Complex history of the Rembrandt basin and scarp system, Mercury

During its second and third flybys, the MESSENGER spacecraft imaged the wellpreserved Rembrandt basin in Mercury’s southern hemisphere. With a diameter of 715 km, Rembrandt is the second largest impact structure recognized on Mercury after the 1550-km-diameter Caloris basin. Rembrandt is also one of the youngest major basins and formed near the end of the Late Heavy Bombardment (~3.8 Ga). Much of the basin interior has been resurfaced by smooth, high-reflectance units interpreted to be of volcanic origin. These units host sets of contractional and extensional landforms generally oriented in directions radial or concentric to the basin, similar to those observed within the Caloris basin; these structures are probably products of multiple episodes of deformation. Of particular note in the Rembrandt area is a 1,000-km-long reverse fault system that cuts the basin at its western rim and bends eastward toward the north, tapering into the impact material. On the basis of its shape, the structure has previously been characterized as a lobate scarp. Its formation and localization have been attributed to the global contraction of Mercury. From MESSENGER flyby and orbital images, we have identified previously unrecognized kinematic indicators of strike-slip motion along the Rembrandt scarp, together with evidence of interaction between the scarp orientation and the concentric basin-related structural pattern described above. Here we show through cross-cutting relationships and scarp morphology that the development of the Rembrandt scarp was strongly influenced by tectonics related to basin formation and evolution.