U/Pb geochronology of the Coney Head Complex, Newfoundland
The Coney Head Complex, White Bay, Newfoundland, comprises allochthonous plutonic rocks and deformed equivalents emplaced over the continental margin during the Ordovician Taconic Orogeny. A U/Pb zircon age of 474 + 2 Ma for tonalite considered as having formed by partial melting in an island arc, i...
| 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
1987
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| Online Access: | http://dx.doi.org/10.1139/e87-104 http://www.nrcresearchpress.com/doi/pdf/10.1139/e87-104 |
| Summary: | The Coney Head Complex, White Bay, Newfoundland, comprises allochthonous plutonic rocks and deformed equivalents emplaced over the continental margin during the Ordovician Taconic Orogeny. A U/Pb zircon age of 474 + 2 Ma for tonalite considered as having formed by partial melting in an island arc, indicates that it crystallized in Arenig time. A microgranite dated by U/Pb (zircon + titanite) at 432 ± 2 Ma cuts the tonalite Inherited Proterozoic zircon in the microgranite indicates that the rock formed from magma generated in part by melting of continental crust or sediments derived from such crust. These relationships indicate that the microgranite was emplaced in Silurian time, after Ordovician transport of the tonalite above a continental substrate. |
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