The paper by Robert A. Berner explores the formation of sedimentary pyrite, a common mineral found in sediments and sedimentary rocks. The study focuses on the experimental synthesis of pyrite from FeS and elemental sulfur at neutral pH and 65°C, demonstrating that pyrite can form under these conditions. The major steps in the process are bacterial sulfate reduction, the reaction of H₂S with iron minerals to form iron monosulfides, and the transformation of iron monosulfides to pyrite. Key factors limiting pyrite formation in marine sediments include the availability of organic matter, the diffusion of sulfate, the concentration and reactivity of iron minerals, and the production of elemental sulfur. In sediments from the Connecticut coast, the availability of metabolizable organic matter is identified as the primary limiting factor. The study also discusses the transformation of FeS to FeS₂, suggesting that elemental sulfur is the primary oxidizing agent. The rate of pyrite formation in the Connecticut coastal sediments is estimated to be around 0.2% S per year, indicating that pyrite can form relatively quickly under optimal conditions.The paper by Robert A. Berner explores the formation of sedimentary pyrite, a common mineral found in sediments and sedimentary rocks. The study focuses on the experimental synthesis of pyrite from FeS and elemental sulfur at neutral pH and 65°C, demonstrating that pyrite can form under these conditions. The major steps in the process are bacterial sulfate reduction, the reaction of H₂S with iron minerals to form iron monosulfides, and the transformation of iron monosulfides to pyrite. Key factors limiting pyrite formation in marine sediments include the availability of organic matter, the diffusion of sulfate, the concentration and reactivity of iron minerals, and the production of elemental sulfur. In sediments from the Connecticut coast, the availability of metabolizable organic matter is identified as the primary limiting factor. The study also discusses the transformation of FeS to FeS₂, suggesting that elemental sulfur is the primary oxidizing agent. The rate of pyrite formation in the Connecticut coastal sediments is estimated to be around 0.2% S per year, indicating that pyrite can form relatively quickly under optimal conditions.