Quantifying channel network morphometrics at Jezero and Eberswalde craters

Abstract

Ancient lakes on Mars and the river deltas which occur along their shorelines offer attractive targets for mission landing sites due to their habitability and high biosignature preservation potential. Deltas are promising targets for finding organic molecules and other signatures of life because on Earth deltas have biodiverse and rich ecosystems. Furthermore, the presence of deltas are used to map paleoshorelines for ancient oceans and lakes on Mars. For instance, Jezero Crater was chosen as the NASA Perseverance landing site because the fan-shaped channel network at the edge of the crater was interpreted as a delta. However, on Earth, fan-shaped channel networks may also form in fluvial fans that are inland terrestrial landforms that can form 1000s of kilometers from shorelines. We demonstrate that morphometric criteria are needed to accurately identify fan-shaped landforms for potential future landing sites. The goal of this research project is to differentiate deltas and fluvial fans on Mars by quantifying fan-shaped paleochannel network morphometrics. To accomplish this, we map Martian fan-shaped paleochannel networks using images from the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experience (HiRISE) and Contex Camera (CTX) photographs in combination with ArcGIS. Morphometric data is statistically analyzed using python and other open-source data visualization libraries. The outcomes of this project will improve our ability to choose appropriate landing sites in search of life, and to map paleo-shorelines on Mars. Preliminary results suggest the channel network at Jezero resembles a fluvial fan, while the landform at Eberswalde crater resembles a delta. Fluvial fan formation has been linked to large sediment and water discharges, and to fluctuations in discharge as a result of highly seasonal precipitation in climatic settings that promote marked seasonal and interannual hydrological changes, leading to variable discharge regimes and exceptional flood events. Alternative evidence is required to identify paleo-shorelines as fluvial fans may also form along shorelines. On Earth, fluvial fans are less sensitive to sea-level rise and coastal hazards than deltas and react differently from deltas due to changing sea levels.