air bubbles in sludgy foam patterns and contours in the thick sludge on the edge of a mineral lake on bottom of meteorite crater

african air background bottom bubbles bubbling close collection contours crater darkened deposit deposits detail dirty discoloration edge encrusted foam foamy image lake light meteorite mineral mineralized natural nature patterns salt saturated scum sediment silt sludge sludgy south surface texture thick tshwaing verge view washing water wet white