Planetary Geomorphology Image of the Month, December 1, 2016: Alexis Rodriguez (Planetary Science Institute). The Martian northern lowlands are thought to currently be extensively covered by an ice-rich deposit, interpreted by some researchers to be the residue of an ancient ocean that existed ~3.4 Ga (Kreslavsky and Head., 2002). However, evidence for this ocean has remained a subject of intense dispute and scientific scrutiny since it was first proposed (Parker et al., 1989, 1993) several decades [ago].
The controversy has largely stemmed in the fact that the proposed Martian paleo-shoreline features exhibit significant elevation ranges (Head et al., 1999), a lack of wave-cut paleoshoreline features (Malin and Edgett, 1999), and the presence of lobate margins (Tanaka et al., 1997, 2005).
The discovery of potential tsunami deposits as discussed in a recent article by Rodriguez et al. (2016) brings in a new perspective in which coastal margins shaped by enormous tsunami waves likely characterized early Mars oceans (Fig. 1)…
The features that Rodriguez et al. (2016) interpreted as tsunami deposits consist of lobate deposits reaching several hundred kilometers in lengths over a few hundred meters of relief gains (Figs. 2 and 3). [More at link and at an earlier RPR item]