Relationship between Sulfate Reduction and Methane Migration in Sediments offshore Southwestern Taiwan
| Autor: | Wei-Chi Hsieh, 謝偉琦 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 This study investigated sulfate reduction and iron sulfide mineral formation in sediments offshore southwestern Taiwan. Special emphasis is placed on sulfate reduction under the influence of methane migration. Analytical works include pore water hydrogen sulfide, sulfate and sediment for organic carbon, carbonate, AVS(acid volatile sulfide) and pyrite-S. Large degree of variations for sulfate reduction, methane, dissolved sulfide, and sulfide minerals concentrations were observed. A complete depletion of sulfate as shallow as 1m was found together with high concentration of methane. Furthermore, dissolved sulfide as high as 9689μM with pyrite reaching 331μmole/g were also observed in the region but organic carbon concentrations remain relatively low with value no more than 1.0%. Even though large variations were found for a number of measured parameters, pyrite concentrations, calculated methane and sulfate flux showed a distinctly high at water depth between 700-1500m.Sulfate reduction in the study region sediments is strongly controlled by the methane migration with downward sulfate flux linearly correlated with upward methane flux. As a result, more pyrite were found in region with high methane flux.However, upward methane migration is not the sole controlling factor for the observed high sulfate reduction.The observed high sulfate reduction is most likely a combine effect of high sedimentation rate as well as high methane flux. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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