Mapping and analysis of a chain of channeled basins in the eastern rim region of Hellas basin, Mars

Abstract

The study is a detailed look on one of the several fluvial systems located on the eastern rim region of the Hellas basin on Mars. We analyzed the morphologic and morphometric characteristics of an extensive channel system, which extends for over 650 km from 35.8°S, 106.4°E in Hesperia Planum to Reull Vallis at 39.5°S, 98.1°E, and has a drainage area of 35,000–40,000 km 2. During its traverse the channel changes its characteristics many times, indicating variations in the surface properties. Based on cross-cutting relations, the fluvial system post-dates the emplacement of the early Hesperian lava plains in Hesperia Planum but predates the Amazonian deposits. We describe the geomorphology and evolution of the system and provide evidence of both surface flow and groundwater sapping processes. A chain of channeled paleolake basins in the central parts of the system (38°S, 102°E) provides a rough estimate for the water volume (250–300 km 3) which was required to form the system. The minimum volume of surface materials eroded by the channel system is ∼74 km 3. Although this study presents the detailed analysis of only one fluvial system, the presence of many similar channel systems along the margin of Hellas suggests that late-stage surface runoff has played a significant role in the degradation of the rim of the basin and also in the transportation of materials towards Hellas floor.