THE TOMS CANYON STRUCTURE, NEW-JERSEY OUTER CONTINENTAL-SHELF - A POSSIBLE LATE EOCENE IMPACT CRATER

The Toms Canyon structure (similar to 20-22 km wide) is located on the New Jersey outer continental shelf beneath 80-100 m of water, and is buried by similar to 1 km of upper Eocene to Holocene sedimentary stra ta. The structure displays several characteristics typical of terrestr ial impact craters (flat floor; upraised faulted rim; brecciated sedim entary fill), but several other characteristics are atypical (an unusu ally thin ejecta blanket; lack of an inner basin, peak ring, or centra l peak; being nearly completely filled with breccia). Seismostratigrap hic and biostratigraphic analyses show that the structure formed durin g planktonic foraminiferal biochron P15 of the early to middle late Eo cene. The fill unit is stratigraphically correlative with impact eject a cored nearby at Deep Sea Drilling Project (DSDP) Site 612 and at Oce an Drilling Program (ODP) Sites 903 and 904 (22-35 km southeast of the Toms Canyon structure). The Toms Canyon fill unit also correlates wit h the Exmore breccia, which fills the much larger Chesapeake Bay impac t crater (90-km diameter; 335 km to the southwest). On the basis of ou r analyses, we postulate that the Toms Canyon structure is an impact c rater, formed when a cluster of relatively small meteorites approached the target site bearing similar to N 50 degrees E, and struck the sea floor obliquely. (C) 1998 Elsevier Science B.V.