AGE RELATIONS OF THE REMBRANDT BASIN AND SCARP SYSTEM, MERCURY.

The 715-km-diameter Rembrandt basin is the largest well-preserved impact feature of the southern hemisphere of Mercury, and was imaged for the first time during the second flyby of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. Much of the basin interior is covered by smooth, high-reflectance plains interpreted to be of volcanic origin that host sets of contractional and extensional tectonic structures. This pattern resembles the arrangement of structures observed within the Caloris basin, with individual sets of radial and concentric landforms most likely due to multiple episodes of deformation. Notably, Rembrandt basin and its smooth plains are cross-cut by a 1,000-km-long reverse fault system that trends ~E–W, bending toward the north within the basin. The individual faults of this system accommo-dated crustal shortening that resulted from global con-traction as Mercury’s interior cooled. The current shape of the reverse fault system may have been influ-enced by the formation of the Rembrandt basin. As the Rembrandt basin area was affected by many commonly found processes that modified the surface of Mercury (i.e., basin formation and impact gardening, global and basin-related tectonics, and volcanic resur-facing), it is well suited for understanding the sequence and duration of such processes. The emplacement of the interior smooth plains predates both the basin-related tectonism and the final development of the giant scarp, which is suggestive of either short-lived volcanic activity immediately after basin formation or a later volcanic phase set against prolonged tectonic activity. In order to quantify the duration of volcanic and tectonic activity in and around Rembrandt basin, we determined the crater count-derived ages of the involved terrains by means of the Model Production Function (MPF) chronology of Mercury, which is rely on the knowledge of the impactors flux on the planet.