PI's will study the distribution, stratigraphic correlation, chemistry and paleotectonic setting of extensive Late Ordovician K-bentonite beds in the eastern midcontinent. Work will focus on the central and southern Appalachians where previous studies indicate the Rocklandian Deicke and Millbrig K-bentonites are widespread. Establishing the correlation of these beds will define several Ordovician chronostratigraphic surfaces extending from the Mississippi Valley across the Michigan Basin and Cincinnati Arch and into the Appalachian Basin. These beds will provide regional time lines for facies correlation from platform carbonates and silliciclastics in the interior of the craton through ramp and slope carbonate deposits to both deep-water and redbed facies of the eastern Valley and Ridge. Chemical data will be evaluated according to current petrotecotnic models to interpret the tectonic setting of the source volcanoes. Results will be combined with lithostratigraphic and biostratigraphic information to produce regional chronostratigraphic, isopach and isochemical maps of the principal Ordovician K-bentonite beds in North America.
