Tectonic implications of an 1846±1 Ma old migmatitic granite in south‐central Sweden

Romer, Rolf L.; Öhlander, Björn

doi:10.1080/11035899509546201

Cited by 16 publications

(4 citation statements)

References 43 publications

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“…1.75 Ga (Huhma 1986;Ehlers et al 1993;Claesson and Lundqvist 1995;Romer and Öhlander 1995;Öhlander and Romer 1996;Andersson and Öhlander 2004;Kurhila et al 2005; Figure 1). Simultaneously in the west and southwest, subduction along the active Svecofennian continental margin created the voluminous Transscandinavian Igneous Belt (TIB) (e.g .…”

Section: Regional Geologymentioning

confidence: 93%

1.8 Ga magmatism in southern Finland: strongly enriched mantle and juvenile crustal sources in a post-collisional setting

Rutanen

Andersson

Väisänen

et al. 2010

International Geology Review

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Section: Regional Geologymentioning

confidence: 93%

1.8 Ga magmatism in southern Finland: strongly enriched mantle and juvenile crustal sources in a post-collisional setting

Rutanen

Andersson

Väisänen

et al. 2010

International Geology Review

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“…Timing of metamorphic events in the Bergslagen region is poorly constrained. Romer &Öhlander (1995) (Romer & Smeds, 1994;Romer, 1997). The studies so far bracket the timing of metamorphism in Bergslagen to the period 1.85-1.78 Ga, where only the titanite skarn age (1.79 Ga) of Romer &Öhlander (1994) is from the northern medium-grade (middlelower amphibolite facies) region.…”

Section: Introductionmentioning

confidence: 97%

“…The northern and western areas of Bergslagen are dominated by volcanic formations, while the sedimentary successions of the Sörmland basin dominate the bedrock in the SE (e.g. Stålhös, 1991;Allen et al 1996;Romer &Öhlander 1995), recently interpreted as an accretionary prism (Korja & Heikkinen, 2005). In the NE large areas are made up by Early Svecofennian intrusive rocks, referred to as the c. 1.89 Ga Uppland batholith (Fig.…”

Section: Introductionmentioning

confidence: 99%

Multistage growth and reworking of the Palaeoproterozoic crust in the Bergslagen area, southern Sweden: evidence from U–Pb geochronology

et al. 2006

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The Svecofennian Domain of the Fennoscandian Shield constitutes a considerable volume of Palaeoproterozoic crustal growth, 2.1–1.86 Ga ago, in between the Archaean craton in the NE and the 1.85–1.65 Ga Transscandinavian Igneous Belt (TIB) in the south and west. The Bergslagen area is a classical ore province located in the southwestern part of the Svecofennian Domain of south-central Sweden. Its northern part is dominated by volcanic and plutonic rocks of a magmatic arc with continental affinity, while the SE part is made up by a sedimentary basin. The Bergslagen area shows a metamorphic zonation from lower to middle amphibolite facies in the north to upper amphibolite facies and locally granulite facies in the south; a small greenschist area exists in the west. Identifying the age spectra of inherited components, magmatic crystallization, as well as metamorphic episodes, provide important constraints on the geodynamic evolution of this centrally located piece of the Shield.U–Pb zircon SIMS data presented in this paper complement the previous, regionally scattered TIMS data from this area. Magmatic zircons from two felsic metavolcanic rocks and two amphibolites (metagabbros) yield 1888±12, 1892±7 and 1887±5, 1895±5 Ma, respectively; i.e. within the 1.91–1.86 Ga range previously obtained for Early Svecofennian magmatism in Bergslagen. An augen gneiss from southern Bergslagen, assigned to the earliest TIB generation, yield an intrusive age of 1855±6 Ma. Metamorphic monazites from the same rock indicate that deformation and elevated thermal activity prevailed 1.83–1.82 Ga ago (TIMS). Metamorphic zircons in high-grade metasedimentary rocks from the south and west yield ages of 1793±5 and 1804±10 Ma, in accordance with ages for regional peak metamorphism and migmatite formation found elsewhere in the southern Svecofennian province of Sweden. More importantly, a few zircon crystals and overgrowths in rocks from the north indicate an early metamorphic episode at c. 1.87 Ga, indicating that Bergslagen has experienced two major metamorphic events. Detrital and inherited zircons span the range 2.78–1.90 Ga, with an apparent gap at 2.45–2.1 Ga, which further emphasize previous observations of a major juvenile (<2.1 Ga) and a minor Archaean provenance. This, and in particular the 1.94–1.91 Ga crystals present in the c. 1.89 Ga amphibolites, support the suggestion of a former Palaeoproterozoic pre-1.91 Ga crust in the Bergslagen area.

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“…Svecofennian domain varies from 1.93 to 1.85 Ga but is weighted at 1.88 Ga (Huhma, 1986;Claesson & Lundqvist, 1995;Romer & Öhlander, 1995;Korsman et al, 1997), which means that the Svecofennian igneous activity partly overlaps the activity in the Karelian domain. The post-tectonic granitoids are younger than 1.83 Ga.…”

Section: Tectonic Consequences and Correlationmentioning

confidence: 99%

Evolution of migmatitic granulite complexes: Implications from Lapland Granulite Belt, Part II: Isotopic dating

Tuisku¹,

Huhma²

2006

Bull Geol Soc Finland

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The migmatitic metapelites of the Lapland granulite belt (LGB) in the NE part of the Fennoscandian Shield represent an arc-related greywacke basin metamorphosed in the granulite facies. Detrital zircons from migmatitic metapelites are derived from 1.94 etrital zircons from migmatitic metapelites are derived from 1.94 zircons from migmatitic metapelites are derived from 1.94 derived from 1.94 − 2.9 Ga old acid source rocks (U-Pb SIMS ages). The clustering of detrital zircon ages between 1.97 and 2.2 Ga is problematic, because abundant felsic crust of this age is absent in the shield. The metasediments are characterized by Sm-Nd model ages of ca. 2.3 Ga. A younger, 1905 − 1880 Ma population of homogeneous zircons was formed during regional metamorphism. The peak high-grade metamorphism took place at ~1900 Ma and the latest chronological record from subsequent decompression and cooling phase is from ca. 1870 Ma. The norite-enderbite series of the LGB represents arc-magmas, which were intruded into the metasediments at ~1920 − 1905 Ma ago according to zircon U-Pb ages and were probably an important heat source for metamorphism. Older, zoned zircon grains in a quartz norite vein, initial ε Nd values of 0 to +1 and the continuous spectrum of LILE enrichment in the enderbite-series probably reflect assimilation of metasediments by magmas. Monazite U-Pb ages of migmatitic metasediments in the range 1906 − 1910 ± 3 Ma overlap the late stage of enderbite intrusion and growth of early metamorphic zircons. Garnetwhole rock Sm-Nd ages from leucosomes in the range 1880 − 1886 ± 7 Ma are concurrent with the growth of the youngest metamorphic zircons and probably indicate the crystallization of leucosomes or the influence of a fluid liberated from them. Isotopic and petrologic data reveal that the evolution of Lapland Granulite belt from the erosion of source rocks to the generation of a sedimentary basin, its burial, metamorphism and exhumation took place within ca. 60 Ma.

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Tectonic implications of an 1846±1 Ma old migmatitic granite in south‐central Sweden

Cited by 16 publications

References 43 publications

1.8 Ga magmatism in southern Finland: strongly enriched mantle and juvenile crustal sources in a post-collisional setting

1.8 Ga magmatism in southern Finland: strongly enriched mantle and juvenile crustal sources in a post-collisional setting

Multistage growth and reworking of the Palaeoproterozoic crust in the Bergslagen area, southern Sweden: evidence from U–Pb geochronology

Evolution of migmatitic granulite complexes: Implications from Lapland Granulite Belt, Part II: Isotopic dating

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