| Aqueous methanol was reacted with various clay minerals to explore the abiotic synthesis and evolution of organic molecules in environments that simulate terrestrial seafloor hydrothermal conditions. Volcanic rocks readily alter to clay minerals when exposed to permeating hydrothermal fluids. The results of hydrothermal experiments conducted at 300 degrees Celsius and 1000 bars show the potential of aqueous methanol solutions to react with clay minerals to form an array of complex classes of molecules including: alkanes, alkenes, alkyl-benzenes, alkyl-naphthalenes, alkyl-phenols, alkyl-naphthols, alkyl-anthrols, methoxy- and alkyl-methoxy-phenols, methoxy- and alkyl-methoxy-naphthols.; Three different clay minerals were reacted in order to evaluate the effect of different layer structures and different temporal structure changes: two smectites (dioctahedral montmorillonite, trioctahedral saponite) and illite. The dioctahedral montmorillonite reacts to nearly 60 percent illite over 5 weeks, while the trioctahedral saponite and illite are unreactive over the same time period. While producing some similar organic products, reactions starting with pure illite yielded significantly lower product concentrations than those with the smectites. Results indicate that the expandable interlayers of the smectite clay minerals provide catalytic sites that are different from those sites found on the exterior surfaces, and allow for the formation of more complex organic molecules. Based on comparison of observed quantities of reaction products, a reaction pathway has been constructed to illustrate the progression from primary carbon species to complex organic molecules. |
