XPost: sci.geo.geology, alt.sci.planetary   
   From: dietz@dls.net   
      
   hrtbreak wrote:   
      
   >  Doesn't the large-scale fixation of CO2 in our atmosphere into   
   > rock formations require living organisms, like diatoms?   
      
   No.  Organisms can cause carbonate formation at lower CO2   
   concentation, or at a faster rate, but enough CO2 and carbonate   
   will form by itself.   
      
   Don't diatoms have silica skeletons?   
      
   	Paul   
      
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    * Origin: you cannot sedate... all the things you hate (1:229/2)