Upper Eocene impactites of the U.S. East Coast; depositional origins, biostratigraphic framework, and correlation
Similar successions of planktonic foraminifera, calcareous nannofossils, and bolboformids document coeval deposition of the Exmore impact breccia (Virginia Coastal Plain) and an impact ejecta layer at DSDP Site 612 (New Jersey Continental Slope). Both impactites accumulated in the late Eocene during the early part of biochrons P15 (planktonic foraminifera) and NP 19-20 (calcareous nannofossils), approximately 35.5-35.2 Ma. The impactite at Site 612 is part of an allochthonous debriite, 22.8 cm thick, displaced from the Toms Canyon impact crater, 40 km north-northwest of Site 612. The Exmore breccia, possibly 2000 m thick, is composed of debris displaced from the Chesapeake Bay impact crater, located in southeastern Virginia, 330 km southwest of Site 612.