GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Oxford :Elsevier Science & Technology,
    Keywords: Paleoceanography -- Cenozoic -- Methodology. ; Geology, Stratigraphic -- Cenozoic. ; Electronic books.
    Description / Table of Contents: The present volume is the first in a series of two books dedicated to the paleoceanography of the Late Cenozoic ocean. The need for an updated synthesis on paleoceanographic science is urgent, owing to the huge and very diversified progress made in this domain during the last decade. In addition, no comprehensive monography still exists in this domain. This is quite incomprehensible in view of the contribution of paleoceanographic research to our present understanding of the dynamics of the climate-ocean system. The focus on the Late Cenozoic ocean responds to two constraints. Firstly, most quantitative methods, notably those based on micropaleontological approaches, cannot be used back in time beyond a few million years at most. Secondly, the last few million years, with their strong climate oscillations, show specific high frequency changes of the ocean with a relatively reduced influcence of tectonics. The first volume addresses quantitative methodologies to reconstruct the dynamics of the ocean andthe second, major aspects of the ocean system (thermohaline circulation, carbon cycle, productivity, sea level etc.) and will also present regional synthesis about the paleoceanography of major the oceanic basins. In both cases, the focus is the "open ocean leaving aside nearshore processes that depend too much onlocal conditions. In this first volume, we have gathered up-to-date methodologies for the measurement and quantitative interpretation of tracers and proxies in deep sea sediments that allow reconstruction of a few key past-properties of the ocean( temperature, salinity, sea-ice cover, seasonal gradients, pH, ventilation, oceanic currents, thermohaline circulation, and paleoproductivity). Chapters encompass physical methods (conventional grain-size studies, tomodensitometry, magnetic and mineralogical properties), most current biological
    Type of Medium: Online Resource
    Pages: 1 online resource (863 pages)
    Edition: 1st ed.
    ISBN: 9780080525044
    Series Statement: Issn Series ; v.Volume 1
    DDC: 551.46
    Language: English
    Note: Front cover -- Proxies in Late Cenozoic Paleoceanography -- Copyright page -- Contents -- Contributors -- Scientific Committee -- Methods in Late Cenozoic Paleoceanography: Introduction -- 1. Tracers and Proxies in Deep-Sea Records -- 2. Overview of Volume Content -- 3. The Need for Multi-tracers and Multi-Proxy Approaches in Paleoceanography -- 4. From the Geological Record to the Sedimentary Signal and the Properties of the Water Column -- 5. How Far Back in Time are the Proxies Effective? -- 6. New Perspectives and Emerging Proxies -- Acknowledgments -- References -- Part 1: Deep-Sea Sediment Properties -- Chapter 1. Deep-Sea Sediment Deposits and Properties Controlled by Currents -- 1. Introduction -- 2. Sediment Transport and Deposition by Deep-Sea Currents -- 3. Sediment Deposition: Quaternary Records of Flow in Large-Scale Features -- 4. Current Problems and Prospects -- References -- Chapter 2. Continuous Physical Properties of Cored Marine Sediments -- 1. Introduction -- 2. Continuous Centimeter-Scale Measurements of Physical Properties -- 3. Continuous Millimeter- to Micrometer-Scale Measurements of Physical Properties -- 4. Recent Applications of Continuous Centimeter- to Millimeter-Scale Physical Properties of Marine Sediments -- 5. Conclusion -- Acknowledgments -- References -- Chapter 3. Magnetic Stratigraphy in Paleoceanography: Reversals, Excursions, Paleointensity, and Secular Variation -- 1. Introduction -- 2. Background -- 3. Soft Sediment Paleomagnetic Methods -- 4. Magnetometers -- 5. Measurements and Magnetizations -- 6. Data Analysis -- 7. Sediment Magnetism -- 8. Development of Paleomagnetic Records -- 9. The Paleomagnetic Record as a Stratigraphic Tool -- 10. Some Perspectives -- References -- Chapter 4. Clay Minerals, Deep Circulation and Climate -- 1. Introduction -- 2. Methodology: The Clay Toolbox in Marine Sediments. , 3. Applications: Clays as a Proxy for Paleocirculation -- 4. Some Perspectives -- Acknowledgements -- References -- Chapter 5. Radiocarbon Dating of Deep-Sea Sediments -- 1. Introduction -- 2. Dating Marine Sediments -- 3. Applications of Marine 14C -- Appendix I - Internet Resources -- References -- Part 2: Biological Tracers and Biomarkers -- Chapter 6. Planktonic Foraminifera as Tracers of Past Oceanic Environments -- 1. Introduction -- 2. Biology and Ecology of Planktonic Foraminifera -- 3. Planktonic Foraminiferal Proxies -- 4. Modifications After Death -- 5. Perspectives -- WWW Resources -- References -- Chapter 7. Paleoceanographical Proxies Based on Deep-Sea Benthic Foraminiferal Assemblage Characteristics -- 1. Introduction -- 2. Benthic Foraminiferal Proxies: A State of the Art -- 3. Conclusions -- Acknowledgements -- 4. Appendix 1 -- References -- Chapter 8. Diatoms: From Micropaleontology to Isotope Geochemistry -- 1. Introduction -- 2. Improvements in Methodologies and Interpretations -- 3. Case Studies -- 4. Conclusion -- Acknowledgments -- References -- Chapter 9. Organic-Walled Dinoflagellate Cysts: Tracers of Sea-Surface Conditions -- 1. Introduction -- 2. Ecology of Dinoflagellates -- 3. Dinoflagellates vs. Dinocysts and Taphonomical Processes (From the Biocenoses to Thanathocenoses) -- 4. Relationships between Dinocyst Assemblages and Sea-Surface Parameters -- 5. The Development of Quantitative Approaches for the Reconstruction of Hydrographic Parameters Based on Dinocysts -- 6. The Use of Dinocysts in Paleoceanography -- 7. Concluding Remarks -- References -- Chapter 10. Coccolithophores: From Extant Populations to Fossil Assemblages -- 1. Introduction -- 2. Taxonomy -- 3. Biogeography, Sedimentation, and Biogeochemical Significance -- 4. Current State of Methods -- 5. Examples of Applications -- Acknowledgments -- References. , Chapter 11. Biomarkers as Paleoceanographic Proxies -- 1. Preliminary Considerations -- 2. Methodological Approaches -- 3. Applications -- 4. Concluding Remarks -- Acknowledgments -- References -- Chapter 12. Deep-Sea Corals: New Insights to Paleoceanography -- 1. Introduction -- 2. Methods and Interpretations -- 3. Landmark Studies -- References -- Chapter 13. Transfer Functions: Methods for Quantitative Paleoceanography Based on Microfossils -- 1. Introduction -- 2. Methods Based on Calibration -- 3. Methods Based on Similarity -- 4. Comparison of Methods with a Worked Example -- 5. Discussion and Future Developments -- 6. The applications of Transfer Functions Sensu Lato in Paleoceanography -- 7. Concluding Remarks -- References -- Part 3: Geochemical Tracers -- Chapter 14. Elemental Proxies for Palaeoclimatic and Palaeoceanographic Variability in Marine Sediments: Interpretation and Application -- 1. Introduction -- 2. Sedimentary Components of Marine Sediments -- 3. Normalization of Elemental Data -- 4. Palaeoclimatic Records from the Sea Floor -- 5. Metalliferous Sedimentation in the Ocean -- 6. Elemental Proxies for Palaeoproductivity -- 7. Proxies for Redox Conditions at the Sea Floor and in Bottom Sediments -- 8. Future Developments -- 9. Afterword -- Acknowledgements -- References -- Chapter 15. Isotopic Tracers of Water Masses and Deep Currents -- 1. Introduction -- 2. Present State of Methodological Approaches and Interpretations -- 3. Examples of Applications -- 4. Conclusion and Perspectives -- References -- Chapter 16. Paleoflux and Paleocirculation from Sediment 230Th and 231Pa/230Th -- 1. Introduction -- 2. Factors Controlling the Distribution of 230Th and 231Pa in the Ocean -- 3. Paleoceanographic Applications -- 4. Conclusions -- References -- Chapter 17. Boron Isotopes in Marine Carbonate Sediments and the pH of the Ocean. , 1. Introduction -- 2. Empirical Observations and Theoretical Background -- 3. Caveats and Complications -- 4. Applications of the Boron Isotope Paleo-pH Proxy -- 5. Summary and Conclusion -- Acknowledgments -- References -- Chapter 18. The Use of Oxygen and Carbon Isotopes of Foraminifera in Paleoceanography -- 1. Introduction -- 2. Notation and Standards -- 3. Stratigraphic and Paleoecological Use of Foraminifera -- 4. Foraminiferal Oxygen Isotopes as Environmental Proxies -- 5. Foraminiferal Carbon Isotopes as Environmental Proxies -- 6. Conclusion and Summary -- References -- Chapter 19. Elemental Proxies for Reconstructing Cenozoic Seawater Paleotemperatures from Calcareous Fossils -- 1. Introduction -- 2. Thermodynamic Effects on Mg Co-Precipitation in Calcites -- 3. Foraminiferal Mg/Ca Paleothermometry -- 4. Ostracode Mg/Ca Paleothermometry -- 5. Coralline Sr/Ca Paleothermometry -- 6. Contributions to Cenozoic Climate History -- References -- Reconstructing and Modeling Past Oceans -- 1. A Brief Historical Overview -- 2. Classification of Climate Models -- 3. Models and Proxy Data -- 4. International Programs -- 5. Conclusion -- References -- Index of Taxa -- Subject Index.
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2021-02-08
    Description: Sea-surface conditions in northeastern Fram Strait since the last glacial maximum (LGM) were reconstructed from cores MSM5/5-712-2 and PS2863/1-2 based on palynological assemblages, ecological preferences of dinocysts and application of the modern analog technique. Dinocyst in LGM sediments are sparse, but their assemblages reflect mild summer conditions. Given the regional context and evidence from other tracers, the dinocyst assemblages of the LGM could relate to regional fluxes of dinocysts during exceptional mild summers. From 19 to 14.7 ka, dinocyst data suggest very cold conditions with extensive sea-ice cover, while abundant reworked palynomorphs indicate intense glacial erosion. An abrupt transition at 14.7-14.5 ka was marked by a peak in summer temperatures coinciding with a rapidly deposited sediment layer related to a regional meltwater plume event in western Svalbard. From 14.7 to 12.6 ka, large seasonal temperature contrasts with mild summers and cold winters together with low salinity indicate continuous melting of the Svalbard Barents Sea ice sheet fostered by warm climate. At 12.6 ka, the regional onset of the Younger Dryas was marked by cooling and increased salinity. On a regional scale, the 12.6-12 ka interval corresponds to an important transition involving enhanced circulation of Arctic waters around Svalbard and establishment of coastal fronts along its northern and western margins. Modern-like oceanic conditions with relatively high salinity and low seasonal temperature contrast developed at about 7.6 ka. Since then, a slight cooling is observed, especially in winter. This study offers a comprehensive picture of the deglacial phases in eastern Fram Strait with unique data on the sea-surface salinity, which controls surface water stratification and plays an important role in ocean circulation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Elsevier
    In:  Marine Geology, 346 . pp. 183-191.
    Publication Date: 2017-06-23
    Description: Geochemical and micropaleontological analyses were carried out on a 35 cm box core (CR06-TCE) spanning the last 6000 years in the Esquiman Channel, a northeast arm of the Laurentian Channel in the Gulf of St. Lawrence. A 0.6‰ decrease of δ18O in benthic foraminifer Globobulimina auriculata shells characterizes the upper 10 cm of the core and suggests a warming of the bottom waters. This change is concomitant with increased percentages of the low-oxygen tolerant benthic foraminifer species Brizalina subaenariensis and the Atlantic water species Oridorsalis umbonatus. Although a precise timing cannot be established, notably because of the smoothing effect of bioturbation, the amplitude of the trend recorded in the Esquiman Channel is coherent with that of the regional warming observed in the bottom water of the main axis of the Laurentian Channel over the last century. Warm bottom water conditions, however, are not exclusive to the recent time interval as shown by data from the lower part of the core, which are also characterized by low δ18O values in G. auriculata and occurrence of both B. subaenariensis and O. umbonatus. Such data suggest the existence of low-oxygen and relatively high temperature conditions in the bottom water of the Esquiman Channel about 4 to 6 kyrs ago likely related to enhanced inflow of Atlantic water in the Gulf of St. Lawrence through the Cabot Strait and the Laurentian Channel. These results highlight the sensitivity of bottom water properties in the Gulf of St. Lawrence to changes in the western North Atlantic circulation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    IUEM
    In:  [Talk] In: ISTAS: Integrating Spatial and Temporal Scales in the Changing Arctic System, 21.10.-24.10.2014, Plouzané, France . ISTAS: Integrating Spatial and Temporal Scales in the Changing Arctic System : Towards Future Research Priorities ; Oct 21 - 24, Plouzané, IUEM ; Book of Abstracts – Plenary Session ; p. 41 .
    Publication Date: 2019-09-23
    Description: Recent observations of enhanced oceanic heat transfer into the Arctic concomitant with the rapid sea-ice decrease temptingly suggest a direct relationship between both features. However, except for marginal areas of the Arctic Ocean where warm and saline Atlantic Water (AW) reaches the surface, the majority of AW heat is presently isolated from the sea-ice cover by a cold and fresh halocline layer. No evidence has been found to suggest a weakening of the halocline across the central Arctic basins that would enhance the AW heat transfer to the surface. A more direct link between sea-ice reduction and AW inflow is, however, seen in the inflowing Barents Sea branch in both historical and observational time series. In this presentation the AW advection into the Arctic Ocean and its influence on sea-ice variability will be reviewed from a geological point of view. Records from the geologic past are of great value as the time span of modern observations and historical data is often too short to comprehend long-term trends and causes of AW variability, changes in the marginal ice zone, and the vertical structure of the Arctic water column. Paleoceanographic studies from the recent interglacial indirectly suggest that the strength of AW advection and its propagation into the Arctic interior is effective in melting sea ice in combination with other factors such as insolation, sea level, freshwater input, and upper water mass stratification. However, to date, very little paleoceanographic work in the Arctic has focused on how the strength and position of the halocline has changed during previous interglacial periods. More direct reconstructions of the Arctic’s vertical stratification in the geologic past are needed to provide a longer-term view on the stability of the halocline, and more generally, the role of Atlantic Water inflow on the stability of sea ice in the interior basins.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2022-01-31
    Description: The palynogical data of two sites from northeastern Fram Strait (MSM5/5–712 and PS2863)encompassing the last 23,000 years are presented here. The data set first includes the palynomorph concentrations: dinocysts (cysts/g)and their fluxes (cysts/cm 2 /yr)as well as pollen grains, spores, organic linings, Halodinium, reworked palynomorphs and Pediastrum represented in #/g. It also includes the relative abundance (%)of dinocyst taxa at sites MSM5/5–712 and PS2863. Finally, this Data in Brief comprises reconstructions of sea-surface conditions at the two sites, which include sea-surface temperature (°C)in summer and winter, sea-surface salinity (psu)in summer and winter, sea-ice cover (month/yr)and productivity (gC/m 2 yr). The most probable values in addition to minimum and maximum possible are reported. The data is presented in function of the cores depth and age. For more details on this data and the chronology of the cores, see [1].
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2024-02-07
    Description: Highlights • Sea-ice cover limits the accumulation of both coccoliths and alkenones in sediments. • Calcite dissolution in shelf sediments may explain the accumulation of alkenones in the presence of few or no coccoliths. • Non-calcifying haptophytes most likely produce alkenones in nearshore environments. Abstract We determined the abundances and concentrations of coccoliths and alkenones in 66 surface sediment samples from the northwest North Atlantic to evaluate the role that surface ocean temperature, salinity, sea-ice cover, and productivity have on the regional distribution of these two biological remains produced by haptophytes in the photic zone. In areas with sea-ice cover of more than 1 month per year, coccolith and alkenone concentrations in sediments are extremely low to nil. Elsewhere, the distribution of coccolith taxa generally displays strong relationships to water temperature, salinity, and productivity. Coccolithus pelagicus is associated with low summer sea-surface temperatures (〈8°C) and relatively high summer sea-surface salinities (〉33.5), whereas Helicosphaera carteri seems to follow the path of the North Atlantic Drift. The distribution of Emiliania huxleyi, the dominant alkenone producer, is not strongly correlated with that of alkenones. Calcite dissolution in shelf sediments could explain the occurrence of alkenones in the absence of coccoliths but alkenone production by non-calcifying haptophytes seems to also exert some control on alkenone concentrations in surface sediments, thus blurring alkenone abundance links to coccolithophorid production and their relative preservation.
    Type: Article , PeerReviewed
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2024-02-07
    Description: Highlights • Porewater calcite dissolution may have occurred during the deglacial interval. • There is a significant decoupling of coccolith and alkenone concentrations in core 004. • Non-calcifying haptophytes most likely produced the alkenones in the glacial interval. Abstract The important changes that took place in the glacial cycle at the termination, from the Last Glacial Maximum to the present interglacial, deserve an examination of ocean sedimentary records that document past productivity, carbon fluxes, and carbonate preservation. In this study, we analyzed coccoliths, alkenones, and foraminifers in core HU2008–029-004 PC (61.46°N and 58.04°W, water depth = 2,674 m) from the northwestern Labrador Sea to document linkages between hydrographic conditions, biogenic carbonate fluxes to the seafloor, and their preservation/dissolution during the last 25,000 years. Large changes in coccolith and foraminifer concentrations are recorded, with sediments from the last glacial interval containing significantly less carbonate microfossils (9.5 ± 3.9 × 105 coccoliths g−1 and 2,860 ± 580 planktonic foraminifers g−1) than sediments from the deglacial and postglacial intervals (up to 3.1 × 108 coccoliths g−1 and 2.9 × 104 foraminifers g−1). Three foraminifer-based calcite dissolution indices were used to evaluate biogenic carbonate preservation: the planktonic foraminifer fragmentation index, the ratio of benthic-to-planktonic foraminifers (B/P), and the ratio of organic linings to benthic foraminifers (OL/B). Fragmentation remained low throughout the postglacial (mean of 4%) but reached up to 8% in the deglacial and peaked at 16% in samples from the Bølling-Allerød of the late glacial interval. Samples from the Bølling-Allerød and the deglacial interval also display a slightly elevated B/P index (〉0.15), which suggests that some dissolution may have occurred. In contrast, with the exception of the Bølling-Allerød and the deglacial interval, near zero OL/B values characterize most of the sequence, suggesting good biogenic carbonate preservation, which implies that the low biogenic carbonate and coccolith content in sediments of the glacial stage mirror low productivity of calcifying organisms. The elevated fragmentation of foraminifers during the Bølling-Allerød and the deglacial interval, a time of elevated productivity and low percentages of ice-rafted debris, may indicate the development of calcite undersaturated porewaters and consequent dissolution resulting from oxic remineralization of sedimentary organic matter. We also identify a significant decoupling of coccolith and alkenone concentrations throughout the core. Colder-than-expected UK37-SST estimates from the alkenones of the glacial interval rule out possible allochthonous inputs from lower-latitude locations. Instead, our records imply that at least during the glacial interval, alkenones were produced by non-calcifying haptophytes that may not follow the canonical UK37-based temperature calibrations.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    Elsevier
    In:  EPIC3Palaeogeography, Palaeoclimatology, Palaeoecology, Elsevier, 546, pp. 109605, ISSN: 00310182
    Publication Date: 2020-06-10
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2023-11-14
    Description: Continuous and multi-decadal records of faunal abundance and diversity helping to identify the impacts of ongoing global warming on aquatic ecosystems are rare in the coastal Arctic. Here, we used a 50-year-long microfaunal record from a sediment core collected in the Herschel Basin (YC18-HB-GC01; 18 m water depth) to document some aspects of the environmental responses of the southern Canadian coastal Beaufort Sea to climate change. The microfaunal indicators include benthic foraminiferal assemblages, ostracods and tintinnids. The carbonate shells of two foraminiferal species were also analyzed for their stable isotope signatures (δ13C and δ18O). We compiled environmental parameters from 1970 to 2019 for the coastal region, including sea ice data (break-up date, freeze-up date, open season length and mean summer concentration), the wind regime (mean speed, direction of strong winds and the number of storms), hydrological data (freshet date, freshet discharge and mean summer discharge of the Firth and the Mackenzie rivers), and air temperature. Large-scale atmospheric patterns were also taken into consideration. Time-constrained hierarchal clustering analysis of foraminiferal assemblages and environmental parameters revealed a near-synchronous shift around the late 1990s. The microfaunal shift corresponds to an increased abundance of taxa tolerant to variable salinity, turbulent bottom water conditions, and turbid waters towards the present. The same time interval is marked by stronger easterly winds, more frequent storms, reduced sea-ice cover, and a pervasive anticyclonic circulation in the Arctic Ocean (positive Arctic Ocean Oscillation; AOO+). Deeper vertical mixing in the water column in response to intensified winds was fostered by increased open surface waters in summer leading to turbulence, increased particle loading and less saline bottom waters at the study site. Stronger easterly winds probably also resulted in enhanced resuspension events and coastal erosion in addition to a westward spreading of the Mackenzie River plume, altogether contributing to high particulate-matter transport. Increase food availability since ∼2000 was probably linked to enhanced degradation of terrestrial organic carbon, which also implies higher oxygen consumption. The sensitivity of microfaunal communities to environmental variations allowed capturing consequences of climate change on a marine Arctic shelf ecosystem over the last 50 years.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...