Published:January 01, 1972
Even the best and fullest knowledge of the topography, sediment cover, and rock outcrops on the ocean floor (as also on land) leaves many questions about the underlying structure and stratigraphy unanswered. Direct sampling at considerable depth below the bottom can be accomplished only by drilling. Pioneering use of drill holes in the ocean floor resulted from the need to know the composition of the bottom for foundation design in the shallow water of seaports. Similarly, the drilling of oil wells proceeded gradually from land to shallow water to depths now in excess of 300 m. The first well-known offshore drilling for general scientific information was that of the British Royal Society at Funafuti Atoll in 1898 (Halligan, 1904), where a rotary drill operated from the bow of an anchored sailing ship and sampled to a maximum depth of 45 m below the lagoon floor at 30 m. Deep-sea drilling began in earnest with the experimental Mohole project, during which a hole reached a depth of 182 m below the bottom at 3,566 m off western Mexico in April 1961 (Riedel et al., 1961). In preparation for a larger drilling program, the Joint Oceanographic Institutions’ Deep Earth Sampling program (JOIDES) drilled six holes off eastern Florida during April and May 1965 with bottom penetrations to 320 m in water depths as great as 1,032 m (Bunce et al., 1965). The main program, termed the “Deep Sea Drilling Project,” began in July 1968; the program is funded through 1972.
Figures & Tables
Western North Atlantic Ocean: Topography, Rocks, Structure, Water, Life, and Sediments
The Atlantic coast of North America was the first part of the New World to be described by maps and texts; its exploration begain with the Vikings nearly a thousand years ago. Since then, the pace of exploration of both land and ocean floor has increased steadily. The concern during the 1960s was with details of geology, water, and life that largely were bypassed during earlier stages of discovery and exploration. The accumulation of knowledge was expressed approximately by the publication of charts, articles, and tabulations of data. This publication is concerned with the Atlantic continental margin of the United States, and it necessarily includes some information about the adjacent land and ocean areas. It is a summary of the existing knowledge of the ocean floor, the water above it, and the life that is in the water or at the bottom. The chapters contained within the publication fall into seven categories: Physiography, Rocks, Structure, Water, Life, Sediments, and Origin of Continental Margin.