Mathematics – Logic
Scientific paper
Oct 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007dps....39.0204m&link_type=abstract
American Astronomical Society, DPS meeting #39, #2.04; Bulletin of the American Astronomical Society, Vol. 39, p.410
Mathematics
Logic
Scientific paper
The global scale tectonic pattern on Enceladus has been interpreted as due to a rotation rate increase, although no mechanism for doing so is known (Porco et al. 2006). We consider an alternative explanation: reorientation of the rotation poles with respect to Enceladus’ surface. Geological observations of equatorial features that resemble the polar "tiger stripes” tectonic features support this scenario (Helfenstein et al. 2006) which is physically plausible, either due to the rise of a hot plume (Nimmo and Pappalardo 2006) or variations in ice shell thickness (Ojakangas and Stevenson 1989).
We find solutions for the stresses associated with triaxial distortions due to reorientation and/or despinning of a tidally deformed satellite. Following the analysis of Melosh (1977), we then predict the tectonic pattern due to different geometries for the reorientation of the rotation and tidal axes, and rotation rate variations. The observed N-S trending fractures in the leading hemisphere, which appear to have formed in response to E-W trending extensional stresses, and the circumpolar south polar terrain boundary at 55° S latitude, which seems to have formed in response to N-S trending compressional stresses (Porco et al. 2006), is more easily explained by a large reorientation ( 90°) of the rotation axis, rather than by a rotation rate increase. If Enceladus has a subsurface Ocean, cooling ultimately leads to expansion due to the water-ice volume change (Nimmo 2004). The predicted tectonic pattern due to the combination of large reorientation and a small radius expansion ( 10-3 %) is also in good agreement with the observed tectonic features. The predicted normal faulting province in the trailing hemisphere and circumpolar thrust faulting province around the north pole have not been observed, perhaps because of contrasts between the mechanical nature of the northern and southern polar regions due to degree-one convection or other unknown processes.
Matsuyama Isamu
Nimmo Francis
No associations
LandOfFree
Reorientation and Tectonic Patterns of Enceladus does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Reorientation and Tectonic Patterns of Enceladus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reorientation and Tectonic Patterns of Enceladus will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1064711