Upper Pennsylvanian Stratigraphy Revision
At the October 2011 Annual Meeting of the Geological Society of America in Minneapolis, John Nelson, Scott Elrick, and Zohrah Askari Khorasgani presented a poster illustrating the first official revision of Illinois Basin Upper Pennsylvanian (Missourian and Virgilian series) stratigraphy in 20 years. For each unit, type sections were tied to the subsurface using core data when available. A network of cross sections was then constructed, maximizing the use of newly acquired long core records. Through this process, many redundant unit names were eliminated. Precise biostratigraphic correlations from palynology, fusulinids, and especially conodonts from Phil Heckel and other workers allowed extending a number of members, particularly black phosphatic shales, from the Western Interior into the Illinois Basin and Appalachian Basin, therefore correlating many units among Appalachian, Western Interior, and Illinois Basin regions. Many long-standing miscorrelations within the Illinois Basin were rectified.