Semiarid climate and hyposaline lake on early Mars inferred from reconstructed water chemistry at Gale.

ABSTRACT: Salinity, pH, and redox states are fundamental properties that characterize natural waters. These properties of surface waters on early Mars reflect palaeoenvironments, and thus provide clues on the palaeoclimate and habitability. Here we constrain these properties of pore water within lacustrine sediments of Gale Crater, Mars, using smectite interlayer compositions. Regardless of formation conditions of smectite, the pore water that last interacted with the sediments was of Na-Cl type with mild salinity (~0.1-0.5 mol/kg) and circumneutral pH. To interpret this, multiple scenarios for post-depositional alterations are considered. The estimated Na-Cl concentrations would reflect hyposaline, early lakes developed in 10⁴-10⁶-year-long semiarid climates. Assuming that pos

SUBMITTER: Fukushi K 

PROVIDER: S-EPMC6814795 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature