Polar wander and surface convergence of Europa's ice shell: Evidence from a survey of strike-slip displacement

Alyssa Rose Sarid, Richard J. Greenberg, Gregory V. Hoppa, Terry A. Hurford, B. R. Tufts, Paul Geissler

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Two global issues regarding Europa are addressed by a survey of strike-slip faults. First, a common type of terrain that appears to represent convergent sites of surface removal, which may help compensate for substantial widespread dilation along tectonic bands elsewhere, thus helping resolve the problem of conserving global surface area, is identified. Second, evidence for polar wander may provide the first confirmation of that theoretically predicted phenomenon. These results, among others, come from an extensive survey of strike-slip faults over the portion of the surface where Galileo images at 200-m/pixel resolution were obtained for regional mapping purposes. The images cover two broad swaths that run from the far north to the far south, one in the leading hemisphere and the other in the trailing hemisphere. Among the faults that have been mapped are a fault 170 km long with a strike-slip offset of 83 km, the greatest yet identified on Europa, and a quasi-circular strike-slip fault that surrounds a 500-km-wide plate, which has undergone rotation as a rigid unit. Reconstruction of specific examples of strike slip reveals sites of lateral convergence. Because Europa is unique in many ways, these sites are not similar to compression features on other bodies, which may explain why they had previously been difficult to identify. The distribution of strike slip in both hemispheres, when compared with predictions of the theory of tidal walking, provides evidence for polar wander: The crust of Europa appears to have slid as a single unit relative to the spin axis, such that the site on the crust that was previously at the north rotational pole has wandered, probably during the last few million years, to a location currently in the leading hemisphere, about 30° away from the spin axis. Such polar wander probably also explains symmetry patterns in the distribution of chaotic terrain, pits, and uplift features.

Original languageEnglish (US)
Pages (from-to)24-41
Number of pages18
JournalIcarus
Volume158
Issue number1
DOIs
StatePublished - Jul 2002

Fingerprint

Europa
ice
slip
strike-slip fault
shell
hemispheres
crust
crusts
dilation
walking
symmetry
pixel
surface area
uplift
compression
tectonics
poles
prediction
pixels
predictions

Keywords

  • Europa
  • Geological processes
  • Ices

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Polar wander and surface convergence of Europa's ice shell : Evidence from a survey of strike-slip displacement. / Sarid, Alyssa Rose; Greenberg, Richard J.; Hoppa, Gregory V.; Hurford, Terry A.; Tufts, B. R.; Geissler, Paul.

In: Icarus, Vol. 158, No. 1, 07.2002, p. 24-41.

Research output: Contribution to journalArticle

Sarid, Alyssa Rose ; Greenberg, Richard J. ; Hoppa, Gregory V. ; Hurford, Terry A. ; Tufts, B. R. ; Geissler, Paul. / Polar wander and surface convergence of Europa's ice shell : Evidence from a survey of strike-slip displacement. In: Icarus. 2002 ; Vol. 158, No. 1. pp. 24-41.
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