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AGU: Geophysical Research Letters

 

Keywords

  • Enceladus
  • heat flow
  • Cassini

Index Terms

  • Planetary Sciences: Solar System Objects: Saturnian satellites
  • Planetary Sciences: Solid Surface Planets: Heat flow
  • Planetary Sciences: Solid Surface Planets: Tectonics
  • Planetary Sciences: Solid Surface Planets: Ices

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L24204, 5 PP., 2008
doi:10.1029/2008GL036149

Enceladus: An estimate of heat flux and lithospheric thickness from flexurally supported topography

Bernd Giese

Institute of Planetary Research, DLR, Berlin, Germany

Roland Wagner

Institute of Planetary Research, DLR, Berlin, Germany

Hauke Hussmann

Institute of Planetary Research, DLR, Berlin, Germany

Gerhard Neukum

Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany

Jason Perry

Department of Planetary Sciences, University of Arizona, Tucson, Arizona, USA

Paul Helfenstein

Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, USA

Peter C. Thomas

Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, USA

We have identified flexural uplift along a rift zone of the Harran Sulci, Enceladus, using Cassini images and stereo-derived topography. On the assumption that the upraised topography is related to a flexed elastic plate, shape modeling yields an effective lithospheric thickness of 0.3 km and, combined with the strength envelope, a mechanical lithospheric thickness of 2.5 km with heat fluxes of 200–270 mW/m2 at the time of formation. The heat fluxes are comparable to average heat flux values measured in Enceladus' active south polar region, and they are consistent with estimates derived via models of unstable extension of the lithosphere at this location. Surface porosity can reduce the obtained heat fluxes to an estimated minimum of 45–60 mW/m2. Crater-size frequency counts fix the time of formation (from present-day) of the rift zone at either 3.5−0.4 +0.1 Ga (assuming an asteroid-type impact chronology) or 0.45−0.3 +1.1 Ga (assuming a comet-type impact chronology).

Received 26 September 2008; accepted 14 November 2008; published 30 December 2008.

Citation: Giese, B., R. Wagner, H. Hussmann, G. Neukum, J. Perry, P. Helfenstein, and P. C. Thomas (2008), Enceladus: An estimate of heat flux and lithospheric thickness from flexurally supported topography, Geophys. Res. Lett., 35, L24204, doi:10.1029/2008GL036149.

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