Migration of iron and sulfur within anaerobic sediments during early diagenesis

Three diagenetic models based on layered situations are presented to illustrate factors affecting migration of iron and sulfur in recent anaerobic sediments. Two important factors are sharp variation with depth of organic matter content, which is assumed to be the same in each model, and the original concentration of reactive (toward H ~2~ S) ferruginous material, which is varied between models. Juxtaposed artificial sediments of greatly differing organic matter content undergo quantitative changes in the laboratory predicted by the three models. The experiments also demonstrate quantitatively the general validity of the low iron-content model. The same reasoning applied to layer models can be recast in a three-dimensional context to describe changes in organic-poor sediment surrounding an organic-rich body.