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Introduction to U.S. Scientific Ocean Drilling

For more than 40 years, results from scientific ocean drilling have contributed to global understanding of Earth’s biological, chemical, geological, and physical processes and feedback mechanisms. The majority of these internationally recognized results have been derived from scientific ocean drilling conducted through three programs—the Deep Sea Drilling Project (DSDP; 1968-1983), the Ocean Drilling Program (ODP; 1984-2003), and the Integrated Ocean Drilling Program (IODP; 2003-2013)—that can be traced back to the first scientific ocean drilling venture, Project Mohole, in 1961. Figure 1.1 illustrates the distribution of drilling and sampling sites for each of the programs, and Appendix A presents tables of DSDP, ODP, and IODP legs and expeditions. Although each program has benefited from broad, international partnerships and research support, the United States has taken a leading role in providing financial continuity and administrative coordination over the decades that these programs have existed. Currently, the United States and Japan are the lead international partners of IODP, while a consortium of 16 European countries and Canada participates in IODP under the auspices of the European Consortium for Ocean Research Drilling (ECORD). Other countries (including China, Korea, Australia, New Zealand, and India) are also involved.

As IODP draws to a close in 2013, a new process for defining the scope of the next phase of scientific ocean drilling has begun. Illuminating Earth’s Past, Present, and Future: The International Ocean Discovery Program Science Plan for 2013-20231 (hereafter referred to as “the science plan”), which is focused on defining the scientific research goals of the next 10-year phase of scientific ocean drilling, was completed in June 2011 (IODP-MI, 2011). The science plan was based on a large, multidisciplinary international drilling community meeting held in September 2009.2 A draft of the plan was released in June 2010 to allow for additional comments from the broader geoscience community prior to its finalization. As part of the planning process for future scientific ocean drilling, the National Science Foundation (NSF) requested that the National Research Council (NRC) appoint an ad hoc committee (Appendix B) to review the scientific accomplishments of U.S.-supported scientific ocean drilling (DSDP, ODP, and IODP) and assess the science plan’s potential for stimulating future transformative scientific discoveries (see Box 1.1 for Statement of Task). According to NSF, “Transformative research involves ideas, discoveries, or tools that radically change our understanding of an important existing scientific or engineering concept or educational practice or leads to the creation of a new paradigm or field of science, engineering, or education. Such research challenges current understanding or provides pathways to new frontiers.”3 This report is the product of the committee deliberations on that review and assessment.

HISTORY OF U.S.-SUPPORTED SCIENTIFIC OCEAN DRILLING, 1968-2011

The first scientific ocean drilling, Project Mohole, was conceived by U.S. scientists in 1957. It culminated in drilling 183 m beneath the seafloor using the CUSS 1 drillship in 1961. During DSDP, Scripps Institution of Oceanography was responsible for drilling operations with the drillship Glomar Challenger. The Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES), which initially consisted of four U.S. universities and research institutions, provided scientific advice. Among its numerous achievements, DSDP

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1 See http://www.iodp.org/Science-Plan-for-2013-2023/.

2 See http://www.marum.de/en/iodp-invest.html.

3 See http://www.nsf.gov/about/transformative_research/definition.jsp.



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1 Introduction to U.S. Scientific Ocean Drilling For more than 40 years, results from scientific ocean international drilling community meeting held in Septem- ber 2009.2 A draft of the plan was released in June 2010 to drilling have contributed to global understanding of Earth’s biological, chemical, geological, and physical processes and allow for additional comments from the broader geoscience feedback mechanisms. The majority of these internationally community prior to its finalization. As part of the planning recognized results have been derived from scientific ocean process for future scientific ocean drilling, the National Sci- drilling conducted through three programs—the Deep Sea ence Foundation (NSF) requested that the National Research Drilling Project (DSDP; 1968-1983), the Ocean Drilling Council (NRC) appoint an ad hoc committee (Appendix B) Program (ODP; 1984-2003), and the Integrated Ocean to review the scientific accomplishments of U.S.-supported Drilling Program (IODP; 2003-2013)—that can be traced scientific ocean drilling (DSDP, ODP, and IODP) and assess back to the first scientific ocean drilling venture, Project the science plan’s potential for stimulating future transfor- Mohole, in 1961. Figure 1.1 illustrates the distribution of mative scientific discoveries (see Box 1.1 for Statement of drilling and sampling sites for each of the programs, and Task). According to NSF, “Transformative research involves Appendix A presents tables of DSDP, ODP, and IODP legs ideas, discoveries, or tools that radically change our under- and expeditions. Although each program has benefited from standing of an important existing scientific or engineering broad, international partnerships and research support, the concept or educational practice or leads to the creation of a United States has taken a leading role in providing financial new paradigm or field of science, engineering, or education. continuity and administrative coordination over the decades Such research challenges current understanding or provides pathways to new frontiers.”3 This report is the product of that these programs have existed. Currently, the United States and Japan are the lead international partners of IODP, the committee deliberations on that review and assessment. while a consortium of 16 European countries and Canada participates in IODP under the auspices of the European HISTORY OF U.S.-SUPPORTED SCIENTIFIC Consortium for Ocean Research Drilling (ECORD). Other OCEAN DRILLING, 1968-2011 countries (including China, Korea, Australia, New Zealand, and India) are also involved. The first scientific ocean drilling, Project Mohole, was As IODP draws to a close in 2013, a new process for conceived by U.S. scientists in 1957. It culminated in drill- defining the scope of the next phase of scientific ocean ing 183 m beneath the seafloor using the CUSS 1 drillship drilling has begun. Illuminating Earth’s Past, Present, and in 1961. During DSDP, Scripps Institution of Oceanography was responsible for drilling operations with the drillship Future: The International Ocean Discovery Program Sci- ence Plan for 2013-20231 (hereafter referred to as “the Glomar Challenger. The Joint Oceanographic Institutions science plan”), which is focused on defining the scientific for Deep Earth Sampling (JOIDES), which initially consisted research goals of the next 10-year phase of scientific ocean of four U.S. universities and research institutions, provided drilling, was completed in June 2011 (IODP-MI, 2011). scientific advice. Among its numerous achievements, DSDP The science plan was based on a large, multidisciplinary 2 See http://www.marum.de/en/iodp-invest.html. 1 3 See http://www.iodp.org/Science-Plan-for-2013-2023/. See http://www.nsf.gov/about/transformative_research/definition.jsp. 5

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6 SCIENTIFIC OCEAN DRILLING a) b) c) FIGURE 1.1 Global distribution of drill holes and sampling sites from (a) DSDP, (b) ODP, and (c) IODP over four decades of scientific ocean drilling. Drill-hole symbols are greatly exaggerated in size. The depths of the drill holes also vary significantly, depending upon sci- entific objectives and technical and logistical considerations at each site. This is a Mollweide (equal area) projection with a color range of -9,000 to 9,000 m, with white marking the 0 m depth. SOURCE: IODP-USIO.

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7 INTRODUCTION TO U.S. SCIENTIFIC OCEAN DRILLNG of the United States, with 18 nations participating. The Box 1.1 JOIDES Resolution, a new ocean drillship (Figure 1.2), was converted from use in the oil industry to use in scientific Statement of Task ocean drilling for this program. The JOIDES Resolution’s The National Science Foundation has requested drilling facilities enabled more effective drilling in both that the National Research Council appoint an ad deep and shallow water depths and had better shipboard hoc committee to review the scientific accomplish- laboratories than the Glomar Challenger. These technologi- ments of U.S.-supported scientific ocean drilling cal improvements facilitated the understanding of continental (Deep Sea Drilling Project [DSDP], Ocean Drilling rifting and Earth’s climate history and the development of the Program [ODP], and Integrated Ocean Drilling Pro- global Geomagnetic Polarity Timescale. ODP also signifi- gram [IODP]) and assess the potential for future cantly moved forward the investigation and understanding transformative scientific discoveries. The study com- of challenging oceanic environments, such as gas hydrates mittee will undertake two tasks: and hydrothermal vents. Throughout ODP, Texas A&M Uni- 1. Identification of DSDP, ODP, and IODP sci- versity (TAMU) was responsible for drilling operations, and entific accomplishments and analysis of their sig- Lamont-Doherty Earth Observatory of Columbia University nificance, with an emphasis on evaluating how (LDEO) was responsible for downhole logging activities. scientific ocean drilling has shaped understanding Core repositories were developed at several locations in of Earth systems and history. Additional emphasis the United States and Germany before the ODP phase of will be placed on assessing the extent to which scientific ocean drilling concluded (Table 1.1). ODP also the availability of deep ocean drilling capabilities saw advancement in the use of boreholes for continued has enabled new fields of inquiry. The analysis will study of the subseafloor. While direct sampling through the include consideration of the drilling programs’ con- tributions to capacity building, science education, acquisition of cores and downhole logging of data continued, and outreach activities. The study will not consider new experimental approaches to seal drill holes and place organizational framework. in situ sensors led to the creation of long-term subseafloor 2. Assessment of the potential for transformative observatories (see Box 3.2 in Chapter 3). Those dual uses of scientific discovery resulting from implementation of scientific ocean drilling continue to increase in importance. the draft science plan for the next proposed phase The most recent program, IODP, has used a process- of international scientific ocean drilling (2013-2023). oriented approach to conduct research within three broadly This assessment will include advice on opportuni- defined, global scientific themes: (1) the deep biosphere and ties resulting from stronger collaboration between the subseafloor ocean; (2) environmental change, processes, ocean drilling and other NSF-supported science and effects; and (3) solid Earth cycles and geodynamics programs and research facilities. (IODP, 2001). Japan and the United States have co-led the program of 24 countries and, together with a consortium of European countries and Canada, have provided multiple types of drilling platforms with new capabilities. These plat- provided conclusive evidence for the theory of seafloor forms have greatly expanded the scope of research addressed spreading and added critical information that was the princi- by scientific ocean drilling and have provided an example pal driver for the development of plate tectonic theory. DSDP of best practices in international scientific cooperation (Box also contributed significantly to the development of the fields 1.2). of paleoceanography and paleoclimatology and developed piston coring technology that enabled better recovery of core To a large extent, the success of IODP and prior samples. The International Phase of Ocean Drilling (DSDP scientific ocean drilling programs has been a result IPOD) began in 1975, with the recognition that the most of strong international collaboration. effective means of scientific ocean drilling was through a cooperative, international program whereby nations could During IODP, the core repository in Japan was estab- share intellectual and financial resources. In many ways, lished, and the Japanese riser drillship Chikyu (Figure 1.2) the DSDP IPOD phase was a precursor for IODP, because entered service. Chikyu is able to drill in water up to 2,500 m it enacted a model for sharing financial resources between deep and can drill holes up to 7,000 m total.4 JOIDES Resolu- interested nations instead of having only U.S.-funded sci- tion underwent a major refurbishment (2006-2009), increas- ence and program management. The Shirshov Institute of ing laboratory space by 34 percent, which led to greater Oceanology in Moscow was the first international partner, efficiency in core handling, improved berthing arrangements, and by 1975 JOIDES included nine U.S. institutions and five enhanced drilling capability, and better ship stability. The international participants. ship re-entered active service with the ability to drill more ODP continued international scientific ocean drilling through the 1980s and 1990s under the primary leadership 4 See http://www.jamstec.go.jp/chikyu/eng/CHIKYU/data.html.

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8 SCIENTIFIC OCEAN DRILLING FIGURE 1.2 Current scientific ocean drilling vessels: (left) JOIDES Resolution and (right) Chikyu. JOIDES Resolution was refurbished from 2006 to 2009. Chikyu began service in 2005. SOURCE: Used with permission from IODP. TABLE 1.1 Scientific Ocean Drilling Core Repository Data Gulf Coast Repository (TAMU) Bremen Core Repository (Germany) Kochi Core Center (Japan) Year established 1985 1994 2005 Geographic region covered Pacific (east of western plate Atlantic and Arctic Oceans (north Pacific (west of western plate boundary), Caribbean Sea, Gulf of of Bering Strait), Mediterranean and boundary), Indian Ocean (north of Mexico, Southern Ocean (south of Black Seas 60°S), Kerguelan Plateau, Bering Sea 60°S except Kerguelan Plateau) Total amount of core (km) 125 141 93 Total sample requests 4,406 4,591 2,380 Total samples taken 1,138,799 1,249,652 342,715 SOURCE: Data from IODP-USIO, 2011, and http://www.iodp.org/repositories/2/. (IODP-MI, 2011). In addition to contributing to research, than 2 km into the ocean floor, and in waters as deep as 6,000 scientific ocean drilling has fostered an integrated approach m and as shallow as 75 m.5 TAMU and LDEO, respectively, to the study of Earth’s history. Drilling samples are collected continue to be responsible for drilling and downhole logging in an integrated biological, geochemical, geophysical, sedi- operations. In addition, ECORD manages the use of mission- mentological, and structural context that has been framed in specific platforms for expeditions that require capabilities a well-defined pre-drill site survey. Some samples are carri- beyond those of the U.S. and Japanese drillships (e.g., drill- ers of chemical proxies for the environment of deposition or ing coral reefs, shallow waters, or high-latitude areas). IODP formation, while others are part of a distinct biogeochemical results have built upon previous program results to increase community. understanding of relationships between glaciation, sea level It is also important to note the impact that scientific changes, ocean circulation, and atmospheric carbon dioxide; volunteers brought to achieving the goals of scientific ocean past climate change; the deep biosphere; evolution of large drilling. Early, mid-career, and internationally established igneous provinces; occurrence of bolide impacts; and inves- scientists recognized that scientific ocean drilling would tigation of fluids and slope failure in the seafloor. open many new fields of inquiry, and they responded by vol- More than 26,000 publications have resulted from these unteering substantial amounts of time and energy to initiate four decades of scientific ocean drilling research, includ- the overall program and to sustain it through the decades. ing program reports, maps, abstracts, and other peer- and non-peer-reviewed publications. About one-third of these TECHNICAL ACHIEVEMENTS OF U.S.- publications have been in peer-reviewed journals, including SUPPORTED SCIENTIFIC OCEAN DRILLING more than 400 in Science, Nature, and Nature Geoscience In concert with the wide range of scientific successes that DSDP, ODP, and IODP have achieved across a wide 5 See http://www-odp.tamu.edu/publications/tnotes/tn31/jr/jr.htm.

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9 INTRODUCTION TO U.S. SCIENTIFIC OCEAN DRILLNG (maintaining position through the use of propellers rather Box 1.2 than an anchor; Box 1.3), deepwater coring equipment and IODP as an International Best Practice practices (Boxes 2.2 and 4.3), taking measurements while coring (Box 3.1), long-term borehole monitoring (Box 3.2), IODP is by far the largest Earth science effort and the ability to obtain drill cores in a variety of environ- to date. Twenty-four countries contribute, with the mental conditions (Box 3.4) have all been spearheaded by United States and Japan as the leading participants. scientific ocean drilling programs. Several of these techno- The coordinated use of core samples, drillships, logical developments, especially those that allow real-time and mission-specific platforms has resulted in a borehole monitoring, have provided additional safety and community- and facility-oriented approach and a hazard assessment tools that permit riserless drilling in dif- concentration of effort by a diverse group of sci- ficult environments. The drilling statistics in Table 1.2 dem- entists. Since the early days of scientific ocean onstrate the general increase in penetration depth of the drill drilling, priorities and technological developments cores as well as percentage core recovery as the programs have been driven by scientific needs, and this is have evolved (also see Figure 1.3). still the case for IODP. An open application process and transparent, science-based peer reviews of proposals guarantee that scientists from all partici- OVERARCHING CONCLUSIONS pating countries are given equal opportunities to set scientific and programmatic goals. The current IODP In response to the first charge in the Statement of Task, structure is designed to ensure that proposals are the committee identified noteworthy scientific and techno- aligned with strategic priorities of an internationally logical advancements and new fields of inquiry spurred by agreed-upon science plan and evaluated on their results accomplished through four decades of scientific ocean scientific merits, but also takes feasibility and risk drilling. Outstanding questions that have yet to be answered into account. The evaluation process is designed to within each major field of study are also outlined. Although counteract vested national interests that can plague these achievements are explored in much more detail in large, international, scientific cooperative programs. following chapters, the committee felt that a conclusion When a decision is made on a specific drilling describing the overall worth of the scientific ocean drilling target, IODP issues a second call to scientists from participating countries, asking them to take part on enterprise was warranted. a drilling cruise by proposing add-on projects or by applying to participate as experts in already planned The committee found that the U.S.-supported sci- projects. The second call provides an important op- entific ocean drilling programs (DSDP, ODP, and portunity for young scientists and graduate students IODP) have been very successful, contributing from many disciplines in Earth and environmental significantly to a broad range of scientific accom- sciences to engage in scientific ocean drilling and plishments in a number of Earth science disciplines. work alongside leading geoscientists. The experi- In addition, their innovations in technology have ence they gain builds capacity for a future career in strongly influenced these scientific advances. the ocean sciences by providing access to a global, multidisciplinary scientific network, as well as by of- The second task focused on assessing the science plan, fering unique opportunities and facilities for original research. Illuminating Earth’s Past, Present, and Future: The Inter- national Ocean Discovery Program Science Plan for 2013- 2023 (IODP-MI, 2011), that was produced for the next phase of scientific ocean drilling. The committee found that each of the four themes span of fields, scientific ocean drilling has excelled in gen- within the science plan identifies compelling chal- erating innovative technologies. Box 1.3 highlights some lenges with potential for transformative science that of the ground-breaking achievements of Project Mohole can only be addressed by scientific ocean drilling. and follow-on scientific ocean drilling programs. Later Some challenges within these themes appear to have boxes (in Chapters 2-4) provide further details of scientific greater potential for transformative science than ocean drilling technologies that have helped advance scien- others. tific discovery. These accomplishments occurred in concert with attempts by program scientists to answer questions of increasing complexity about processes affecting the Earth REPORT ORGANIZATION system, including the solid Earth, hydrosphere, and atmo- sphere. Some of these spin-off technologies have had an For the first task, numerous reports by ODP and IODP enormous impact on the evolution of commercial deepwater have summarized the major accomplishments during specific drilling and oceanographic research. Dynamic positioning phases of the program’s existence (e.g., JOI, 1990, 1996,

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10 SCIENTIFIC OCEAN DRILLING Box 1.3 Innovations in Riserless Drilling: Project Mohole and Beyond In 1957, a number of prominent scientists suggested an ambitious project to drill to the Mohorovičić discontinuity (Moho), the sharp increase in seismic velocity 4 to 6 km below the seafloor in the ocean and 30 to 40 km below the surface of the continents. Such a project would require drilling in far deeper water than the routine depths of 20 to 50 m that commercial drilling attempted at the time. There were two major hurdles to accomplishing this feat: drilling in deep water without anchoring (the standard practice for drill ships at that time), and drilling or coring without a riser (a pipe with an outer casing, allowing drilling fluid to circulate between the ship and borehole while maintaining constant pressure within the borehole; see figure below). From 1958 to 1961, many engineering challenges associated with deep scientific ocean drilling were discussed and new approaches designed: a dynamic positioning (DP) system consisting of four shipboard propellers and a series of sonar buoys; a guide shoe to relieve stress on the drill string; a landing base for hole re-entry; and diamond drill bits for biting into hard rock (NRC, 2000; Winterer, 2000; Pete Johnson, PowerPoint presentation, 2011). During the March 1961 Project Mohole cruise, the CUSS 1 drillship used dynamic positioning to maintain its position over a small circle at a site in the Pacific Ocean offshore of Guadalupe Island, Mexico. The scientists and engineers aboard the ship managed to retrieve both soft sediment and basement rock, reaching a depth of 183 m beneath the seafloor while drilling in 3,570 m of water (NRC, 2000). This definitively proved that an unanchored drillship could main- tain station in deep water and have continuous drilling or coring operations. Today, the majority of modern deepwater drillships and other self-contained floating drilling machines (also referred to as mobile offshore drilling units) have DP systems that can maintain a watch circle of 3 to 10 m under normal surface conditions (Ambrose et al., 2003). Without DP systems, many deepwater oil and gas discoveries worldwide would not have been economically viable. In some cases these sites could not have been drilled without DP, especially in water depths beyond 2,000 m (Smith and Parlas, 1979). Conventional offshore drilling in the 1960s and 1970s with a mobile offshore drilling unit was limited by water depth because of the heavy riser pipe and blowout preventers required for well control purposes. Drilling for sediments and hard rock, while specifically avoiding hydrocarbon formations, could instead be done without a riser system and blowout preventers. The DSDP drillship Glomar Challenger was specially built to do non-riser drilling by circulating drilling fluids through the drill pipe and out the borehole to the ocean. This practice ultimately led to the now-common deepwater oil field practice of drilling a surface hole before the first long string of casing is installed and a riser employed. The next drillship for scientific ocean drilling, the JOIDES Resolution, was converted from a commercial oil drillship to a riserless scientific vessel. The JOIDES Resolution improved capability for scientific ocean drilling because it could drill in deeper and shallower water depths, had superior station-keeping capabilities, and better heave compensation (Cullen, 1994; NRC, 2000). TABLE 1.2 Scientific Ocean Drilling Technical Achievements Distance Total Total Core Traveled Cored Recovered Number of Deepest Core Deepest Water Number of Program (nmi) (km) (km) Sites Visited Penetration (m) Depth (m) Cores Recovered DSDP 375,632 170 97 624 1,741 7,044 19,119 ODP 355,781 321 222 669 2,111 5,980 35,772 IODPa 81,008 40 33 91 1,928 5,708 4,840 a Through April 2011. There were commissioning delays with Chiyku and shipyard delays with JOIDES Resolution that led to fewer expeditions and core drilled than were otherwise expected. SOURCE: Data from IODP-USIO, 2011.

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11 INTRODUCTION TO U.S. SCIENTIFIC OCEAN DRILLNG Riser drilling configuration (left) and riserless drilling configuration (right). SOURCE: JAMSTEC/IODP. 1997, 2004; IODP, 2001; Gröschel, 2002; ODP, 2007). Initial speakers in a variety of scientific disciplines during the June and technical reports related to specific DSDP,6 ODP,7 and 2010 committee workshop in College Station, Texas. The IODP8 legs also provided detailed information. The com- committee commissioned white papers from the workshop mittee reviewed those reports as well as previous external speakers (see Appendix C); some of this report’s contents assessments (e.g., NRC, 1992) and community-led activi- build upon those materials. ties. The information-gathering process also included pre- Scientific ocean drilling accomplishments are organized sentations by and discussions with DSDP, ODP, and IODP into three chapters that follow the broad IODP themes: scientists and engineers, program managers, and invited solid Earth cycles (Chapter 2); fluids, flow, and life in the subseafloor (Chapter 3); and Earth’s climate history (Chap- ter 4). Those chapters present the analyses of significant 6 See http://www.deepseadrilling.org/index.html. accomplishments in 14 solid Earth and oceanographic areas, 7 See http://www-odp.tamu.edu/publications/. the accomplishments’ impacts on understanding the Earth 8 See http://www.iodp.org/scientific-publications/.

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12 SCIENTIFIC OCEAN DRILLING Year Hole Started 1974 1975 1976 1977 1979 1987 1988 1989 1992 2002 2003 2004 2004 801C 896A 1256D 1275D U1309D U1301B 332A 332B 333A 395A 396B 417A 417D 418A 504B 735B 765D 0 IODP Exp. 304 DSDP Leg 70 Leg 69 ? ODP Leg 206 ODP Leg 118 200 ? 400 1999 ? Depth (meters subbasement) 600 IODP Exp 309 DSDP Leg 83 IODP Exp. 305 800 ODP Leg 176 1000 Exp. 312 Leg 111 1200 Volcanics 2005 137 Lava-Dike Transition 1400 148 ODP Leg 140 Sheeted Dikes 2005 Dike - Gabbro Transition 1997 1600 Gabbros 1800 1993 2000 FIGURE 1.3 Graphical representation of DSDP, ODP, and IODP holes drilled between 1974 and 2005 that extend more than 200 m into ocean crust. The most striking observation on this diagram is that most of the holes are shallower than 500 m and sample only the volcanic section (pillows and sheeted dikes) of the basement below the sedimentary cover. SOURCE: Modified from Dick et al., 2006. system and their importance in developing new fields of the September 2010 meeting. The committee also received inquiry, and identification of goals not yet accomplished. The some revised chapters in September and October 2010, report also examined capacity building, education, and out- which were significantly different in both content and style reach conducted through DSDP, ODP, and IODP (Chapter 5). from the June 2010 version. Revisions continued throughout For the second task, the committee relied upon pre- the rest of 2010, and the revised document was reviewed by sentations by the science plan writing team, discussions an external panel of eight international scientists in early with representatives from IODP and NSF, and review of 2011 (IODP-MI, 2011). The final science plan was released the plan itself. The committee was presented with several in June 2011 and provides the basis for the committee’s versions of Illuminating Earth’s Past, Present, and Future: assessment of future opportunities for transformative science through scientific ocean drilling (Chapter 6). The committee The International Ocean Discovery Program Science Plan for 2013-2023 (IODP-MI, 2011) during the course of the also identified linkages between scientific ocean drilling, study. The draft plan was released in June 2010; the com- other NSF-supported programs, and non-NSF programs. mittee met with science plan writing team members during