| Titre | Linking clinoform trajectory analysis and sequence stratigraphy: improved stratigraphic understanding of the Labrador margin, offshore eastern Canada |
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| Auteur | Dafoe, L T ;
Dickie, K; Williams, G L |
| Source | GAC-MAC-IAH-CNC-CSPG, Halifax 2022; 2022 p. 79  Accès
ouvert |
| Liens | Online - En ligne (Complete volume - volume complet,
PDF, 7.43 MB
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| Image |  |
| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210585 |
| Éditeur | Association géologique du Canada |
| Réunion | GAC-MAC-IAH-CNC-CSPG, Halifax 2022; Halifax, NS; CA; mai 15-18, 2022 |
| Document | publication en série |
| Lang. | anglais |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Région extracotière de l'est; Terre-Neuve-et-Labrador |
| SNRC | 3; 13; 14; 15 |
| Région | Labrador |
| Lat/Long OENS | -63.0000 -54.0000 63.0000 53.0000 |
| Sujets | stratigraphie systématique; morphologie; paléoenvironnement; lithostratigraphie; antecedents de sedimentation; antécédents tectoniques; Bassin d'Hopedale ; Bassin de Saglek ; Formation de Markland ;
Formation de Cartwright ; Membre de Gudrid ; Formation de Kenamu ; Formation de Mokami ; stratigraphie; sédimentologie; Sciences et technologie; Nature et environnement; Phanérozoïque; Cénozoïque; Tertiaire; Mésozoïque; Crétacé |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Région de Baffin |
| Diffusé | 2022 05 15 |
| Résumé | (disponible en anglais seulement)
The concept of a clinoform has been around for decades, but has received renewed attention in its application to stratigraphic studies. These morphological
features develop in different depositional settings, including shorelines, subaqueous deltas, and shelf-edges, with a clinothem corresponding to the body of rock bounded by successive clinoforms. The passive margin of Labrador began forming during
rifting in the Cretaceous, with subsequent seafloor spreading starting in the Maastrichtian and ceasing in the earliest Oligocene. The resultant stratigraphic record includes a number of Late Cretaceous through Pleistocene clinothem units that we
have identified and mapped. Focusing on the Hopedale Basin, where sufficient well and seismic data exist, we combined paleoenvironmental interpretations, biostratigraphic constraints, and seismic data to produce paleogeographic maps and seismic
profiles that delineate seven shoreline, five subaqueous delta, one shelf-edge, and three shelf-edge delta clinothems. Changes in paleoenvironments and clinoform trajectories (relative lateral and vertical movements) were used to define eight
second-order sequences, which allowed for refinements to the Labrador margin lithostratigraphic column and to an improved understanding of tectonic, eustatic, and climatic influences throughout the region's depositional history. Upper Cretaceous
shoreline clinothems of the Freydis Member (Markland Formation) developed during late rift and characterize lowstand and highstand intervals. Subsidence occurred at this time, but a global sea level low in the Cenomanian-Turonian was also likely a
major factor during regression. The Gudrid Member (Cartwright Formation) represents a forced regressive and lowstand interval during the Paleocene to Early Eocene, tied to seafloor spreading, a Selandian eustatic low, and sediment supply driven by
the Paleocene-Eocene Thermal Maximum. Kenamu Formation shales represent a major transgression of the margin in the Early Eocene, with a small shoreline clinothem developed during stillstand. Subsequent Middle Eocene regression formed the Leif Member
shoreline clinothem and associated subaqueous delta and shelf-edge clinoforms, with the Middle Eocene Climatic Optimum possibly contributing to enhanced sediment influx. Subtle subaqueous delta clinothems developed in the Late Eocene and Early
Oligocene within the Mokami Formation during highstand conditions. The Saglek Member of this formation includes three shelf-edge delta clinoform units developed during falling stage and lowstand conditions, and were influenced by the Oi2 glaciation
and global sea level fall in the Oligocene, the Miocene Climate Optimum, and Pliocene-Pleistocene Northern Hemisphere glaciation. This study demonstrates the utility of integrating clinoform trajectory and sequence stratigraphy analyses at
second-order scale on a margin that underwent several major regressive and transgressive events. |
| Sommaire | (Résumé en langage clair et simple, non publié)
La marge extracôtière du Labrador s'est formée durant l'expansion de la plaque tectonique qui a débuté au Crétacé, laquelle a entraîné un
amincissement de la croûte continentale, la formation de points de sédimentation maximum où les roches sédimentaires se sont accumulées, et à terme, la formation de la mer du Labrador. La présente étude se penche sur la nature de la stratigraphie,
c'est-à-dire des couches de roches qui se sont accumulées au fil du temps, au moyen de la cartographie des clinoformes, des entités semblables à celles qui se forment dans les deltas créés par la rencontre de fleuves et du milieu océanique. Les
mouvements de ces clinoformes vers le centre du bassin océanique et vers le continent indiquent des régressions et des transgressions importantes de la marge continentale au fil du temps et peuvent être associés à un cadre de stratigraphie
séquentielle. Ces indications permettent une nouvelle compréhension des couches rocheuses au large du Labrador, un cadre qui sera précieux lors d'études subséquentes et de futures activités de prospection de ressources énergétiques et minérales le
long de la marge. |
| GEOSCAN ID | 329503 |
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