Biostratigraphy, paleoenvironmental, and paleomagnetic synthesis of the Goban Spur region, Deep Sea Drilling Project Leg 80

A composite stratigraphic section based on the four DSDP-IPOD Leg 80 drill sites provides a nearly complete record of syn-rift and post-rift events in the vicinity of Goban Spur. Syn-rift sediments were deposited in marginal marine to outer shelf environments. Above the "breakup" unconformity (hiatus spanning most of the Aptian), post-rift Albian sediments indicate the development of a deep-water seaway in the Goban Spur region. The latest Campanian/Maestrichtian interval records the initiation of rather uniform, widely distributed marine sedimentation throughout the region. Climatic changes, rather than changes in water depth, became conspicuous during the Tertiary. Widespread, nearly synchronous periods of nondeposition or erosion occurred in the Paleocene, middle Eocene, middle Oligocene, and late Miocene. Differences in the sediment record among sites are due to their varying positions (1) along the margin of the developing Atlantic seaway and (2) within their respective half-graben depositional basins.