Initial Reports of the Deep Sea Drilling Project - Volume 49

This volume covers Leg 49 of the cruises of the Drilling Vessel Glomar Challenger. Leg 49 of the International Phase of Ocean Drilling (IPOD) was designed with a wide spectrum of problems in mind. Topics investigated were (1) variation with time of mantle sources of spreading-center magmas, (2) aging of the volcanic layer, (3) degree of hydrothermal alteration and metamorphism of the volcanic layer, (4) lateral and vertical variation of the petrochemistry, magnetic properties, and structure of the volcanic layer, (5) north-south variability of spreading-center magmas through the North Atlantic, (6) initiation of glaciation during the late Pliocene, and (7) the influence of bottom currents originating at the Iceland-Faeroes Ridge on sediments of the ridge flank province of the western North Atlantic. Our drilling program included three holes (407, 408, and 409) on the west flank of the Reykjanes Ridge and seven in the crestal regions of the Mid-Atlantic Ridge. Glomar Challenger left Aberdeen, Scotland on 18 July 1976 and docked 49 days later, on 4 September, at Funchal, Madeira. During the cruise, Glomar Challenger steamed 4275 miles and carried out operations at eight sites. We drilled 10 holes in water 832 to 2977 meters deep.