Fractured mounds in Elysium Planitia

Fractured mounds at the southern edge of Elysium Planitia. Elysium Planitia is a wide plain that lies to the south of the volcanic region Elysium. These features are found in a region of uplift that is theorized to be a massive lava inflation feature. The structures have a good chance of being tumuli because they are of the same scale as Earth tumuli and their patterns of cracks are similar to Earth tumuli. (HiRISE image PSP_002542_1765)

Tumuli are structures usually associated with slow-moving flows. When the top of the flow crusts over, the lava beneath can well upward and create an elliptical, domed structure. Oftentimes, the pressure creates an axial fracture along the length of the structure. The lava might burst through the crust, squeeze out slowly, or only push the crust so far before it freezes.  Tumuli typically range from 2 to 10 meters high. While tumuli are most often associated with pahoehoe lavas, they have been documented in ‘a’a lava as well. Tumuli are one of several related features formed by inflation of lava flows.

Due to their relatively small size, tumuli are difficult to spot aerially. There is often debate over images of suggested Martian tumuli.