Open AccessInsolation driven variations of Mercury's lithospheric strength
Author(s) -
Williams JeanPierre,
Ruiz Javier,
Rosenburg Margaret A.,
Aharonson Oded,
Phillips Roger J.
Publication year - 2011
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010je003655
Subject(s) - lithosphere , geology , crust , fault scarp , geophysics , mars exploration program , tectonics , astrobiology , seismology , physics
Mercury's coupled 3:2 spin‐orbit resonance in conjunction with its relatively high eccentricity of ∼0.2 and near‐zero obliquity results in both a latitudinal and longitudinal variation in annual average solar insolation and thus equatorial hot and cold regions. This results in an asymmetric temperature distribution in the lithosphere and a long wavelength lateral variation in lithosphere structure and strength that mirrors the insolation pattern. We employ a thermal evolution model for Mercury generating strength envelopes of the lithosphere to demonstrate and quantify the possible effects the insolation pattern has on Mercury's lithosphere. We find the heterogeneity in lithosphere strength is substantial and increases with time. We also find that a crust thicker than that of the Moon or Mars and dry rheologies for the crust and mantle are favorable when compared with estimates of brittle‐ductile transition depths derived from lobate scarps. Regions of stronger and weaker compressive strength imply that the accommodation of radial contraction of Mercury as its interior cooled, manifest as lobate scarps, may not be isotropic, imparting a preferential orientation and distribution to the lobate scarps.