Multistage ice-damming of volcanic flows and fluvial systems in Northeast Syrtis Major

© 2019 The northeast edge of the Syrtis Major volcanic complex records a diverse history of volcanism and climate of early Mars which has long been argued to be dominated by icy or wet conditions. This region contains a stratigraphic record that spans the period of phyllosilicate secondary mineralogy from moderate pH alteration of the Early Noachian crust, to the more acidic, sulfate-forming, Hesperian period dominated by the adjacent volcanic plains of Syrtis Major Planum. A paleo-fluvial basin and channel system etched in the Syrtis Major volcanics is identified and analyzed using multiple instruments onboard the Mars Reconnaissance Orbiter. These observations and analysis link the current landscape and the basin\u27s existence at the base of the Syrtis Major lava flow to a paleo-glaciation within the Isidis Basin. This paleo-glaciation formed ice sheets kilometers thick and ranged over hundreds of kilometers laterally and is responsible for halting the Syrtis Major flows in the Northeast Syrtis area to form the observed steep cliffs and the topographically flat mesa. Following this large scale glaciation, channels fed primarily by precipitation were etched into the Hesperian volcanics before filling the basin and flowing out an area of higher topography than is currently available due to the existence of an episodic ice dam before terminating in a potential, highly eroded, fan. The dynamic relationship between the climate and landscape evolution has left an imprint on the local geologic record of this complex region of Mars, with testable observations that could be made with the Mars 2020 Rover in the form of a highly jointed surface formed from lava ice interactions on the cliff face of the volcanic mesa