Magma-country rock interaction and the genesis of Ni-Cu deposits in the Vammala Nickel Belt, SW Finland

Peltonen, P.

doi:10.1007/bf01163124

Cited by 33 publications

(22 citation statements)

References 26 publications

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“…2) Because the wall rock Sm-Nd isotopic composition does not necessarily correlate with that of the intrusion, crustal contamination has also taken place during magma ascent, either in flow conduits or in intermediate magma chambers. Therefore, in such cases sulfide segregation has probably taken place before the final emplacement of the magma, as also proposed by Peltonen (1995aPeltonen ( , 1995bPeltonen ( , 2005 and Lamberg (2005).…”

Section: Tectonic Implicationsmentioning

confidence: 56%

“…Many earlier studies of Svecofennian 1.88 Ga mafic-ultramafic have also presented evidence for crustal contamination (e.g. Peltonen, 1995aPeltonen, , 1995bPeltonen, , 2005Mäkinen & Makkonen, 2004;Lamberg, 2005;Makkonen et al, 2007). Mäk-inen & Makkonen (2004) found that in the Rytky intrusion, the first and the most primitive intrusive phase (represented by the coarse-grained lherzolite) was the most contaminated.…”

Section: Discussionmentioning

confidence: 99%

“…The parental magma for the Svecofennian intrusions has been shown to be of basaltic composition, but different crystallization trends have produced a wide variety of cumulate rocks (Mäkinen, 1987;Peltonen, 1995a;Peltonen, 2005;Lamberg, 2005). The CMA plot (Fig.…”

Section: Geochemistry Of the Intrusionsmentioning

confidence: 99%

“…The magmatism that produced the ore-bearing intrusions was broadly coeval with the Svecofennian orogeny and the emplacement of the magma took place during the maximum intensity of deformation and metamorphism (Mäk-inen & Makkonen, 2004;Makkonen, 2005;Pelto-nen, 2005). It has been suggested that the composition of the parental magma was basaltic with a MgO content of about 12 wt.% (Peltonen, 1995a(Peltonen, , 2005. Emplacement of magma was accompanied the gently dipping D 2 folding and thrusting event (Mäkinen & Makkonen, 2004;Makkonen, 2005), which was a response to convergence and thrusting of Svecofennian terranes over the Archaean cratonic foreland (Koistinen, 1981).…”

Section: Introductionmentioning

confidence: 99%

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Sm-Nd data for mafic-ultramafic intrusions in the Svecofennian (1.88 Ga) Kotalahti Nickel Belt, Finland - Implications for crustal contamination at the Archaean/Proterozoic boundary

Makkonen¹,

Huhma²

2007

Bull Geol Soc Finland

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Sm-Nd data were determined for eight mafic-ultramafic intrusions from the Svecofennian (1.88 Ga) Kotalahti Nickel Belt, Finland. The intrusions represent both mineralized and barren types and are located at varying distances from the Archaean/Proterozoic boundary. The samples for the 23 Sm-Nd isotope analyses were taken mostly from the ultramafic differentiates. Results show a range in initial ε Nd values at 1880 Ma from -2.4 to +2.0. No relaNo relationship can be found between the degree of Ni mineralization and initial ε Nd values, while a correlation with the geological domain and country rocks is evident. The Majasaari and Törmälä intrusions, which have positive ε Nd values, were emplaced within the Svecofennian domain in proximity to 1.92 Ga tonalitic gneisses, which have previously yielded initial ε Nd values of ca. +3. In contrast, the Luusniemi intrusion, which has an ε Nd value of -2.4 is situated close to exposed Archaean crust. Excluding two analyses from the Rytky intruArchaean crust. Excluding two analyses from the Rytky intru-. Excluding two analyses from the Rytky intrusion, all data from the Koirus N, Koirus S, Kotalahti, Rytky and Kylmälahti intrusions, within error limits, fall in the range -0.7 ± 0.3. The results support the concept of contamination by Archaean material in proximity to the currently exposed craton margin. The composition of the proposed parental magma for the intrusions is close to EMORB, with initial ε Nd values near +4.

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Section: Tectonic Implicationsmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Geochemistry Of the Intrusionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sm-Nd data for mafic-ultramafic intrusions in the Svecofennian (1.88 Ga) Kotalahti Nickel Belt, Finland - Implications for crustal contamination at the Archaean/Proterozoic boundary

Makkonen¹,

Huhma²

2007

Bull Geol Soc Finland

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“…The geochemistry of the intrusions in the belt, and contrast between mineralized and barren intrusions, has been the subject of papers by Mäkinen (1987), Peltonen (1995a), Makkonen (1996), Mäkinen & Makkonen (2004), Lamberg (2005), Makkonen et al (2008).…”

Section: Introductionmentioning

confidence: 99%

The 1.88 Ga Kotalahti and Vammala nickel belts, Finland: Geochemistry of the mafic and ultramafic metavolcanic rocks

Barnes¹,

Makkonen²,

Hill³

et al. 2009

Bull Geol Soc Finland

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The mafic and ultramafic volcanic rocks within the Svecofennian (1.88 Ga) Kotalahti and Vammala Nickel Belts, Finland, are spatially associated and coeval with a suite of mineralized mafic-ultramafic intrusions. They have been divided into five suites based on major element geochemistry and spatial distribution: the Rantasalmi high-and low-Mg suites, the Vammala high-Mg suite, and the Rantasalmi, Kestilä and Pielavesi low-Mg suites. The Rantasalmi and Vammala high-Mg suites are very similar and probably comagmatic, and the Kestilä and Rantasalmi low-Mg suites are derived from them by a combination of fractionation and crustal assimilation. The Pielavesi suite is interpreted as an unrelated suite of island-arc affinity. On the basis of their trace element contents, the Kotalahti Belt intrusions are comagmatic with part of the analyzed volcanic rocks. In the Vammala Belt it is likely that the parent magmas to the intrusions and picrite magmas have a common mantle source but have evolved along distinct paths, and the picrites probably do not represent parent magmas tapped directly from the intrusions. Platinum-group element data show localised evidence for depletion by sulfide extraction. Vammala picrites are predominantly S-undersaturated, with the exception of lavas in the Stormi area. In the Kotalahti Belt the volcanic rocks are predominantly S-undersaturated, while the volcanic rocks in the more northern part of the Belt are predominantly S-saturated. These spatial differences imply that the PGE contents of the metavolcanic rocks can be used as regional area selection criteria for intrusive nickel-copper-(PGE) deposits within the Finnish Svecofennian.

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Re-Mo-Cu-Os sulphide from the Ekojoki Ni-Cu deposit, SW Finland

Peltonen

Pakkanen

Johanson

1995

Mineralogy and Petrology

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Magma-country rock interaction and the genesis of Ni-Cu deposits in the Vammala Nickel Belt, SW Finland

Cited by 33 publications

References 26 publications

Sm-Nd data for mafic-ultramafic intrusions in the Svecofennian (1.88 Ga) Kotalahti Nickel Belt, Finland - Implications for crustal contamination at the Archaean/Proterozoic boundary

Sm-Nd data for mafic-ultramafic intrusions in the Svecofennian (1.88 Ga) Kotalahti Nickel Belt, Finland - Implications for crustal contamination at the Archaean/Proterozoic boundary

The 1.88 Ga Kotalahti and Vammala nickel belts, Finland: Geochemistry of the mafic and ultramafic metavolcanic rocks

Re-Mo-Cu-Os sulphide from the Ekojoki Ni-Cu deposit, SW Finland

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