The Ocean Drilling Program

The recent exploration of planets in our solar system, such as Mars and Jupiter, has been prominent in the media. The images of the surface of Mars from the Sojourner rover have captured our imagination and demonstrated that the human desire for exploration is still very strong. As we look to the stars, we need to remember that much of our own planet still remains unexplored.The oceans cover two-thirds of the surface of the earth. It is ironic that we have a higher resolution view of the surface of the moon than we do of the earth beneath the sea. This summer marked the passing of an individual who did an enormous amount to initiate the exploration of the seas. Jacques Cousteau, an inventor, explorer, and environmentalist realized the vast unexplored nature of the oceans and their important role in sustaining life on Earth. Through his books, pictures, and films, he increased public awareness of the oceans and profoundly influenced how ocean resources are managed.
     In this issue of Maritimes, we look at an exploration program that has not received the kind of public recognition that the space program has but has, nevertheless, led to fundamental discoveries about the Earth. The program, called the Ocean Drilling Program (ODP), began 19 years ago as the Deep Sea Drilling Project. Conceived by earth scientists who wanted to drill deep into the earth's interior, it has evolved into an international multidisciplinary program of cooperative research. ODP is now funded by seven international partners representing 21 countries. These partners are the Australia/Canada/Chinese Taipei/Korea consortium for Ocean Drilling; the European Science Foundation Consortium for Ocean Drilling comprising Belgium, Denmark, Finland, Iceland, Italy, Norway, Portugal, Spain, Sweden, Switzerland, the Netherlands, and Turkey; France; Germany; Japan; the United Kingdom; and the United States.
     The basis of the program is drill into the seafloor and recover deep cores by using a ship that is, in essence, a floating drill platform. Since 1985, the Ocean Drilling Program has utilized the 143m long JOIDES Resolution as its primary research vessel. It travels the world's oceans carrying a permanent crew of 50 with space for an additional 50 scientists and technicians. Each cruise, or leg, lasts for two months, and the ship operates on an almost year-round basis. With technology developed for the oil industry, the program has drilled more than 1,000 holes throughout the world's oceans. More than 138km of sediment and rock have been recovered, providing more than 1 million samples for more than 1,700 shipboard scientists. These samples have led to the confirmation of theories regarding seafloor spreading, the Earth's magnetic field reversals, undersea volcanism, and plate tectonics. It has provided the long-term records necessary to look at the variations in Earth's climate over millions of years.
     Over the years, the University of Rhode Island has maintained a strong presence in the program through participation of scientists on cruises, service on advisory panels, and the gneration of proposals to drive the scientific objectives of the cruises. A former Graduate School of Oceanography faculty member, Jeff Fox, is the director of ODP. In this issue, we highlight the role that the Graduate School of Oceanography has played and will continue to play in the future of the Ocean Drilling Program. As we move into the next millenium, the oceans will prove to be increasingly important in sustaining the well-being of the world's growing population. Its continued exploration will remain a fundamental priority.

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Drilling Aboard JOIDES Resolution
There is no other ship in the world with the same capabilities as the JOIDES Resolution. Outfitted with sophisticated technology that stabilizes the ship during drilling and coring, modern navigation equipment, and labs, the ship has drilling capabilities for 99.9 percent of the world's oceans. The derrick on the ship rises 61.5m above the water line and the drilling system can handle 9,150m of drill pipe. Illustration courtesy of the Joint Oceanographic Institutions.

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The Future of Ocean Drilling

Jeff Fox, Director of Science Operations
ODP, Texas A&M

Much to my surprise and delight, I have found that living in Texas, in general, and in the land of the Texas A&M Aggies, in particular, has not been deleterious to my or my family's Yankee-bred health. Fond memories of my 14 years at GSO/URI, and the collegial environment of the Bay Campus, have helped bridge the challenges associated with relocation, adjusting to a major careeer change, and building a house.

The Ocean Drilling Program (ODP) is a consortium of 20 countries that have combined their resources to sponsor an international science initiative. The science program is designed to utilize the unique capabilities of the drilling ship JOIDES Resolution. The JOIDES Resolution operates in global ocean depths ranging from 75 m to 6,500m and can drill hole and recover core to depths below the sea floor in excess of 2,000m. The goal of the program is to use the remarkable capabilities of the JOIDES Resolution to elucidate the secrets of our planet's history that are preserved with great fidelity in the sediments and rocks that compose the sea floor.
      The resources of ODP are finite, and every effort is made to ensure that only the best and most compelling scientific questions are addressed. The international community of scholars who determine the investigative strategies and the scientific priorities for the program have created a long range plan establishing a course for the program into the 21st century. Two major themes have been defined: Dynamics of Earth's Environment and Dynamics of Earth's Interior. Within each theme, several core endeavors and specific initiatives are identified that capitalize on new scientific frontiers, interdisciplinary approaches, greater collaboration with international geoscience programs, and enhancements in drilling technologies.
      Dynamics of Earth's Environment: Understanding the climate system, and its response to factors such as global warming from greenhouse gases, is critical to the future of humankind. The program will investigate decade-to-century time scale variations by collecting long and extremely high-resolution sedimentary sections. These data will allow ODP to investigate the relative sensitivity of climate to greenhouse gases and Earth's orbital changes, the role of polar ice sheets in regulating climate change, and the history of Pacific and Atlantic deep waters. During the next five years, a high priority of ODP is to provide scientists with the following: 1) a first-order global sampling of key climatic systems so that decade-to-century scale variations in climate and their impact on sea-level changes can be resolved, 2) cores from stable areas of seafloor where high-resolution, orbitally tuned geologic time scales can be established extending to at least 40 million years ago, 3) sampling transects to better define northern and southern hemisphere heat transport. These high resolution data will allow us to resolve how the Earth climate system in the past has responded to a variety of changing factors. These insights, in turn, will allow scientists to understand how the Earth's climate system is likely to respond in the future.
     Variations in the chemical composition of sediments deposited through time, the nature of subsurface fluids, and the biochemical process associated with bacteria within the substrate all act to change Earth's environment in ways that are appreciated but still poorly understood. A high priority for ODP will be to focus on the cycling of carbon through the ocean, atmosphere, and landmasses by recovering sediments from key intervals in Earth's history when extreme perturbations in the carbon cycle and climate are known to have occurred, and to explore the distribution, extent, and formation of gas hydrates, a major carbon reservoir trapped in the sediments of the submerged continental margins. ODP will also explore the interactions of fluids, sediments and bacteria, and how these physical, chemical, and biological processes react in time and space to create mineral deposits, hydrocarbon reservoirs, and global geochemical cycling.
     Earth's deep biosphere represents a new and exciting pilot project. Bacteria live in sediments at depths of at least 1,000m below the seafloor, and in volcanic rocks along mid-ocean ridges. In fact, some investigators suggest that the biomass of the bacteria in these environments may surpass the biomass known to inhibit the more familiar environments on our planet. ODP will explore the distribution, depth, extent, and genetic range of the deep biosphere, in order to understand its biology, ecology, and contribution to the global carbon budget. Another goal in the next five years will be to implement hydrogeological experiments addressing the magnitude of fluid flow and geochemical cycling in different tectonic settings.
      Dynamics of Earth's Interior: ODP will focus on mantle dynamics, the formation and structure of oceanic crust, hydrothermal processes and sulfide mineralization, crustal alteration, and recycling of material at subduction zones. Moreover, it is planned that in the next five years ODP will have laid the foundations of a global network of seafloor borehole seismic observatories, as part of the International Ocean Network designed to improve our understanding of Earth's dynamic interior. ODP will also quantify the substantial interior-to-surface energy transfer represented by the emplacement of Large Igneous Provinces, regions of the Earth where massive outpouring of magma have taken place in the geologic past.
     A long-standing problem in marine geology is the deep structure and composition of the oceanic crust because these elements have been difficult to directly observe or sample. A major goal for the Program is to compare the structure of fast and slow spreading crust down to depths of about 3km, quantify the mass and heat budgets associated with the formation of oceanic crust, and test the geophysically determined model of oceanic crust. The oceanic crust that is created along the axis of the world-encircling mid-oceanic ridge system results in vigorous hydrothermal circulation and chemical reaction of hot rocks and seawater. These processes are responsible for the exchange of heat and mass between the lithosphere and hydrosphere. Assessing these exchanges requires long-term monitoring of subsurface physical, chemical, and hydrogeological processes within the oceanic crust. Hydrothermal circulation leads to the formation of massive sulfide deposits, a potentially valuable source of certain metals. A goal during the next five years will be to provide scientists with the data to determine the structure of a sulfide deposits and to support setting up a ridge-axis observatory designed to monitor key processes.
     Subduction at convergent plate margins is the mechanism by which sediment and crustal material is recycled into the mantle. ODP will provide scientists with the means to determine subduction zone fluxes by quantifying both the inputs (oceanic sediment and crust) and the outputs (volcanic sediments, fluids and magmas). An ongoing initiative is to produce estimates of subduction fluxes at Pacific convergent margins during the next five years. The processes associated with subduction have formed some of the largest mountain ranges, and an ongoing goal is to establish the links between deformation, fluid flow and exhumation during convergence and mountain building. Some of the largest earthquakes in the world are associated with convergent margins, and ODP aims to advance the understanding of earthquake mechanisms by providing the necessary boreholes and hardware support for scientists to carry out in situ monitoring of key physical properties involved in faulting. A major goal is to understand the initiation and propagation of earthquakes at a convergent margins, and the relationship between fluid flow and geohazards.
     Understanding the processes that give rise to the structure and stratigraphy of continental margins that form by the splitting of a large landmass, specifically the partitioning of deformation due to strain, is a key ODP objective. ODP aims to investigate the mechanism of how continents break up, and the nature of the boundary between the continetns and oceans by direct sampling of the deepest portions of shallow continental margins (especially pre--rift basement rocks, rift-related volcanics, and the oldest xsediments deposited on the margin).
     If ODP is to be successful in executing this ambitious scientific plan during the next six years, some critical technologies and innovations will have to be implemented in the near future. Those developments include: higher resolution tools for enhanced imaging of drillholes; new technologies to increase drilling depth, hole stability and core recovery; and microbiological systems for better detection and on-board analysis. In addition, there is a need for improved techniques for collecting downhole logs of data at the same time that drilling is taking place, a better correlation of logging and coring data, and the development of advanced borehole observatories (instruments place in drillholes for long periods of time), for improved monitoring of active processes at depth.     
      The global ocean is this planet's last frontier. The JOIDES Resoluiton is to the history of the Earth contained in the seabed what the Hubble telescope is to astronomy and the history of the universe.

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URI Involvement in Deep Sea Drilling

Margaret S. Leinen, Dean of the Graduate School of Oceanography
and Vice Provost for Marine Programs

Margaret Leinen, appointed dean of GSO in 1991, is one of only three women in the United States to head a major oceanographic institution. Leinen earned a Ph.D. in 1980 from GSO and became a full professor of oceanography in 1989. Leinen serves on many domestic and international scientific committees, is a Fellow of the Geological Society of America, and has participated in more than 15 scientific cruises since 1974.

The faculty, research scientists, graduate students, and deans of the Graduate School of Oceanography (GSO) have had a long history with the Deep Sea Drilling Project (DSDP) and its successor, the Ocean Drilling Program (ODP). The drilling programs have been managed by the Joint Oceanographic Institutions (JOI), an organization comprising U.S. oceanographic institutions including GSO, that play a leadership role in the drilling program. JOI institutions have each had a representative on the scientific Planning Committee (PCOM) of DSDP and ODP, and the deans and directors of the JOI institutions serve on the Executive Committee (EXCOM) of the program to provide links between the organizations that do ocean research and the scientists.
      GSO first joined the Drilling Project as a partner and member of JOI in the early 1970's. DSDP was expanding from a program run by a few institutions to one with broad support from the oceanographic and geoscience communities. (Roger Larson's article describes early achievements of DSDP.) Our partnership in the scientific planning and management of DSDP opened new opportunities for GSO faculty and students and led to the expansion of the geological oceanography program at GSO.
      During the first phase of drilling, Jim Kennett, GSO faculty member, and his colleagues and students at GSO, focused on high-latitude drilling. Kennett served as paleontologist on Leg 21, the first high-latitude drilling leg, and was co-chief scientist of Leg 29 between New Zealand and Antarctica which produced the first cores near the Antarctic Circle. Kennett's work provided the first long-term histories of sedimentation in the Southern Ocean and emphasized the remarkably rapid changes in sedimentation, ocean circulation, and climate that took place during the Miocene (5 to 23 myBP). The critical role of high-latitude oceans in controlling climate became a long-term theme of GSO paleoceanography leading to Kennett's role as co-chief scientist on Legs 90 and 113 in the Southern Ocean and later to the role played by Michael Arthur, GSO faculty member and co-chief scientist on Leg 105 of ODP in the northern high latitudes. Others who participated in high latitude drilling legs have included Monty Hampton, URI geology professor (Leg 29).
      In 1974, GSO recruited Ross Heath and Ted Moore (then at Oregon State) to join Kennett and Norm Watkins, who were already here, in an exciting new paleoceanographic initiative at GSO. Heath and Moore were no strangers to DSDP. Moore had sail-ed on Leg 8 (back when scientists had private staterooms) and Heath had been a co-chief on Leg 16. These two legs had formed the backbone of a new understanding of equatorial Pacific history. Equatorial Pacific studies, especially paleoceanographic studies, have been another recurring research theme at GSO. This theme was developed further by Heath and Moore's students, Nick Pisias (scientist Leg 85; co-chief scientist Leg 138), Dean Dunn (scientist, Leg 85), Karen Romine (scientist, Leg 92), me (scientist, Legs 68 and 138), and others who spent time at GSO, like Larry Mayer (now a scientist at the University of New Brunswick and a member of the Ocean Drilling Program Council; scientist on Legs 68 and 130, co-chief scientist on Legs 85 and 138), Lloyd Keigwin (a GSO student now a scientist at Woods Hole Oceanographic Institution; scientist on Leg 68), and Terri King (a student of Nick Pisias who became a GSO faculty member; scientist on Legs 138, 154, and 162).
      In 1974, Germany and the USSR joined the Deep Sea Drilling Program as full members, and the program made the transition to the International Program of Drilling (IPOD). During this time, GSO was also expanding its capabilities in geological oceanography. GSO recruited oceanography professors Roger Larson, Jeff Fox, and Bob Detrick who had a profound influence on the nature of geophysical and ridge crest drilling in IPOD and its successor, ODP.
      One of Larson's interests was the unique geophysical character of the Pacific Ocean during the Jurassic and Cretaceous (205 to 63 myBP, the ages of the great dinosaurs). Obtaining sediments and igneous rock from the oldest part of the ocean has been one of Larson's quests since his earliest participation in DSDP (co-chief, Leg 31), IPOD (co-chief, Leg 62), and ODP (co-chief, Leg 129 and scientist, Leg 144). In the course of this search for the oldest crust, Larson made significant advances in our ability to drill long sediment sequences and to drill through the flinty cherts of the North Pacific.
      Fox joined GSO while serving as the chair of the Ocean Crustal panel, responsible for drilling through the ocean basement rocks and in hydrothermal environments. Under his leadership, the first hydrothermal systems were drilled in the Galapagos Islands (Bender, GSO faculty, scientist, Leg 70), and hydrothermal history transects were drilled in the Pacific (Leinen, co-chief, Leg 92).
      During the late 1970's, the drilling community realized that new drilling capabilities were necessary for several types of geologic problems, especially the evolution of the polar oceans and the crust at active spreading centers. The community envisioned an international effort with expanded international membership and became engaged in a lively debate about upgrading the existing ship or buying a new vessel. One suggestion was to convert the Glomar Explorer, a vessel that had been used to raise a Soviet submarine from the deep Pacific seafloor, into a drill ship. Others argued for the construction of a new vessel capable of drilling in environments that had oil potential. This discussion culminated in the Conference on Scientific Ocean Drilling (COSOD) in 1981 led by a steering committee chaired by Larson. Detrick, Arthur, and Moore (then at EXXON) all served on working groups of that conference.
      As the international geological community debated the scientific problems to be addressed and how to stimulate the international investment for a new drilling vessel, it became clear that we might be looking at a substantial time interval between the end of the approved DSDP program, agreement on a new vessel, and the beginning of a new drilling program. Kennett played a major role in addressing the need for a continuation of drilling during this transition. Kennett, his colleagues, and students highlighted the importance of "thresholds and gateways" for ocean circulation changes that caused dramatic changes in the chemistry and circulation of the ocean and in the atmospheric and climatic response to these changes. He emphasized the capabilities of the Glomar Challenger for pale-oceanographic drilling, and his work stimulated a proposal for a transition period that emphasized this paleoceanographic drilling and set the state to continue drilling. The "thresholds and gateways" theme has extended into the current Ocean Drilling Program.
      The Ocean Drilling Program (ODP) leased a new drilling vessel, the SEDCO/BP 471, later named the JOIDES Resolution. The new ship was bigger, had more laboratory and bunk space, more drill depth capability, better stability in heavy weather, and fit the expanded goals of the program.
      Larson played a pivotal role in the scientific leadership of the newly formed Ocean Drilling Program. He was the first chair of the primary science Planning Committee (PCOM) and hosted the first international JOIDES office.
      ODP began with fanfare and high hopes. By the mid-1980's, it was clear that technological development and perhaps even alternate drilling platforms would be needed in the future to drill the most exciting targets. EXCOM commissioned another Conference on Scientific Ocean Drilling (COSOD II). Fox was a member of the steering committee, and I served on a working group.
      During this time, Fox and Detrick played an important role in the leadership of the Lithosphere Panel. They were very influential in convincing the drilling program to develop technology for drilling in young crustal areas with little sediment cover to support the drill string and for the development of a suite of tools for studying the hydrothermal fluids circulating in these rocks. Detrick served as a co-chief scientist on the first leg (Leg 106) to experiment with new hard rock guide bases (which now have become routine) for drilling a ridge crest. Several legs have explored this challenging technical problem since.
      Larson served as co-chief scientist on one of the most memorable ODP legs (Leg 129) on which he realized his goal to drill crust of Jurassic age (200 myBP), the oldest rocks ever recovered from the ocean. But even more exciting were Larson's ideas about the origin of Earth's magnetic field changes during the Mesozoica superplume of igneous and volcanic activity arising from changes at the core/mantle boundary and resulting in the generation of massive submarine volcanic eruptions.
      Michael Arthur, a paleoceanographer with interests in the Jurassic and Cretaceous ocean, had been a staff scientist with the DSDP before becoming a faculty member. He led one of the very first ODP cruises (Labrador Sea, Leg 105). He was joined by three GSO students, Kathleen Dadey (who also participated on Legs 126 and 138), Frank Hall, and Jim Zachos (participants on Leg 120).
      Haraldur Sigurdsson and Steve Carey have long been interested in explosive volcanism and have been actively involved in the debate about the extinctions associated with the end of the Cretaceous period and beginning of the Paleocene (the Cretaceous/Tertiary boundary). Among those extinctions are extinctions of several dinosaur groups. In their research, they showed that features of this important transition period could not be explained by explosive volcanism. With Steve D'Hondt, they focused instead on field work in the Caribbean to look at the relationship between a major asteroid impact in Mexico at the end of the Cretaceous and the oceanographic and evolutionary events at the same time. Their work culminated in an ODP leg (Leg 165) in the Caribbean which drilled holes to test the hypothesis that the Mexican asteroid impact generated ocean tsunamis and other effects that could be seen in the sediments. They were joined by several other GSO and GSO-trained scientists, including John King and Rick Murray. The cruise was enormously successful and drilled the first complete sequence of sediments that showed the fallout from the collision debris itself and a "Strangelove Ocean" devoid of almost all microscopic life because of the sulfuric acid generated from the volcanic gas interaction with the atmosphere. Now the Ocean Drilling Program is in the process of another transition in which it considers new and alternate drilling platforms. An exciting proposal for Japanese construction of a very large drilling vessel is being considered by the international community. ODP has renewed its scientific advisory structure to focus on the themes identified in its long-range plan: the dynamics of the environment and the ocean crust and mantle. GSO scientists are strong contributors to this evolution of the program. Larson serves as a member of the Science Committee that guides the entire program, and D'Hondt is a member of the Science Steering and Evaluation Panel on Earth's Environment.
      Some of our contributions have been the people who left GSO to have greater involvement with the drilling program. Bob Duce, dean from 1987 to 1991, left URI to become dean of the College of Geosciences and Maritime Studies at Texas A&M. This college is the home of the Ocean Drilling Program, and Duce became the dean responsible for its administration. In 1996, Fox left GSO to become the chief scientist of the Ocean Drilling Program. Both Duce and Fox have made substantial contributions to improving the quality of the program and its responsiveness to the scientific community.
      The most interesting thing for me to watch over these past 20 years at GSO has been the way in which faculty participation has led students to participate in the drilling program and to establish their own new research themes. Among the former students who participated in cruises and have not already been mentioned are Lowell Stott, Eve Arnold (who describes her experience in Ocean Drilling Fellowships), Alexandra Isern, Gail Lombari, Marion Rideout, Sassan Salehipour, Lew Abrams, and Christian Lacasse.

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Scientific Ocean Drilling: An American Success Story

Roger L. Larson, Professor of Oceanography
Graduate School of Oceanography

Roger Larson earned a B.S. in geology from Iowa State University and a Ph.D. from Scripps Institution of Oceanography. He was a researcher at Lamont-Doherty for 10 years until he came to URI in 1980. He specializes in the history of world-wide crustal production, geological consequences of superplume episodes, and tectonic and volcanic history of the Mesozoic-aged Pacific.

The Ocean Drilling Program, or more generally, scientific ocean drilling, began in the late 1950's at Scripps Institution of Oceanography. Several scientists from diverse backgrounds conceived of the idea to drill a hole beneath the deep seafloor and into the Earth's mantle. This idea eventually led to a program called "The Mohole Project" in the early 1960's which resulted in the drilling of one test hole. But then the program became entangled in politics and cost overruns and was eventually abandoned as a classic example of pork barrel science. However, out of the ashes of the Mohole Project grew a different idea, to drill not just one very deep hole, but many shallower holes into all the ocean basins, concentrating mainly on the sediments and what they could tell us about the evolution of Earth. This became the Deep Sea Drilling Project (DSDP) which first went to sea with the drill ship Glomar Challenger in August 1968. It was entirely an American-funded program, although non-American scientists were invited to participate almost from the beginning. The original DSDP members were Scripps, the Lamont Geological Observatory, the University of Miami, the University of Washington, and the Woods Hole Oceanographic Institution.
      No one knew quite what they would find once drilling began. In those early days, there were no samples deeper than the longest piston core that had been taken from about 20m into the seabed. Marine geology at the time was in a state of great upheaval. The concept of "sea-floor spreading" had recently been proposed as an oceanic extension of "continental drift," a very unpopular idea in most American circles. For example, in 1967 when I was a graduate student and one year before Leg 1 of DSDP left the dock, one of our professors offered to bet anyone in the room $20 that DSDP would recover a continuous Phanerozoic sediment section and bottom out in Precambrian basement beneath the deep seafloor. In doing this, he echoed the views of the famous American geologist James D. Dana more than 100 years earlier who also believed in the fixity of continents and ocean basins. In addition, my professor demonstrated that it is hard to make major advances in scientific thinking without improved technology. As Bertolt Brecht put it, "Astronomy did not progress for 1,000 years because astronomers did not have a telescope."
      Glomar Challenger became an inward-looking "telescope" that revolutionized the way we think about the Earth almost as completely and as quickly as Galileo changed our view of the solar system in 1610 when he first saw moons revolving around Jupiter. Ken Hsu, a Chinese scientist by birth and a scientist aboard Leg 3, wrote a book entitled "Challenger at Sea" that includes a dramatic description of his reaction to the results of that cruise. On that historic leg, the seafloor spreading hypothesis was directly tested and supported by every hole drilled. "The drilling campaign of Leg 3 was one of the greatest triumphs in geology," Hsu wrote. "I was lucky to be there, and to make a conversion from Saul to Paul. Twenty years after I left China, I finally learned to think like an American, like a European."
      Leg 13 in 1970 brought a completely different but also dramatic discovery and eventually led to the shared international funding of DSDP. Scientists on Leg 13 discovered that the Mediterranean Sea had completely dried up eight million years ago, as the Straits of Gibralter were dammed shut by the continents of Africa and Europe jostling together a bit more closely than usual. This was big news, not only in Europe but also in the United States. The co-chief scientists were Bill Ryan, an American from Lamont and Hsu. During a news conference in the U.S., Ryan was asked how many of the other nine scientists aboard Leg 13 were Americans besides himself. His answer? None. This was not a problem for scientists, as the experts on Mediterranean geology naturally were mainly Europeans. However, this was something of a paradox to the National Science Foundation (NSF). NSF was paying 100 percent of the costs with American dollars for a project that was, during Leg 13, 90 percent non-American. Thus, negotiations began for a new phase, the International Phase of Ocean Drilling (IPOD), which began on Leg 35 in 1974 with Germany and the USSR as the original international members. Eventually, they were joined by France, the United Kingdom, Japan, and other American universities: the University of Hawaii, Oregon State University, the University of Rhode Island, Texas A&M University, and the University of Texas. Even with this international funding and participation, the U.S. still provided about half the funding and about half the shipboard scientists. DSDP-IPOD was operated by Scripps, and Glomar Challenger was an American ship.
      DSDP-IPOD lasted until Leg 96 in 1983. I'm not sure why it was shut down, other than government funding agencies don't like to have projects go on indefinitely, and the ship was getting old. It certainly was not for lack of interest or success. In any event, knowing of the imminent demise of DSDP, we convened the first Conference on Ocean Drilling (COSOD-I) that I chaired in 1981 to build the rationale and support for a new scientific ocean drilling program. Out of COSOD-I grew the present Ocean Drilling Program (ODP) that first went to sea in 1985 with a new ship, the JOIDES Resolution and a new science operator, Texas A&M. The original international partners, minus the USSR, were joined by two international consortiums: one of smaller European countries and the other from Canada and Australia. The funding and participation levels have remained with at least 50 percent shares coming from the U.S. ODP has just finished its 73rd leg, and probably will be extended through 2003. We drilled the 1,000th site in the combined DSDP-ODP program in January 1996.
      U.S. interests are looked after in ODP by the American scientists who sit on the international committees and panels and by an all-U.S. group of scientists, the U.S. Science Advisory Committee (USSAC) for ODP. I chair USSAC, a committee of about 15 scientists with interests and experience in scientific ocean drilling. Originally conceived at the beginning of ODP as a group to simply manage post-cruise science funding for American shipboard scientists, USSAC recently has become a group that speaks for U.S. interests in many scientific and policy matters. For example, about a year ago, USSAC proposed that U.S. representation on the Planning Committee, the most powerful scientific committee within ODP, should be broadened from just the 10 member U.S. institutions, each holding a reserved seat from the start, to any U.S. scientist at any institution with strong scientific credentials and broad ODP experience. This recently has been implemented, and half of the U.S. members on the ODP planning committee now come from beyond the original U.S. institutions. More recently, NSF asked USSAC to comment for the U.S. in an NSF document on the possibility of expanding scientific ocean drilling after 2003 to include not only our existing drilling capabilities, but also a new drilling system called deep riser, an extension of oil-drilling technology. USSAC agreed, and Japan is actively considering building a ship that could deploy deep-riser technology.
      Besides these special issues, USSAC is always about its usual business, which has expanded from doling out post-cruise funding grants to U.S. shipboard scientists. USSAC maintains a Fellowship Program for U.S. graduate students working on ODP science projects, operates a Distinguished Lecturer Series of U.S. scientists who carry the results of scientific ocean drilling to U.S. institutions not heavily involved in ODP, funds Americans to attend workshops on topics of drilling-related interests, and creates educational tools for the classroom, such as CD-ROMs based on scientific problems that can be attacked by scientific ocean drilling.
      USSAC's latest project is a compilation of one-page, illustrated abstracts called "ODP's Greatest Hits" which highlights the accomplishments of American scientists with the Ocean Drilling Program. This coincides with the proposed extension of ODP funding from NSF for the next five years. It contains a number of independent and startling results. For example, within this volume scientists present evidence that explain the formation of huge present-day, ore-grade deposits of iron, copper, and zinc precipitated out of hydrothermal fluids heated to more than 300°C and rising as hot springs from the center of spreading ridges. Perhaps even more astonishing is the evidence for much larger amounts of lesser-heated water percolating through the ridge flanks now. Earth was even more thermally active in the Cretaceous than it is now. During the Cretaceous, enormous plumes of mantle rock rose beneath the lithosphere and triggered the formation of individual volcanoes and volcanic plateaus at rates unknown in today's world. Large volumes of natural gas are frozen in marine sediments, and we have discovered that there is enough locked up in a field off the Carolina coast to supply U.S. needs for more than 100 years. It appears likely that the oceanic crust is home to an unforseen microbial community called the deep biosphere whose concentration is small, but because oceanic crust is the most common rock sequence on Earth, may contain a significant fraction of Earth's biomass. Throughout all of this, the periodicities of Earth's orbit about the Sun have hammered out a climatic rhythm like a snare drummer keeping the beat in a tune with seemingly endless verses.
      All of this would have been considered science fiction 30 years ago, but after more than 170 legs of DSDP and ODP drilling, we now believe that many of these "amazing sea stories" and more are true. Future studies will bring more startling and unexpected discoveries that were not part of anyone's long-range plan, for certainly no one predicted any of the just-cited examples 30 years ago. As Wilbur Wright said in about 1908, "We can see enough now to know that the next Century will be magnificent; only let us be the first to open the roads."

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Deep-Sea Evidence for Explosive Volcanism in the Western Caribbean (ODP Leg 165)

Steven N. Carey, Associate Professor of Oceanography,
Haraldur Sigurdsson, Professor of Oceanography
Graduate School of Oceanography

Steve Carey earned his Ph.D. from GSO in 1983. His research interests include the mechanisms of explosive volcanism and the deposition of volcaniclastic sediments in the ocean.

Haraldur Sigurdsson received his Ph.D. from Durham University in England. His research interests include the study of explosive volcanism and the environmental consequences of major asteroid impacts with the Earth. He was recently co-chief scientist on ODP Leg 165 in the Caribbean Sea.

Volcanic eruptions are fundamental in the exchange of material and energy from the earth's interior to the oceans and atmosphere. Throughout history mankind has been fascinated with the power of volcanoes and the dangers that they pose to the people who live around them. In the last few decades new research has shown that large volcanic eruptions can cause both local and global scale environmental effects. Thus, it is important to understand the processes of volcanism, the role they have played in the past, and what we might expect in the future.
      Many people's view of volcanism has been shaped by popular images of red hot lava flows erupting from Hawaiian volcanoes. Although this constitutes an important type of volcanic activity, a far more dangerous style of activity involves the explosive eruption of magma. In this type of eruption, magma is explosively broken up into small pieces by the tremendous force of rapidly expanding volcanic gases. The eruption of Mount St. Helens in the Pacific Northwest (May 18, 1980) is a good example of this type of event. During such eruptions, large amounts of volcanic particles and gases can be injected up into the air by large mushroom-shaped clouds that rise from the vent. These clouds can reach altitudes of 40 km in the Earth's atmosphere and often resemble the large plumes developed when an atomic bomb is detonated. The volcanic plumes are transported by local wind and can form a global belt of high altitude aerosols. A particularly important aerosol that forms from explosive eruptions are tiny droplets of sulfuric acid that can reside in the atmosphere for several years. These droplets can affect the energy balance of the atmosphere and, in many cases, reduce incoming sunlight and lower surface temperatures.
      How large are potential eruptions? This is an important question about explosive volcanism. Some insight can be derived from historical observations of volcanic eruptions. Volcanologists gauge the size of eruptions by calculating the volume of magma that has been erupted. The unit that is commonly used is km3 of magma (a volume equivalent to a cube of magma 1 km long on each side). The eruption of Mount St. Helens in May 1980 ejected about 0.5 km3 of magma. Although the eruption looked quite spectacular, in reality it was actually a relatively small explosive eruption. The largest historic explosive eruption was the 1815 eruption of Tambora volcano in Indonesia. About 50 km3 of magma was discharged during this event and more than 90,000 people were killed. There is, however, evidence in the geologic record of much larger explosive eruptions. For example, an eruption in Indonesia from the Toba caldera discharged more than 1000 km3 of magma about 75,000 years ago. This raises a variety of interesting questions. If such an event occurred today, what would the environmental consequences be? How would the world's population be impacted? Are these kinds of eruptions likely to occur in the future?
      Recent drilling on Leg 165 of the Ocean Drilling Program in the Caribbean Sea has provided a fascinating new record to evaluate these types of questions. Five sites were drilled in the Caribbean Basin ( see Fig. 1). Four of the sites revealed evidence of extensive explosive volcanism in the circum-Caribbean area. This evidence takes the form of thin bands of volcanic ash that are between layers of sediment which accumulated very slowly in the deep sea. The layers are usually a few to tens of centimeters thick with a very sharp bottom contact and a diffuse upper contact. The ash was formed when magma was cooled very quickly by contact with air (turning to glass) and broken up into very small pieces by the expansion of gases during the eruption (see Fig. 2). In essence, these are layers of broken glass that extend over hundreds of kilometers. Each layer represents the fallout of material that was injected high into the atmosphere during an explosive eruption and transported downwind. In all, over two thousand layers were recovered, ranging in age from 0 to 67 million years.
      The thickness and lateral extent of the layers are related to the size of the eruption and the strength of the winds that blow the volcanic ash into the ocean. These parameters can be used to calculate the volume of material ejected during individual eruptions. In the western Caribbean the layers cover an enormous area with the thickest total accumulation centered around site 999. Judging from the thickness of individual layers as a function of distance from source, the layers in the Caribbean cores suggest enormous eruptions, probably in the range of 100 to 1,000 km3 of magma.
      What was the source of all of this explosive volcanism? The rims of the Caribbean basin today are volcanically active, with explosive volcanism occurring along the eastern margin, in the Lesser Antilles island arc, and on the western margin, through Mexico and Central America (see Fig. 1). One way to assess the potential source areas of volcanism is to look at the atmospheric circulation, or transporting agent, of volcanic ash in the area. In most of the Caribbean, the surface winds blow from the east to the west, in a belt known as the trade winds. However, starting at aboiut 14 km up to 24 km in the atmosphere, the winds shift direction by 180o ,blowing west to east transecting the boundary between the troposphere and the stratosphere. Most large explosive eruptions can easily inject volcanic ash and gases to stratospheric levels and thus the most significant amount of transport occurs from the west (Central America) to the east (Caribbean Sea). Based on the present day wind patterns, it is apparent that most volcanic ash transported into the Caribbean must be derived from sources to the west. Volcanic ash fallout from explosive eruptions in the Lesser Antilles, on the other hand, mostly ends up in the eastern equatorial Atlantic.
      A computer simulation of the ash fallout has been developed to evaluate the types of conditions necessary to produce the observed layers in the cores. Input to the model consists of the wind strengths and directions in the Caribbean area based on a large meteorological database. The size of the eruption can then be varied to match the size of volcanic ash found at a particular distance downwind from source. Preliminary results indicate that transport was most likely from the west, but with eruption column heights that must have reached well into the stratosphere (see Fig. 3).
      If, as we suspect, most of the explosive volcanism recorded in the Caribbean deep sea sediments is derived from a western source, then there should be evidence on land to support this hypothesis. As previously mentioned, active volcanism is occurring along Central America. This volcanism is the result of Pacific sea floor being forced under, or subducted, beneath the Central American landmass. As this ocean floor returns deep into the earth, overlying rocks melt supplying the magma necessary for volcanic activity. There is evidence on land of major volcanic deposits produced by explosive volcanism in Honduras, Nicaragua, and Guatemala. These deposits are similar in age to many of the volcanic ash layers in the deep sea cores. Ignimbrites, a distinctive rock preserved on land, are created from pyroclastic flows, formed when an eruption column collapses into a deadly mixture of hot gases and particles that move at hurricane speeds down the slope of a volcano. In Central America, there are abundant, thick ignimbrites that undoubtedly correlate to the widespread ash fall layers found in the deep sea cores.
      Research at the Graduate School of Oceanography will attempt to link the record of volcanism on land with the excellent record of ash layers in the deep sea. By using computer simulations of the volcanic events the size, nature and potential environmental impacts of these eruptions will be evaluated. The Leg 165 deep sea record holds tremendous potential for reconstructing the detailed history of explosive volcanism in the Central American area and contributing to a better understanding of this important type of volcanism.

Recommended Readings
Volcanoes: A planetary perspective, by P. W. Francis. Oxford University Press, Oxford, pp. 209-234, 1993.

Sigurdsson, H, Leckie, M, Acton, G. et al., 1997. Proc. ODP, Inititial reports, 165. College Station, TX (Ocean Drilling Program)

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Ocean Drilling Fellowships

Eve M. Arnold, Assistant Professor of Geology
Indiana University of Pennsylvania

Eve Arnold received a B.A. and an M.A. in geology from SUNY Buffalo and earned her doctorate at the Graduate School of Oceanography in 1996. Arnold worked as a post- doctoral fellow for GSO Dean Margaret Leinen, and in the fall of 1997, Arnold began teaching at Indiana University of Pennsylvania after returning from ODP Leg 174B in August.

As a Ph.D. candidate at GSO, my research focused on the present-day eolian transport processes in the North Pacific Ocean. (Eolian means carried, produced, or deposited by the windit originates from the word Aeolus, the Greek god of the winds.) Simply put, I study dust that is blown from the arid regions of Asia and transported through the atmosphere until it settles back onto Earth's surface. While atmospheric dust may seem like a strange thing for a geological oceanographer to be interested in, it is important because ancient dust deposits on the continents (loess) and in the deep sea (pelagic clays), tell us a lot about ancient climate and how atmospheric circulation has changed in the past.
      While working on my doctorate, I read an ad describing fellowships from the Joint Oceanographic Institutions (JOI) which provide funding for students to expand on their thesis research by studying sediments collected aboard the Ocean Drilling Program's drill ship, the JOIDES Resolution. JOI provides fellowships for one or two years including salary and tuition, in addition to financial support for analytical expenses. The ad solicited proposals for several ODP trips or "legs." One of these cruises, Leg 145, was sailing across the North Pacific Ocean, the region that I was studying for my dissertation.
      Excited by the idea of sailing for two months from Yokohama, Japan, to Victoria, British Columbia, instead of spending the summer in a windowless lab analyzing sediment, I applied for the fellowship. The application process is a good education for someone planning to write grants as part of their career as a research scientist. I had to describe how my thesis research and the project I planned to do for Leg 145 would relate to the objectives of the cruise. One cruise objective was to document the paleoclimate changes recorded in the eolian sediments of the central North Pacific Ocean. Since I was developing techniques to interpret the paleoclimatic signal of sediments characteristic of the central North Pacific for my dissertation research, writing the science portion of the application was easy. (For example, during times that the Earth was drier than today, the amount of dust transported in the atmsphere and deposited in the ocean was higher. These dusty intervals are preserved in ice cores, loess, and deep sea sediment records.) I would look at how the sediment composition changed and relate those changes to shifting atmospheric circulation patterns and the aridification of the deserts of Asia through time. Filling out myriad forms for budgets was an entirely different matter, but with the help of GSO staff, I got it done. A few months later, I was pleased to learn that I had been awarded the fellowship.
      When I left to meet the drill ship in Yokohama, I didn't know any of the other scientists who would be sailing on the leg. From the perspective of a scientist, one of the great things about the Ocean Drilling Program is the international membership. I would sail with scientists who are experts in the field of paleoclimatology from all over the world. This is an important opportunity for new researchers; these scientists would be my colleagues in the future and an important resource for science and career advice while at sea. Even though I started my travels alone, along the way I met other scientists at airports in Detroit and Narita. (It is easy to identify scientists in airports; they are often lugging an assortment of carry-on baggage of strange shapes and sizes. I distinguished myself by carrying a large crate of equipment for taking atmospheric samples during the cruise.)
      We made our way from Narita to Yokohama by train, where we took a cab to the port and boarded the drill ship. We had assumed that finding the rig would be easy, since the drill tower stands more than 128 feet above the deck. What we hadn't counted on was the acres of cars waiting to be exported from Japan. Yokohama is one of the world's largest ports, and the drill ship was tiny compared with the many merchant vessels tied up around it. Nonetheless, after an hour of searching, we eventually found the ship, and met the group of technicians, scientists, and crew members with whom we would spend the next two months at sea.
      Life on the JOIDES Resolution is a graduate student's dream: you only have to work one 12-hour watch a day, seven days a week, and if you leave your clothes outside the cabin door, they come back clean and folded in a few hours. Not only that, but there are four meals a day and cookie breaks every six hours. Someone even makes your bed and cleans the bathroom. While each of the scientists that sail have a specific project that they are going to work on after the cruise, we spend the time on board collecting and cataloging cores which are recovered from the seafloor. I sailed as a sedimentologist, meaning that I spent my shift describing (both graphically and in writing) the sediment composition and physical characteristics of the recovered material using both visual and microscopic techniques. Other scientists catalogue the magnetic, chemical, biological, and engineering characteristics of the material recovered. Together, all of the ship board scientists produce a catalogue which is used by the global scientific com-munity as a guide to selecting samples for research in the future.
      The ship board scientists also collect samples to conduct research. The scientists that sail have access to the sediment cores before they are made available to the larger scientific community. I planned on collecting samples from a pelagic clay site off the coast of Japan to conduct my research. I had an unhappy surprise (OK, I panicked.) when the material that we recovered turned out to be biogenic silicathe shells of diatoms which had accumulated over millions of years. We didn't recover an inch of pelagic clay at this site. It was a good reminder that although we think we know a lot about oceanic sediments, we don't know everything. We did not recover pelagic clay until nearly a month and four sites later in the center of the Pacific Ocean. I was greatly relieved to know that my fellowship research was still on track after all.
      The next thing I learned about being a research scientist was that the people who are your colleagues are also your competition. There are restrictions on the amount of sediment you can collect for yourself while at sea; the rest is saved for future use on shore. While I collaborated with several scientists on some of the studies I planned, I also had to learn to look out for Number One, which meant that I had to dive into the snarling pack of scientists at the sampling table and ensure that I got what I needed to complete my project.
      Life aboard the drill ship is not all drudgery and battling for sediment. Leg 145 took us across the international date line, which required those who had not crossed the line before to offer a gift to the Golden Dragon (a 7-foot driller dressed in an elaborate dragon costume) and his court. We created a treasure chest of gifts, made costumes, and prepared skits and songs for our passage. Fortunately, we were all found worthy, and none of us were cast into the nether regions of the North Pacific.
      Armed with a large box of sediment, I departed the ship to complete the analytical phase of the fellowship. I had 18 months (which sounds like a long time but wasn't) to perform mineralogical analysis of a few hundred sediment samples; perhaps I overdid it at the sampling table, I thought to myself. I also realized that I was going to be spending a lot more time in the windowless lab in the basement at GSO than my prefellowship dissertation would have required. Happily, I got the analysis done and prepared the manuscript in time for publication in the scientific results volume for the leg. It was well worth the extra effort; I completed two manuscripts and attended two meetings to present the results of this fellowship.
      My research demonstrated that the sediments in the North Pacific Ocean were very sensitive to major climatic changes on Earth. The eolian sediments in the central basin accumulated at a much higher rate with the onset of northern hemisphere glaciation. Not only did the sediments accumulate more rapidly, but the composition of the sediments changed, indicating that Asia became cooler and drier in response to the global climatic shifts driven by the formation of glaciers much farther to the north.
      I completed my fellowship three years ago, and defended my dissertation more than a year ago. I still collaborate with the scientists that I met on Leg 145, and I continue to do work with ODP and JOI. The JOI Fellowship was a terrific experience, not only for the science, but to learn how scientists work in the world outside a windowless basement laboratory.

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Ocean Evidence of the K/T Impact

Steven L. D'Hondt, Associate Professor of Oceanography
Graduate School of Oceanography

Steven D'Hondt earned a B.S. degree in geology from Stanford University (1984) and a Ph.D. in geological and geophysical sciences from Princeton University (1989). He has been a faculty member of GSO since 1989. His research interests include the biological and environmental consequences of large asteroid impacts and ocean-climate interactions of warm and cool climate intervals.

Sixty-five million years ago, a large asteroid or comet slammed into the Yucatan peninsula of southeastern Mexico. The impacting object was 10 to 15km in diameter. If it was an asteroid, it probably moved at a velocity of about 20km per second. If it was a comet, it could have moved as fast as 60km per second. These velocities are phenomenally high. They far exceed the speed of sound and are 20 to 60 times greater than the speed of a fast bullet.
      At a velocity of 20km per second or greater, the initial impact would have been over in less than a second. The initial release of energy by the impact would have converted the impacting object and some of the target to silicate and metal vapor with a temperature of several thousand degrees Celsius. Within a couple of minutes, the extraordinarily hot vapor would have spread over the better part of a continent. The next fraction of energy would be released by ejection of melted target from the impact site. Most of the remaining energy would have been quickly released by ejection of solid debris from the growing crater. Dust from that solid debris would have spread globally within hours.
      It is widely believed that this impact drove most species of animals to extinction. An extraordinary range of organisms went extinct at about that time including dinosaurs, ammonites (which resembled shelled squid or cuttlefish), most of the clams, oysters, and other animals on the continental shelf, and many kinds of mammals and marine plankton. This mass extinction traditionally defines a boundary between two major periods in Earth history, the Cretaceous age of dinosaurs and ammonites, and the Tertiary age of mammals.
      The causes of extinction would have varied roughly with distance from the crater. Last year, Peter Schultz (Brown University) and I suggested that the impacting object struck at a low angle from the northeast and that extinctions in North America (and perhaps northeastern Asia) resulted from vaporization of the landscape by the downrange vapor cloud. However, the tremendous extinction of marine organisms and of animals on other continents must have been caused by a different mechanism, because the hot vapor cloud probably did not extend over the entire earth. In 1980, Luis Alvarez and his colleagues at University of California-Berkeley first proposed that dust from the impact caused global darkness, leading to cessation of photosynthesis and the collapse of food chains throughout the world. Although this proposal is difficult to test, it has real explanatory power, because it provides a reasonable explanation for mass extinction on land and in the sea at all latitudes. Analyses of congealed impact melt by Haraldur Sigurdsson (GSO faculty) and his colleagues further strengthened global darkness and cooling scenarios by showing that tremendous quantities of sulfur dioxide (SO2 ) were released from the Yucatan target (see Maritimes, August 1991). High atmospheric concentrations of SO 2 would have greatly enhanced the darkness and cooling that followed the impact.

Whatever the outcome of these Caribbean studies, URI studies of DSDP and ODP cores have already shown that events occurring in less than a heartbeat can change the entire world for millions of years.

Recommended Reading
D'Hondt, S., J. King, and C. Gibson, 1996. An oscillatory marine response to the Cretaceous/Tertiary impact. Geology, 24, 611-614.

D'Hondt, S., T.D. Herbert, J. King, and C. Gibson, 1996. Planktic foraminifera, asteroids, and marine production: death and recovery at the Cretaceous-Tertiary boundary. In New developments regarding the K/T event and other catastrophes in earth history, Geological Society of America Special Paper 307, ed. by G.T. Ryder, D.E. Fas-tovsky, and S. Gartner, 303-317.

Schultz, P., and S. D'Hondt, 1996. The Cretaceous/Tertiary (Chicxulub) impact angle and its consequences. Geology, 24, 963-967.

Sheehan, P.M., D.E. Fastovsky, R.G. Hoffmann, C.B. Berghaus, and D.L. Gabriel, 1991. Sudden extinction of the dinosaurs: Latest Cretaceous, Upper Great Plains, USA. Science, 254, 835-839.

Sigurdsson, H., S. D'Hondt, and S. Carey, 1992. The impact of the Cretaceous/Tertiary bolide on evaporite terrane and generation of a major sulfuric acid aerosol. Earth and Planetary Science Letters, 109 (3/4), 543-559.

Zachos, J.C., M.A. Arthur, and W.E. Dean, 1989. Geochemical evidence for suppression of pelagic marine productivity at the Cretaceous/Tertiary boundary. Nature, 337, 61-64.

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Credits

Margaret Leinen, Ph.D. Dean of the Graduate School of Oceanography and Vice Provost for Marine Programs

Jackleen de La Harpe, Editor

Steven Carey, Guest Editor

R. Darrell McIntire, Design

Maritimes is published four times a year by the University of Rhode Island in the spring, summer, fall, and winter by the Office of Marine Programs.

Address correspondence to: Jackleen de La Harpe, Editor University of Rhode Island Graduate School of Oceanography, Office of Marine Programs, Narragansett Bay Campus Narragansett, RI 02882-1197, jack@gsosun1.gso.uri.edu

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