The continental shelf and rifted continental margins of offshore Newfoundland revisited using constrained 3-D gravity inversions: tracking inheritance trends and rift scars
Notice bibliographique
Résumé
<p>The rifted continental margins of Newfoundland represent one of the best-studied examples of non-volcanic/magma-poor margins in the world. In addition to hosting proven prolific resources within the rift basins on the continental shelf, the rifted margins also host many promising frontier regions for oil and gas exploration in both the Flemish Cap and Orphan basins. Prior to rifting and opening of the North Atlantic Ocean during the breakup of Pangaea, the Newfoundland margins lay conjugate to the Iberian margin to the southeast and the Irish Atlantic margin to the northeast. Rifting and breakup evolved from south to north during three rift phases of varying orientation: NW-SE oriented Late Triassic-Early Jurassic rifting between Iberia/Eurasia and North America, W-E oriented Late Jurassic to Early Cretaceous rifting between Eurasia (Ireland) and North America, and SW-NE oriented Late Cretaceous rifting in the Labrador Sea. While the first phase of rifting exploited pre-existing Caledonian-Appalachian basement structures and tectonic fabrics, later rifting reactivated and crosscut these same inherited structures.</p><p>While multichannel seismic reflection imaging has been extensively undertaken across the Newfoundland shelf and rifted margins, deep crustal structure from seismic refraction profiling has been more sparsely constrained. To interpolate between existing crustal-scale seismic refraction profiles, constrained 3-D gravity inversion has previously been undertaken, providing regional constraints on Moho depth, crustal thickness, and beta factors. However, these early inversion attempts suffered from coarse parameterizations of densities within the sedimentary column and an inability to incorporate sparse deep seismic constraints. In this work, we present 3-D density anomaly models for the crust and upper mantle across the Newfoundland margin using constrained 3-D gravity inversions performed using two independent inversion methodologies (minimum structure and probabilistic). Common features to both inversions are deemed robust and provide an improved regional view of the crustal architecture of the offshore margins. In particular, crustal thinning is observed to align with earlier projections of ancient terrane boundaries such as the boundary between the Avalonian terrane and the Meguma terrane at the southeastern limit of the Grand Banks. Furthermore, the derived crustal thicknesses also provide a clear means of delimiting rafted continental fragments, revealing rift trends and the resulting crustal scars. This is particularly evident for the Orphan Basin where the southeastward rotation and displacement of the Flemish Cap has left a trail of orphaned continental pieces. These form crucial components for future deformable plate reconstructions in GPlates and, until then, provide a detailed regional view of the segmentation of the margin during rifting.</p>
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».