East Carolina University, United States

Evidence for the Chesapeake Bay bolide impact, now recognized as the source for the North American Strewn Field, is provided by an upper Eocene ejecta deposit that occurs on the New Jersey continental margin at Ocean Drilling Program (ODP) Sites 904 and 903. The mineralogy, major oxide composition of fine-grained tektites and coarse-grained unmelted ejecta materials, and biostratigraphic age of the enclosing sediments link the origin of these ejecta to the Chesapeake Bay impact crater, located only 300 km away. The sediment associated with the ejecta provides new and important information about the dynamics of impact events. The 35-cm-thick ejecta-bearing layer can be subdivided into three subunits that indicate a sequence of events: 1) sediment failure, 2) deposition of gravel-sized fragments, 3) deposition of abundant sand-sized ejecta by gravity settling, and 4) accumulation of a 12-cm-thick sedimentary deposit containing rare silt-sized tektites and evidence of waning currents. These events are interpreted by linking sediment deposition to seismic ground motion and subsequent tsunami waves triggered by both the Chesapeake Bay impact and slope failures.