Seismic and geoelectric evidence for collisional and extensional events in the Fennoscandian Shield implications for Precambrian crustal evolution

Korja, Annakaisa; Korja, T.; Luosto, U.; Heikkinen, Pekka

doi:10.1016/0040-1951(93)90292-r

Cited by 159 publications

(83 citation statements)

References 45 publications

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“…The crustal structure across the Vøring Margin is first constrained from available seismic data, from published ocean bottom seismograph (OBS) data (Mjelde et al, 2001) and expanded spread and wide aperture CDP profiling data (Mutter & Zehnder, 1988;Zehnder, Mutter, & Buhl, 1990). In the Trøndelag Platform and the offshore section of the profile, we use seismic results from Planke et al (1991) and Korja, Korja, Luosto, & Heikkinen (1993), respectively. For the Vøring Marginal High and Vøring Basin, we use the crustal structure obtained from a combined 3D seismic and gravity analysis (Torne et al, 2003).…”

Section: Integration Of Extensional Structure In Crustal-scale Sectionsmentioning

confidence: 99%

Extensional geometry of the Mid Norwegian Margin before Early Tertiary continental breakup

Gómez

Vergés

Fernández

et al. 2004

Marine and Petroleum Geology

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Section: Integration Of Extensional Structure In Crustal-scale Sectionsmentioning

confidence: 99%

Extensional geometry of the Mid Norwegian Margin before Early Tertiary continental breakup

Gómez

Vergés

Fernández

et al. 2004

Marine and Petroleum Geology

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“…692 Korja et al (1993) proposed a mantle underplating 693 model to account for the thick crust in central Finland, 694 whereas Lahtinen (1994) presented a model for the 695 Svecofennian of Finland involving several accretion-696 ary units and three collisional stages at 1.91 to 1.90, 697 1.89 to 1.88, and 1.86 to 1.84 Ga. Korja (1995) 698 introduced the concept of orogenic collapse to account 699 for the variation in crustal thickness in southern Fin-700 land, and Nironen (1997) presented a kinematic plate 701 tectonic model for the Svecofennian Orogen starting 702 with the opening of an ocean at 1.95 Ga, followed by 703 progressive accretion of two arc complexes on to the 704 Archaean craton between 1.91 and 1.87 Ga.…”

mentioning

confidence: 99%

8: Precambrian geodynamics and ore formation: The Fennoscandian Shield

Weihed

Arndt

Billström

et al. 2005

Ore Geology Reviews

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15Compared with present-day global plate tectonics, Archaean and Palaeoproterozoic plate tectonics may have involved faster 16 moving, hotter plates that accumulated less sediment and contained a thinner section of lithospheric mantle. This scenario also 17 fits with the complex geodynamic evolution of the Fennoscandian Shield from 2.06 to 1.78 Ga when rapid accretion of island 18 arcs and several microcontinent-continent collisions in a complex array of orogens was manifested in short-lived but intense 19 orogenies involving voluminous magmatism. With a few exceptions, all major ore deposits formed in specific tectonic settings 20 between 2.06 and 1.78 Ga and thus a strong geodynamic control on ore deposit formation is suggested. 21All orogenic gold deposits formed syn-to post-peak metamorphism and their timing reflects the orogenic younging of the 22 shield towards the SW and west. Most orogenic gold deposits formed during periods of crustal shortening with peaks at 2.72 to 23 2.67, 1.90 to 1.86 and 1.85 to 1.79 Ga. 24The ca. 2.5 to 2.4 Ga Ni-Cu F PGE deposits formed both as part of layered igneous complexes and associated with mafic 25 volcanism, in basins formed during rifting of the Archaean craton at ca. 2.5 to 2.4 Ga. Svecokarelian ca. 1.89 to 1.88 Ga Ni-Cu 26 deposits are related to mafic-ultramafic rocks intruded along linear belts at the accretionary margins of microcratons. 27All major VMS deposits in the Fennoscandian Shield formed between 1.97 and 1.88 Ga, in extensional settings, prior to 28 basin inversion and accretion. The oldest bCyprus-typeQ deposits were obducted onto the Archaean continent during the onset of 29 convergence. The Pyhäsalmi VMS deposits formed at 1.93 to 1.91 Ga in primitive, bimodal arc complexes during extension of 30 the arc. In contrast, the Skellefte VMS deposits are 20 to 30 million years younger and formed in a strongly extensional intra-arc 31 region that developed on continental or mature arc crust. Deposits in the Bergslagen-Uusimaa belt are similar in age to the 32 Skellefte deposits and formed in a microcraton that collided with the Karelian craton at ca. 1.88 to 1.87 Ga. The Bergslagen- ARTICLE IN PRESS33 Uusimaa belt is interpreted as an intra-continental, or continental margin back-arc, extensional region developed on older 34 continental crust. 35Iron oxide-copper-gold (IOCG) deposits are diverse in style. At least the oldest mineralizing stages, at ca. 1.88 Ga, are 36 coeval with calc-alkaline to monzonitic magmatism and coeval and possibly cogenetic subaerial volcanism more akin to 37 continental arcs or to magmatic arcs inboard of the active subduction zone. Younger mineralization of similar style took place 38 when S-type magmatism occurred at ca. 1.80 to 1.77 Ga during cratonization distal to the active N-S-trending subduction zone 39 in the west. Possibly, interaction of magmatic fluids with evaporitic sequences in older rift sequences was important for ore 40 formation. 41Finally, the large volumes of anorthositic magmas that characterize the S...

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“…A corresponding ramp has also been reported on SVEKA'81 (e.g., Grad and Luosto, 1987;Korja et al, 1993;Korsman et al, 1999), BALTIC and FIRE1 (Kontinen and Paavola, 2006;Kukkonen et al, 2006) transects. It has been interpreted as a boundary that separates the Archean crust from the crust that is both under-and overthrust by the younger Svecofennian crust (Korja et al, 1993;Korja and Heikkinen, 2008). The western termination of the bulge is more gradational but roughly aligned with the N-S striking Kainuu schist belt (Kb).…”

Section: Moho Depth Mapmentioning

confidence: 79%

Crustal seismic structure and depth distribution of earthquakes in the Archean Kuusamo region, Fennoscandian Shield

Uski¹,

Tiira²,

Grad³

et al. 2012

Journal of Geodynamics

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Seismic and geoelectric evidence for collisional and extensional events in the Fennoscandian Shield implications for Precambrian crustal evolution

Cited by 159 publications

References 45 publications

Extensional geometry of the Mid Norwegian Margin before Early Tertiary continental breakup

Extensional geometry of the Mid Norwegian Margin before Early Tertiary continental breakup

8: Precambrian geodynamics and ore formation: The Fennoscandian Shield

Crustal seismic structure and depth distribution of earthquakes in the Archean Kuusamo region, Fennoscandian Shield

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