Structural geology of Grundfors, a quartz vein related gold deposit in the Skellefte district, northern Sweden

Bergman, J.

doi:10.1080/11035899209453887

Cited by 8 publications

(6 citation statements)

References 14 publications

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“…Tallberg and Kopsa (Gafil and Isohanni 1979;Weihed et al 1987), epigenetic gold lode deposits in a number of rock types, e.g. Middagsberget, Bj6rkdal, Grundfors, Laivakangas, Kangaskylfi and Osikonm/iki (Markkula 1988;M/ikel/i et al 1988 a,b;Weihed and Bergstr6m 1988;Kontoniemi and Ekdahl 1990;Bergman 1992), and epigenetic gold lode deposits in volcanogenic massive sulphide systems, e.g. Boliden (Bergman et al 1989).…”

Section: Gold Depositsmentioning

confidence: 98%

Source of metals and age constraints for epigenetic gold deposits in the Skellefte and Pohjanmaa districts, central part of the Fennoscandian Shield

et al. 1993

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Abstract. The lead isotopic compositions of galena in Early Proterozoic gold deposits have been determined for three districts in northern Sweden and central Finland. The deposits are hosted by a variety of ~ 1870-1890 Ma Svecofennian host rocks including the volcanosedimentary succession within the Skellefte District island arc in Sweden as well as I-type tonalites at J6rn (Sweden) and Pohjanmaa (Finland). The deposits are epigenetic in relation to these Svecofennian rocks and are part of a goldbearing metallogenetic belt, which can be followed for 600 km parallel to the southwestern margin of the Archaean Domain. In spite of these epigenetic relationships, the lead isotopic data indicate that the deposits are not dramatically younger than the ~1870-1890 Ma Svecofennian host rocks (probably not exceeding 10-20 million years). Two principal lead sources were activated when the gold deposits were formed.-The most significant source is represented by the I-type tonalites, which constitute a relatively primitive (/~ = 9.3) and widely distributed source in the entire metaUogenic belt. In addition, the volcanic components in the westernmost part of the Skellefte District constitute an extremely primitive (~ < 9.0) source, which only locally was an important contributor to the epigenetic deposits in this metallogenetic belt. The significantly different lead isotopic composition estimated for these sources indicates that the volcanic rocks in the western part of the SkeUefte District were not comagmatic with the I-type tonalites recognized at J6rn and central Finland.partly related to volcanogenic massive sulphide deposits of the Skellefte type, partly related to synkinematic intrusions of the J6rn type and partly related to major shear zone structures. This complex metallogenetic province can be followed over a length of about 600 km and includes the Skellefte mining district in northern Sweden, and the 'main sulphide belt' of central Finland (Fig. 1). Volcanogenic massive sulphide deposits (VMS) and Niores were until recently the only ore types which were mined in this province, but during the last decade, increasing interest has also been focused on gold lode deposits and two gold mines have come into production since 1988.The origin of the massive sulphide deposits and the Ni-ores has been discussed in a number of papers (see e.g.

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Section: Gold Depositsmentioning

confidence: 98%

Source of metals and age constraints for epigenetic gold deposits in the Skellefte and Pohjanmaa districts, central part of the Fennoscandian Shield

et al. 1993

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“…Björkdal; Broman et al 1994;Weihed et al 2003), and also deposits of possible metamorphogenic origin in supracrustal settings (e.g. Grundfors; Bergman 1992).…”

Section: Introductionmentioning

confidence: 97%

Geochronological, stable isotopes and fluid inclusion constraints for a premetamorphic development of the intrusive-hosted Björkdal Au deposit, northern Sweden

Billström

Broman

Récio

et al. 2008

Int J Earth Sci (Geol Rundsch)

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The Björkdal gold deposit, bound to a quartz vein system which is mainly hosted by a quartz-monzodioritic intrusion, is situated at the easternmost part of the 1.9 Ga Skellefte base metal district in the Fennoscandian shield. Three fluid stages may be distinguished, referred to as a ''barren'' stage, a main gold stage, and a remobilization stage, respectively. From oxygen and hydrogen isotope evidence, it is argued that fluids of different origins (magmatic and surface waters) penetrated the ore zone at the inferred stages, but regional metamorphic fluids appear essentially only to have redistributed elements. Early quartz veining took place during a pre-metamorphic stage at ca. 1.88 Ga, as evidenced by unradiogenic galena data and an Sm-Nd scheelite errorchron of 1,915 ± 32 Ma (MSWD = 0.25). Temporarily, the main ore-forming stage was closely related to the first barren stage and took place during a major uplift event close to 1.88 Ga. Although other source rocks cannot be totally ruled out, available isotope data (O, S, Sr and Pb) are seemingly consistent with the view that these elements, and by inference other ore elements, were derived from the host intrusion.

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“…Hence, with respect to the overall features recognized for typical intrusion-related deposits, the Åkerberg gold occurrence provides a good example of such a type. In contrast, other gold deposits in the Skellefte district region, such as, e.g., Grundfors [16], may exemplify an orogenic type of gold deposit, which is widely held to result from crustal-scale flow in connection with metamorphic dehydration [20]. (1) SOD = Skellefte ore district; (2) qz=quartz; (3) py=pyrite; (4) po=pyrrothite; (5) cpy=chalcopoyrite; (6) apy=arsenopyrite; (7) sp=sphalerite; (8) sch=scheelite; (9) tour=tourmaline; (10) cc=calcite; (11) loell=loellingite; (12) amp =amphibole.…”

Section: Classifying the åKerberg Gold Deposit: An Intrusion-related mentioning

confidence: 99%

“…This is different from the characteristics of the wider N-S trending arsenopyrite-bearing veins that occur not only in the gabbro but also in the surrounding sedimentary rocks. Arsenopyrite-bearing and gold-associated quartz veins are also important at other localities near the Skellefte district (e.g., at Fä boliden, Svartliden, Grundfors and Skä ggträ skberget; see earlier stated references), where sedimentary rocks predominate, and have been interpreted to be part of the 1.8 Ga metamorphic history [16,18]. These circumstances add some support to the view that quartz veins actually may have formed at different times at Åkerberg and could represent two generations, one early dominant system expressed by E-W veins forming the Au-rich zone, followed by a younger (1.8 Ga) N-S arsenopyrite-bearing vein system into which gold, to some minor extent, was mobilized from earlier existing sites.…”

Section: Factors Controlling Gold Transport Ore-associated Alteratiomentioning

confidence: 99%

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Geology and Age Constraints on the Origin of the Intrusion-Related, Sheeted Vein-Type Åkerberg Gold Deposit, Skellefte District, Sweden

et al. 2012

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Abstract:The Early Proterozoic (~1.9 Ga) Skellefte mining district in northern Sweden hosts abundant base metal deposits, but there are also gold-only deposits. The Åkerberg gold ore is unusual given the noted lack of alteration, a scarcity of sulfides and gold associated with thin (mm-cm wide) parallel quartz veins hosted in a gabbro. The gold content is positively correlated with the density of quartz veins, but gold often occurs between veins and also in parts of the gabbro where there is no veining. The gabbro is intruded by a granodiorite and associated pegmatite bodies, and U-Pb dating of zircon and baddeleyite suggest that these lithologies developed close in time at around 1.88 Ga ago. There are no primary inclusions in quartz veins, but different types of secondary aqueous inclusions occur. The Åkerberg ore is interpreted as a sheeted vein complex, with veins constrained to tensional cracks induced when a granodioritic magma intruded the competent, sheet-like gabbro intrusion. It is suggested that unmixing of the felsic magma also produced pegmatite bodies and a gel-like melt which invaded fractures in the gabbro OPEN ACCESSMinerals 2012, 2 386 and deposited silica. In a comparison, the Åkerberg ore shares many characteristics with the intrusion-related style of gold mineralizations.

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Structural geology of Grundfors, a quartz vein related gold deposit in the Skellefte district, northern Sweden

Cited by 8 publications

References 14 publications

Source of metals and age constraints for epigenetic gold deposits in the Skellefte and Pohjanmaa districts, central part of the Fennoscandian Shield

Source of metals and age constraints for epigenetic gold deposits in the Skellefte and Pohjanmaa districts, central part of the Fennoscandian Shield

Geochronological, stable isotopes and fluid inclusion constraints for a premetamorphic development of the intrusive-hosted Björkdal Au deposit, northern Sweden

Geology and Age Constraints on the Origin of the Intrusion-Related, Sheeted Vein-Type Åkerberg Gold Deposit, Skellefte District, Sweden

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