| Titre | Zircon fission-track ages from Newfoundland-A proxy for high geothermal gradients and exhumation before opening of the Central Atlantic Ocean |
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| Auteur | Willner, A P; Thomson, S N ; Glodny, J; Massonne, H J; Romer, R L; van
Staal, C R; Zagorevski, A |
| Source | Terra Nova vol. 31, 1, 2018 p. 1-10, https://doi.org/10.1111/ter.12361 |
| Image |  |
| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200283 |
| Éditeur | Wiley |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1111/ter.12361 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Terre-Neuve-et-Labrador |
| SNRC | 1M; 1N/03; 1N/04; 1N/05; 1N/06; 1N/11; 1N/12; 1N/13; 1N/14; 11O/01; 11O/02; 11O/07; 11O/08; 11O/09; 11O/15; 11O/16; 2C; 2D; 2E; 2F; 2L; 2M; 12A; 12B; 12G; 12H; 12I; 12J; 12N; 12O |
| Lat/Long OENS | -59.0000 -53.0000 52.0000 47.0000 |
| Sujets | zircon; gradient géothermique; orogenèse; roches métamorphiques; traces de fission; datations par traces de fission; Trias supérieur; géochronologie; Sciences et technologie; paléontologie;
Trias |
| Illustrations | cartes de localisation; graphiques; histogrammes; tableaux |
| Diffusé | 2018 10 09 |
| Résumé | (disponible en anglais seulement)
Following Appalachian orogenesis, metamorphic rocks in central Newfoundland were exhumed and reburied under Tournaisian strata. New zircon fission-track (ZFT)
ages of metamorphic rocks below the Tournaisian unconformity yield post-depositionally reset ages of 212-235 Ma indicating regional fluid-absent reheating to at least >= 220 degrees C. Post-Tournaisian sedimentary thicknesses in surrounding basins
show that burial alone cannot explain such temperatures, thus requiring that palaeo-geothermal gradients increased to >= 30-40 degrees C/km before final late Triassic accelerated cooling. We attribute these elevated palaeo-geothermal gradients to
localized thermal blanketing by insulating sediments overlying radiogenic high-heat-producing granitoids. Late Triassic rifting and magmatism before break up of Pangaea likely also contributed to elevated heat flow, as well as uplift, triggering late
Triassic accelerated cooling and exhumation. Thermochronological ages of 240-200 Ma are seen throughout Atlantic Canada, and record rifting and basaltic magmatism on the conjugate margins of the Central Atlantic Ocean preceding the onset of oceanic
spreading at similar to 190 Ma. |
| GEOSCAN ID | 326695 |
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