Arabia Terra is one of the more dusty regions on Mars, where ever-falling red dust covers the surface allowing only minor variations in color and tone. One exception is when wind-driven, dark-toned sand moves across the surface ejecting the bright dust into the atmosphere to reveal the dust-free surface below.
This HiRISE image shows sand dunes with surrounding larger tear drop-shaped light streaks pointing west (or, to the left). This orientation, along with the morphology of the local dunes, indicates winds from the east have stripped sand particles off the dunes and carried them downwind to form these light streaks. More importantly, active sand has a role in the slow erosion of the rocks here and the overall landscape evolution of the region.
Image credit: NASA/JPL/University of Arizona
Note: For more information, see PIA18931: Dunes and Wind Streaks in Arabia Terra.