Highlights—Mudstone Description Tools

Much of the sedimentary record comprises mudstone, and recent interest is driven by recognition of hydrocarbon sources, reservoirs, and seals in deposits of mudstone. Beyond this importance, they also influence groundwater dynamics and provide important perspectives on the global carbon cycle and climate and oceanography through geologic time. Yet, traditional mudstone descriptors neither capture the variability in their physical, biogenic, and chemical attributes, nor facilitate appropriate characterization and interpretation of controlling processes on their formation. Here, Lazar et al. discuss the utility of existing mudstone nomenclature, provide context for the information required to fully characterize mudstone, and recommend guidelines that facilitate consistent, repeatable, and efficient capture of key attributes to evaluate and compare fine-grained rocks. The application of their simple, integrated descriptive scheme to the Cretaceous Eagle Ford Shale demonstrates the utility of the technique for assessing and predicting rock properties.

Capturing keyattributes of fine-grained sedimentary rocks in outcrops, cores, and thinsections: nomenclature and description guidelines by O. Remus Lazar, Kevin M. Bohacs, Joe H.S. Macquaker, Juergen Schieber, and Timothy M. Demko