Initial Reports of the Deep Sea Drilling Project - Volume 80

This volume covers Leg 80 of the cruises of the Drilling Vessel Glomar Challenger. Deep Sea Drilling Project Leg 80 investigated the structural evolution and depositional history of the Goban Spur and the adjacent Porcupine Abyssal Plain. This is the second DSDP leg devoted to documenting the development of the continental margin of northwest Europe. We placed Sites 548 to 551 along a transect across the continent/ocean boundary on the sediment-starved Goban Spur to attempt the following: (1) to establish the geologic ages, lithofacies, depositional environments, and subsidence rates of the pre-, syn-, and post-rift phases of development of the continental margin; (2) to determine the duration of rifting and the age and nature of the post-rift unconformity; (3) to document the age and nature of significant post-rift chronostratigraphic boundaries and prominent seismic unconformities and assess the relationships between these features and the processes of basin subsidence, global sea level changes, and tectonism; (4) to analyze the effects of changing paleoceanographic conditions (paleodepths, paleoclimates, rates of subsidence, and rates of deposition) upon the accumulation, composition, and erosion of continental margin sediments; (5) to determine heat flow rates and other aspects of the thermal regime of this margin and acquire additional information about the crustal thinning near the continent/ocean boundary; and (6) to compare and correlate the geologic and geophysical record of this continental margin with the known record for other margins, for the deep sea, and for the adjacent European landmass. Leg 80 commenced on 30 May 1981 at Brest, France, and it terminated on 22 July 1981 at Southampton, England.