U–Pb geochronology of a Paleoproterozoic continental magmatic arc on the western margin of the Archean Nain craton, northern Labrador, Canada
The Paleoproterozoic Torngat Orogen, in northernmost Labrador and northeastern Quebec, records the collision between the western margin of the Nain Province and the eastern margin of the Rae Province. Six samples from a suite of calc-alkaline plutonic rocks that intrude the Nain craton have been dat...
| Published in: | Canadian Journal of Earth Sciences |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
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Canadian Science Publishing
1995
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| Online Access: | http://dx.doi.org/10.1139/e95-144 http://www.nrcresearchpress.com/doi/pdf/10.1139/e95-144 |
| Summary: | The Paleoproterozoic Torngat Orogen, in northernmost Labrador and northeastern Quebec, records the collision between the western margin of the Nain Province and the eastern margin of the Rae Province. Six samples from a suite of calc-alkaline plutonic rocks that intrude the Nain craton have been dated using the U–Pb method at 1895 ± 2, 1888 ± 2, [Formula: see text], 1885 ± 2 (two samples), and >1859 Ma, and support the interpretation that east-dipping subduction occurred below the Nain craton during this interval. A granitic dyke that truncates the sinistral shear fabric in the Abloviak shear zone is 1824 ± 2 Ma, placing a younger limit on the timing of this deformation in the area. A second granitic dyke, emplaced synchronously with dextral deformation in the bend in the Abloviak shear zone, is 1798 ± 3 Ma. A model is proposed in which subduction occurred beneath the Nain craton along its entire exposed length from 1.91 to 1.86 Ga, and collision occurred between 1.86 and 1.84 Ga, followed by oblique uplift of the southern part of the Rae craton from 1.80 to 1.71 Ga. |
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