To this date no one knows for sure what caused these.  And there may be plans to examine them further:

Scientists continue to debate the true nature of the RSL phenomenon; no guess as to what they are and why they occur yet satisfies all observations. And just how RSL sites should be explored generates spirited debate, as evidenced by the discussions that emerged during the second Mars 2020 Landing Site Workshop, which was held last month in Monrovia, California

I just think that these features are the best places to look for extant life,” Stillman told Space.com at the workshop.

Features called recurring slope lineae (RSL), which could indicate seasonal flows of salty water, are found on some Martian slopes in warmer months. Red arrows point out an RSL in this image taken by the High Resolution Imaging Science Experiment (HiRISE) camera system on NASA’s Mars Reconnaissance Orbiter.

What do you think?  Is this the best area to search for evidence of life or are other regions of the planet a better bet?

thanks to space.com for the great info

thanks to NASA for the pics