Scientific Accomplishments That
Could Not Have Been Achieved Without
Scientific Ocean Drilling
Solid Earth Cycles
• Verification of the seafloor spreading hypothesis and plate tectonic theory
• Development of an accurate geological time scale for the past 150 myr
• Confirmation that the structure of oceanic lithosphere is related to spreading rate
• Exploration of the emplacement history of submarine large igneous provinces
• Contribution to a new paradigm for continental breakup due to studies of rifted margins
• Definition of subduction zone inputs and confirmation of subduction erosion
Fluids, Flow, and Life in the Subseafloor
• In situ investigation of fluid flow processes, perÂmeability, and porosity in ocean sediments and basement rocks
• Characterization of the sediment- and rockÂhosted subseafloor microbial biosphere
• Study of subseafloor water-rock interactions and the formation of seafloor massive sulfide deposits in active hydrothermal systems
• Examination of the distribution and dynamics of gas hydrates in ocean sediments
Earth’s Climate History
• Reconstruction of global climate history for the past 65 myr, based on ocean sediments
• Development and refinement of the Astronomical Geomagnetic Polarity Timescale
• Documentation of the pervasive nature of orbital forcing on global climate variability
• Recognition of past geological analogs (for example, the Paleocene-Eocene Thermal Maximum) for Earth’s response to increases in atmoÂspheric carbon dioxide
• Discovery of the history of polar ice sheet initiaÂtion, growth and variability, and their influence on fluctuations in global sea level
in the Earth sciences. During ODP, informal activities aimed at undergraduates, K-12, and community outreach were initiated. More structured and extensive programs during IODP included a vigorous education initiative aimed at K-12, undergraduate, graduate, and informal science educators. The education, outreach, and capacity-building programs are of significant value, but evaluations of each of them would enable a better understanding of the impacts of these activities on different groups and would demonstrate the broader impacts of scientific ocean drilling.
RECOMMENDATION: Formal evaluation of education, outreach, and capacity-building activities should be implemented to demonstrate the broader impacts of scientific ocean drilling.
The committee also assessed the potential for future transformative scientific discoveries envisioned in Illuminating Earth’s Past, Present, and Future: The International Ocean Discovery Program Science Plan for 2013-2023, which was released in June 2011 by Integrated Ocean Drilling Program Management International. The science plan is divided into four research themes: climate and ocean change, biosphere frontiers, Earth connections (deep Earth processes), and Earth in motion (direct time series observations on human scales). There are 14 scientific challenges within these four themes, which the committee evaluated individually for potential for transformative discovery, synergy between science plan challenges and themes, and linkages to NSF-supported and other research programs. Each of the four themes within the science plan identifies compelling challenges with potential for transformative science that can only be addressed by scientific ocean drilling. Some challenges within these themes appear to have greater potential for transformative science than others.
The committee was particularly positive about the potential for transformative discoveries resulting from subseafloor biosphere exploration and for continuing paleoclimate investigations to provide constraints on projected climate change. It also noted the need for data in under-represented regions such as high latitudes and for deeper sampling into intact ocean crust. The themes and challenges identified in the science plan were well-justified and timely, although there was a lack of guidance as to which challenges were most important.
RECOMMENDATION: The scientific ocean drilling community should establish a mechanism to prioritize the challenges outlined in the science plan in a manner that complements the existing peer-review process.
The scientific ocean drilling programs have a history of making excellent use of legacy samples and data that have helped to quickly advance new areas of research. Using legacy data and samples to their maximum capabilities will continue to increase the scientific value of the scientific ocean drilling programs. Expanded use of legacy materials could help, for example, with prioritization of drilling objectives in the next phase of scientific ocean drilling.
There are several natural areas of synergy between the challenges and themes, and more detailed examination of potential integration would be valuable in lending strength to the overall program. Integration of scientific ocean drilling