Arctic Ocean Sediments

Although it is generally accepted that the Arctic Ocean is a very sensitive and important region for changes in the global climate, this region is the last major physiographic province of the earth whose short-and long-term geological history is much less known in comparison to other ocean regions. This lack of knowledge is mainly caused by the major technological/logistic problems in reaching this harsh, ice-covered region with normal research vessels and in retrieving long and undisturbed sediment cores. During the the last about 20 years, however, several international and multidisciplinary ship expeditions, including the first scientific drilling on Lomonosov Ridge in 2004, a break-through in Arctic research, were carried out into the central Artic and its surrounding shelf seas. Results from these expeditions have greatly advanced our knowledge on Arctic Ocean paleoenvironments. Published syntheses about the knowledge on Arctic Ocean geology, on the other hand, are based on data available prior to 1990. A comprehensive compilation of data on Arctic Ocean paleoenvironment and its short-and long-term variability based on the huge amount of new data including the ACEX drilling data, has not been available yet. With this book, presenting (1) detailed information on glacio-marine sedimentary processes and geological proxies used for paleoenvironmental reconstructions, and (2) detailed geological data on modern environments, Quaternary variability on different time scales as well as the long-term climate history during Mesozoic-Tertiary times, this gap in knowledge will be filled. *Aimed at specialists and graduates *Presents background research, recent developments, and future trends *Written by a leading scholar and industry expert

Proceedings of the NATO Advanced Research Workshop, Bremen, Germany, October 10-14, 1988

This volume of 18 papers describes the glacial-marine sedimentary environment in a variety of temporal and spatial settings. The volume's primary emphasis is the characteri zation of Quaternary glacial-marine sedimentation to show (1) the significant differences that exist between glacial marine environments in different geographic settings and (2) their resulting glacial-marine deposits and facies. Addi tionally, papers describing ancient glacial-marine environ ments are also presented to illustrate lithified analogs of the Quaternary deposits. With the Doctrine of Uniformitarianism in mind (the present is the key to the past), it is hoped that this volume will serve to expand the horizons of geologists working on the rock record, especially those whose primary criteria for recognition of ancient glacial-marine environments is the presence of dropstones in a finer-grained matrix. As the papers presented here show, diamictite is only one of many types of deposits that form in the glacial-marine sedimentary environment. Papers presented in this volume examine the Quaternary glacia1-marine sedimentary picture in subarctic Alaska, Antarctica, the Arctic Ocean, the Kane Basin, Baffin Island, the Puget-Fraser Lowland of Washington and British Columbia, and the North Atlantic Ocean. Ancient glacia1-marine depos its described are the Neogene Yakataga Formation of southern Alaska, the Late Paleozoic Dwyka Formation of the Karoo Basin of South Africa, and the Precambrian Mineral Fork Formation of Utah. For continuity, a paper summar1z1ng the temporal and spatial occurrences of glacial-marine deposits is also presented.

The Arctic region has long held a fascination for explorers and scientists of many countries. Despite the numerous voyages of exploration, the na ture of the central Arctic was unknown only 90 years ago; it was believed to be a shallow sea dotted with islands. During Nansen's historic voyage on the polarship Fram, which commenced in 1893, the great depth of the central basin was discovered. In the Soviet Union, investigation of the Arctic Ocean became national policy after 1917. Today research at several scientific institutions there is devoted primarily to the study of the North Polar Ocean and seas. The systematic exploration of the Arctic by the United States com menced in 1951. Research has been conducted year-round from drifting ice islands, which are tabular fragments of glacier ice that break away from ice shelves. Most frequently, ice islands originate off the northern coast of Ellesmere Island. These research platforms are occupied as weather sta tions, as well as for oceanographic and geophysical studies. Several inter national projects, conducted by Canadian, European, and U. S. groups, have been underway during the last three decades. Although much new data have accumulated since the publication of the Marine Geology and Oceanography of the Arctic Seas volume in 1974 (Yvonne Herman, ed. ), in various fields of polar research-including present-day ice cover, hydrogra phy, fauna, flora, and geology-many questions remain to be answered.

To understand the global oceanic carbon budget and related climate change, exact measurements of organic carbon flux in all oceans environments, especially the continental margins, are crucial. In fact, data have been available for some time on organic carbon sources, pathways, and burial for most of the world’s oceans, with the notable exception of the Arctic. With this book, the editors remedy this gap in knowledge, presenting an overview of organic-carbon sources, pathways, and burial of the circum-Arctic continental margin and deep-sea areas. Data from each Arctic shelf and basin are collated, presented in common and parallel formats, and related to the global carbon cycle. The book is suitable for lecturers, graduate students as well as scientists interested in the organic-carbon-cycle and Arctic Ocean (paleo-)environment.

"Offshore oil development in Arctic Alaska is expanding. Since biodegradation is a major removal mechanism of petroleum hydrocarbons from the environment, baseline data on microorganisms present are important. I estimated microbial populations and their degradation activities in Arctic Ocean sediments, and examined how sediment affects phenanthrene bioavalability. Populations of hydrocarbon degraders were significantly higher in sediments from near Prudhoe Bay than near Barrow. However, microbial counts from Prudhoe Bay were similar to those measured in the 1970s suggesting that the difference was not due to oil development activities. Total microbial counts were higher than in more temperate regions. All sediments had low hexadecane and phenanthrene mineralization potentials. The apparent partition coefficient, Kp, for phenanthrene in sediment/seawater slurries generally increased with increasing sediment organic carbon. But without aging, sediment did not influence the mineralization of phenanthrene. Overall, biodegradation will likely be a slow removal mechanism of contaminants from the Arctic marine environment"--Leaf iii.

The Foraminifera populations and distributions of five deep sea sediment cores recovered from the Arctic Ocean yielded data on 126 species of Foraminifera. Abundance data and species appearance and mortality data across geomagnetic reversal intervals in the cores show no positive correlation. Arctic Ocean Foraminifera apparently do not respond in any significant way to magnetic reversals of the earth's magnetic field. (Modified author abstract).

Lorsqu'il n'est pas en notre pouvoir de discerner les plus vraies opinions, nous devons suivre les plus pro babies.-Rene Descartes When, in the early 1960's I undertook to covered, due to limitations imposed by a single study Arctic Ocean deep-sea cores, I did not volume. anticipate that 10 years later the climatic history Although not comprehensive, it is hoped that of the north polar basin would be still a matter of this book will provide an insight into the current debate. Although much new data have accumu status of Arctic research and will also serve as a lated in various fields of Arct.

This open access book presents the most current research results and knowledge from five multidisciplinary themes: Vulnerability of Arctic Environments, Vulnerability of Arctic Societies, Local and Traditional Knowledge, Building Long-term Human Capacity, New Markets for the Arctic, including tourism and safety. The themes are those discussed at the first ever UArctic Congress Science Section, St. Petersburg, Russia, September 2016. The book looks at the Arctic from a holistic perspective; how the environment (both marine and terrestrial) and communities can adapt and manage the changes due to climate change. The chapters provide examples of the state-of-the-art research, bringing together both scientific and local knowledge to form a comprehensive and cohesive volume. Except where otherwise noted, this book is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Following a decision by the Arctic Ocean Sciences Board (AOSB) in July 1996 the then chainnan, Geoffrey Holland, wrote a letter of invitation to a meeting to plan a "Symposium on the Freshwater Balance of the Arctic". The meeting was held in Ottawa on November 12-13 1996 and was attended by representatives of various organisations, including the U.S. National Science Foundation (NSF), as well as individual scientists. Results of this meeting included: • Co-sponsorship with AOSB by the Scientific Committee on Ocean Research (SCOR), the Arctic Climate System Study (ACSYS) and the Global Energy and Water Cycle Experiment (GEWEX). • A decision to apply for funding as a Advanced Research Workshop (ARW) of the North Atlantic Treaty Organisation (NATO) Scientific Affairs Division. • That expenses would be covered in part by funds available through an existing NSF grant to the SCOR Executive offices in Baltimore, MD. • The appointment of myself to be Chairman/Manager for the Symposium. • Provision of a recommended list of Scientific Advisors to assist the Chainnan in selecting key speakers.

The primary goal of the research was to use 87Sr/86Sr as a geochronometer in Arctic Ocean sediments. This attempt was unsuccessful because the analytical precision of the analysis (+/-0.000010) was insufficient to differentiate the expected change in oceanic 87Sr/86Sr. New data published after the submission of this proposal indicated that the change was on 0.000025, half that of previously published data. However, a study of the strontium isotopic composition of foraminifera from the Arctic implied that there is enrichment of radiogenic strontium in the Arctic halocline. Although the mean values are statistically different in the Arctic Ocean and the South Atlantic, contamination by clay minerals in the Arctic cannot be ruled out. A simple box model indicates that some enrichment of strontium in surface waters must occur, but the amount is very sensitive to the strontium isotopic composition of Arctic rivers. Models using the most recent riverine data do not produce the observed enrichment.

The Arctic Ocean sediment (AOS) is highly sensitive to global climate changes and has become a focus of much paleoclimatic research. In this study, paleoclimatic characteristics of the AOS have been studied using downcore X-Ray Fluorescence (XRF) data from 13 Healy-Oden TransArctic Expedition cores. Lithological and multi-element variations representing glacial and interglacial cycles were correlated using the variable-based Varimax-rotated Principal Component Analysis (VPCA) of the XRF data. The main components generated by the VPCA have been interpreted as related to terrigenous (erosional) sources (F1, Ti-K-Rb-Fe-Ba-Cr), changes in Laurentide Ice Sheet (LIS) (F3, Ca-P-I), pore water concentration/ biogenic productivity (F5, P-Cl-S), bottom-water ventilation (F6, Mn-Ni-Cu) and siliciclastics (F7, Sr-Zr). Component variations are well consistent with glacial ("gray beds")-interglacial("brown beds") cycles and associated deglacial carbonate pulses in the core 8JPC with identified age controls of Adler et al., 2009 and Polyak et al., 2009. Mn-rich layers (corresponding F6 peaks) of interglacial origin are generally anticorrelated with Ca pulses (F3 peaks) generated during deglaciations. Cl data show general enhancement with interglacials and glacial gray beds with coarse detrital sand pulses suggesting saline pore water trapped within the porosity of these coarser beds. Pleistocene sedimentation is characterized with only a few shallow carbonate spikes, which indicate a weakened Beaufort Gyre and stronger Transpolar Drift as indicated by the lower abundance of Laurentide material in the Eurasian Basin. The Visible-Near Infrared (VNIR) derivative spectroscopy study of the sediment core P1-92AR-P25 (or P25) demonstrates cyclic variations in downcore mineralogy. VPCA of the downcore VNIR data show three mineral assemblages reflecting glacial-interglacial cyclicity. The results are consistent with clay mineral cycles identified by previous studies (Yurco et al. 2010). The downcore mineralogical cyclicity provides a glacial-interglacial portrait of changes in sediment provenance indicative of both Laurentide and Eurasian sources and delivery mechanisms associated with changes in sea level, configurations of Arctic ice sheets and oceanic/atmospheric circulation. The study further reveals that the VNIR spectroscopy can be used as an effective tool in semi quantitative prediction of dolomites. Wavelet analysis in component scores of 8JPC (XRF data) and P25 (VNIR data) identifies significant periodicities; eccentricity (~100 kyr), Obliquity (~40 kyr) and precession (~21 kyr). In both 8JPC and P25 glacial-interglacial variations show eccentricity whereas in 8JPC, LIS changes and biogenic productivity represent precession cycles and in P25 carbonate sedimentation displays strong obliquity (~40 kyr) cycles with moderate influence of precession (~21 kyr) cycles probably representing IRD events in stadial/ interstadial cycles associated with Heinrich and Bond cycles. These findings agree with Adler et al., 2009 that AOS reflects insolation-controlled paleoclimatic processes with longer-term glacial cycles interrupted with abrupt iceberg/melt water discharges of both Laurentide and Eurasian sources. High resolution age control is critical for better evaluation of periodicities of paleoclimatic variations.