Re-evaluation of the Albian–Cenomanian boundary in the U.S. Western Interior based on dinoflagellate cysts

High precision U–Pb zircon geochronology for Cenomanian Dakota Formation floras in Utah

“…Frequent sea level fluctuations of the Western Interior Seaway are preserved in some of the sedimentary rocks of the Dakota Formation (Leckie et al, 1991;Shanley and McCabe, 1991;Shanley and McCabe, 1993;Shanley and McCabe, 1995), providing precise ammonite and inoceramid biostratigraphy that helps determine the age of the marine strata and also creates bounding ages for the adjacent terrestrial units (Cobban and Scott, 1972;Kauffman and Caldwell, 1993;Elder et al, 1994;Cobban et al, 2000). For the exclusively non-marine portions of the Dakota Formation in Utah, of particular interest to this study, the relative age continues to be determined using palynology (May and Traverse, 1973;Nichols and Sweet, 1993;Oboh-Ikuenobe et al, 2007;Currie et al, 2008;Sprinkel et al, 2012). Despite the many tools researchers have used to determine the age of the Dakota Fm., most of the fossil localities within the Dakota Formation can only be constrained to the Stage level using biostratigraphy (McClammer and Crabtree, 1989), which is problematic because mid-Cretaceous Stages are 4e12 Ma long.…”

Multi-Taxa Isotopic Investigation of Paleohydrology In the Lower Cretaceous Cedar Mountain Formation, Eastern Utah, U.S.A.: Deciphering Effects Of the Nevadaplano Plateau On Regional Climate

“…Several ash ages range from 98.37 6 0.07 Ma (Cifelli et al 1999) to 96.7 6 0.5 Ma (Garrison et al 2007). Palynologic studies of correlative strata (Oboh-Ikuenobe et al 2007) and geochronology of the Mussentuchit suggest deposition from the end of the Albian to the basal Cenomanian (Sprinkle et al 2012). Most of the Mussentuchit Member consists of interbedded gray smectitic mudstones, lignitic mudstones, siltstones, and occasional fine-grained sandstones.…”

Ammonite Biostratigraphy of the Cretaceous—An Overview

“…Graphic correlation is rarely based on ammonite data alone, since the combination of different types of stratigraphic data has proven to be the most successful (e.g., Immenhauser et al 2000;Oboh-Ikuenobe et al 2007;Scott 2009). Furthermore, more advanced quantitative …”