Mineral Deposits Associated with Stromatolites

This chapter discusses mineral deposits associated with stromatolites. The process of mineralization of stratiform deposits associated with stromatolites is an integral part of the development of sedimentary basins during sedimentation and diagenesis, and it is perhaps significant that many of the deposits discussed are in intracratonic basins. This chapter highlights where mineral deposits are formed, the contribution of the microorganisms can be indirect, helping to create a favorable physical and chemical environment, or more direct in trapping enriched material, helping to precipitate the valuable elements organically, or supplying other necessary elements such as sulphur. Alternatively, the organisms can merely survive in an environment where deposition of these elements is taking place, without playing any part in the process. After sedimentation and the diagenetic period, mineralization take place through the agency of connate brines that leach the valuable elements from their wide dispersion or from already-formed deposits, or through brines bringing them from a source external to the sediments; the brines would move, up-dip, till precipitation takes place in a favorable environment.