Relationship between primary iron sulphide species, sulphur source, depth of formation and age of submarine exhalative sulphide deposits

Plimer, I. R.; Finlow-Bates, T.

doi:10.1007/bf00206573

Cited by 25 publications

(13 citation statements)

References 51 publications

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“…On the other hand, as the metals of the iron mineralizations were probably derived through volcanic activity, a high-temperature fractionation of the sulphur cannot be rejected. The high positive 634S values could be explained in accordance with the model by Plimer and Finlow-Bates (1978). The continual withdrawal of isotopically light sulphur from seawater by sulphide deposition, will, due to isotopic fractionation, enrich the basinal sulphur in 34S.…”

Section: Iron and Sulphide Ores In The Greenstone Groupsupporting

confidence: 62%

Sulphur isotopes in Lower Proterozoic iron and sulphide ores in northern Sweden

1995

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Abstract. The present investigation deals with sulphur isotope distribution in Lower Proterozoic iron and sulphide mineralizations in northern Sweden. The contrastmg sulphur isotope patterns are indicative of different genesis. Some 267 sulphur isotope analyses of pyrite, pyrrhotite, chalcopyrite, sphalerite, galena and bornite from 23 occurrences have been performed. Some deposits exhibit uniform compositions, although the mean 634S values are clearly different, while other mineralizations have widely fluctuating values.The 634S values in syngenetic, exhalative sedimentary skarn iron ores, quartz-banded iron ores and sulphide mineralizations of the 2.0-2.5 Ga old (Lapponian) Greenstone group show a large spread, supporting the existence of bacteriogenic sulphate reduction processes. The spread of the sulphur isotope values (&34S = -8 to + 25%o), and the non-equilibrium conditions, point to a biogenic rather than to an inorganic reduction of seawater sulphate.The isotopic composition of the sulphides in the epigenetic Lannavaara iron ores which were formed by a hydrothermal scapolite-tourmaline-related process, indicates a sulphur source similar to that of the Greenstone group. The &34S values of Cu-(Au) sulphide mineralizations in the Malmberget region (e.g. Aitik), which were formed by a similar process and hosted by the volcanicsvolcanoclastics of the 1.9Ga old Porphyry group, are slightly below zero %0, indicating a magmatic origin. The existence of different sulphur compositions for these mineralization types formed by a similar hydrothermal process, probably reflects the influence of the host rock, the solutions leaching pre-existing sulphides.In southern Norrbotten, epigenetic, Cu-Zn-Pb veintype mineralizations in metavolcanics and metasediments have 634S values close to zero %0 indicating a magmatic origin. The sulphur isotope data of the volcanogenic, massive sulphide ores of the Skellefte district, in particular the ores of the Adak dome, are close to zero %0.The lead and sulphur isotopic features of the sulphides in northern Sweden show that the ore-forming processes were of a different nature on both sides of the ArcheanProterozoic border, implying differences in the crustal development. Lead isotopes show that lead was mobilized from specific sources on each side of the border. The sulphur of the sulphides in the Greenstone group in NE Sweden and Finland was introduced by sedimentary processes, whereas the sulphur of the sulphide occurrences towards the SW, mainly in the Porphyry group, is dominated by a magmatic sulphur component.

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Section: Iron and Sulphide Ores In The Greenstone Groupsupporting

confidence: 62%

Sulphur isotopes in Lower Proterozoic iron and sulphide ores in northern Sweden

1995

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“…Pyrrhotite in these deposits has been considered to be mainly a product of metamorphism (Vokes 1976, Sangster & Scott 1976), but it may be a primary mineral (Plimer & Finlow-Bates 1978), because deposits in some metamorphic belts do not show a correlation between the pyrite:(pyrrhotite + pyrite) ratio and grade of metamorphism (Rui & Bakke 1975, Misra 1992. Pyrrhotite in these deposits has been considered to be mainly a product of metamorphism (Vokes 1976, Sangster & Scott 1976), but it may be a primary mineral (Plimer & Finlow-Bates 1978), because deposits in some metamorphic belts do not show a correlation between the pyrite:(pyrrhotite + pyrite) ratio and grade of metamorphism (Rui & Bakke 1975, Misra 1992.…”

Section: Mineralogy and Texturesmentioning

confidence: 99%

Understanding Mineral Deposits

Misra¹

2000

103

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“…Some interpretations of the depositional environment have been governed by the genetic models proposed for the formation of the contained orebodies. Proponents of syngenetic, relatively deep‐water, subaqueous exhalative models ( Mathias & Clark 1975; Plimer & Finlow‐Bates 1978) proposed a deep‐water environment. McClay and Carlile (1978) proposed a marginal sabkha environment for part of the Mt Isa mine succession, mainly on the basis of interpreted sulfate evaporite pseudomorphs.…”

Section: Previous Investigationsmentioning

confidence: 99%

Evolution of the Palaeoproterozoic Prize, Gun and lower Loretta Supersequences of the Surprise Creek Formation and Mt Isa Group

Domagala¹,

Southgate

McConachie³

et al. 2000

Australian Journal of Earth Sciences

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Sequence‐stratigraphic interpretations of the 4200 m‐thick Palaeoproterozoic (1700–1650 Ma) Mt Isa Group and underlying Surprise Creek Formation identify three unconformity‐bounded packages termed the Prize, Gun and Loretta Supersequences. Siliciclastic rocks of the Surprise Creek Formation and Warrina Park Quartzite comprise the Prize Supersequence. Rapid facies changes from proximal, conglomeratic fluvial packages to distal, fine‐grained and deep‐water, rhythmites characterise this supersequence. Conglomeratic intervals in the Mt Isa area reflect syndepositional movement along basin‐margin faults during the period of supersequence initiation. A major unconformity, which extends over a period of about 25 million years, separates the Gun and Prize Supersequences. In the Leichhardt River Fault Trough uplift and incision of Prize sedimentary rocks coincided with emplacement of the Sybella Granite (1671 ± 8 Ma) and Carters Bore Rhyolite (1678 ± 2 Ma) and the removal of an unknown thickness of Prize Supersequence section. Deep‐water, turbiditic rhythmites of the Mt Isa Group dominated the Gun and Loretta Supersequences. Tempestites are present over discrete intervals and represent times of relative shallowing. High accommodation and sedimentation rates at the base of the Gun Supersequence resulted in the deposition of transgressive nearshore facies (uppermost Warrina Park Quartzite) overlain by a thick interval of deep‐water, siltstone–mudstone rhythmites of the Moondarra Siltstone and Breakaway Shale. With declining rates of siliciclastic sedimentation and shallowing of the succession, calcareous sediments of the Native Bee Siltstone prograded over the deeper water deposits. Two third‐order sequences, Gun 1 and 2, characterise these lower parts of the Gun Supersequence. An increase in accommodation rates near the top of the Native Bee Siltstone in Gun 3 time, resulted in a return to deep‐water sedimentation with deposition of dolomitic rhythmites of the Urquhart Shale and Spear Siltstone. The Pb–Zn–Ag ore‐ hosting interval of the Urquhart Shale is interpreted to occur in progradational highstand deposits of the Gun 3 Sequence. In the Leichhardt River Fault Trough the Loretta Supersequence boundary forms a correlative conformity. Coarser grained and thicker bedded sediments of the Kennedy Siltstone comprise lowstand deposits at the base of this cycle. These sediments fine up into the transgressive, deep‐water, siliciclastic facies of the Magazine Shale, which in turn are truncated against the Mt Isa Fault.

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Relationship between primary iron sulphide species, sulphur source, depth of formation and age of submarine exhalative sulphide deposits

Cited by 25 publications

References 51 publications

Sulphur isotopes in Lower Proterozoic iron and sulphide ores in northern Sweden

Sulphur isotopes in Lower Proterozoic iron and sulphide ores in northern Sweden

Understanding Mineral Deposits

Evolution of the Palaeoproterozoic Prize, Gun and lower Loretta Supersequences of the Surprise Creek Formation and Mt Isa Group

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