The tectonics of Mercury: The view after MESSENGER's first flyby

Period of the Slichter mode of Mercury and its possible observation

“…An inner core is also consistent with thermal evolution models of Mercury although they cannot rule out a fully liquid core (Hauck II et al 2004;Breuer et al 2007), and with the lobate scarps on the surface of Mercury (e.g. Melosh & McKinnon 1988;Watters et al 2004Watters et al , 2009, which are thought to be created by the contraction of the planet and may partly be caused by the formation of a solid inner core.…”

Stereo topographic models of Mercury after three MESSENGER flybys

“…Large portions of the DTM show topographic fabric consisting of relatively narrow, positive-and negative-relief landforms oriented radial to Caloris, most prominently expressed to the southwest and east-northeast of the basin (see arrows on figure). In addition, the DTM features a large and complex fault system near Beagle Rupes, one of the largest lobate scarps seen on Mercury (Watters et al, 2009a).…”

Accommodation of lithospheric shortening on Mercury from altimetric profiles of ridges and lobate scarps measured during MESSENGER flybys 1 and 2

“…Images from Mariner 10 (Strom et al, 1975;Melosh and McKinnon, 1988) and MESSENGER (Solomon et al, 2008;Watters et al, 2009) indicate that tectonic structures on Mercury are dominantly contractional in nature. Structural features include lobate scarps, high-relief ridges, and wrinkle ridges, with lobate scarps being the most widespread (Watters et al, 2009).…”

“…Structural features include lobate scarps, high-relief ridges, and wrinkle ridges, with lobate scarps being the most widespread (Watters et al, 2009). Many of these structures, particularly the lobate scarps, are believed to have formed primarily in response to a decrease in planetary radius (Solomon, 1977;Solomon et al, 2008;Watters et al, 2004Watters et al, , 2009) that accompanied cooling of the interior over the course of the planet's evolution (Solomon, 1977;Hauck et al, 2004;Watters et al, 2004;Zuber et al, 2007).…”

“…Whether deformation takes place in a localized (e.g., along discrete faults) or a spatially distributed (e.g., sets of faults) manner provides pertinent information on lithospheric structure and stress history. In this study we combine altimetric observations (Zuber et al, 2008a,b;Smith et al, 2010) of localized shortening across contractional ridges and lobate scarps on Mercury acquired by the Mercury Laser Altimeter (MLA) (Cavanaugh et al, 2007) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft (Solomon et al, 2008;Watters et al, 2009) with analytical and numerical models of localization processes to gain insight into the nature of strain accommodation in the planet's lithosphere.…”