The Deep Sea Drilling Project (DSDP) was an

ocean drilling Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum that lies in rock formations beneath the seabed. Most commonly, the te ...

project operated from 1968 to 1983. The program was a success, as evidenced by the data and publications that have resulted from it. The data are now hosted by

Texas A&M University Texas A&M University (Texas A&M, A&M, or TAMU) is a public university, public, Land-grant university, land-grant, research university in College Station, Texas. It was founded in 1876 and became the flagship institution of the Texas A&M Unive ...

, although the program was coordinated by the

Scripps Institution of Oceanography The Scripps Institution of Oceanography (sometimes referred to as SIO, Scripps Oceanography, or Scripps) in San Diego, California, US founded in 1903, is one of the oldest and largest centers for ocean and Earth science research, public servi ...

at the

University of California, San Diego The University of California, San Diego (UC San Diego or colloquially, UCSD) is a public land-grant research university in San Diego, California. Established in 1960 near the pre-existing Scripps Institution of Oceanography, UC San Diego is ...

. DSDP provided crucial data to support the seafloor spreading hypothesis and helped to prove the theory of

plate tectonics Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of larg ...

. DSDP was the first of three international scientific ocean drilling programs that have operated over more than 40 years. It was followed by the Ocean Drilling Program (ODP) in 1985, the Integrated Ocean Drilling Program in 2004 and the present International Ocean Discovery Program in 2013.

History

The initial contract between the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...

(NSF) and the

Regents of the University of California The Regents of the University of California (also referred to as the Board of Regents to distinguish the board from the corporation it governs of the same name) is the governing board of the University of California (UC), a state university sy ...

was signed on June 24, 1966. This contract initiated the first phase of the DSDP, which was based in

at the

. Global Marine, Inc. conducted the drilling operations. The Levingston Shipbuilding Company laid the keel of the ''

Glomar Challenger ''Glomar Challenger'' was a deep sea research and scientific drilling vessel for oceanography and marine geology studies. The drillship was designed by Hugues Global Marine, Global Marine Inc. (now Transocean, Transocean Inc.) specifically for a l ...

'' on October 18, 1967, in

Orange, Texas Orange is a city and the county seat of Orange County, Texas, United States. As of the 2020 census, the city population was 19,324. It is the easternmost city in Texas, located on the Sabine River at the border with Louisiana, and is from Hous ...

. It sailed down the Sabine River to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

, and after a period of testing, DSDP accepted the ship on August 11, 1968. Through contracts with Joint Oceanographic Institutions (JOI), NSF supported the scientific advisory structure for the project and funded pre-drilling geophysical site surveys. Scientific planning was conducted under the auspices of the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES). The JOIDES advisory group consisted of 250 distinguished scientists from academic institutions, government agencies, and private industry from all over the world. Over the next 30 months, the second phase consisted of drilling and coring in the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, Pacific, and

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...

as well as the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...

and

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...

. Technical and scientific reports followed during the period. The second phase of DSDP ended on August 11, 1972. The success of the ''Glomar Challenger'' was almost immediate. On one of the sites with a water depth of , core samples revealed the existence of salt domes. Oil companies received samples after an agreement to publish their analysis. The potential of oil beneath deep ocean salt domes remains an important avenue for commercial development today. As for the purpose of the scientific exploration, one of the most important discoveries was made when the crew drilled 17 holes at 10 different locations along an oceanic ridge between

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and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. The retrieved core samples provided strong proof for

continental drift Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of pl ...

and seafloor renewal at rift zones. This confirmation of Alfred Wegener's theory of continental drift strengthened the proposal of a single, ancient land mass, which is called Pangaea. The samples gave further evidence to support the plate tectonics theory, which at the time attempted to explain the formation of mountain ranges, earthquakes, and oceanic trenches. Another discovery was how youthful the ocean floor is in comparison to Earth's geologic history. After analysis of samples, scientists concluded that the ocean floor is probably no older than 200 million years. This is in comparison with the 4.5 billion-year age of the Earth. The International Phase of Ocean Drilling (IPOD) began in 1975 with the

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Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

, the

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, the

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, and

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joining the

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in field work aboard the ''Glomar Challenger'' and in post-cruise scientific research. The Glomar Challenger docked for the last time with DSDP in November 1983. Parts of the ship, such as its dynamic positioning system, engine telegraph, and thruster console, are stored at the

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in Washington, D.C. With the advent of larger and more advanced drilling ships, the JOIDES Resolution replaced the ''Glomar Challenger'' in January 1985. The new program, called the Ocean Drilling Program (ODP), continued exploration from 1985 to 2003, at which point it was replaced by the Integrated Ocean Drilling Program (IODP).

Coring operations

Although itself a remarkable engineering accomplishment, the ''

'' saw many advances in deep-ocean drilling. One problem solved involved the replacement of worn drill bits. A length of pipe suspended from the ship down to the bottom of the sea might have been as long as . The maximum depth penetrated through the ocean bottom could have been as great as . To replace the bit, the drill string must be raised, a new bit attached, and the string remade down to the bottom. However, the crew had to thread this string back into the same drill hole. The technique for this formidable task was accomplished on June 14, 1970, in the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

in of water off the coast of

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

. This re-entry was accomplished with the use of

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on o ...

scanning equipment and a re-entry cone that had a diameter of and height of . One major technological advance was the extended use of the holes after drilling. Geophysical and geochemical measurements were made during and after drilling, and occasionally long-term seismic monitoring devices were installed in the holes. This extended understanding of the dynamic processes involved in

. Another technological advance involved the introduction of the

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...

piston corer (HPC) in 1979, which permitted the recovery of virtually undisturbed cores of sediment. This greatly enhanced the ability of scientists to study ancient ocean environments. From August 11, 1968, to November 11, 1983, the Glomar Challenger achieved the following accomplishments:

Core samples, publications, and data

The ship retrieved core samples in cores with a diameter of . These cores are currently stored at three repositories in the US, Germany, and Japan. One half of each core is called the archive half and is preserved for future use. The working half of each core is used to provide samples for ongoing scientific research. The scientific results were published as the "Initial Reports of the Deep Sea Drilling Project", which contains the results of studies of the recovered core material and the associated geophysical information from the expeditions from 1968 to 1983. These reports describe the core materials and scientific data obtained at sea and in shore-based laboratories post-cruise. These volumes were originally prepared for NSF under contract by the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, University of California, Irvine, Irvine, University of Califor ...

. In 2007, the printed books were scanned and prepared for electronic presentation by the

College of Geosciences.

Discovery and accomplishment in Antarctic region

DSDP completed four drilling programs; Legs 28, 29, 35 and 36 around Antarctica during four Austral summers, 1972–73, 1973–74, 1974–75 and 1975–76. These programs were focused on two main objectives: Cenozoic global paleoclimatic changes and plate tectonic movements around Antarctica.Hayes, D. E. and Frakes, L. A. 1975. General synthesis, Deep Sea Drilling Project Leg 28. Initial Reports of the Deep Sea Drilling Project, Vol. 28, p. 919.Kennett, J. P., 1975. Cenozoic Paleoceanography in the Southwest Pacific Ocean, Antarctic Glaciation, and the Development of the Circumantarctic Current. DSDP Proc. Vol. 29, p. 144.Barker, P. F., Dalziel, Ian. W. D. and Wise, S. W ., (1977) Introduction, Deep Sea Drilling Project Leg 36. Initial Reports of the Deep Sea Drilling Project, Vol. 36, p. 5. There were a total of 15 wells drilled around the Antarctic continent, including 4 wells in the Ross Sea, 5 wells on the continental margins, 2 wells in the abyssal plain and 4 wells across the SE Indian Ridge, among which the Site 270 was drilled at the highest latitude (77° 26.45′ S) Analyses of data collected from the drilling accomplish the following results:

Sea floor spreading

Prior to the deep sea drilling program, the ages of the oceanic basalt were estimated based on magnetic lineations generated at the spreading center as the sea floor pulled apart. Sediments immediately overlying the basalt should have ages similar to the age of magnetic stripes. This is confirmed by the micropaleontologic analyses of the basal sediments sampled above the penetrated basalts. These analyses furthermore substantiate that Australia was separated from Antarctic 85 Mya illion years agoref name="Frakes">Frakes, L. A. and Kemp, E. M. 1973. Palaeogene continental positions and evolution of climate. In: Tarling, D. H. and Runcorn, S. K.eds. Implications of continental drift to the earth sciences. Vol 1. London, Academic Press, p. 539.Thomson, M. A, Crakes, J. A., and Thomson J. W. 1987. Geological Evolution of Antarctica. International Symposium on Antarctic Earth Sciences 5th, Cambridge, England.

Inception of Antarctic ice cap

Based on paleo-soil study, the Ross shelf began to sink below sea-level about 25 Mya in the Oligocene. This suggests that Antarctic glaciers already advanced to the Ross Sea shelf.Drewry, D. J. 1975. Initiation and growth of the East Antarctic ice sheet. Journal of the Geological Society (London), Vol. 131, p. 255.Ehrmann, W. U., and Mackensun, Andreas. 1992 Sedimentological evidence for the formation of an East Antarctic ice sheet in Eocene/Oligocene time Palaeogeography, palaeoclimatology, & palaeoecology ISSN 0031-0182, 1992, Vol. 93(1–2), pp. 85–112. This age is consistent with the dating of the shallow unconformity seen on the seismic profiles. The unconformity was attributed to the glacier erosion when advancing to the coastal area. Development of the Circum Antarctic Current was also initiated in the Oligocene.Fillon, R. H. 1975. Late Cenozoic Paleo-Oceanography of the Ross Sea, Antarctica. Geological Society of America Bulletin, Vol. 86, p. 839. In addition, drilling onshore around the Ross Sea and on the Antarctic Peninsular also confirms that Antarctic ice sheet already existed at least since the Oligocene.Webb, P. N. and Hanwood, D. V., 1991.Late Cenozoic glacial history of the Ross embayment, Antarctica. Quaternary Science Reviews. 10(2–3), p. 215.Davies, B. J., Hambrey, M. J., Smellie, J. L., Carrivick, J. L., and Glasser, N. F., 2012. Antarctic Peninsula Ice Sheet evolution during the Cenozoic Era. Quaternary Science Reviews, 2012. 31(0): p. 30–66.

Ice-rafted debris

The occurrence of ice-rated debris in marine sediments is an indication of icebergs presence. Hence the earliest occurrence in the high latitudes could possibly reveal the inception of sea-level glaciations. It should be pointed out that there are factors influencing the distribution of ice-rated debris, such as ocean currents, and sea water near surface temperatures. Hence the earliest occurrence should be considered as the minimum age of ice rafting at sample locations. Investigations of ice-rated debris reasonably conclude that the Antarctic ice sheet was initiated at least 25 Mya and cumulated at about 4.5 Mya, as evidenced by ice-rated debris reaching farthest away from the continentWilson, G. S., et al., 2012. Neogene tectonic and climatic evolution of the Western Ross Sea, Antarctica — Chronology of events from the AND-1B drill hole. Global and Planetary Change. Volumes 96–97, October–November 2012, p. 189.Margolis, S. V., 1975. Paleoglacial History of Antarctica Inferred from Analysis of Leg 29 Sediments by Scanning-Electron Microscopy. DSDP Proc. Vol. 29 p. 130. This interpretation of Antarctic glaciation history based on marine sediments was subsequently supported by the onshore study of the Antarctic Peninsular Ivany L.C. et al., 2006. Evidence for an earliest Oligocene ice sheet on the Antarctic Peninsula. Geology (2006) 34 (5): 377–380. and by the coring results around McMurdo Ice Shelf.Wilson, G. S., et al., 2012. Late Neogene chronostratigraphy and depositional environments on the Antarctic Margin: New results from the ANDRILL McMurdo Ice Shelf Project.Global and Planetary Change.Volumes 96–97, October–November 2012, p 1.Passchier, S., et al., 2011. Early and middle Miocene Antarctic glacial history from the sedimentary facies distribution in the AND-2A drill hole, Ross Sea, Antarctica. GSA Bulletin (2011) 123 (11–12): 2352–2365.

Paleoclimate

Micropaleontologic data from deep sea sediments around the Antarctic continental margin indicate that since at least the late Oligocene-early Miocene, surface waters were relatively cool. With the continued cooling trend, the cold water mass gradually expanded northward until early Pliocene during which an intensified cooling episode resulted in a temperature minimum as evidenced by the northward shift of the silica/carbonate facies boundary. This deduction is similar to the conclusion based on ice-rated debris studies.Kemp, E. M. and others. 1975. Paleoclimatic significance of diachronous biogenic facies, Leg 28, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project, Vol. 28, p. 909.Kennett, J. P. and Vella, P. 1975. Late Cenozoic planktonic foraminifera and paleoceanography at DSDP Site 284 in the cool sub-tropical south Pacific. Initial Reports of the Deep Sea Drilling Project, Vol. 29, p. 769. Surface temperatures inferred from the oxygen and carbon isotope analyses of both benthonic and planktonic foraminerals in high-latitude marine sediments show a general continuous cooling since early Eocene with a significant temperature drop at the Oligocene/Eocene boundary. This surface water temperature appears to indicate that Antarctic ice sheet probable at this time already reached to the coast. Glaciers on the continent at higher altitudes, however, may have started to grow since the early Eocene.Shackleton, N. J. and Kennett, J. P. 1975. Paleotemperature history of the Cenozoic and the initiation of Antarctic glaciation: oxygen and carbon isotope analyses in DSDP Sites 277, 279, 281. Initial Reports of the Deep Sea Drilling Project, Vol. 29, p. 743. This conclusion is in consistence with other reports documented above.

Notes

Citations

References

External links

Deep Sea Drilling Project Reports and Publications

Deep Sea Drilling Project , Encyclopedia.com

Archiving of scientific results of DSDP in PANGAEA
{{Petroleum industry Marine geology Projects established in 1968 Projects disestablished in 1983 1968 in science 1983 in science