Holes in the Bottom of the Sea: History, Revolutions, and Future Opportunities

No other international scientific collaboration has contributed as much to our knowledge of Earth processes as scientific ocean drilling (SOD). These contributions include geophysical surveys, core samples, borehole well logs, and sub-seafloor observatories. After more than half a century, involving thousands of scientists from around the world, SOD has been instrumental in developing three geoscience revolutions: (1) plate tectonics, (2) paleoceanography, and (3) the deep marine biosphere. Without SOD, it is unlikely that our current understanding of Earth processes could have developed. Building upon prior scientific results, the current science plan is guided by four interlinked themes: Planetary Dynamics, Climate and Ocean Change, Biosphere Frontiers, and Earth in Motion. SOD has also been a leader in international collaborations and the open sharing of samples, data, and information. Results from SOD expeditions are open access and available online. Almost 2.5 million samples have been taken from over 360 km of core located in three repositories. Today about half the members of scientific teams, including co-chief scientists, are women. This program is needed in the future for geoscientists to continue exploring our planet to understand how it functions and to create predictive models. INTRODUCTION Scientific ocean drilling (SOD) celebrated its 50th birthday in 2018. As of December 2018, 283 expeditions (formerly called legs) have been completed and >1600 sites have been drilled (see Fig. S1 in the GSA Data Repository1). These sites represent <0.0005% of the ocean floor, yet have provided essential information about plate tectonics, ocean chemistry, evolution, life in harsh environments, and climate change. Scientists from across the world have benefited from and contributed to the program. Geophysical site survey data, cores, and associated information are available to the global scientific community to study and sample. More than 1000 international scientists, ranging in age from early career to retired, are proponents on active proposals for upcoming drilling. This article, by no means comprehensive, highlights parts of the history and a few major discoveries of SOD. More complete histories are available in Ocean Drilling: Accomplishments and Challenges (National Research Council, 2011), Earth and Life Processes Discovered from Subseafloor Environments: A Decade of Science Achieved by the Integrated Ocean Drilling Program (IODP) (Stein et al., 2014), and Koppers et al. (2019). GSA Data Repository Table S1 (see footnote 1) provides URLs to detailed, preliminary information for all SOD expeditions and legs, including co-chief scientists, sites cored, and year.