Convective Systemmentioning

confidence: 99%

Tidally Heated Convection and the Occurrence of Melting in Icy Satellites: Application to Europa

et al. 2020

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Observations of icy satellites have revealed widespread marks of cryovolcanism. Because aqueous cryomagmas are negatively buoyant, two processes are required to explain these observations: one mechanism to generate melt close enough to the surface and another one to transport this melt to the surface. Here, we investigate the generation of melting in a systematic way, using a set of 85 numerical simulations where we vary the viscosity contrast, Rayleigh number, and tidal heating rate. Applied to Europa, considering a hydrosphere composed of pure water, our simulations suggest that isolated melt pockets can be generated close to the surface ( ∼5 km) as long as the ice layer thickness ( d*) remains modest ( 15≤d*≤35 km). However, the generation of melting becomes increasingly difficult as the amount of antifreeze compounds in the subsurface ocean increases. Furthermore, the proportion of melting increases very sharply with increasing tidal heating rate. In particular, when the tidal heating rate exceeds a threshold, an asymptotic regime is reached where the surface heat flux remains constant indicating that the tidal heat generated above this threshold is only used for melting the ice shell. In that regime, we found a direct relationship between the surface heat flux and d*. Finally, we provide a new assessment of Europa's thermal state. Based on available constraints, we propose that the ice shell thickness should exceed 15 km. However, d*∼15–35 km implies a tidal power ( >2 TW) much larger than expected. An extrapolation of the trends suggested by our results indicates that a more reasonable tidal power ( ∼1 TW) would involve d*∼50–90 km.

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“…Several mechanisms have been proposed for the accommodation of contractional strain on Europa. In some locations, tectonic reconstructions of Europa's surface (i.e., realigning regions that have undergone lateral offset and/ or spreading) suggest regions of ''missing'' surface material (e.g., Sarid et al, 2002;Mével and Mercier, 2005). These missing regions, dubbed ''convergence bands,'' imply a loss of crustal material during surface contraction.…”

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confidence: 99%

“…These missing regions, dubbed ''convergence bands,'' imply a loss of crustal material during surface contraction. The strain accommodated in these convergence bands may be large; e.g., Mével and Mercier (2005) suggest the accommodation of $10% contraction. and Greenberg (2004) have also suggested that dilational bands themselves may act as zones of weakness that can accommodate contraction (as much as 75% at Corick Linea (Greenberg, 2004;Kattenhorn and Hurford, 2009)) if the local stress regime changes from tensile to compressional.…”

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confidence: 99%