Drilling at Deep Sea Drilling Project Site 603 has provided the first deep (>1000-m) penetration of strata beneath the continental rise off the Atlantic margin of North America. Nearly continuously cored through 1585 m of section down to Berriasian pelagic limestones, the site 435 km (270 mi) east of Cape Hatteras intersected an extensive Lower Cretaceous deep-sea fan complex, which provides new information on the petroleum potential of the continental rise. Hauterivian to early Aptian in age, this 208-m interval of interbedded limestones, sand, and black shale turbidites begs the existence of any post-Valanginian reefs along the Baltimore Canyon Trough. Less extensive terrigenous turbidites were encountered higher in the section up to the Cretaceous/Tertiary boundary, which is marked by a current-laminated sand rich in dark spherules. Pelagic early Paleogene clays are disconformably overlain by Miocene pelagic mud. Turbiditic silts and clays began to accumulate rapidly at this site during the middle Miocene, leading to deposition of muddy contourites that formed the Lower Continental Rise Hills of the Hatteras Outer Ridge as sand turbidites were ponded concurrently on its landward side. The section at Site 603 confirms the concept that eustatic and other large-scale events subdivide Earth history into distinct chapters allowing the correlation of deep-sea seismic sequence boundaries with continental shelf and margin unconformities.

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