Rift-related igneous activity and metallogenesis in SW Bergslagen, Sweden

Oen, I. S.

doi:10.1016/0301-9268(87)90064-7

Cited by 32 publications

(14 citation statements)

References 24 publications

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“…Consequently, in Table 2, there is only one flood basalt sequence with an age uncertainty of more than 10 Myr. A smaller percentage of the mafic dike swarms listed in Table 3 and the layered igneous intrusions listed in Table 4 Ga BIFs deposited at Bergslagen, which are quartz-banded iron ores interbedded with rhyolite ash-siltstones [Allen et al, 1996], are also considered "Algoma-type" [Oen, 1987]. Given the variations in the lithological associations of this category of BIF, the two favored palcotectonic models for iron formation deposition (island arc/back arc basin [Veizer, 1983] …”

Section: Compiling the Ages Of Mantle Plume Eventsmentioning

confidence: 99%

Plume‐related mafic volcanism and the deposition of banded iron formation

Isley¹,

Abbott²

1999

J. Geophys. Res.

389

211

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Abstract. We have compiled a record of the geochronology of mantle plume activity between 3.8 and 1.6 Ga. Over this time period, the ages of komatiites, and those of global plumes, correlate strongly, at the 99% confidence level, with the ages of banded iron formations (BIFs). The ages of continental plumes correlate more weakly, at an overall 85% confidence level. Using the geochronological records of these events, we can define four periods characterized by mantle superplume activity. Three of these periods are also times of enhanced BIF deposition. The fourth mantle plume period may similarly be coeval with increased BIF accumulation, but the BIF chronostratigraphic resolution is not accurate enough to test this rigorously. Mantle superplume volcanism may promote BIF deposition by increasing the Fe flux to the global oceans through continental weathering and/or through submarine hydrothermal processes. It may also be enhanced by increasing the number of paleotectonic environments appropriate for BIF deposition (particularly plume-induced ocean plateaus, seamounts, and intracratonic rifts) and by promoting global anoxic, Fe-rich hydrothermal plumes in the shallow to intermediate marine water column.

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Section: Compiling the Ages Of Mantle Plume Eventsmentioning

confidence: 99%

Plume‐related mafic volcanism and the deposition of banded iron formation

Isley¹,

Abbott²

1999

J. Geophys. Res.

389

211

View full text Add to dashboard Cite

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“…The Mg-enriched metavolcanic rocks are spatially linked to the iron-oxide mineralization and the gabbro intrusion, a common association in this part of Bergslagen that can be explained by small-scale synvolcanic hydrothermal circulation of seawater generated by the heat of intrusions (Oen 1987;Lundström 1995). The fact that the magnesite horizons are situated in the middle of the zone of intense Mgenrichment makes it difficult to deny the importance of this process.…”

Section: Discussionmentioning

confidence: 99%

“…Metasomatic replacement iron-oxide mineralizations in contact zones of metabasic intrusives have been reported from several other localities in the western parts of the Bergslagen area (e.g. Oen 1987;Lundström 1995).…”

Section: Location and Geological Setting Of The Kämpetorp Magnesite Dmentioning

confidence: 96%

“…The Bergslagen ore province formed in an extensional tectonic setting within continental crust, previously interpreted as a continental rift setting (Oen et al 1982;Oen 1987), but GFF volume 134 (2012), pp. 7-18.…”

Section: Regional Geologymentioning

confidence: 99%

“…Heat from the GDG suite intrusions and cooling volcanic rocks initiated sub-seafloor hydrothermal circulation, giving rise to the innumerable polymetallic sulphide and iron-oxide deposits with associated synvolcanic hydrothermal Na-and K-alteration and Mgmetasomatism of the volcano-sedimentary rocks (Hellingwerf 1987;Oen 1987). The supracrustal series was subsequently metamorphosed, deformed and intruded by the alkali-calcic granitoid-syenitoid-dioritoid-gabbroid suite during several stages of the c. 1.87 -1.8 Ga Svecokarelian orogeny (Stephens et al 2009).…”

Section: Regional Geologymentioning

confidence: 99%

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An epigenetic magnesite deposit in the Bergslagen area, central Sweden

Högmalm

Hellingwerf

Cornell

et al. 2012

GFF

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A Palaeoproterozoic magnesite deposit in the Bergslagen ore province in Sweden is characterized in terms of petrography and major element, trace element and stable isotope compositions. The magnesite horizons are situated at the contact between a metamorphosed gabbro intrusion and felsic metavolcanic rocks, in association with iron-oxide mineralizations and intense Mg-metasomatism. The alteration of the surrounding rocks is used to explain the formation of the magnesite, and chemical dating of hydrothermal monazite constrains the timing of Mg-alteration to a pre-metamorphic age of 1911^16 Ma (2s). High Y contents in hydrothermal monazite in both metavolcanic and magnesite samples indicate a temperature of . 4008C for the hydrothermal alteration. C and O isotopic composition of the magnesite points to interaction with seawater at 200-2508C. We conclude that the magnesite was formed by replacement of a carbonate precursor through hydrothermal alteration, induced by the emplacement of the gabbro intrusion.

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Ore genesis of the unusual Talate Pb–Zn(–Fe) skarn‐type deposit, Altay, NW China: constraints from geology, geochemistry and geochronology

Zhang

Chen

et al. 2014

Geological Journal

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The Talate ore field is located in the Abagong polymetallic metallogenic belt of the Altay Orogen, NW China. Lenticular ore bodies occur in the Kangbutiebao Formation, a package of intermediate-felsic marine volcanic rocks and terrigenous clastic sedimentary-carbonate rocks. Skarn alteration (mainly garnet) is present in both ore and wall rocks, especially the carbonate rocks. The mineral assemblages and crosscutting relationships of veins allow the alteration and mineralization process to be divided into four stages. From early to late, these are the early skarn (E-skarn), the late skarn with quartz-magnetite veins (QM), the quartz-sulphide (QS) and the quartz-carbonate (QC) assemblages. Quartz crystals are important gangue minerals in the latter three stages, in which four distinct compositions of fluid inclusions are identified based on petrography, microthermometry and laser Raman microspectroscopy, namely aqueous inclusions (W-type), pure CO 2 inclusions (PC-type), CO 2 -rich inclusions (C-type) and daughter mineral-bearing inclusions (S-type). Microthermometric data and laser Raman analyses show that the quartz crystals from the QM stage contain all four inclusion types, with the W-type being predominant. Homogenization temperatures range between 271 and 426°C. The salinities of the W-and C-type fluid inclusions range from 0.5 to 22.4 wt.% NaCl eqv., whereas the S-type fluid inclusions in the QM stage range from 31 to 41 wt.% NaCl eqv. Daughter minerals in the fluid inclusions include halite, sylvite, pyrite and calcite. Quartz from the QS stage (main mineralization stage) contains the W-, C-and PC-type inclusions, which are homogenized at temperatures of 204-269°C, with salinities of 0.2-15.6 wt.% NaCl eqv. Only W-type fluid inclusions have been identified in the QC stage. These yielded homogenizing temperatures of 175-211°C and salinities of 1.1-9.9 wt.% NaCl eqv. The C-type fluid inclusions of the main (QS) mineralization stage yield trapping pressures of 107-171 MPa, corresponding to a depth of 4-6 km. The sulphur isotope values (À1.7‰ and À6.6‰) imply that the QS stage may not be directly associated with the early skarn (À7.4‰) and quartz-magnetite stages (À4.8‰ and À5.0‰), though the QS stage is probably dominated by magmatic-hydrothermal fluids.40 Ar/ 39 Ar isotope plateau ages of 227.6 and 214.1 Ma for biotite separated from the QM and QS stages are significantly younger than the host Kangbutiebao Formation (ca. 410 Ma). The Talate Pb-Zn(-Fe) deposit is interpreted to be an unusual skarn-type system formed in a continental collision orogeny.

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Rift-related igneous activity and metallogenesis in SW Bergslagen, Sweden

Cited by 32 publications

References 24 publications

Plume‐related mafic volcanism and the deposition of banded iron formation

Plume‐related mafic volcanism and the deposition of banded iron formation

An epigenetic magnesite deposit in the Bergslagen area, central Sweden

Ore genesis of the unusual Talate Pb–Zn(–Fe) skarn‐type deposit, Altay, NW China: constraints from geology, geochemistry and geochronology

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