USING HIGH-RESOLUTION EVENT STRATIGRAPHY (HIRES) TO REVISE THE CHRONOSTRATIGRAPHIC CORRELATION OF WENLOCK-PRIDOLI (SILURIAN) STRATA OF THE CENTRAL AND WESTERN APPALACHIAN FORELAND BASIN (OHIO, WEST VIRGINIA, VIRGINIA)

The Appalachian Foreland Basin contains some of the most extensive Silurian strata in North America, which have been studied for well over a century. The global chronostratigraphic correlation of most of the strata in the central and western Appalachian Basin (Ohio, West Virginia, Virginia) have been known in a general way for decades, but precise correlation of these units has been impeded by a rarity of zonally diagnostic fossils. As part of an ongoing study, we utilized HiRES methodologies, integrating high-resolution carbon isotope chemostratigraphy, conodont biostratigraphy, and sequence stratigraphy from drill core and outcrops in the region that demonstrate the need to substantially revise the global chronostratigraphic correlation of many of these units, in two cases by more than a series.

Here, we provide new data that create the first continuous biochemostratigraphic record of the Wenlock through Pridoli series from the Appalachian Basin. These data include precise demonstration of the position of the Ireviken and Mulde positive carbon isotope excursions and revised conodont biostratigraphy of the central Appalachian Basin. Specifically, these findings demonstrate that the Cosner Gap and McKenzie members of the Mifflintown Formation, and the Williamsport, Wills Creek, and Tonoloway formations all require significant chronostratigraphic recalibration with respect to global Silurian series and stage boundaries. Thus, for example the Consner Gap and lower McKenzie now fall within the early Sheinwoodian or Ireviken positive C-isotope excursion, whereas the Williamsport Ss-lower Wills Creek interval contains the mid-Homerian or Mulde Event. The exact position of the Lau Event at present, remains uncertain. Additionally, the data presented here greatly improve our ability to correlate Silurian strata between the central Appalachian Basin and the western margin of the basin preserved in Ohio.