The Deep Sea Drilling Project (DSDP) was an ocean drilling 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, TA&M, or TAMU) is a public university, public, Land-grant university, land-grant, research university in College Station, Texas, United States. It was founded in 1876 and became the flagship institution of ...

, although the program was coordinated by the

Scripps Institution of Oceanography Scripps Institution of Oceanography (SIO) is the center for oceanography and Earth science at the University of California, San Diego. Its main campus is located in La Jolla, with additional facilities in Point Loma. Founded in 1903 and incorpo ...

at the

University of California, San Diego The University of California, San Diego (UC San Diego in communications material, formerly and colloquially UCSD) is a public university, public Land-grant university, land-grant research university in San Diego, California, United States. Es ...

. DSDP provided crucial data to support the

seafloor spreading Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener ...

hypothesis and helped to prove the theory of

plate tectonics Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

. 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 The Ocean Drilling Program (ODP) was part of an international project to explore and study the composition and structure of Earth's oceanic basins. This collaborative effort spanned multiple decades and produced comprehensive data that improved un ...

(ODP) in 1985, the

Integrated Ocean Drilling Program The Integrated Ocean Drilling Program (IODP) was an international marine research program, running from 2003 to 2013. The program used heavy drilling equipment mounted aboard ships to monitor and sample sub-seafloor environments. With this rese ...

in 2004 and the present

International Ocean Discovery Program The International Ocean Discovery Program (IODP) is an international marine research collaboration dedicated to advancing scientific understanding of the Earth through drilling, coring, and monitoring the subseafloor. The research enabled by IODP ...

in 2013.

History

The initial contract between the

National Science Foundation The U.S. National Science Foundation (NSF) is an Independent agencies of the United States government#Examples of independent agencies, independent agency of the Federal government of the United States, United States federal government that su ...

(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 sys ...

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'' on October 18, 1967, in

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

. It sailed down the Sabine River to the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

, 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 oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

, and

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

and

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

. 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 sample A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill. The ...

s 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 A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a div ...

between

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. The retrieved core samples provided strong proof for

continental drift Continental drift is a highly supported scientific theory, originating in the early 20th century, that Earth's continents move or drift relative to each other over geologic time. The theory of continental drift has since been validated and inc ...

and seafloor renewal at rift zones. This confirmation of

Alfred Wegener Alfred Lothar Wegener (; ; 1 November 1880 – November 1930) was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher. During his lifetime he was primarily known for his achievements in meteorology and ...

's theory of continental drift strengthened the proposal of a single, ancient land mass, which is called

Pangaea Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...

. 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 Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic t ...

. Another discovery was how youthful the

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

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

Federal Republic of Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen constituent states have a total population of over 84 ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

, and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

joining the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

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

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...

Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

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

(ODP), continued exploration from 1985 to 2003, at which point it was replaced by the

(IODP).

Coring operations

Although itself a remarkable engineering accomplishment, the '' Glomar Challenger'' 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 borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

in of water off the coast of New York. 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 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 () 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 counterpart of pneumatics, which concer ...

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 university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...

. 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-rafted 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-rafted 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-rafted 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-rafted 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 foraminifera 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
{{Authority control Marine geology Projects established in 1968 Projects disestablished in 1983 1968 in science 1983 in science