D/V GLOMAR CHALLENGER AND THE DEEP SEA DRILLING PROJECT

Abstract

The unique dynamically positioned drilling vessel Glomar Challenger, which made its scheduled port call at Darwin, Australia in early January, and is now operating in the Indian Ocean, has successfully accomplished drilling and coring of deep ocean sediments for more than three and one -half years. Approximately 340 holes at 225 sites have been drilled in water depths to 20,316 ft., and with a maximum single penetration of 3,888 ft. into the oceanic floor. Less than 1% breakdown time has been experienced. Re-entry capability has been developed and used. Calculated to the end of Leg 20, accounting for about 40 months of operations, the Deep Sea Drilling Project has established an impressive record: a total of 279,848 ft. of rock penetration, 88,849 ft. of attempted coring and 52,052 ft. of recovered core.

Scientific information recovered and its interpretation bear on many aspects of geology and geophysics, including: the new global tectonics, interpretation of seismic reflection and refraction profiles, variations in oceanic chemistry and the history of oceanic current systems, plankton biostratigraphy, the nature and composition of oceanic sediments and economic potential, chemical changes to sediments after burial, organic evolution and productivity and response to isolation, vertical tectonic motions, activity at and near trench systems and continental margins, and the determination of amount of latitudinal shift of the crust of the earth relative to the rotational co-ordinates of the earth.

Plans for the future include an additional three years of drilling, bringing the total time under contract to seven years of uninterrupted work between Global Marine Inc., Scripps Institution of Oceanography, the National Science Foundation (an Agency of the U.S. Federal Government) and the JOIDES consortium of oceanographic institutions. The feasibility of an Antarctic drilling program is being investigated and will be undertaken insofar as possible. Heave compensation and usage of longer drill strings are planned for the future.