I was wondering if aerobic decomposition of organic rich soils, also rich in calcium and sulfur, can result in the precipitation of gypsum. My thinking is the decomposition would release the organically bound Ca to soluble form, and the mineralization of organic sulfur would release in sulfate. Then over time as the soil decomposes more higher concentrations of both calcium and sulfur would precipitate out gypsum. Am I correct in saying this?


  • $\begingroup$ AFAIK bacteria reduce sulfur, not oxidise it. You end up with sulfide as H2S or solids such as pyrite (FeS2). Furthermore, gypsum is a very soluble mineral, not I'm not sure how much of it will you get even if it is precipitating. $\endgroup$
    – Gimelist
    Dec 17, 2017 at 10:40
  • $\begingroup$ Hello Michael, thank you for your the comment. Sulfate reduction will only occur under anaerobic conditions, the setting I am describing is a drained environment, where aerobic conditions dominate. I just wanted to know if it was possible for calcium to be released following decomposition of the soil. $\endgroup$
    – Henry
    Dec 18, 2017 at 17:39


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