Evidence for paleolakes in Erythraea Fossa, Mars: Implications for an ancient hydrological cycle

There is now widespread agreement that the surface of Mars underwent some degree of fluvial modification, but there is not yet full understanding of its surface hydrological cycle and the nature of standing bodies of water, rivers, and precipitation that affected its surface. In this paper we explore Erythraea Fossa (31.5 W, 27.3 S), a graben adjacent to Holden crater, which exhibits strong evidence that it once housed a chain of three lakes, had overland water flow, and was subject to precipitation. The inlet valley, outlet valley, and fan morphologies in the paleolakes are used to qualitatively discern the hydrologic history of the paleolakes; based on topography constraints, the three basins combined once held 56 km3 of water. Depositional features within the basins that change with drainage area and nearby valleys that start near drainage divides indicate that the paleolakes may have been fed by precipitation driven runoff. This suggests the presence of an atmosphere, at least locally, that was capable of supporting a hydrological cycle.

► Erythraea Fossa, Mars (31.5 W, 27.3 S) is a graben near Holden crater. ► Evidence for a chain of paleolakes in Erythraea Fossa is presented. ► A hypothesis of the hydrology of the paleolakes is put forth. ► Evidence for precipitation in Erythraea Fossa is presented. ► Findings in this area are contextualized with the global martian paleoclimate.