A 70 Ma record of suprasolidus conditions in the large,hot, long‐duration Grenville Orogen |
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| Authors: | François Turlin Clara Deruy Aurélien Eglinger Olivier Vanderhaeghe Anne‐Sylvie André‐Mayer Marc Poujol Abdelali Moukhsil Fabien Solgadi |
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| Institution: | 1. GeoRessources lab., UMR 7359, Université de Lorraine, CNRS, CREGU, Faculté des Sciences et Technologies, Vand?uvre‐lès‐Nancy, France;2. Géosciences Environnement Toulouse, GET, Université de Toulouse, CNRS, IRD, UPS, CNES, Toulouse, France;3. Univ Rennes, CNRS, Géosciences Rennes– UMR 6118, Rennes, France;4. Ministère de l’énergie et des Ressources naturelles, Direction du Bureau de la connaissance géoscientifique du Québec, (Canada) |
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| Abstract: | Petrochronology of magmatic monazite and apatite from a single paragneiss leucosome derived by in situ partial melting documents the thermal evolution of the Allochthonous Belt of the central Grenville Province. Monazite records suprasolidus metamorphism from ca. 1080 to 1020 Ma under high temperature up to 850°C. Apatite from the same leucosome yields an age of 960 Ma, consistent with cooling of this crustal segment down to subsolidus conditions of ca. 450°C. A pegmatitic granite dyke, with lobate contacts, previously dated at ca. 1005 Ma (Turlin et al., 2017 ) is interpreted to intrude the paragneisses at a temperature of ca. 650°C close to the wet‐solidus. These data document slow cooling at a rate of 2–6°C/Ma for the middle crust of this part of the Grenville hinterland marked by protracted suprasolidus conditions for at least 70 Ma. It supports the definition of the Grenville Orogen as a large, hot, long‐duration orogen. |
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