 
 
  
Analyzed “microbial” gases in Cretaceous sediments in the Western 
  Canada Sedimentary Basin, considering only production gases with d13C methane 
  < -55 and showing narrow range of methane values but very broad range of 
  ethane values.
 
 
  
Analyzed “microbial” gases in Cretaceous sediments in the Western 
  Canada Sedimentary Basin, considering only production gases with d13C methane 
  < -55 and showing narrow range of methane values but very broad range of 
  ethane values.