The mechanical and thermal structure of Mercury's early lithosphere

[1] Insight into the mechanical and thermal structure of Mercury's early lithosphere has been obtained from forward modeling of the largest lobate scarp known on the planet. Our modeling indicates the structure overlies a thrust fault that extends deep into Mercury's lithosphere. The best-fitting fault parameters are a depth of faulting of 35 to 40 km, a fault dip of 30degrees to 35degrees, and a displacement of similar to2 km. The Discovery Rupes thrust fault probably cut the entire elastic and seismogenic lithosphere when it formed (similar to4.0 Gyr ago). On Earth, the maximum depth of faulting is thermally controlled. Assuming the limiting isotherm for Mercury's crust is 300 to 600degreesC and it occurred at a depth of similar to40 km, the corresponding heat flux at the time of faulting was similar to10 to 43 mW m(-2). This is less than old terrestrial oceanic lithosphere but greater than the present heat flux on the Moon.