Different Sources Of Sulfur Research Articles

Madouzi-type (nodular) sedimentary copper deposit associated with the Emeishan basalt

Ore minerals in the sedimentary-type Cu deposits in the Xuanwei Formation overlying the Emeishan basalt are dominated by copper sulfides and native copper. As the ores mostly exhibit concretionary structure, previous researchers named them the “Madouzi-type Copper Deposit”. Here the authors carried out mineralogical and isotopic studies on copper nodules in this ore deposit. The mineralogical study shows that copper nodules are composed of copper sulfides that have been cemented by ferruginous amorphous minerals, clay, and carbonaceous fragments in the modes of metasomatism and sedimentation. The nodules are preliminarily present as aggregates of gelatinous material. The isotopic analysis shows that the δ13CPDB values of anthraxolite are within the range of −24.8‰–−23.9‰, indicating that the anthraxolite is the product of sedimentary metamorphism of in-situ plants. The δ34SV-CDT values of chalcocite are within the range of 7.6‰–13.1‰, close to those (about 11‰) of Permian seawater. The δ34SV-CDT values of bornite and chalcopyrite are 21.6‰–22.2‰, similar to the sulfur isotopic composition (20‰) of marine sulfate, indicative of different sources of sulfur. The above characteristics indicate that the copper nodules were formed in such a process that Cu-bearing basalt underwent weathering-leaching and copper-bearing material was transported into waters (e.g., rivers, lakes, and swamps) and then adsorbed on clay and ferruginous amorphous mineral fragments. Then, the copper-bearing material was suspended and transported in the form of gelinite. In lake or swamp environment, it was co-deposited with sediments to form copper nodules. At later stages there occurred metasomatism and hydrothermal superimposition, followed by the replacement of chalcocite by bornite and the superimposition of chalcopyrite over bornite, finally resulting in the formation of the “Madouzi-type” nodular copper deposit.

Precipitation of lead–zinc ores in the Mississippi Valley‐type deposit at Trèves, Cévennes region of southern France

AbstractThe Trèves zinc–lead deposit is one of several Mississippi Valley‐type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ34S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to −21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur‐rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore‐forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault‐controlled and mineralogically similar MVT deposits in the Cévennes region.

Comparing different sources of sulfur for high-rainfall pastures insouth-western Australia

The dry herbage yield increase (response) of subterranean clover (Trifolium subterraneum L.)-based pasture (>85% clover) to applications of different sources of sulfur (S) was compared in 7 field experiments on very sandy soils in the > 650 mm annual average rainfall areas of south-western Australia where S deficiency of clover is common when pastures grow rapidly during spring (August–November). The sources compared were single superphosphate, finely grained and coarsely grained gypsum from deposits in south-western Australia, and elemental S. All sources were broadcast (topdressed) once only onto each plot, 3 weeks after pasture emerged at the start of the first growing season. In each subsequent year, fresh fertiliser-S as single superphosphate was applied 3 weeks after pasture emerged to nil-S plots previously not treated with S since the start of the experiment. This was to determine the residual value of sources applied at the start of the experiment in each subsequent year relative to superphosphate freshly-applied in each subsequent year. In addition, superphosphate was also applied 6, 12 and 16 weeks after emergence of pasture in each year, using nil-S plots not previously treated with S since the start of the experiment. Pasture responses to applied S are usually larger after mid-August, so applying S later may match plant demand increasing the effectiveness of S for pasture production and may also reduce leaching losses of the applied S.At the same site, yield increases to applied S varied greatly, from 0 to 300%, at different harvests in the same or different years. These variations in yield responses to applied S are attributed to the net effect of mineralisation of different amounts of S from soil organic matter, dissolution of S from fertilisers, and different amounts of leaching losses of S from soil by rainfall. Within each year at each site, yield increases were mostly larger in spring (September–November) than in autumn (June–August). In the year of application, single superphosphate was equally or more effective than the other sources. In years when large responses to S occurred, applying single superphosphate later in the year was more effective than applying single superphosphate 3 weeks after pasture emerged (standard practice), so within each year the most recently applied single superphosphate treatment was the most effective S source. All sources generally had negligible residual value, so S needed to be applied each year to ensure S deficiency did not reduce pasture production.

Sulphur management in balckgram and its effect on yield and economics

Field trials were conducted during kharif and rabi seasons of 1995 and 1996 to study the effect of sources and levels of sulphur on the growth, yield and economics of irrigated blackgram. Three different sources of sulphur viz. Gypsum, Elemental sulphur, and Pyrite were tried at five levels of sulphur viz. 0,10,20,30 and 40 kg ha-1. The results proved that gypsum was the superior sulphur source which was evident from the yield increase due to gypsum application. Elemental sulphur and pyrite were on par in their effect. Among the levels 30 kg S/ha was best, but this was on par with 40 kg S/ha. Highest benefit cost ratio was also realised from gypsum source and at levels of 30 and 40 kg S/ha.

Modelling the contribution of different sources of sulphur to atmospheric deposition in the United Kingdom.

In order to understand relationships between sources and receptors of atmospheric deposition, computer models must be used. This paper describes a Lagrangian acid deposition model that represents emissions of trace species across Northern Europe. The chemistry of sulphur dioxide, dimethyl sulphide and hydrogen sulphide is represented and the model tested against estimates of UK wet and dry deposition. Mean UK wet and dry deposition for the period 1992–1994 was 206 and 145 ktonne S yr-1, respectively. The model predicted wet and dry deposition of 222 and 166 ktonne S yr-1, in good agreement with measurements. The model has been used to examine the sources of deposited S to the UK. For a base year of 1992, 86% of the UK's SO2 emissions are exported. The S deposition attributable from mainland European sources was 36% of the UK total S deposition, in good agreement with other UK models but this differs substantially from the calculations of the EMEP model. Natural sources of S deposition from planktonic emissions of dimethyl sulphide, biological emissions of hydrogen sulphide and non-eruptive volcanic emissions of sulphur dioxide contributed approximately 1% of the modelled UK S deposition, of which 95% originated from dimethyl sulphide. The explicit chemical scheme for dimethyl sulphide incorporated into the model showed that 24% of the resultant deposited S was methane sulphonic acid. Boundary conditions of the model were tested and it was found that initialisation of sulphur dioxide and sulphate concentrations to representative ambient conditions had a very small effect. The modelled contribution of UK and European sources to UK S deposition was approximately 40 and 60%, respectively, showing the dramatic change arising from projected UK SO2 emissions in 2010.

TRANFORMATION OF SULPHUR IN SOILS OF NORTH KARNATAKA AS INFLUENCED BY SOURCES AND LEVELS OF SULPHUR

A Laboratory incubation experiment was conducted in Vertisol and an Inceptisol of North Karnataka to know the effect of different sources and levels of sulphur and time of incubation on transformation of available S in soils. Among the different sources of sulphur, ammonium sulphate recorded the highest release of 5 due to its more soluble. nature compared to other sources. The available S content was more in inceptisol. There was a rapid release of S during the first fifteen days of incubation followed by a slower linear release.

Ore lead and sulphur isotope pattern from the low-temperature veins of the Catalonian Coastal Ranges (NE Spain)

The lead isotopic composition of galenas from low-temperature veins of the Catalonian Coastal Ranges (NE Spain) displays a small but distinct range of values: 18.318 ≤206Pb/204Pb ≤ 18.678; 15.678 ≤207Pb/204Pb ≤ 15.767 and 38.534 ≤ 208Pb/204Pb ≤ 39.189. The data define a linear trend in the 208Pb/204Pb versus 206Pb/204Pb diagram that can be interpreted in terms of mixing of lead from different reservoirs. The lead appears to be derived from a solution that preferentially leached granites of Late-Hercynian age. Sulphur isotopic compositions of the galenas range from −8.5 to + 7.3‰ but variations in a single deposit are small (1–2‰), pointing to different sources of sulphur. In a δ34S versus 206Pb/204Pb plot no clear correlation trends appear. Lead isotope data from deposits of similar characteristics situated within the Hercynian orogenic belt as the Linares-La Carolina district (S Spain) and the Inglesiente-Sulcis area (Sardinia) show slight differences indicating a source area of similar lead isotopic composition. In the CCR and Linares-La Carolina districts, the main source of lead is related to the Hercynian granites of each area, although small contributions from metasediments cannot be ruled out. The contribution of lead from metasedimentary rocks is particularly seen in the Sardinian (Hercynian vein-type) ores.

La composición isotópica del azufre y del plomo en las mineralizaciones de Zn-Pb del Valle de Arán (Pirineo central) y su significado metalogenético

The sulfur isotopic composition of sulfides from sedex-type deposits enclosed within Upper Ordovician rocks in the valle de Aran (Central Pyrenees) ranges from +3.5 to + 15.1 %0 in mineralizations enclosed in carbonates and from -2.7 %0 to +5.5 in minerali­ zations enclosed in detritic rocks. These values suggest two different sources of sulfur: a heavy source of crustal origin, probably related to the reduction of seawater sulfate, and a lighter one, resulting from leaching of underlying detritic and/or volcanic rocks of cambro-ordovician age. Hercynian metamorphism has not significantly altered the origi­ nal sulfur isotopic composition of sulfides and their variation at the deposit scale can be explained by changes in T, pH or f02 during sulfide deposition. Lead isotope composi­ tion of 6 galena samples have the following ratios: 18.02::; 206Pbp04Pb ::; 18.08; 15.66 ::; 207PbP04Pb::; 15.70 and 38.16 s 208PbP04Pb ::; 38.29, similar to those reported by Mar­ coux (1987) in the Pierrefitte deposits (Central Pyrenees, France). These values are very homogeneous and suggest alead source situated within the upper crust. Calculated ages based on Cumming and Richards (1975) lead evolution model range from 422 to 452 m.a. (Upper Ordovician), which is the age of the enclosing rocks. These data confirm the hypothesis of a sedimentary-exhalative origin of the deposits.

Synthesis of Au2S and Au2S3 Using H2S, Short-Chain and Ring-Structured Sulfur as Sulfur Sources

Abstract To determine which of the two known gold sulfides (containing either mono- or trivalent gold) are formed by reacting trivalent gold with differnt allotropes of sulfur, experiments were made using three different sources of sulfur. When trivalent gold in the form of Au2(SO4)3 in concentrated acid is reacted with electrolytically formed short-chain sulfur, monovalent gold sulfide (Au2S) is formed. If hydrogen sulfide gas reacts with the same solution, trivalent gold sulfide (Au2S3) is produced. Alternatively, if ordinary a-sulfur (ring structure) is used, a 50/50 mixture of Au2S and Au2S3 is formed. The synthesis procedure for the two gold sulfides is substantially simpler than previously reported methods of preparation

SULPHUR AND PHOSPHORUS REQUIREMENTS OF THREE FUNGI CAUSING DISEASES IN STORAGE.

The effect of different sulphur and phosphorus compounds on the growth and reproduction of three fungi causing storage rot, viz.,Fusarium solani, Botryodiplodia ananassae andMacrophomina phaseoli has been studied. Sixteen different sources of sulphur were used and out of them magnesium sulphate was found to be most favourable for the growth and reproduction of all the three fungi. Sodium sulphite and sodium bisulphite were toxic. Potassium metabisulphite prevented growth ofF. solani and M. phaseoli while it supported moderate growth ofB. ananassae. Only magnesium sulphate could induce the sporulation ofB. ananassae while sporulation and sclerotial development ofF. solani andM. phaseoli respectively varied with the type of sulphur sources used. Optimum concentration of magnesium sulphate was also determined and it was found that the growth and sporulation ofF. solani andB. ananassae were best at 0.375 g/l and 0.75 g/l.M. phaseoli tolerated higher doses of this substance as the best growth and excellent sclerotial development were recorded at 3.0 g/l (the maximum concentration used). Phosphorus was found to be essential for the present fungi as none of them could grow in complete absence of this substance. Onthophosphates and nucleic acid, were found to be favourable sources for growth and reproduction of the 3 organisms.