This observations targets some unknown fill or mantling material within valleys on a crater floor and within a central pit.
High resolution imagery can help determine what this material may be (e.g., ice-rich fill, dust, or other mantling unit?) and estimates of its thickness . With knowledge of its thickness, we can discern how deep the valleys and pit would be without its presence. This is necessary information, because without knowing the thickness of the material, appropriate discharge values for the valleys cannot be determined and neither can the history of the crater prior to infill.
This caption is based on the original science rationale.
Written by: HiRISE Science Team (audio: Tre Gibbs) (3 June 2015)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_039925_1360
Image: NASA/JPL/University of Arizona