Late Aptian to Recent sedimentological history of the lower continental rise off New Jersey, Deep Sea Drilling Project Site 603.

Abstract

Site 603 is interpreted to overlie Jurassic oceanic crustal basement and was only influenced by pelagic sedimentation during the late Berriasian to Valanginian, with terrigenous sediment not appearing until the late Valanginian to Aptian. The first evidence of clastic sedimentation is the development of a large turbidite system during a time when deltas were being built on the shelf. From the Hauterivian through the Late Cretaceous, black shale turbidites were intermittently deposited at this site. The maximum abundance of the carbonaceous claystone occurs interbedded with red and green claystone in the Aptian-Albian interval. Sea level rose during the Albian. The site then dropped below the calcite compensation depth. Less extensive terrigenous turbidite deposits represent pelagic sedimentation during the Late Cretaceous. A turbidite containing dark green spherules of montmorillonite, and anomalously high concentrations of Ni, Co, and As, is interpreted to represent exotic sediment that was reworked from the Cretaceous/Tertiary (K/T) boundary sediment. This is similar to a dated K/T boundary lamina cored at DSDP Hole 390B on the Blake Plateau. Late Paleocene to early middle Eocene pelagic claystone is disconformably overlain by middle Miocene hemipelagic claystone. Terrigenous turbidites ponded landward of Site 603 and formed the adjacent continental rise terrace. -from Authors