///Iron, as one of the most abundant elements in the Earth crust, cycles within a series of geochemical processes. The iron in the modern ocean mostly comes from riverine, glacial and aeolian by the input of iron oxide particles and dissolved iron ions. The iron oxides will change their form and finally be buried during the early diagenetic process characterized by the burial and degradation of organic matter, which is called the reactive iron cycling. Iron oxides would continue to be formed or at least not to be dissolved under oxic conditions, and the sediments in brown to red color will then be dominant. Because the phosphorus is the constraining element for the marine production, the ocean will become more productive under reducing conditions; but less organic matter will be produced under more-oxic environment. Such feedback mechanism has been preliminarily proved in the deposition of Cretaceous anoxic and more-oxic sediments. But more works are still needed to elucidate the contribution of different forms of iron burial to the occurrence of such special sediments.