Reconstructing paleolakes in Nepenthes Mensae, Mars, using the distribution of putative deltas, coastal-like features, and terrestrial analogs

Abstract

Nepenthes Mensae is an equatorial region situated north of the Martian dichotomy, northwest of Gale crater. It is characterized by a NW-SE-oriented belt of interconnected depressions, Late Noachian to Early Hesperian in age, with knobby terrains with residual relief. The highlands south of Nepenthes Mensae, Middle Noachian in age, correspond to the Licus Vallis region, which is dissected by drainage networks with valley mouths located along the dichotomy boundary scarp. This work presents a detailed geomorphological analysis of ten fan-shaped and fifty-four coastal-like benches identified in Nepenthes Mensae. The combination of detailed mapping, morphological and morphometric analyses, spatial-altitudinal distribution relationships, crater counting, spectral analysis, and comparison with terrestrial analogs suggest that (1) the fan-shaped and coastal-like benches are likely putative Gilbert-type deltas and paleoshore platforms, respectively, and (2) these features may be attributable to paleoshorelines developed along the margins of an ancient inner sea or interconnected paleolakes. These findings reveal the important morphogenetic role that liquid water played in the evolution of Nepenthes Mensae and Licus Vallis regions during the Late Noachian-Early Hesperian transition, and contribute to contextualize the continuous findings on the environmental and climatic conditions of the nearby Gale crater during such time period.