Sulphur contents and partition of iron in ODP Leg 112 sediments
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| Autores principales: | , |
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| Formato: | Dataset Open Access |
| Lenguaje: | en |
| Publicado: |
PANGAEA
1996
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| _version_ | 1867171357057351680 |
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| author | Raiswell, Robert Canfield, Donald E |
| author_facet | Raiswell, Robert Canfield, Donald E |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Porewaters in site 680 Peru Margin sediments contain dissolved sulfide over a depth of approximately 70 m which, at a sedimentation rate of 0.005 cm/yr, gives a sediment exposure time to dissolved sulfide of about 1.4 Myr. Reactions with dissolved sulfide cause the site 680 sediments to show a progressive decrease in a poorly-reactive silicate iron fraction, defined as the difference between iron extracted by dithionite (FeD) at room temperature and that extracted by boiling concentrated HCl (FeH), normalised to the total iron content (FeT). Straight line plots are obtained for ln[(FeH - FeD)/FeT] against time of burial, from which a first order rate constant of 0.29 1/Myr (equivalent to a half-life of 2.4 Myr) can be derived for the sulfidation of this silicate iron. Comparable half-lives are also found for the same poorly-reactive iron fraction in the nearby site 681 and 684 sediments. This silicate Fe fraction comprises 0.8-1.0% Fe, only 30-60% of which reacts even with 1.5-3 million years exposure to dissolved sulfide. Diagenetic models based on porewater concentrations of sulfate and sulfide, and solid phase iron contents, at site 680 are consistent in indicating that this poorly-reactive iron fraction is only sulfidized on a million year time scale. Silicate iron not extracted by HCl can be regarded as unreactive towards dissolved sulfide on the time scales encountered in marine sediments. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_708059 |
| institution | PANGAEA |
| language | en |
| publishDate | 1996 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Sulphur contents and partition of iron in ODP Leg 112 sediments Raiswell, Robert Canfield, Donald E 112-680; 112-681; 112-684; COMPCORE; Composite Core; Joides Resolution; Leg112; Ocean Drilling Program; ODP; South Pacific Ocean Porewaters in site 680 Peru Margin sediments contain dissolved sulfide over a depth of approximately 70 m which, at a sedimentation rate of 0.005 cm/yr, gives a sediment exposure time to dissolved sulfide of about 1.4 Myr. Reactions with dissolved sulfide cause the site 680 sediments to show a progressive decrease in a poorly-reactive silicate iron fraction, defined as the difference between iron extracted by dithionite (FeD) at room temperature and that extracted by boiling concentrated HCl (FeH), normalised to the total iron content (FeT). Straight line plots are obtained for ln[(FeH - FeD)/FeT] against time of burial, from which a first order rate constant of 0.29 1/Myr (equivalent to a half-life of 2.4 Myr) can be derived for the sulfidation of this silicate iron. Comparable half-lives are also found for the same poorly-reactive iron fraction in the nearby site 681 and 684 sediments. This silicate Fe fraction comprises 0.8-1.0% Fe, only 30-60% of which reacts even with 1.5-3 million years exposure to dissolved sulfide. Diagenetic models based on porewater concentrations of sulfate and sulfide, and solid phase iron contents, at site 680 are consistent in indicating that this poorly-reactive iron fraction is only sulfidized on a million year time scale. Silicate iron not extracted by HCl can be regarded as unreactive towards dissolved sulfide on the time scales encountered in marine sediments. |
| title | Sulphur contents and partition of iron in ODP Leg 112 sediments |
| topic | 112-680; 112-681; 112-684; COMPCORE; Composite Core; Joides Resolution; Leg112; Ocean Drilling Program; ODP; South Pacific Ocean |
| url | https://doi.org/10.1594/PANGAEA.708059 |