Initial Reports of the Deep Sea Drilling Project - Volume 93

This volume covers Leg 93 of the cruises of the Drilling Vessel Glomar Challenger. Glomar Challenger departed from Norfolk, Virginia, on May 4, 1983, to drill the upper and lower continental rise of the northwestern Atlantic Ocean on DSDP Leg 93, and returned to Norfolk on June 17, 1983. Six holes were drilled at three sites during Leg 93, not counting the unsuccessful attempt to emplace a reentry cone at Hole 603A. The original objective of this leg was to drill a deep hole through sediments at the foot of the continental rise and to sample Jurassic basement. It was hoped that one reentry hole would obtain a complete sedimentary record dating from the initial opening of the North Atlantic to the present, showing the development and sedimentation processes of the North American Basin. Drilling in Hole 603B recovered strata of Miocene to Early Cretaceous (Valanginian) age, but because of operations difficulties the last few hundred meters of Jurassic sediments above basement were not cored. Being unable to complete drilling and coring the stratigraphic section to basement at Site 603, Glomar Challenger was diverted to the upper continental rise off New Jersey, where it commenced drilling the New Jersey Transect at Sites 604 and 605. Two holes at Site 604 and one hole at Site 605 were drilled; when combined, these holes provide a detailed record of late Maestrichtian to Quaternary sedimentation. A highlight of Site 605 drilling was the recovery of a Cretaceous/Tertiary boundary section in Section 605-66-1.