UPPER EOCENE IMPACTITES OF THE US EAST-COAST - DEPOSITIONAL ORIGINS, BIOSTRATIGRAPHIC FRAMEWORK, AND CORRELATION

Similar successions of planktonic foraminifera, calcareous nannofossil s, and bolboformids document coeval deposition of the Exmore impact br eccia (Virginia Coastal Plain) and art impact ejecta layer at DSDP Sit e 612 (New Jersey Continental Slope). Both impactites accumulated in t he late Eocene during the early part of biochrons P15 (planktonic fora minifera) and NP 19-20 (calcareous nanofossils), 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 no rth-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.