Paleomagnetism of Archean volcanics and Proterozoic dikes in La Grande Riviere area of Nouveau-Quebec

Séguin, Maurice K.; Sharma, K. N. M.; Woussen, G.; Seymour, Karen St.; Symons, D. T. A.

doi:10.1139/e83-031

Cited by 4 publications

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“…As a result, the acquisition times for their remanent magnetizations are even more poorly known. Thus, the Archean apparent polar wander paths (APWP) that have been constructed for North America (e.g., Irving and Naldrett 1977;Irving 1979;Seguin et al 1983;Dunlop 1984a) are for the most part based on paleopoles with large error limits on their ages. This age problem was demonstrated most recently when a more precise U-Pb zircon age for the Matachewan-Hearst dikes of 2454 2 2 Ma was detennined (Heaman 1988), replacing the previous Rb-Sr isochron age of 2633 +-91 Ma (Gates and Hurley 1973;Easton 1986).…”

Section: Introductionmentioning

confidence: 99%

Paleomagnetism of Archean granites and Matachewan dikes in the Wawa Subprovince, Ontario: reevaluation of the Archean apparent polar wander path

Vandall¹,

Symons²

1990

Can. J. Earth Sci.

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Paleomagnetic measurements have been completed on 400 specimens from dated Archean granites and Matachewan dikes in the Michipicoten and Gamitagama greenstone belts in the western Wawa Subprovince of the Superior Province, Ontario. Detailed alternating-field and thermal step demagnetization analyses were used to isolate stable remanence directions. A single-component remanence was isolated within three adjacent dated granitic plutons on the eastern margin of the Michipicoten belt, including the Hawk Lake trondhjemite, the Southern external granite, and the Eastern external granite (HSE). The maximum possible age for this remanence is constrained by the intrusion of the last pluton at 2694 Ma. The corresponding HSE paleopole is located at 10°W, 41°S (dp = 8°, dm = 13°). A second paleopole, NB, is derived from the Northern external granite and the Baldhead River quartz monzonite, which give U–Pb zircon ages of 2662 and 2668 Ma, respectively. Their single-component remanence defines a paleopole on the Archean apparent polar wander path (APWP) at 15°E, 27°S (dp = 8°, dm = 13°), with a maximum possible age of 2.66 Ga. A third paleopole, GD, is derived from the north-northwest-trending Gamitagama diabase dikes and yields a position of 57°E, 41°N (dp = 7°, dm = 14°), which agrees with poles determined by other workers from the 2454 Ma Matachewan dike swarm. The GD pole, along with previously determined Matachewan dike poles, demonstrates that a tectonically stable craton has existed since intrusion of this extensive dike swarm, and it improves the precision of the 2454 Ma Matachewan pole on the APWP. These poles, when compared with coeval poles from the eastern side of the Kapuskasing Structural Zone in the Superior Province, imply no tectonic rotation or translation between the Wawa and Abitibi subprovinces along this Early Proterozoic structure.

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Section: Introductionmentioning

confidence: 99%

Paleomagnetism of Archean granites and Matachewan dikes in the Wawa Subprovince, Ontario: reevaluation of the Archean apparent polar wander path

Vandall¹,

Symons²

1990

Can. J. Earth Sci.

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Paleomagnetic evidence for post‐2.55‐GA tectonic tilting and 1.1‐Ga Reactivation in the Southern Kapuskasing Zone, Ontario, Canada

Costanzo-Alvarez¹,

Dunlop²

1988

J. Geophys. Res.

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We report paleomagnetic results from two traverses in the southern part of the Kapuskasing structural zone (KSZ) of north-central Ontario, which is hypothesized to be an oblique cross section through upper and middle Archean crust exposed by uplift and tilting. Anorthosites and granulite-grade gneisses were sampled to the east in the Shawmere traverse, while amphibolite-grade tonalitic gneisses were sampled to the west in the Racine traverse. Three distinct remanent magnetization (RM) components were isolated by alternating field and thermal demagnetization. The ARM has mean directions D = 50', I = +62* (k = 138, •x95 = 5', N = 5 sites (23 samples)) for the Shawmere traverse and D = 23', I = +53* (k = 49, = 7', N = 8 sites (46 samples)) for the Racine traverse. Because of the high (>500'C) laboratory unblocking temperatures of the ARM in the Shawmere granulite-grade rocks, we believe this magnetization was acquired in early slow uplift, without tilting, from about 24-km to about 16-km depths, and has survived the later main KSZ uplift and tilting event. The Racine ARM has laboratory unblocking temperatures down to =400'C and was blocked prior to uplift from a shallower crustal level (about 8 km). With tilt corrections of 30* and 15', respectively, about the 35øE striking axis of the KSZ, the Shawmere and Racine A paleomagnetic poles fall on the Laurentian apparent polar wander path around 2.55 Ga, dating the time of initial uplift. Crustal tilting in the KSZ occurred after 2.55 Ga and was greater in the east than in the west. The B RM, found mainly in Shawmere anonhosites, has D = 115', I = -68* (k = 17, c•95 TM 17', N = 4 sites (14 samples)), with a paleopole at 144'W, 49'N, near 1.1 Ga Keweenawan reverse poles and the normal pole of the nearby 1.0 Ga Nemegosenda carbonatite. The B RM is probably a thermochemical overprint related to reactivation of the KSZ at the time of Keweenawan rifting and volcanism in the Lake Superior region. A novel C RM, with D = 64', I = +2* (k = 18, c•95 TM 13', N = 6 sites (10 samples)), is either an unresolved hybrid of the A and B RMs or an earliest Keweenawan (1.3 Ga) overprint. Runcorn, Elsevier, New York, 1967.

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Paleomagnetism, U–Pb geochronology, and geochemistry of Lac Esprit and other dyke swarms, James Bay area, Quebec, and implications for Paleoproterozoic deformation of the Superior Province

et al. 2007

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An extensive set of north- to northwest-trending diabase dykes, termed the Lac Esprit swarm, is identified in the Superior Province east of James Bay based on geological mapping and a distinctive paleomagnetic pole (61.7°N, 169.1°E, dm = 7.7°, dp = 5.5°). The Lac Esprit swarm yields a U–Pb baddeleyite age of 2069 ± 1 Ma similar to that of the 2076+5–4 Ma Fort Frances swarm of the western Superior Province. Their paleomagnetic declinations differ by 23° ± 12° after correction to a common reference locality. The difference is likely due mainly to counterclockwise rotation about a vertical axis of the Fort Frances area relative to the Lac Esprit area. Differential rotation of 10°–20° has been proposed more locally across the Kapuskasing Structural Zone separating the eastern and western Superior Province in earlier paleomagnetic studies of ca. 2450 Ma Matachewan and 2170 Ma Biscotasing dyke swarms. Thus, relative rotation may have involved the entire eastern and western Superior Province, perhaps in response to collisional events associated with the Trans-Hudson Orogen to the north or the Penokean orogen to the south, or in response to rifting beneath Hudson Bay. Other dykes in the study area are interpreted from a combination of paleomagnetism, trend, and geochemistry to belong to the Senneterre, Matachewan, and Mistassini swarms. The 2216 Ma Senneterre dykes form part of a giant swarm that fans across the eastern Superior Province. Paleomagnetic directions and geometry of this swarm rule out substantial block rotations within the eastern Superior Province since dyke emplacement.

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Paleomagnetism of Archean volcanics and Proterozoic dikes in La Grande Riviere area of Nouveau-Quebec

Cited by 4 publications

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Paleomagnetism of Archean granites and Matachewan dikes in the Wawa Subprovince, Ontario: reevaluation of the Archean apparent polar wander path

Paleomagnetism of Archean granites and Matachewan dikes in the Wawa Subprovince, Ontario: reevaluation of the Archean apparent polar wander path

Paleomagnetic evidence for post‐2.55‐GA tectonic tilting and 1.1‐Ga Reactivation in the Southern Kapuskasing Zone, Ontario, Canada

Paleomagnetism, U–Pb geochronology, and geochemistry of Lac Esprit and other dyke swarms, James Bay area, Quebec, and implications for Paleoproterozoic deformation of the Superior Province

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