CHARACTERIZING FAN DEPOSITS ACROSS THE MARTIAN SURFACE: JEZERO'S NORTHERN FAN AND BEYOND

International audience ; Although Mars is a planet dominated by dust and aeolian processes today, many areas of its surface show clear evidence of having been shaped by water in its early history. While fluvial processes no longer play a prominent role on Mars currently, the sedimentary deposits of former rivers can aid in constraining the planet’s geologic history. Fan-shaped deposits are of particular interest, as the ones interpreted to be deltaic could indicate the presence of longstanding water, which in turn implies the potential to preserve biosignatures. In fact, the presence of ancient valley networks and apparent open-basin lakes is often taken as evidence for overland flow of liquid water – in turn implying a warmer climate on early Mars that might have supported precipitation and runoff [1]. In sites where such features occur within craters or cratered surfaces, stratigraphically older materials are often more easily accessible due to excavation by impact, and there is a preserved record of subsequent deposition – making them doubly valuable from a geologic perspective. Previous research has focused extensively on characterizing deposits interpreted to be fluviolacustrine in places such as Gale crater (landing site of the Mars Science Laboratory Curiosity rover [2]), Hypanis Valles (one of the largest deltas on Mars [3]), and the western fan and its remnants in Jezero crater (landing site of the Mars 2020 Perseverance rover [4-6]). However, recent surveys of fan-shaped deposits across the martian surface indicate that there are many more sites where these deposits exist that have been studied minimally, if at all (e.g., [7-10]). Even within Jezero crater (~50 km diameter) itself, fan deposits along the crater’s northern interior rim have been studied far less extensively than the fan delta that dominates the crater’s western interior rim (Fig.1). To understand the fluvial and sedimentological history of Jezero, as well as to place the rover's in situ observations in proper geologic context, it is ...