Geochemistry of a continental site of serpentinization, the Tablelands Ophiolite, Gros Morne National Park: A Mars analogue

► The Tablelands Ophiolite is a site of serpentinization and a Mars analogue. ► Ultra-basic, reducing, Ca2+-OH− type fluids discharge from ultramafic rocks. ► Isotopic composition of carbonate deposits suggest non-equilibrium precipitation. ► Dissolved methane in fluids is primarily non-microbial in origin. ► Methane and higher molecular weight hydrocarbons may be thermogenic and/or abiogenic in origin.