Spatial distribution of ice blocks on Enceladus and implications for their origin and emplacement

Martens, H. R.; Ingersoll, Andrew P.; Ewald, S. P.; Helfenstein, P.; Giese, B.

doi:10.1016/j.icarus.2014.09.035

Cited by 22 publications

(30 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is thus plausible that the pinnacles formed due to sublimation-aided erosion from a formerly or intermittently active adjacent geyser, but not from a geyser along Baghdad Sulcus, which is more than a kilometer away. We concur with the suggestion of Martens et al (2015) that sublimation does not likely act alone to sculpt features like the pinnacle ridges. Rather, some combination of sublimation and ablation may be at work, or sublimation may preferentially erode cracks so that material to mobilize mass wasting processes.…”

Section: Sublimation-aided Erosionsupporting

confidence: 91%

“…Martens et al (2015) proposed that sublimation as a possible mechanism for disaggregating and eroding ice blocks along ubiquitous small cracks and seams that dissect heavily fractured exposures of solid ice (Porco et al 2006). Goguen et al (2013) showed through thermal modeling that sublimation should be an effective agent for ablating and widening the opening through which geysers erupt.…”

Section: Sublimation-aided Erosionmentioning

confidence: 99%

See 1 more Smart Citation

Enceladus’ Geysers: Relation to Geological Features

Helfenstein

Porco

2015

Self Cite

View full text Add to dashboard Cite

We apply histogram analysis, photogeological methods, and tidal stress modeling to Porco et al.ʼs survey of 101 Enceladus South Polar Basin geysers and their three-dimensional orientations to test if the jet azimuths are influenced by their placement relative to surface morphology and tectonic structures. Geysers emplaced along the three most active tiger stripe fractures (Damascus Sulcus, Baghdad Sulcus, and Cairo Sulcus) occur in local groupings with relatively uniform nearest-neighbor separation distances (∼5 km). Their placement may be controlled by uniformly spaced en echelon Riedel-type shear cracks originating from left-lateral strike-slip fault motion inferred to occur along tiger stripes. The spacing would imply a lithosphere thickness of ∼5 km in the vicinity of the tiger stripes. The orientations of tilted geyser jets are not randomly distributed; rather their azimuths correlate with the directions either of tiger stripes, cross-cutting fractures, or else fine-scale local tectonic fabrics. Diurnal tidal stress modeling suggests that periodic changes of plume activity are significantly affected by crosscutting fractures that open and close at different times than the tiger stripes that they intersect. We find evidence of sub-kilometer scale morphological modification of surface geological features surrounding geysers from sublimation-aided erosion, and ablation, and scouring. We propose that the simultaneous crushing and shearing action of periodic transpressional tidal stress on ice condensing on the inside walls of geyser conduits is the mechanism that extrudes the peculiar, paired narrow ridges known as "shark fins" that flank the medial tiger stripe fissures. We present a gallery of high-resolution image mosaics showing the placement of all the jets in their source region and consequently their geological context.

show abstract

Section: Sublimation-aided Erosionsupporting

confidence: 91%

Section: Sublimation-aided Erosionmentioning

confidence: 99%

Enceladus’ Geysers: Relation to Geological Features

Helfenstein

Porco

2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Boulders of 20-50 m in size are composed of coarse-grained ($100 mm) ice crystals (mostly pure-water ice) and are littered along the TSF trough floors (Porco et al, 2006;Spencer et al, 2009;Martens et al, 2015). High thermal emission is concentrated along narrow zones (probably <10 m) within the TSF, expressed by high ($180-200 K) surface temperatures (Spencer et al, 2009Goguen et al, 2013;Porco et al, 2014), which contrasts the average surface temperatures below 100 K in regions between tigerstripe fractures (Spencer et al, 2009) and at 50-80 K outside the SPT (Howett et al, 2010).…”

Section: Regional Geologic Settingmentioning

confidence: 99%

Gravitational spreading, bookshelf faulting, and tectonic evolution of the South Polar Terrain of Saturn’s moon Enceladus

Yin

Pappalardo

2015

Icarus

View full text Add to dashboard Cite

“…Importantly, frictional failure tends to relax ambient tectonic stresses [ Martens et al ., ; Sleep , ]. The process is qualitatively simple.…”

Section: Introductionmentioning

confidence: 99%

“…The heat flow is elevated in this region [e.g., O'Neill and Nimmo , ]. The discussion of this paper is applicable to folding and thrusting that occur on the periphery of the South Polar Terrain [ Barr and Preuss , ], to pervasively fracturing of the surface over much of the South Polar Terrain into ice‐block terrain [ Martens et al ., ], and to the dynamics of the whole icy shell.…”

Section: Introductionmentioning

confidence: 99%

Long‐term deformation driven by small ambient tectonic stresses and strong oscillating tidal within Enceladus with analogy to rock behavior near the San Andreas Fault

Sleep

2015

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Strong tidal stresses brought much of the icy shell of Enceladus into frictional failure at past times of high orbital eccentricity. The frictional behavior of shallow terrestrial rock exposed to repeated episodes of strong seismic waves provides analogy. Frictional failure produces cracks that lower the shear modulus. Seismic regolith develops where the shear modulus increases linearly with depth. Imposed peak strains barely cause frictional failure within self-organized regolith. With regard to Enceladus, eccentricity could continue to build up in the past since little anelastic strain, and hence tidal dissipation occurred within the self-organized regolith and within the underlying cold ice. A frictional instability analogous to the formation of weak major faults on the Earth likely occurred once the regolith was many kilometers thick. The effective coefficient of friction dropped to low levels along major faults within the deep cold ice. Tidal dissipation on these faults heated the ice starting thermal convention within the South Polar Terrain. Once thermal buoyancy produced stresses, the oscillating stresses from tides nonlinearly enhanced the rate of tectonic convection. Warm ice that dissipates tides now exists within Enceladus. The eccentricity will likely decrease and the object will then freeze.

show abstract

Spatial distribution of ice blocks on Enceladus and implications for their origin and emplacement

Cited by 22 publications

References 51 publications

Enceladus’ Geysers: Relation to Geological Features

Enceladus’ Geysers: Relation to Geological Features

Gravitational spreading, bookshelf faulting, and tectonic evolution of the South Polar Terrain of Saturn’s moon Enceladus

Long‐term deformation driven by small ambient tectonic stresses and strong oscillating tidal within Enceladus with analogy to rock behavior near the San Andreas Fault

Contact Info

Product

Resources

About