Pyrite formation in the Lower Cretaceous Mowry Shale: effect of organic matter type and reactive iron content

Abstract

Geochemical analysis of the Lower Cretaceous Mowry Shale in Wyoming and Montana shows that organic matter type and reactive iron content limited pyrite formation during early diagenesis. Consequently, direct interpretation of paleosalinity cannot be made from a carbon/sulfur plot. However, it can be estimated that the Mowry Sea was not a fresh water body but was either of normal marine salinity or contained brackish water with greater than one-half normal salinity. -Authors