The Tectonic Character of Mercury

Mercury is a tectonic world: the planet has experienced a long and complicated history of deformation, recorded by its preserved tectonic landforms. As the study of tectonics naturally intersects with volcanology, chemistry, interior structure, and thermal evolution, understanding the tectonic character of Mercury is a crucial means by which to more fully comprehend the planet’s geological history. In this chapter, we seek to tie together the various strands of observational and analytical studies of the tectonics of Mercury conducted since the first Mercury flyby of the MESSENGER mission. We describe the shortening and extensional structures on the innermost planet, as well as an enigmatic set of long-wavelength topographic warps that may have been tectonically driven, before reviewing our understanding of the structure and properties of Mercury’s lithosphere. The mechanisms for tectonic deformation are next discussed, and we then explore the other major aspect of Mercury’s tectonics - when deformation took place - as we work to describe at least in broad terms the tectonic history of the planet. The influence of tectonics on Mercury’s volcanic activity is then addressed. Finally, we list some major questions regarding Mercury’s tectonics that remain open and suggest how they might yet be answered.