Was Gale Crater (Mars) Connected to a Regionally Extensive Groundwater System?

Abstract

Gale crater, home of the Curiosity rover, contains some of the best geomorphic and sedimentologic evidence on Mars for large lakes during the Hesperian and Amazonian. Orbital data and rover observations of delta deposits and terminations of gully networks suggest several phases of stable lake levels. However, the regional extent, water source (groundwater vs. surface water), and climate during each lake stand are debated. Consistent gully network termination elevations (GNTEs) within Gale and 17 regional craters suggest that GNTEs record paleolake levels. Hydrologic modeling indicates these lakes may have been coeval and the result of a regional groundwater table, recording a drying trend from subhumid conditions to semiarid conditions. Crater counting indicates that most lake-hosting craters impacted after ∼3.7 Ga and surface water persisted intermittently until the Early Amazonian, constraining the timing but not duration of lakes. This work has implications for understanding water sources and volumes affecting sediments investigated by Curiosity.