Experimental investigation of the role of water in impact vaporization chemistry

Here we present results of impact simulation experiments to investigate the role of water vapor in the chemistry of water-silicate interactions during an impact event. Experiments shows three main effects: the formation of hydrous silicate structures, the change of redox state of condensed material, and the hydration of volatile elements (particularly, enhanced formation of complex hydrocarbons). The hydration of condensed material proceeds mainly by the formation of hydrated silicate structures rather than by the formation of separate hydroxides. The hydration of condensed silicate structures results in the trapping of up to similar to10 wt% of water. Practically all major elements (except Ca) participate in bonding with (OH) groups. Synthesized hydrocarbons have a rather high degree of complexity, with mass number ranging up to 700. Only surface reactions on condensing particles during their formation can account for the hydrocarbons. (C) 2002 Elsevier Science Ltd. All rights reserved.