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Opportunities and Priorities in Arctic Geoscience Executive Summary There is broad agreement in the scientific community that the floor of the Arctic Ocean Basin contains potential answers to major unsolved problems in the earth sciences and that many of them pertain to questions that are of global scientific significance or pressing societal concern. However, because of the perennial sea ice, harsh climate, high field costs, and the absence of research platforms suitable for many types of investigations, this region is also one of the most poorly known on earth. Recent political and technological developments, including the apparent end of the Cold War and the prospective availability of nuclear submarines and powerful icebreakers as arctic research platforms, appear to provide possible means to overcome these formidable obstacles and, therefore, have the potential to enable revolutionizing our knowledge of the solid earth beneath the Arctic Ocean Basin. Some of the details of the circum-arctic geology are becoming known from efforts by government agencies, academic institutions, and industry. Because of the prospective logistic opportunities, and because of the disparity in geologic understanding that exists between the Arctic Ocean Basin and the circum-arctic landmasses, the Committee on Arctic Solid-Earth Geosciences recommends that the Arctic Ocean Basin and its margins, instead of the circum-arctic landmasses, be the focus of the next major augmentation of solid-earth geoscience research in the Arctic. Aspects of arctic solid-earth geoscience with important implications for science and society beyond the Arctic include its tectonic evolution, resource potential, paleoceanographic and climatic history, and geologic processes. A satisfactory level of understanding of the plate tectonic history of the Northern Hemisphere cannot be achieved until sufficient geologic and geophysical data to reconstruct the plate tectonics of the Arctic are obtained. Such reconstructions will improve understanding of the geologic structure and history of all of the Northern Hemisphere and provide valuable insights into the origin and distribution of the mineral fuels and other mineral deposits of the northern continents and their continental shelves. The gas hydrate (probably methane hydrate) deposits of the Arctic Ocean Basin, for example, may contain more than 1,000 times the volume of natural gas in the Prudhoe Bay field. Paleomagnetic data indicate that one of the earth's magnetic dipoles, and therefore presumably also the geographic North Pole, have resided in or near the Arctic Ocean Basin since it began to form in Jurassic time. Thus, the sediments of the Arctic Ocean Basin and its margins contain a 200-million-year record of earth's north polar climate and oceanographic history and document the climatic deterioration from temperate conditions in the Cretaceous to cyclic glaciation in the Late Tertiary and Quaternary. Because the polar regions contain perhaps the most sensitive indicators of climate change, and because current evidence suggests a major difference in timing of chilling in the Northern and Southern Hemispheres, the arctic record is
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Opportunities and Priorities in Arctic Geoscience critical to understanding the evolution of global climate and may contribute to understanding the mechanisms of climate change. The availability of both the marine and the nonmarine records of environmental conditions in the Arctic will permit comparison of oceanographic changes in the Arctic Ocean with terrestrial conditions on the adjacent arctic landmasses, and with coeval conditions in the Atlantic and Pacific Oceans. The records will provide close correlation between marine and continental conditions during the crucial transitions from an ice-free to an ice-covered Arctic Ocean and from nonglacial to glacial regimes on the surrounding continents. Comparison of the arctic marine paleoenvironmental record with the record being obtained from the Greenland, arctic island, and antarctic ice sheets or ice caps will also provide data critical to understanding the history and mechanisms of global climate change. This presents an unparalleled opportunity to devise and test theories of global change in relation to natural and anthropogenic forces and to develop useful models for forecasting climate change. A better understanding of arctic geologic processes will improve our ability to interpret the geologic record of environmental change in ancient polar regions throughout the geologic column. Especially important are the effects of perennial sea ice and glacial cycles on the marine record. An understanding of arctic geologic processes is also necessary for the planning of economic development, environmental management, and environmental monitoring in the Arctic, particularly on the arctic continental shelves and coasts. The Arctic is strongly affected by processes and conditions such as sea ice, subsea permafrost and gas hydrate accumulations, and exceptionally strong seasonal control of sedimentation and erosion for which adequate analogs do not exist in more southerly regions. Human activities in the Arctic can have adverse impacts on, and can be negatively affected by, some of these processes and conditions. The Committee on Arctic Solid-Earth Geosciences believes that a three-part program of solid-earth studies in the Arctic Ocean Basin would address the identified opportunities for geoscience research in the Arctic Ocean region and would serve societal needs by increasing understanding of the earth's crust beneath the Arctic Ocean Basin, thereby expanding our data base on resources, climate, and basic geologic processes. Part one, Geologic Framework and Tectonic Evolution, which concentrates on the less-understood Amerasia Basin, includes selected problems in the Eurasia Basin and proposes extensive studies of arctic continental margins. Knowledge of the structural character and history of the arctic margins is necessary to reconstruct the tectonic character and history of the Arctic Ocean Basin and the circum-arctic landmasses and is of direct relevance to the discovery of nonrenewable resources in arctic shelves and landmasses. Special studies that would advance understanding of the geologic framework and evolution of the Arctic are seabed imaging and digital mapping of the Arctic Ocean Basin from nuclear submarines; magnetic and gravity surveys of the Arctic Ocean Basin from submarines or airplanes; comparative studies of trans-arctic geologic structure and stratigraphy; paleomagnetic analysis of arctic tectonic problems, particularly on the basis of studies of terranes near the margins of the Arctic Ocean Basin; and seismological investigations based on an improved network of standardized digital circum-arctic seismograph stations. Part two of the program, The Sedimentary Record and Environmental History, proposes a detailed exploration of the 200-million-year-old record of arctic climate, oceanographic conditions, and faunal evolution and migration that is incorporated in the arctic and circum-arctic sedimentary record. This rich record has both terrestrial and marine components of great variety, has the potential for closely comparing marine and nonmarine conditions in the Arctic through geologic time, and has bearing on global change studies. For example, the Quaternary part of this record would be especially informative if it were to be closely correlated and compared to the record in ice cores from the polar ice sheets and ice caps. The committee believes that an extensive program of piston coring, gravity coring, and shallow-core drilling sited on the basis of improved bathymetric and seismic reflection data from the ridges and plateaus of the Arctic Ocean Basin can provide a general stratigraphic column and marine environmental history of the Arctic Ocean region. This record would not be as complete as one that might be obtained by continuous deep coring in the Arctic Ocean Basin, but there is no present technological assurance that deep coring can be accomplished in the Arctic except in the marginal ice zone or at times and localities with especially favorable sea-ice conditions. A complementary record on
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Opportunities and Priorities in Arctic Geoscience arctic shelves and coastal plains, perhaps not as complete as the marine record in some aspects, would be available for drilling and sampling with present technology. Part three, Arctic Geologic Processes and Environmental Indicators, examines a variety of processes and conditions that are either unique to or well-developed in the Arctic and that, if better understood, would improve our ability to interpret the environmental history of the Arctic and, therefore, to predict climate change. They include chemical and mineralogic indicators of past environmental conditions in the stratigraphic record from which estimates of past conditions can be made, an examination of the processes and environmental significance of the accumulation and transportation of continental shelf and other sediment by rafting in arctic sea ice, and study of arctic sedimentation—including variations in the character and quantity of sediment derived from glacial and nonglacial sources in the circum-arctic landmasses in modern and Quaternary times and the processes whereby these sediments are transported and deposited in the Arctic Ocean Basin. Proposed studies include the evolution of the arctic biota through time, their adaptation to the special conditions of temperature and winter darkness in the Arctic, and their migrations into and out of the Arctic in response to changes in environmental conditions and the oceanic and epicontinental pathways by which the Arctic was episodically connected with other parts of the world ocean. Examination of the hypothesis that the presence of the north magnetic pole produced a detectable enrichment of extraterrestrial material or collision products of cosmic radiation in the sediments of the Arctic Ocean Basin or deep arctic lakes is suggested as a possible way to study solar-terrestrial interactions and variations in strength of the earth's magnetic field through time. Further, the committee proposes a study of the three-dimensional distribution and stability of gas hydrate deposits known to underlie the continental slopes of the Arctic Ocean Basin and to be associated with permafrost deposits beneath arctic coastal plains and inner continental shelves. The volume and stability of these deposits under changing climatic conditions are of great interest because greenhouse gas methane is believed to be the principal gaseous component of arctic hydrates. If the stability of arctic hydrate deposits is susceptible to climatic change, these large deposits may play a significant role in future changes in climate. Recent technologic developments have provided the means for conducting research on the solid earth beneath the Arctic Ocean Basin, and recent political developments have made it conceivable that nuclear icebreakers and nuclear submarines may be available for nonmilitary research in the Arctic. Icebreakers could serve as moving platforms for seismic refraction, seismic reflection, bathymetric, and other geophysical measurements as well as for subseabed coring, shallow drilling, heat flow measurements, and dredging operations. Icebreakers and ice-capable vessels now available in the western world could conduct such activities, provided that the nuclear icebreakers of the USSR could be chartered to supplement and assist them. However, to ensure that U.S. science is not dependent on another country's scientific and political priorities, the committee reaffirms a Polar Research Board recommendation that an ice-capable vessel able to operate routinely in the central Arctic Ocean be added to the U.S. icebreaker fleet (NRC, 1988b). If a sufficiently strong commitment were made to an augmented arctic geoscience program, nuclear submarines could map the arctic seabed with side-scan sonar and echo sounders, record its potential field with gravimeters and magnetometers, and probe its subseabed geologic structure and stratigraphy with continuous seismic reflection profiling methods. Over-ice surveys by air-transportable snow vehicles and by icebreaker-transportable amphibious vehicles capable of working in areas of mixed ice and open water would permit the collection of relatively low-cost seismic reflection, refraction, and other types of data in selected areas. If nuclear submarines were not available or if the submarine tracks were too widely spaced to provide adequate coverage, aeromagnetic and aerogravity coverage of the entire Arctic Ocean Basin could be accomplished by long-range aircraft. Global Positioning System satellites have greatly simplified arctic navigation; they have improved accuracy by orders of magnitude. The continuing reduction in size and weight of modern geophysical instruments has reduced significantly the logistic requirements for many types of field studies. Together, these technological developments can revolutionize our understanding of the character of the solid earth beneath the Arctic
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Opportunities and Priorities in Arctic Geoscience Ocean Basin. The scientific information thus acquired will address quickly and economically some current societal concerns and contribute insight into scientific issues of global interest. A comprehensive arctic solid-earth geoscience program requires a substantial measure of international cooperation, which could now be facilitated in part by the newly established International Arctic Science Committee and by an organized effort in bibliographic and translation programs. In addition, such research would benefit from the establishment of a directory of arctic geoscientists and research projects and from the conduct of small meetings of working scientists to encourage cooperation in recommended studies and the exchange of data and information.
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