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Sulphur geodynamic cycle.

Kagoshima T, Sano Y, Takahata N, Maruoka T, Fischer TP, Hattori K - Sci Rep (2015)

Bottom Line: Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry.The S/(3)He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y.The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.

View Article: PubMed Central - PubMed

Affiliation: Division of Ocean-Earth System Science, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba 277-8564, Japan.

ABSTRACT
Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/(3)He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/(3)He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.

No MeSH data available.


Related in: MedlinePlus

Correlation diagram between δ34S and S/3He ratios of high-temperature volcanic gases in circum-Pacific regions.Model end-members of the upper mantle, sedimentary pyrite and subducted sulphate are included. The curve shows mixing among the end-members. #Data are of the following volcanoes: (#1) Avacha, (#2) Mutonovsky, (#3) Kudryavy, (#4) Usu, (#5) Kuju, (#6) Satsuma-Iwojima, (#7) Lewotolo, (#8) White Island, (#9) Ngauruhoe, (#10) Momotombo, (#11) Galeras, (#12) Colima. All data are from Table 2.
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f2: Correlation diagram between δ34S and S/3He ratios of high-temperature volcanic gases in circum-Pacific regions.Model end-members of the upper mantle, sedimentary pyrite and subducted sulphate are included. The curve shows mixing among the end-members. #Data are of the following volcanoes: (#1) Avacha, (#2) Mutonovsky, (#3) Kudryavy, (#4) Usu, (#5) Kuju, (#6) Satsuma-Iwojima, (#7) Lewotolo, (#8) White Island, (#9) Ngauruhoe, (#10) Momotombo, (#11) Galeras, (#12) Colima. All data are from Table 2.

Mentions: Fig. 2 presents the relation between S/3He ratios and δ34SΣS values of volcanic gases in subduction zones. The figure particularly shows end-member data for the upper mantle, sedimentary pyrite with reduced sulphur derived from slab, and subducted sulphate. The δ34S values of sedimentary pyrite vary considerably due to the result of bacterial reduction of seawater sulphate, and have a mean value of −20.9‰ in the Western Pacific22. Results of a recent study23 of the oceanic basement in northern Italy suggest that low-temperature serpentinization produces a negative δ34SΣS value with (−8.9 ± 8.0)‰. Then the δ34S value of sedimentary pyrite is defined as (−14.9 ± 6.0)‰. No source of primordial helium exists in the pyrite, and the slab may have lost the original mantle helium as well24. It is therefore possible to adopt S/3He larger than 1 × 1013 for the sedimentary pyrite. Seawater sulphate has a δ34S value of +21.0‰25. Metasomatic fluids released from sediment, of which the sulphur is mostly in the form of sulphate, have a δ34S value of +14‰ when their sulphur compositions resemble the bulk sediment composition21. Using these values, the δ34S value of subducted sulphate is here defined as (+17.5 ± 3.5)‰. A defined S/3He larger than 1 × 1013 for sedimentary sulphate is consistent with the seawater SO4/3He of 1.0 × 1014.


Sulphur geodynamic cycle.

Kagoshima T, Sano Y, Takahata N, Maruoka T, Fischer TP, Hattori K - Sci Rep (2015)

Correlation diagram between δ34S and S/3He ratios of high-temperature volcanic gases in circum-Pacific regions.Model end-members of the upper mantle, sedimentary pyrite and subducted sulphate are included. The curve shows mixing among the end-members. #Data are of the following volcanoes: (#1) Avacha, (#2) Mutonovsky, (#3) Kudryavy, (#4) Usu, (#5) Kuju, (#6) Satsuma-Iwojima, (#7) Lewotolo, (#8) White Island, (#9) Ngauruhoe, (#10) Momotombo, (#11) Galeras, (#12) Colima. All data are from Table 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321164&req=5

f2: Correlation diagram between δ34S and S/3He ratios of high-temperature volcanic gases in circum-Pacific regions.Model end-members of the upper mantle, sedimentary pyrite and subducted sulphate are included. The curve shows mixing among the end-members. #Data are of the following volcanoes: (#1) Avacha, (#2) Mutonovsky, (#3) Kudryavy, (#4) Usu, (#5) Kuju, (#6) Satsuma-Iwojima, (#7) Lewotolo, (#8) White Island, (#9) Ngauruhoe, (#10) Momotombo, (#11) Galeras, (#12) Colima. All data are from Table 2.
Mentions: Fig. 2 presents the relation between S/3He ratios and δ34SΣS values of volcanic gases in subduction zones. The figure particularly shows end-member data for the upper mantle, sedimentary pyrite with reduced sulphur derived from slab, and subducted sulphate. The δ34S values of sedimentary pyrite vary considerably due to the result of bacterial reduction of seawater sulphate, and have a mean value of −20.9‰ in the Western Pacific22. Results of a recent study23 of the oceanic basement in northern Italy suggest that low-temperature serpentinization produces a negative δ34SΣS value with (−8.9 ± 8.0)‰. Then the δ34S value of sedimentary pyrite is defined as (−14.9 ± 6.0)‰. No source of primordial helium exists in the pyrite, and the slab may have lost the original mantle helium as well24. It is therefore possible to adopt S/3He larger than 1 × 1013 for the sedimentary pyrite. Seawater sulphate has a δ34S value of +21.0‰25. Metasomatic fluids released from sediment, of which the sulphur is mostly in the form of sulphate, have a δ34S value of +14‰ when their sulphur compositions resemble the bulk sediment composition21. Using these values, the δ34S value of subducted sulphate is here defined as (+17.5 ± 3.5)‰. A defined S/3He larger than 1 × 1013 for sedimentary sulphate is consistent with the seawater SO4/3He of 1.0 × 1014.

Bottom Line: Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry.The S/(3)He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y.The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.

View Article: PubMed Central - PubMed

Affiliation: Division of Ocean-Earth System Science, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba 277-8564, Japan.

ABSTRACT
Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/(3)He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/(3)He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.

No MeSH data available.


Related in: MedlinePlus