Khensu crater is a crater on Jupiter's moon Ganymede. The dark component may be residual material from the impactor that formed the crater. Another possibility is that the impactor may have punched through the bright surface to reveal a dark layer beneath. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Ganymede they are named after gods and heroes of ancient Fertile Crescent people.
Image Source. Marker locations are approximate and may not always appear to align with image on map.