Iodine diagenesis in non-pelagic deep-sea sediments
Journal Article
·
· Geochim. Cosmochim. Acta; (United States)
Measurements of sediment geochemistry and pore water speciation have been made using eight cores containing turbidite sections from the Madeira and Nares Abyssal Plains. The results have been used to evaluate how the diagenetic chemistry of iodine in these sediments compares with that in sediments undergoing steady-state diagenesis. The behavior of iodine is related to the development of a redox front within the turbidite, between the organic-rich anoxic sediment and its oxic cap, and the downward migration of the front through the turbidite with time. In contrast to the steady-state case, sediment I contents and I/C ratios increase downwards through the oxidized section reaching a maximum at the redox front (Up to approx. 100 ..mu..g/g I; molar I/C approx. 20 x 10/sup -4/) below which values drop dramatically (I/C approx. 5 x 10/sup -4/). A strong iodate enrichment (up to approx. 3 ..mu..mol kg/sup -1/) is observed in the oxidized section of the sediment. At the front interconversion of I/sup -/ and IO/sub 3//sup -/ species occur and below the front pore water IO/sub 3//sup -/ is absent and I/sup -/ concentrations increase with depth up to approx. 10 ..mu..mol kg/sup -1/. In the oxidized section of the sediment the I enrichment has been supplied by upward transport of iodide with the increasing I content, with depth being accounted for by progressive diagenetic enrichment with time.
- Research Organization:
- Univ. of Cambridge (England)
- OSTI ID:
- 5064767
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:9; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
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