Lost City Hydrothermal Field

A hydrothermal system on the Atlantis Massif, where seawater reacts with mantle rock to produce alkaline fluids that build carbonate towers without magma-driven heating.

Serpentinization: A hydration reaction that transforms ultramafic rock into serpentine minerals and can release heat and hydrogen. Water reacting with exposed mantle rock powers the field’s fluids without nearby magma.
Atlantis Massif: A large underwater mountain near the Mid-Atlantic Ridge, formed largely from uplifted mantle rocks. The Lost City towers sit on this massif, where tectonics exposes mantle to seawater.
Poseidon (Lost City tower): A prominent carbonate chimney in the Lost City Hydrothermal Field, rising roughly 60 meters above the seafloor. Poseidon is a striking example of the large structures built by the field’s fluids.
Chemosynthesis: The production of organic compounds using energy from chemical reactions rather than sunlight. Microbes at Lost City can draw energy from hydrogen and other compounds in vent fluids.
Origin of life: The set of scientific questions about how the first living systems arose from nonliving chemistry. Lost City offers a natural setting for testing whether geochemical energy can sustain prebiotic reactions.
Hydrothermal vent: A seafloor opening that emits fluid heated or chemically altered beneath Earth’s surface. Lost City is a hydrothermal system with a chemistry and heat source unlike typical volcanic vents.
Peridotite: A coarse-grained ultramafic rock composed mainly of olivine and pyroxene, common in Earth’s upper mantle. Peridotite exposed at the massif supplies the minerals transformed by serpentinization.
Lost City discovery: The 2000 discovery of the Lost City Hydrothermal Field during an expedition to the Atlantis Massif. The discovery established a non-volcanic hydrothermal system with towering carbonate chimneys.
Hydrogenotrophic methanogenesis: A microbial metabolism that produces methane by reducing carbon dioxide with hydrogen. It is one route by which Lost City microbes can use the field’s hydrogen-rich chemistry.
Hydrothermal vent hypothesis: A family of hypotheses proposing that life began in chemically energetic seafloor hydrothermal environments. Lost City’s alkaline vents resemble settings proposed for early life, though their role remains debated.

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SerpentiniteBroader topic: Its vents demonstrate active serpentinization and hydrogen-rich fluid production.