Ladon Basin was a large impact structure that was filled in by the deposits from Ladon Valles, a major ancient river on Mars.
These wet sediments were altered into minerals such as various clay minerals. Clays imply chemistry that may have been favorable for life on ancient Mars, if anything lived there, so this could be a good spot for future exploration by rovers and perhaps return of samples to Earth .
Written by: Alfred McEwen (audio: Tre Gibbs) (22 January 2018)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_013045_1615
Image: NASA/JPL/University of Arizona