Summit Dunes and Their Sand Sources

The ultimate origin of the sediment that forms Martian dunes has long been debated. While sand dunes on Earth are primarily sourced by quartz-bearing components of granitic continental crust, it's often suggested that sand on Mars derives from eroded volcanic flows or sedimentary deposits, but exact sources are often vague. This image reveals a unique situation where this small dune field occurs along the summit of the large 1-mile-tall mound near the center of Juventae Chasma.