Knowledge of oceanic sediments has been acquired in two ways: 1) directly by sampling and observation, and 2) indirectly through seismic investigations. Until the past decade, direct sampling and observation techniques could only provide information on the surficial materials of the ocean floor. The development of the piston corer (Kullenberg, 1947) has permitted oceanographic vessels to sample the upper 20 meters, and more recently the upper 30 meters, of the ocean floor, but such cores rarely penetrate the Pleistocene and enter older sediments. Until recently, most knowledge of the deeper sedimentary materials in the ocean basins was obtained through seismic reflection studies (Ewing and Ewing, 1970).
Since the early part of the last decade, the development of deep ocean drilling techniques has permitted sampling of the sediments of the oceans to depths in excess of 1,000 meters. Starting with the experimental Moholes drilled off Southern and Baja California (AMSOC Committee, 1961) the recovery of cores taken using oil-field drilling techniques has been increasingly successful. To plan a large scale program of deep sea drilling, several major oceanographic institutions formed an organization known as JOIDES (Joint Oceanographic Institutions Deep Earth Sampling). The original JOIDES members were Woods Hole Oceanographic Institution, La-mont-Doherty Geological Observatory of Columbia University, Rosenstiel School of Marine and Atmospheric Science of the University of Miami, and Scripps Institution of Oceanography of the University of California at San Diego; the Department of Oceanography of the University of Washington, joined subsequently. Scripps Institution of Oceanography submitted the proposal for ocean drilling and manages the program. Known as the Deep Sea Drilling Project, this program has been in effect since 1967, and is expected to continue through the summer of 1975, with the funding being provided by the National Science Foundation. In the early phase of the Deep Sea Drilling Project areas under investigation were limited to the tropical and subtropical regions of the Atlantic and Pacific Oceans. Since 1970, the deep sea drilling vessel Glomar Challenger has made excursions into higher latitudes, and will investigate the Southern Ocean during the coming austral summers. During 1971-1972, the Glomar Challenger drilled and cored a number of sites in the Indian Ocean, and by the end of the project there will have been reconnaissance drilling in all of the oceans except the Arctic.