Characterization of iron-phosphate-silicate chemical garden structures.
Chemical gardens form when ferrous chloride hydrate seed crystals are added or concentrated solutions are injected into solutions of sodium silicate and potassium phosphate. Various precipitation morphologies are observed depending on silicate and phosphate concentrations, including hollow plumes, bulbs, and tubes. The growth of precipitates is controlled by the internal osmotic pressure, fluid buoyancy, and membrane strength. Additionally, rapid bubble-led growth is observed when silicate concentrations are high. ESEM/EDX analysis confirms compositional gradients within the membranes, and voltage measurements across the membranes during growth show a final potential of around 150-200 mV, indicating that electrochemical gradients are maintained across the membranes as growth proceeds. The characterization of chemical gardens formed with iron, silicate, and phosphate, three important components of an early earth prebiotic hydrothermal system, can help us understand the properties of analogous structures that likely formed at submarine alkaline hydrothermal vents in the Hadean-structures offering themselves as the hatchery of life.
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA. laura.m.barge@jpl.nasa.gov
Laura M
LM
Barge
Ivria J
IJ
Doloboff
Lauren M
LM
White
Galen D
GD
Stucky
Michael J
MJ
Russell
Isik
I
Kanik
D005296:Ferrous Compounds / Q000737:chemistry; D060086:Hydrothermal Vents / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*
D005296:Ferrous Compounds; D010710:Phosphates; D017640:Silicates; D007501:Iron; C029451:ferrous chloride