U–Pb geochronologic constraints on Paleoproterozoic orogenesis in the northwestern Makkovik Province, Labrador, Canada

Ketchum, J. W. F.; Dunning, G. R.; Culshaw, Nicholas

doi:10.1139/e17-087

Cited by 27 publications

(17 citation statements)

References 28 publications

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“…The decrease in age correlates with a decrease in darkness and in U content of the grains. Although these are very common features of multigeneration titante populations (e.g., Ketchum et al 1997;Corfu and Stone 1998;Søderlund et al 1999), in the present case a visual distinction between old and young titanite domains/grains is very difficult to achieve. The two dates of ca.…”

Section: Monzonite (Sample C-99-47)mentioning

confidence: 72%

U–Pb ages of the Dalsfjord Complex, SW Norway, and their bearing on the correlation of allochthonous crystalline segments of the Scandinavian Caledonides

Corfú

Andersen

2002

Int J Earth Sci (Geol Rundsch)

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The Dalsfjord Complex is an allochthonous crystalline unit in the hanging wall of a major extensional detachment of the Caledonian orogen on the western coast of Norway. U-Pb geochronology has been carried out to test a previously proposed correlation between this unit and the Jotun Nappe Complex, a member of the Middle Allochthon now occupying a foreland position to the east. A monzonite sample of the Dalsfjord suite yields a zircon age of 1,634±3 Ma, whereas a crosscutting gabbro was formed at 1,464±6 Ma. Both rocks were strongly overprinted during the Sveconorwegian orogeny, especially the monzonite whose zircons U-Pb data were strongly pulled towards a lower intercept age of 882±29 Ma, and whose titanite indicates a two-stage growth history at >960 Ma and <920 Ma. These relationships support the correlation of these units with the Jotun Complex, and to some degree also with the Lindås Nappe in the Bergen Arcs.

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Section: Monzonite (Sample C-99-47)mentioning

confidence: 72%

U–Pb ages of the Dalsfjord Complex, SW Norway, and their bearing on the correlation of allochthonous crystalline segments of the Scandinavian Caledonides

Corfú

Andersen

2002

Int J Earth Sci (Geol Rundsch)

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“…Perhaps the most significant domain boundary in both Labrador and Greenland occurs at the southern limit of contiguous Archean crust. In the Makkovik Province this corresponds to the Kaipokok-Aillik domain boundary, which is marked by a number of high-strain zones collectively termed the Kaipokok Bay shear zone (Ketchum et al 1997a;Culshaw et al 2000a). In the Ketilidian mobile belt, the equivalent structure is the Kobberminebugt shear zone marking the boundary between the Border zone and the Julianehåb Batholith (Fig.…”

Section: Regional Geological Frameworkmentioning

confidence: 99%

“…Measurements made on a Finnigan-MAT 262 thermal ionization mass spectrometer. See Ketchum et al (1997a,) for additional details. a All fractions are multigrain unless otherwise indicated.…”

Section: Reworked Archean Gneissmentioning

confidence: 99%

“…4) developed as D1 thin-and thick-skinned thrust zones, respectively, at ca. 1.9 Ga (Ketchum et al 1997a(Ketchum et al , 2001bCulshaw et al 2000a). Thin-skinned thrusts of comparable age also occur at the base of the Moran Lake Group (Ryan 1984;Kerr et al 1992), and D1 straight gneiss is locally preserved in the Island Harbour Bay area (Culshaw et al 2000a).…”

Section: Kaipokok Bay Shear Zone (Kaipokok-aillik Domain Boundary)mentioning

confidence: 99%

“…Lithoprobe also funded a number of onshore and offshore supporting geoscience projects (e.g., Wasteneys et al 1996a;Ketchum et al 1997aKetchum et al , 2001aKetchum et al , 2001bBarr et al 2001;Culshaw et al 2000aCulshaw et al , 2000bCulshaw et al , 2002Sinclair et al 2002). The findings of these and earlier studies, synthesized within the new seismic framework, have allowed for the first time a comprehensive evaluation of pre-, syn-, and post-orogenic events in the Makkovikian crust and upper mantle (e.g., Culshaw et al 2000a).…”

Section: Introductionmentioning

confidence: 98%

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Anatomy and orogenic history of a Paleoproterozoic accretionary belt: the Makkovik Province, Labrador, Canada

Ketchum¹,

Culshaw²,

Barr³

2002

Can. J. Earth Sci.

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The Makkovik Province is a segment of a Paleoproterozoic accretionary belt (the Makkovik-Ketilidian orogen) that developed on the southern margin of Laurentia at 1.9-1.7 Ga. In contrast to coeval Laurentian orogenic belts that mainly resulted from collision of Archean plates, Makkovikian-Ketilidian orogenesis was dominated by active-margin processes including continental margin arc plutonism and juvenile terrane accretion, both of which were accompanied by regional transpression. In the Makkovik Province, earliest deformation and amphibolite-facies metamorphism of Paleoproterozoic rift-drift assemblages (Post Hill and Moran Lake groups) and the Archean foreland (Nain Province) occurred at 1.9 Ga in response to accretion of a Paleoproterozoic island arc. Following this collision, cratonward-dipping subduction was established, resulting in the formation of the 1895-1870 Ma Island Harbour Bay Plutonic Suite, a calc-alkaline magmatic arc built on reworked Archean crust. Crust formation continued between ca. 1860 and 1850 Ma with deposition of the Aillik Group on a largely juvenile basement in a rifted-arc or back-arc setting. Sometime before 1802 Ma this depositional basin was tectonically inverted, with resultant northwestward thrusting of the Aillik Group over reworked Archean crust. This phase of deformation may have been driven by accretion of a second island arc potentially represented by the Cape Harrison Metamorphic Suite. Regional transpression and amphibolite-facies metamorphism at ca. 1815-1780 Ma were accompanied by widespread granitoid plutonism. These events were mainly concentrated in the juvenile domains and are thought to reflect processes in a broad continental back-arc setting. A final orogenic pulse, marked by regional greenschist-facies transpression and emplacement of A-type granitoid plutons, occurred between 1740 and 1700 Ma, with deformation and plutonism potentially linked to crust-mantle detachment and incursion of mafic magmas at the base of the crust, respectively. The record of crustal development suggests that the coeval themes of spatially and temporally linked structural and plutonic activity, oceanward migration of this activity over time, and a trend toward increasingly more localized deformation occurred throughout the orogenic history of the Makkovik Province. These characteristics are thought to broadly reflect oceanward crustal growth of the orogen over time. In the correlative Ketilidian mobile belt of southern Greenland, these themes were also operative but appear to have been less pronounced, most likely due to minimal or a complete absence of accretion of island-arc material. 730Résumé : La Province de Makkovik est un segment d'une ceinture d'accrétion paléoprotérozoïque (l'orogène Makkovikkétilidien) qui s'est développée sur la bordure sud de la Laurentia vers 1,9-1,7 Ga. Contrairement aux ceintures orogéniques contemporaines laurentiennes qui résultent principalement de la collision de plaques archéennes, l'orogène Makkovikkétilidien a été dominé par des processus de marges...

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Advances in in-situ Rb-Sr dating using LA-ICP-MS/MS: applications to igneous rocks of all ages and to the identification of unrecognized metamorphic events

et al. 2022

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U–Pb geochronologic constraints on Paleoproterozoic orogenesis in the northwestern Makkovik Province, Labrador, Canada

Abstract: A 45 h wide, shear-zone-bounded segment of the northwestern Makkovik Province, Labrador, is underlain by Archean gneisses derived from the adjacent Nain craton. This lithotectonic blaek (Kaipokok domain) was reworked at high metamorphic grade, overthrust by supracrustal sequences (Lower

Cited by 27 publications

References 28 publications

U–Pb ages of the Dalsfjord Complex, SW Norway, and their bearing on the correlation of allochthonous crystalline segments of the Scandinavian Caledonides

U–Pb ages of the Dalsfjord Complex, SW Norway, and their bearing on the correlation of allochthonous crystalline segments of the Scandinavian Caledonides

Anatomy and orogenic history of a Paleoproterozoic accretionary belt: the Makkovik Province, Labrador, Canada

Advances in in-situ Rb-Sr dating using LA-ICP-MS/MS: applications to igneous rocks of all ages and to the identification of unrecognized metamorphic events

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