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NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The experiments reported in this thesis were motivated by a desire to explain the small present [...] pressure in the Martian atmosphere, given the hypothesis that Mars once possessed a much denser [...] atmosphere. We adopted the premise that carbonate production on the surfaces of regolith particles, mediated by small amounts of [...], might explain the decline in the surface pressure over geologic timescales. We exposed powders [...] of basalt glass, and of monominerallic diopside, olivine, plagioclase, and quartz, to conditions simulating the past and present surface of Mars ([...], and [...] contents equivalent to <1 to >5000 monolayers on particle surfaces). A sensitive manometer was used to acquire precise measurements of pressure over periods of [...] days. Initial pressure drops were attributed to adsorption of [...] on particle surfaces and dissolution of [...]. Continuing uptake of gas in most experiments suggested that [...] reacted with powders to form carbonate. Fits to [...] after [...] day gave [...], implying logarithmic reaction kinetics (i.e., reaction rate, [...]. Subsequent fits to [...], incorporating adsorption and dissolution, gave rates of D = 0.01-2 monolayers [...] per [...], with [...] day. Reaction amounts totaled [...] monolayers. Parabolic kinetics, arising from diffusion through a product layer, probably did not exceed P(t) [...] Rates varied with sample composition (basalt and diopside > olivine > plagioclase and quartz). Basalt glass was not more reactive than diopside. Basalt powder pretreated with weak acid displayed rates reduced by over an order of magnitude (although diopside did not), suggesting something removed by acid contributes to [...] uptake. Rates increased with [...] content, temperature, and CO2 pressure, vA fit to data for basalt at 295 K gave [...], where H is [...] content in monolayers and D is in mo

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The experiments reported in this thesis were motivated by a desire to explain the small present [...] pressure in the Martian atmosphere, given the hypothesis that Mars once possessed a much denser [...] atmosphere. We adopted the premise that carbonate production on the surfaces of regolith particles, mediated by small amounts of [...], might explain the decline in the surface pressure over geologic timescales. We exposed powders [...] of basalt glass, and of monominerallic diopside, olivine, plagioclase, and quartz, to conditions simulating the past and present surface of Mars ([...], and [...] contents equivalent to <1 to >5000 monolayers on particle surfaces). A sensitive manometer was used to acquire precise measurements of pressure over periods of [...] days. Initial pressure drops were attributed to adsorption of [...] on particle surfaces and dissolution of [...]. Continuing uptake of gas in most experiments suggested that [...] reacted with powders to form carbonate. Fits to [...] after [...] day gave [...], implying logarithmic reaction kinetics (i.e., reaction rate, [...]. Subsequent fits to [...], incorporating adsorption and dissolution, gave rates of D = 0.01-2 monolayers [...] per [...], with [...] day. Reaction amounts totaled [...] monolayers. Parabolic kinetics, arising from diffusion through a product layer, probably did not exceed P(t) [...] Rates varied with sample composition (basalt and diopside > olivine > plagioclase and quartz). Basalt glass was not more reactive than diopside. Basalt powder pretreated with weak acid displayed rates reduced by over an order of magnitude (although diopside did not), suggesting something removed by acid contributes to [...] uptake. Rates increased with [...] content, temperature, and CO2 pressure, vA fit to data for basalt at 295 K gave [...], where H is [...] content in monolayers and D is in mo

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The experiments reported in this thesis were motivated by a desire to explain the small present [...] pressure in the Martian atmosphere, given the hypothesis that Mars once possessed a much denser [...] atmosphere. We adopted the premise that carbonate production on the surfaces of regolith particles, mediated by small amounts of [...], might explain the decline in the surface pressure over geologic timescales. We exposed powders [...] of basalt glass, and of monominerallic diopside, olivine, plagioclase, and quartz, to conditions simulating the past and present surface of Mars ([...], and [...] contents equivalent to <1 to >5000 monolayers on particle surfaces). A sensitive manometer was used to acquire precise measurements of pressure over periods of [...] days. Initial pressure drops were attributed to adsorption of [...] on particle surfaces and dissolution of [...]. Continuing uptake of gas in most experiments suggested that [...] reacted with powders to form carbonate. Fits to [...] after [...] day gave [...], implying logarithmic reaction kinetics (i.e., reaction rate, [...]. Subsequent fits to [...], incorporating adsorption and dissolution, gave rates of D = 0.01-2 monolayers [...] per [...], with [...] day. Reaction amounts totaled [...] monolayers. Parabolic kinetics, arising from diffusion through a product layer, probably did not exceed P(t) [...] Rates varied with sample composition (basalt and diopside > olivine > plagioclase and quartz). Basalt glass was not more reactive than diopside. Basalt powder pretreated with weak acid displayed rates reduced by over an order of magnitude (although diopside did not), suggesting something removed by acid contributes to [...] uptake. Rates increased with [...] content, temperature, and CO2 pressure, vA fit to data for basalt at 295 K gave [...], where H is [...] content in monolayers and D is in mo