Recurring Slope Lineae on the Northern Hemisphere of Mars: an investigation into the new candidate sites

Abstract

Recurring Slope Lineae (RSL), are dark markings found on slopes with a steepness of 25°- 45°. Their width is between 0.5-5 m but they can become hundreds of meters long. They grow incrementally during warm seasons; fade during cold seasons and appear again the following Mars year. They occur mainly in the equatorial and southern mid-latitudes and appear less abundant in the northern hemisphere. After the first confirmed observations of RSL, research about them accelerated quickly. This is mainly because of their possible origin as water flows at the modern day martian surface. The main scope of this thesis is to find new RSL candidate sites in the less investigated northern hemisphere. Furthermore, the thesis investigates if potential candidate sites are wet- or dry flows since the processes behind RSL are still debated. By using a GIS ArcMap model, data from the High Resolution Imaging Science Experiment (HiRISE) instrument and parameters based on previous literature, new optimal sites for RSL were found with 27 of those areas having features being classified as new candidate RSL. Analyses of interesting candidate sites with modelled temperature measurements, grain size approximations, modelled water vapour data and parameters derived from previous studies suggests that a combination of wet flows and dry flows may be responsible for the creation of RSL. The reason for the scarcity in the northern region is due to less favourable RSL forming areas, less HiRISE coverage and less favourable temperature parameters on the northern hemisphere. For future studies it is suggested that more HiRISE images are gathered for the candidate sites and more research is done on a combined model of RSL creation.