Mohole, Project

Mohole, Project,

program proposed in 1957 to drill a hole down to the boundary between the crust and the mantlemantle,
portion of the earth's interior lying beneath the crust and above the core. No direct observation of the mantle, or its upper boundary, has been made; its boundaries have been determined solely by abrupt changes in the velocities and character of seismic waves passing
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, known as the Mohorovičić discontinuity at about 4 to 43 mi (7 to 70 km) below the earth's surface. Initiated by the American Miscellaneous Society, a loose organization of scientists, the main purposes of the project were to determine the nature of this boundary and to attempt to fill gaps in the geologic record from samples of the rocks encountered. The technology of such a project, however, was beyond the state of drilling technology at that time. Groups such as the National Science Foundation and the National Academy of Science eventually backed phase 1, in which five holes were drilled off the coast of Mexico, the most successful entering 601 ft (183 m) into the ocean floor under 2.2 mi (3.5 km) of water. The project was abandoned by 1966, as funding to support the ever-increasing costs of the project failed to gain congressional approval. Nevertheless, ship positioning and design, along with deepwater drilling technology developed for Project Mohole, were employed in the Deep Sea Drilling ProjectDeep Sea Drilling Project,
U.S. program designed to investigate the evolution of ocean basins by core drilling of ocean sediments and underlying oceanic crust. Funded by the National Science Foundation, the project was directed by the Joint Oceanographic Institution for Deep
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 and future drilling projects.