Teichert, Barbara M A; Gussone, Nikolaus; Torres, Marta E (2009): Calcium isotope ratios of porewaters of ODP Leg 204 holes [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.785684, Supplement to: Teichert, BMA et al. (2009): Controls on calcium isotope fractionation in sedimentary porewaters. Earth and Planetary Science Letters, 279(3-4), 373-382, https://doi.org/10.1016/j.epsl.2009.01.011
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Abstract:
The calcium isotopic composition of porewaters and authigenic carbonates in the anoxic sediments of a convergent continental margin drilled during Ocean Drilling Program (ODP) provides first insight into the different processes that control Ca geochemistry in clastic marine, organic-rich sedimentary environments. In 4 sites drilled during Leg 204 at Hydrate Ridge (Cascadia Margin, offshore Oregon/USA), sulfate is consumed during anaerobic oxidation of methane and of organic matter via sulfate reduction within the upper meters of the sedimentary section. These reactions promote the precipitation of authigenic carbonates through the generation of bicarbonate, which is reflected in a pronounced decrease in calcium concentration. Although Ca isotope fractionation is observed during carbonate precipitation, Ca concentration in the pore fluids from ODP Leg 204 is decoupled from Ca isotopy, which seems to be mainly controlled by the release of light Ca isotopes that completely overprint the carbonate formation effect. Different processes, such as the release of organically bound Ca, ion exchange and ion pair formation may be responsible for the released light Ca. Deeper within the sedimentary section, additional processes such as ash alteration influence the Ca isotopic composition of the porewater. Two sites, drilled into the deeper core of the accretionary prism, reveal the nature of fluids which have reacted with the oceanic basement. These deep fluids are characterized by relatively high Ca concentrations and low d44/40Ca ratios.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 44.580270 * Median Longitude: -125.122503 * South-bound Latitude: 44.568610 * West-bound Longitude: -125.150300 * North-bound Latitude: 44.586300 * East-bound Longitude: -125.073960
Date/Time Start: 2002-07-13T01:00:00 * Date/Time End: 2002-08-27T21:30:00
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
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Datasets listed in this publication series
- Teichert, BMA; Gussone, N; Torres, ME (2009): (Table 2) Ca, Sr and C isotope ratios of authigenic carbonate samples of ODP Site 204-1244B. https://doi.org/10.1594/PANGAEA.785683
- Teichert, BMA; Gussone, N; Torres, ME (2009): (Table 1) Calcium concentration and Ca isotope ratios of porewater samples of ODP Leg 204 holes. https://doi.org/10.1594/PANGAEA.785682