Abstract
The tectonic patterns and stress history of Europa are exceedingly complex1 and many large-scale features remain unexplained. True polar wander, involving reorientation of Europa’s floating outer ice shell about the tidal axis with Jupiter, has been proposed2 as a possible explanation for some of the features. This mechanism is possible if the icy shell is latitudinally variable in thickness and decoupled from the rocky interior. It would impose high stress levels on the shell, leading to predictable fracture patterns3. No satisfactory match to global-scale features has hitherto been found for polar wander stress patterns3. Here we describe broad arcuate troughs and depressions on Europa that do not fit other proposed stress mechanisms in their current position. Using imaging from three spacecraft, we have mapped two global-scale organized concentric antipodal sets of arcuate troughs up to hundreds of kilometres long and 300 m to ∼1.5 km deep. An excellent match to these features is found with stresses caused by an episode of ∼80° true polar wander. These depressions also appear to be geographically related to other large-scale bright and dark lineaments4,5, suggesting that many of Europa’s tectonic patterns may also be related to true polar wander.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Greeley, R. et al. in Jupiter (eds Bagenal, F., Dowling, T. & McKinnon, W.) 329–362 (Cambridge Univ. Press, Cambridge, UK, 2004)
Ojakangas, G. & Stevenson, D. Polar wander of an ice shell on Europa. Icarus 81, 242–270 (1989)
Leith, A. & McKinnon, W. Is there evidence for polar wander on Europa? Icarus 120, 387–398 (1996)
Prockter, L., Pappalardo, R. & Head, J. Strike-slip duplexing on Jupiter’s icy moon Europa. J. Geophys. Res. 105, 9483–9488 (2000)
Schenk, P. & McKinnon, W. Fault offsets and lateral crustal movement on Europa: Evidence for a mobile ice shell. Icarus 79, 75–100 (1989)
Schenk, P. & McKinnon, W. Ring geometry on Ganymede and Callisto. Icarus 72, 209–234 (1987)
Grundy, W. et al. New Horizons mapping of Europa and Ganymede. Science 318, 234–238 (2007)
Schenk, P. & McKinnon, W. Topographic variability on Europa from Galileo stereo images. Lunar Planet. Sci. Conf. 32, abstr. 2078 (2001)
Figueredo, P. & Greeley, R. Geologic mapping of the northern leading hemisphere of Europa from Galileo solid-state imaging data. J. Geophys. Res. 105, 22629–22646 (2000)
Prockter, L. & Schenk, P. Origin and evolution of Castalia Macula, an anomalous young depression on Europa. Icarus 177, 305–326 (2005)
Figueredo, P. & Greeley, R. Resurfacing history of Europa from pole-to-pole geologic mapping. Icarus 167, 287–312 (2004)
Schenk, P. Crop circles of Europa. Lunar Planet. Sci. Conf. 30, abstr. 2081 (2005)
Greenberg, R. The evil twin of Agenor: Tectonic convergence on Europa. Icarus 167, 313–319 (2004)
Nimmo, F. Stresses generated in cooling viscoelastic ice shells: Application to Europa. J. Geophys. Res. 109 E12001 10.1029/2004JE002347 (2004)
Greenberg, R. et al. Tectonic processes on Europa: Tidal stresses, mechanical response, and visible features. Icarus 135, 64–78 (1998)
Melosh, H. J. Global tectonics of a despun planet. Icarus 31, 221–243 (1977)
Greenberg, R. & Weidenschilling, S. How fast do Galilean satellites spin? Icarus 58, 186–196 (1984)
Hoppa, G., Tufts, B. R., Greenberg, R. & Geissler, P. Formation of cycloidal features on Europa. Science 285, 1899–1902 (1999)
Geissler, P. et al. Evidence for non-synchronous rotation of Europa. Nature 391, 368–370 (1998)
Matsuyama, I. & Nimmo, F. Tectonic patterns of a reoriented and despun planetary bodies. Icarus 10.1016/j.icarus.2007.12.003 (in the press)
Melosh, H. J. Tectonic patterns on a reoriented planet — Mars. Icarus 44, 745–751 (1980)
Sarid, M. et al. Polar wander and surface convergence of Europa’s ice shell: Evidence from a survey of strike-slip displacement. Icarus 158, 24–41 (2002)
Matsuyama, I. & Nimmo, F. Rotational stability of tidally deformed planetary bodies. J. Geophys. Res. 112 E11003 10.1029/2007JE002942 (2007)
Stevenson, D. Limits on the variation of thickness of Europa’s ice shell. Lunar Planet. Sci. Conf. 31, abstr. 1506 (2000)
Matsuyama, I., Nimmo, F. & Mitrovica, J. Reorientation of planets with lithospheres: The effect of elastic energy. Icarus 191, 401–412 (2007)
Willemann, R. Reorientation of planets with elastic lithospheres. Icarus 60, 701–709 (1984)
Matsuyama, I., Mitrovica, J., Manga, M., Perron, J. & Richards, M. Rotational stability of dynamic planets with elastic lithospheres. J. Geophys. Res. 111 E02003 doi: 10.1029/2005JE002447 (2006)
Nimmo, F. & Pappalardo, R. Diapir-induced reorientation of Saturn’s moon Enceladus. Nature 441, 614–616 (2006)
Janes, D. M. & Melosh, H. J. Sinker tectonics — an approach to the surface of Miranda. J. Geophys. Res. 93, 3127–3143 (1988)
Acknowledgements
This work was supported in part by the NASA Outer Planets Research and Planetary Geology and Geophysics programmes. LPI contribution no. 1399.
Author Contributions Global mapping and topographic analyses were conducted by P.S.; P.S. and F.N. conducted preliminary examination of alternative models; numerical modelling of stress patterns was conducted by I.M.; and P.S wrote the paper, with contributions from I.M. and F.N.
Author information
Authors and Affiliations
Corresponding author
Supplementary information
Supplementary information
The file contains Supplementary Figures 1-4 with Legends. (PDF 3391 kb)
Rights and permissions
About this article
Cite this article
Schenk, P., Matsuyama, I. & Nimmo, F. True polar wander on Europa from global-scale small-circle depressions. Nature 453, 368–371 (2008). https://doi.org/10.1038/nature06911
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature06911
This article is cited by
-
Planned Geological Investigations of the Europa Clipper Mission
Space Science Reviews (2024)
-
True polar wander in the Earth system
Science China Earth Sciences (2023)
-
A Late Cretaceous true polar wander oscillation
Nature Communications (2021)
-
A magnetically driven equatorial jet in Europa’s ocean
Nature Astronomy (2019)
-
Formation of metre-scale bladed roughness on Europa’s surface by ablation of ice
Nature Geoscience (2018)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.