The role of "excess" CO2 in the formation of trona deposits

摘要: Abstract The prevailing theory for the formation of trona [Na3(CO3)(HCO3) · 2(H2O)] relies on evaporative concentration Na + – HCO 3 - water produced by silicate hydrolysis volcanic rock or volcaniclastic sediments. Given abundance closed drainage basins dominated volcanics, it is puzzling that there are so few deposits and present-day lakes would yield dominantly Na–CO3 minerals upon evaporation. Groundwater in San Bernardino Basin (southeastern Arizona, USA northeastern Sonora, Mexico) mainly evaporation, but waters surrounding not. Analysis chemical evolution this groundwater shows critical difference from not lithology, injection magmatic CO2. Many major Na–CO3-type appear to have had “excess” CO2 input, either sources decay organic matter. It proposed that, along with presence addition an important pre-condition deposits.