The Caloris Planitia basin is particularly notable for its concentric rings, which are thought to have formed as a result of the impact event that created the basin. These rings are composed of uplifted and fractured material that was ejected during the impact, and they extend outward from the center of the basin for hundreds of kilometers. The rings are best observed in the northern portion of the basin, and they provide important clues about the impact process and the subsequent geological evolution of Mercury.
In addition to the concentric rings, Caloris Planitia also exhibits other surface features that are associated with impact basins, such as a central peak, a series of secondary craters, and a surrounding ejecta blanket. The central peak, which is located near the center of the basin, is thought to have formed as a result of the rebound of material after the impact. The secondary craters are smaller craters that were created by debris ejected from the primary impact, and they are distributed around the basin in a radial pattern. The ejecta blanket, which extends outward from the basin for hundreds of kilometers, is composed of material that was ejected during the impact and deposited on the surrounding surface.