Fig. 9
Maximum lithospheric strength at the North Pole and Solis Planum on Mars as a function of time. The maximum lithospheric strength was calculated from the rheological structures determined in this study. Shaded sections represent the range of lithospheric strength that allows the planetary surface to form plate boundaries (e.g., Tackley 2000). Heavy arrows indicate the evolution of lithospheric strength on Mars, as inferred from water loss during the Noachian. a Evolution of the lithospheric strength at the North Pole under dry (red lines) and wet (blue lines) conditions. The gray line indicates the lithospheric strength that considers the frictional coefficient of hydrous phyllosilicates. The strain rates of 10−14 (solid lines) and 10−16 (dashed lines) s−1 are from Laskar et al. (2004), Phillips et al. (2008), and Tesauro et al. (2007). b Evolution of the lithospheric strength at Solis Planum for strain rates of 10−16 s−1 (solid lines) and 10−19 s−1 (dashed lines) under dry (red lines) and wet (blue lines) conditions. The gray line indicates the result that consider the frictional coefficient of hydrous phyllosilicates