An igneous origin for features of a candidate crater‐lake system in western Memnonia, Mars

TLDR

Channels, inner terraces, and delta‑like features around Martian impact craters have been taken as evidence for past crater lakes. Our study shows that features of a candidate crater‑lake system in western Memnonia are better explained by igneous lava flow and volcanic deposits, indicating that previously inferred crater lakes may need to be reexamined.

Abstract

The association of channels, inner terraces, and delta‐like features with Martian impact craters has previously been interpreted as evidence in favor of the past existence of crater lakes on Mars. However, examination of a candidate crater‐lake system in western Memnonia suggests instead that its features may have formed through igneous processes involving the flow and ponding of lava. Accumulations of material in craters and other topographic lows throughout much of the study region have characteristics consistent with those of volcanic deposits, and terraces found along the inner flanks of some of these craters are interpreted as having formed through drainage or subsidence of volcanic materials. Channels previously identified as inlets and outlets of the crater‐lake system are interpreted instead as volcanic rilles. These results challenge previous interpretations of terrace and channel features in the study region and suggest that candidate crater lakes located elsewhere should be reexamined.