Unstable extension of Enceladus' lithosphere

Michael T. Bland, Ross A. Beyer, Adam Showman

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Regions near Enceladus' equator, Sarandib and Diyar Planitia, contain extensive sets of parallel ridges and troughs that may be diagnostic of the region's formation conditions. We present photoclinometry profiles across these ridges and troughs, which indicate that they are periodic, low-slope features with dominant wavelengths of 3 to 4 km and amplitudes between 100 and 400 m. The morphology of these terrains is consistent with formation via unstable extension of the lithosphere. Our numerical modeling demonstrates that unstable extension can generate large-scale topography under Enceladus-like conditions. Comparison of our photoclinometry profiles with the dominant wavelengths produced by our numerical model permits estimation of the background heat flow at the time the Sarandib-Diyar province formed. We estimate heat flows of 110 to 220 mW m-2, suggesting that resurfacing of the planitiae was accompanied by strong, localized heating. The extension necessary to produce the ridges and troughs may have been caused by now-inactive diapirs, internal phase changes, or other mechanisms. Our heat flux estimates imply elastic thickness at the time of resurfacing of 0.4 to 1.4 km, which are sufficient to have allowed satellite reorientation if the province was underlain by a low-density region. It is therefore plausible that Enceladus has experienced multiple heating events, each leading to localized resurfacing and global reorientation.

Original languageEnglish (US)
Pages (from-to)92-105
Number of pages14
JournalIcarus
Volume192
Issue number1
DOIs
StatePublished - Dec 1 2007

Fingerprint

Enceladus
troughs
lithosphere
ridges
trough
photogrammetry
heat transmission
heat flow
retraining
heating
wavelength
equators
estimates
profiles
wavelengths
heat flux
topography
slopes
modeling
province

Keywords

  • Enceladus
  • Satellites
  • surfaces
  • Tectonics

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Unstable extension of Enceladus' lithosphere. / Bland, Michael T.; Beyer, Ross A.; Showman, Adam.

In: Icarus, Vol. 192, No. 1, 01.12.2007, p. 92-105.

Research output: Contribution to journalArticle

Bland, Michael T. ; Beyer, Ross A. ; Showman, Adam. / Unstable extension of Enceladus' lithosphere. In: Icarus. 2007 ; Vol. 192, No. 1. pp. 92-105.
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