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--> Executive Summary Over geologic time, depressions on Earth's surface are filled with sediments and organic materials that have been transported by wind, rivers, and ocean currents. Known as sedimentary basins, these features come in many shapes and sizes. They are pervasive on Earth and form in response to complex geologic processes. At their largest, sedimentary basins can be hundreds to thousands of kilometers in horizontal dimensions and contain more than 1015 m3 of buried materials. This basin fill is important in two respects. First, it preserves unique information regarding the history of tectonic, biologic, oceanographic, and atmospheric events during Earth's evolution. Second, basin fill contains most of the fuel and water, and many of the mineral resources, that are critical for society and industrial civilization. For intellectual and economic reasons, research on sedimentary basins is at a watershed. First, basin research is poised to reap the benefits of decades of disciplinary research that has amassed a vast data set on basin properties. Utilizing this information in the broad context of plate tectonics, there are now great opportunities for multidisciplinary research on sedimentary basins touching on a wide range of fundamental problems in the earth sciences. Unfortunately, these opportunities come at a time of intense financial pressure on the funding sources for research on sedimentary basins. Cutbacks in industrial support for research, coupled with declining federal budgets, present significant challenges for developing a strong research agenda for basin studies. At this time of
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--> transition, this report by a panel of the National Research Council's U.S. Geodynamics Committee (USGC) assesses the status, opportunities, and goals for multidisciplinary research on the formation and evolution of sedimentary basins. Through its survey of current research, the USGC's Panel on the Geodynamics of Sedimentary Basins identified a broad range of research topics focusing on the tectonics of sedimentary basins, the historic record of climate and oceans preserved in basin materials, and fluid and chemical transport in sedimentary basins. In part, this research is driven by the development of new technologies for studying and modeling sedimentary basins. The panel finds that there is an emerging research agenda incorporating the concerns of resource identification and extraction together with the issues of global climate change, fluid flow, and geodynamics. Today, multidisciplinary research teams are common in basin research. Much of their effort is focused on understanding and predicting basin formation within the framework of plate tectonics and mantle convection; hydrocarbon generation and migration during basin evolution; present and historic ground-water flow and chemical transport; changes in basin fill and thermal evolution with tectonic environment; spatial and temporal variations of subsurface porosity and permeability; and the record of tectonics, climate, and sea-level change preserved in sedimentary basins. To address these topics, it will be important to develop a broad and integrated research agenda for basin studies because advances in one research area will often rely on advances in distant fields and because of the extreme heterogeneity of basins and basin materials. For this work the panel makes the following recommendations. Development of a Comprehensive Set of Basin Models. The panel recommends that a focused effort be made to develop a comprehensive set of models for studying the origin and evolution of sedimentary basins. In detail, such models would provide improved understanding of such diverse processes as fluid flow along fractures, the
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--> history of mineral and fluid reactions with basin subsidence, and the record of global climate change preserved in basin materials. Linked together, such models would contribute to a new integrated understanding of sedimentary basins with broad implications for research across the geosciences, for identifying and extracting mineral and fossil fuel resources, and for preserving the quality of vital water resources for society. Strategies for this modeling effort should focus on improved characterization of basin materials over all length scales; strengthened efforts to collect and archive subsurface data on sedimentary basins; refined theoretical understanding of the processes that modify basins through geologic time, including mantle convection and plate tectonics, subsurface porous flow of fluids, and the thermodynamics of reactions among fluids, minerals, and biomass at depth; and synthesis and linking of existing models to form a comprehensive yet flexible set of models for describing the formation and evolution of sedimentary basins. Supporting this effort will require innovative funding mechanisms that emphasize collaboration among federal agencies, industry, and the academic community and that link disciplinary research programs related to sedimentary basins. Data for Basin Research. To provide primary data to constrain the modeling effort on basins, the panel recommends continued funding for efforts to preserve, archive, and disseminate data on sedimentary basins. A diverse and substantial body of information was collected through massive investments by the petroleum industry, and it is unlikely that data gathering on this scale will ever be repeated for sedimentary basins in the United States. If adequately preserved, these data sets will sustain continued advances in basin research for many years. Role of Scientific Societies. Finally, the panel recommends that the broad range of geoscience societies take an active role in facilitating progress toward the development of a comprehensive set of models for sedimentary basins. Examples of important efforts would include collaborative special sessions and research conferences, joint industry-
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--> academic-government roundtable discussions on critical organizational issues for strengthening multidisciplinary research on sedimentary basins, and increased liaison with existing international programs.
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