Sulfur isotopic composition

Evaporitic sulfur has a range of sulfur isotopic composition from +10%o to +30%o, while sedimentary sulfur is depleted in the heavy isotope and has a range of isotopic composition of about —40%o to +10%o. Most of this variation reflects systematic changes with geological age. The source fractions of a river water can be estimated from an isotopic mass balance ... 

Figure 1.4]. Sulfur isotopic compositions of sulfide minerals from Kuroko deposits (Shikazono, 1987b).

Se,o,s Sulfur isotopic composition of oxidized sulfur species. S S. r.s Sulfur isotopic composition of reduced sulfur species. 8 Stotaf Total sulfur isotopic composition of aqueous sulfur species. 

Figure 1.109. Sulfur isotopic compositions of Neogene Au-Ag vein-type and disseminated-type deposits. Sulfur isotopic compositions on the samples from the Yatani deposits (Sample No. YT26 from Zn-Pb vein S S = -)-3.3%o), and HS72050305-YT1, YT24 and NS-3 from Au-Ag vein (average S S = +3.3%c)) by Shikazono and Shimazaki (1985) are also plotted. Base-metal rich implies the sample containing abundant sulfide minerals but no Ag-Au minerals from base-metal rich deposits and also from Ginguro-type deposits (Shikazono, 1987b).

Figure 1.112. Sulfur isotopic composition of pyrrhotite-bearing (solid) and hematite-bearing (open) samples from base-metal-rich deposits in Green tuff region (Shikazono, 1987b).

Sulfur isotopic compositions (S S) of sulfides and sulfate (barite) from the Se-type and Te-type are summarized in Fig. 1.122. Almost all S S values from the Se-type and Te-type fall in a range from —3%o to - -6%o (Fig. 1.122). In general, the 5 S values from the Se-type are similar to those of the Te-type. However, some S S values from the Se-type are lower than those from the Te-type. 

This mechanism as a main cause for epithermal-type Au deposition is supported by sulfur isotopic data on sulfides. Shikazono and Shimazaki (1985) determined sulfur isotopic compositions of sulfide minerals from the Zn-Pb and Au-Ag veins of the Yatani deposits which occur in the Green tuff region. The values for Zn-Pb veins and Au-Ag veins are ca. +0.5%o to -f4.5%o and ca. -l-3%o to - -6%c, respectively (Fig. 1.126). This difference in of Zn-Pb veins and Au-Ag veins is difficult to explain by the equilibrium isotopic fractionation between aqueous reduced sulfur species and oxidized sulfur species at the site of ore deposition. The non-equilibrium rapid mixing of H2S-rich fluid (deep fluid) with SO -rich acid fluid (shallow fluid) is the most likely process for the cause of this difference (Fig. 1.127). This fluids mixing can also explain the higher oxidation state of Au-Ag ore fluid and lower oxidation state of Zn-Pb ore fluid. Deposition of gold occurs by this mechanism but not by oxidation of H2S-rich fluid. 

Figure 1.151. Sulfur isotopic compositions of sulfides in the vein-type and Kuroko deposits. Solid box represents sulfur isotopic data from the ore deposits occurring in basement rocks (Shikazono and Shimizu, 1993).

Factors in controlling chemical compositions of gold in equilibrium with the ore fluids are temperature, pH, concentration of aqueous H2S and Cl in the ore fluids, concentration ratio of Au and Ag species in the ore fluids, activity coefficient of Au and Ag components in gold, and so on (Shikazono, 1981). In the Yamizo Mountains, as a result, Ag/Au ratios of gold are correlated with a kind of the host rocks and sulfur isotopic compositions of the deposits. This correlation could be used to interpret Ag/Au ratios of gold. 

Kiyosu, Y. (1977a) Sulfur isotopic compositions of epithermal vein type sulfides from the Toyoha mine, Hokkaido, Japan. J. Earth Sci. Nagoya U., 22, 23-32. 

Kusakabe, M. and Chiba, H. (1983) Oxygen and sulfur isotopic composition of barite and anhydrite Irom the Fukazawa deposit, Japan. Econ. Geol. Mon. 5, 292-301. 

Shikazono, N. (1999b) Sulfur isotopic composition and origin of sulfide sulfur of epithermal Au-Ag veins. Resource Geology Special Is.sue, 20, 39-46. 

A large number of sulfur isotope data on the Besshi-type deposits are available, although the variation in individual deposit has not been studied well (Yamamoto et al., 1968, 1984a,b Kajiwara and Date, 1971 Miyake and Sasaki, 1980) (Fig. 2.52). The sulfur isotopic compositions of sulfides are different in different regions. 

It is suggested that the mode of subduction of the Pacific Plate since the middle Miocene age related to Jackson s episode, hence oscillation of direction of lateral movement of Pacific plate. Synchronized igneous and hydrothermal activities and Jackson s episode indicate that the formations and characteristics of hydrothermal ore deposits (Kuroko and epithermal vein-type deposits) are largely influenced by plate tectonics (mode of subduction, direction of plate movement, etc.). For example, sulfur isotopic composition of sulfides is not controlled by /o and pH, but by of... 

J. L. Mann and W. R. Kelly. Measurement of Sulfur Isotope Composition (834S) by Multiple-Collector Thermal Ionization Mass Spectrometry Using a 33S-36S Double Spike. Rapid Commun. Mass Spectrom., 19(2005) 3429-3441. 

Beaudoin G, Taylor BE, Rumble III D, Thiemens M (1994) Variations in the sulfur isotope composition of troilite from the Canon Diablo iron meteorite. Geochim Cosmochim Acta 58 4253-4255 Birck JL, Allegre CJ (1988) Manganese-chromium isotope systematics and the development of the early solar system. Nature 331(6157) 579-584... 

The combined effects of /02. nd pH variation on the sulfur isotopic compositions of ore-forming minerals are shown in figure 11.42 for a temperature of 250 °C and 0%o. The dashed lines delineate the stability limits of con-... 

Figure 11.42 elucidates in a rather clear fashion the marked control exerted by the chemistry of the fluid on the sulfur isotopic compositions of ore-forming minerals. At the T and conditions dehneated in the figure, an increase in... 

The most notable feature of the sulfur isotope geochemistry of lunar rocks is the uniformity of 8 " S-values and their proximity to the Canyon Diablo standard. The range of published 8 " S-values is between -2 to +2.5%o. However, as noted by Des Marais (1983), the actual range is likely to be considerably narrower than 4.5%o due to systematic discrepancies either between laboratories or between analytical procedures. The very small variation in sulfur isotope composition supports the idea that the very low oxygen fugacities on the Moon prevent the formation of SO2 or sulfates, thus eliminate exchange reactions between oxidized and reduced sulfur species. 

Interesting differences in sulfur isotope compositions are observed when comparing high-S peridotitic tectonites with low-S peridotite xenoliths (Fig. 3.7). Tec-tonites from the Pyrenees predominantly have negative 5 " S-values of around —5%c, whereas low-S xenoliths from Mongoha have largely positive 8 S-values of up to - -l%o. Ionov et al. (1992) determined sulfur contents and isotopic compositions in... 

Elucidation of the origin of sulfur in volcanic systems is complicated by the fact that next to SO2, significant amounts of H2S, sulfate and elemental sulfur can also be present. The bulk sulfur isotope composition must be calculated using mass balance constraints. The principal sulfur gas in equilibrium with basaltic melts at low pressure and high temperature is SO2. With decreasing temperature and/or increasing... 

A huge amount of literature exists about the sulfur isotope composition in hydrothermal ore deposits. Some of this information has been discussed in earlier editions and, therefore, is not repeated here. Out of the numerous papers on the subject, the reader is referred to comprehensive reviews by Rye and Ohmoto (1974), Ohmoto and Rye (1979), Ohmoto (1986), Taylor (1987) and Ohmoto and Goldhaber (1997). The basic principles to be followed in the interpretation of -values in sul-fidic ores were elucidated by Sakai (1968), and subsequently, were extended by Ohmoto (1972). 

Fig. 3.13 Influence of f02 and pH on the sulfur isotope composition of sphalerite and barite at 250°C and = 0 (modified after Ohmoto, 1972)...

The isotopic compositions of the industrial sulfur sources are generally so variable, that the assessment of anthropogenic contributions to the atmosphere is extremely difficult. Krouse and Case (1983) were able to give semiquantitative estimates for a unique situation in Alberta where the industrial SO2 had a constant value near 20%c. Generally, situations are much more complicated which limits the fingerprint character of the sulfur isotope composition of atmospheric sulfur to such rare cases. 

Baroni M, Thiemens MH, Delmas RJ, Savarino J (2007) Mass-independent sulfur isotopic composition in stratospheric volcanic eruptions. Science 315 84-87 Barth S (1993) Boron isotope variations in nature a synthesis. Geologische Rundschau 82 640-651... 

Ku TCW, Walter LM, Coleman ML, Blake RE, Martini AM (1999) Coupling between sulfur recycling and syndepositional carbonate dissolution evidence from oxygen and sulfur isotope composition of pore water sulfate, South Florida Platform, USA, Geochim Cosmochim Acta 63 2529-2546... 

Paytan A, Kastner M, Campbell D, Thiemens MH (1998) Sulfur isotope composition of Cenozoic seawater sulfate. Science 282 1459-1462... 

Tachibana, S. and Huss, G. R. (2005) Sulfur isotope composition of putative primary troilite in chondrules from Bishunpur and Semarkona. Geochimica et Cosmochimica Acta, 69, 3075-3097. 

Sulfur isotope compositions in sulfonic acids show a mass-independent enrichment in 33S. Determining fractionations that are not controlled by mass is made possible because sulfur has so many stable isotopes. This feature has been attributed to ultraviolet irradiation of carbon disulfide in space, prior to its reaction to make sulfonic acid. 

Sulfur Isotope Composition and the Sources of Sulfur in Coal. Sulfur has four stable isotopes of atomic masses 32, 33, 34, and 36. The sulfur isotopic composition of a sample is generally characterized by its 34S/32S ratio, expressed in terms of 834S. It is the permil (%o) deviation in the 34S/32S ratio of a sample from a standard (troilite in the Canon Diablo meteorite) (102). 

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