Biogenic Barium as a Proxy for Paleoproductivity: Methods and Limitations of Application
| Autor: | Sabine Kasten, C. C. Nürnberg, Franz Gingele, Matthias Zabel, W. J. Bonn |
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| Rok vydání: | 1999 |
| Předmět: |
Total organic carbon
chemistry.chemical_classification 010504 meteorology & atmospheric sciences Geochemistry Sediment chemistry.chemical_element Barium 010502 geochemistry & geophysics 01 natural sciences Diagenesis chemistry.chemical_compound Oceanography chemistry 13. Climate action TRACER Organic matter Sedimentary rock 14. Life underwater Sulfate Geology 0105 earth and related environmental sciences |
| Zdroj: | Use of Proxies in Paleoceanography ISBN: 9783642636813 |
| DOI: | 10.1007/978-3-642-58646-0_13 |
| Popis: | The obvious link between sedimentary barium and past and present ocean productivity has propagated numerous studies on this tracer in the past years. In this paper a summary is given on what is known of the generation of the barium signal and its link to the flux of organic carbon. We describe procedures to assess barium contents, distinguish biogenic from detrital barium and calculate barium accumulation rates. Two approaches to estimate absolute paleoproductivity rates from barium contents are described and compared. A considerable part of the paper is dedicated to synsedimentary and early diagenetic constraints involved in the application of the barium method. It is demonstrated that the most significant diagenetic overprinting of the barium signal occurs in sulfate depleted sediments by dissolution of barite. Examples from selected sites in the Atlantic Ocean show that barium may be a reliable proxy in this part of the world ocean to assess changes in ocean productivity, whereas other proxies are restricted to certain sedimentary environments. Recent studies suggest that for the oligotrophic areas of the Atlantic Ocean barium might be a more reliable tracer for past productivity than organic carbon. This is attributed to the action of oxidation fronts which resulted in a very efficient degradation of the organic matter initially present within the sediment. Nevertheless, quantitative paleoproductivity reconstructions are based on regional studies and future investigations must be carried out in a range of environments before a worldwide application can be obtained. |
| Databáze: | OpenAIRE |
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