Delta Formation in Craters on Mars Under Different Gravitational Acceleration and Lake Water Levels

Abstract:

One of the primary targets for exploration of Mars are landforms that show indications of past hydrological activity, such as river deltas. For instance, the rovers—NASA Mars 2020, ESA’s ExoMars and CNSA TW-1—that are currently on their way to Mars or scheduled to launch, aim to search for signs of past life in areas with a high probability of sustained paleo-water flow. As the Perseverance (NASA) and Rosalind Franklin (ESA) rovers are planning to take ground samples for biosignatures at and near ancient deltaic deposits, it is important to understand the best places to drill. Therefore, the aim of our research is to better understand the stratigraphy of crater deltas formed under different lake water levels, and how these deltaic deposits might differ from deposits on Earth.

Our approach is to use a 2-D hydro-morphodynamic model to simulate the flow of water, transport and deposition of sediment, and the evolution of topography. We adapted the modeling framework Delft3D Flexible Mesh for simulating deltas on Mars. Delft3D-FM is a state-of-the-art code for simulating alluvial rivers and coastal processes on Earth, and we altered the code to include Martian gravity. Numerical experiments include simulating the same crater delta under both Mars and Earth gravity to study the effect of differing gravitational acceleration on sediment transport, stratigraphy, and formation time. We also are investigating how different lake water levels can influence the stratigraphy of the delta, using Jezero crater as an example, to help identify the locations of mudstones that may contain biomarkers.