Growth of Self‐Assembling Tubular Structures of Magnesium Oxy/Hydroxide and Silicate Related With Seafloor Hydrothermal Systems Driven by Serpentinization

Abstract Tubular structures self‐assemble from precipitating magnesium salts under the chemical garden chemobrionic growth process. Two experimental procedures, the dissolution of magnesium salt pellets and the injection of magnesium salt solutions into silicate solutions, were explored to reproduce in the laboratory the geochemical conditions under which similar structures may form from mineral‐rich fluids at some seafloor hydrothermal vents driven by serpentinization. X‐ray diffraction and Raman microspectroscopy applied to the materials formed indicated the presence of layers of magnesium silicate and magnesium oxide/hydroxide. Quantum mechanical calculations based on density functional theory were performed on models of hydrated magnesium silicate surfaces and related minerals to explain the Raman spectroscopy results. We examine the precipitate morphology, chemical structure, and crystal or mineral structure in our experiments and how these change with the reaction conditions. This is a fascinating example in geochemistry of a self‐organizing nonequilibrium process that creates complex structures.