But further study of these recurring slope lineae, known as RSL, is revealing something else.Those dark streaks may be the result of granular flows like sand and dust, according to a study published Monday in the journal Nature Geoscience. The study is the product of a research team made up of representatives from the US Geological Survey, the Planetary Science Institute, the University of Arizona and Durham University in England.The study is based on observations made with the High Resolution Imaging Science Experiment camera on the Mars Reconnaissance Orbiter.