CHEMOSTRATIGRAPHIC CORRELATION OF A DARRIWILIAN UNCONFORMITY IN THE APPALACHIAN BASIN
This study focuses on a Darriwilian unconformity in Laurentia that is exposed in two localities: Germany Valley (WV) and Collierstown (VA). The unconformity in both sections is characterized by abrupt facies shift from a fenestral limestone facies (New Market Formation) to a cherty fossiliferous packstone and grainstone facies (Whistle Creek/Lincolnshire Formation). Bulk rock and conodont strontium isotope data (87Sr/86Sr) from the underlying and overlying strata of the unconformity in both localities show similar values of 0.70840 and 0.70845 suggesting age similarities of the unconformity. Furthermore, the strontium isotope data also suggest that the unconformity can be correlated to other unconformities in different parts of the continent (e.g., Nevada, Oklahoma) with different tectonic settings suggesting a common driver. This finding suggests a glacio-eustasy origin of these unconformities and potentially lends credence to the protracted Ordovician glaciation hypothesis.