Abstract Pitted cones have been studied on Earth for at least two millennia, and they are often linked to an origin that requires H 2 O in some form. Identified on Mars half a century ago, pitted cones have been studied on the red planet with remote sensing data, and different formation models have been proposed based on terrestrial examples. In this work, we examine pitted cones on Mars that formed in patterns along the perimeter of circles, but have heretofore not been detailed in the literature. Pitted cones in these circular macrostructures are found in large quantities only in a small, ∼7,000 km 2 region of Elysium Planitia, which has been dated to <10 Myr. We propose that these circular macrostructures follow the rims of buried impact craters, and that sediment‐laden H 2 O and/or steam breached the surface where the most recent resurfacing is thinnest and therefore weakest, tracing these buried crater rims. Such a formation method is a mud volcano. Mud volcanoes typically require subsurface volatiles such as H 2 O and a buried heat source or tectonic triggering, both of which are non‐controversial in Elysium's recent past. If our preferred interpretation is correct, this work would bolster the case for extremely recent and potentially shallow water in this region of Mars.
Robbins et al. (Thu,) studied this question.