Initial Reports of the Deep Sea Drilling Project - Volume 7

This volume covers Leg 7 of the cruises of the Drilling Vessel Glomar Challenger. Glomar Challenger left Guam on August 8, 1969 to begin Leg 7 and arrived in Honolulu on October 2, 1969, for a total of 56 days at sea. 29 days were spent drilling 15 holes at seven different sites. Leg 7 of the Deep Sea Drilling Project was designed principally to explore the western equatorial Pacific—seaward of the island arcs and trenches—to learn something of the age of the crust in various parts of this region by drilling all the way through the sediment cover, to establish standard biostratigraphic sections by continuous coring in the thick sequences of biogenous sediments, and to examine the nature and age of the many acoustic reflectors observed on seismic reflection profiles taken in this region. Four rather different provinces were to be sampled: 1. The Mariana Basin, immediately east of the Mariana Trench, near the island of Guam. 2. The region of small basins and shallow ridges and plateaus lying south of the Caroline Ridge and north of New Guinea and the Solomons. 3. The deep Central Basin, between the Marshall and Gilbert Ridges on the west, and the Line Islands Ridge on the east. And 4. The Hawaiian Arch, north of the island of Oahu, which lies west of Magnetic Anomaly No. 32.