Initial Reports of the Deep Sea Drilling Project - Volume 46

This volume covers Leg 46 of the cruises of the Drilling Vessel Glomar Challenger. The Glomar Challenger sailed on Leg 46 from San Juan, Puerto Rico, on 28 January 1976. Legs 45 and 46 were to be the first cruise of IPOD (International Program of Ocean Drilling) to drill a very deep multiple re-entry hole near the Mid-Atlantic Ridge axis. This hole was to be the first of a longitudinal Atlantic transect planned by the JOIDES Ocean Crust Panel. Leg 46 drilled two holes (396A and 396B) in a sediment pond about 150 km east of the Mid-Atlantic Ridge at 22°59.14'N, 43°30.90'W. Leg 45 had previously drilled Hole 396 to about 100 meters into basement in the sediment pond. Hole 396A was a mudline test with only 0.64 meters recovered from the two cores taken at the top of the sediment column. Hole 396B was a multiple re-entry hole which penetrated 150.5 meters of sediment and 205 meters into basaltic basement.