A New Look at Northwind Ridge: Implications for the History of the Canada Basin
Notice bibliographique
Résumé
Researchers from the US and Canada are conducting collaborative seismic, multibeam, and sampling studies in the mostly ice-covered regions of the Canada Basin (CB) of the Arctic Ocean. Recently acquired data sets, together with older acoustic and coring data, yield new details about the stratigraphic and structural history of CB, particularly regarding its boundary with Northwind Ridge (NR). As previously interpreted, NR represents the eastern edge of a rifted, submerged continental block known as Chukchi Borderland. Gradients along the remarkably linear slope are generally between 10o and 30o, but can be locally as high as ~70o. Water depths across the ridge vary from ~1000 m to ~3800 m. The new data reveal perched half grabens within the escarpment, and numerous complex reflection packages, including at least one possible talus deposit. These deeper reflection packages continue east for ~ 100 km (off northern NR) to ~200 km (off central NR) beneath the oldest on-lapping deposits of CB. This continuity suggests that the shallow basement extending east of NR consists of rocks that may be similar to those on NR, but more highly stretched and therefore more deeply subsided. A low-amplitude positive gravity anomaly coincides with this inferred continental-basement remnant. The profound unconformity at the top of these oldest reflection packages is generally highly reflective, gently sloping, and low relief. This reflection character of basement changes abruptly to high-relief and minimally reflective adjacent to and beneath a distinctive curvilinear gravity low that extends most of the length of CB, previously interpreted as a possible seafloor spreading center. The transition in basement reflection character can be mapped on multiple seismic lines and may represent the basement expression of the final breakup position of the continent (west) to ocean (east) boundary. Two consequences of this possible buried and subsided continental-basement fragment are that (1) models of the opening of CB may not require complete closure and therefore (2) NR may not overlap the continental margin of northern Canada, a problem with previous reconstructions. The northeast orientation of NR is subparallel to the inferred orientation of a deeply buried graben complex that is characterized by a northeast-trending negative gravity anomaly and offset ~250 km to the east of NR. Three northeast-trending bathymetric ridges also occur in the Sever Spur area or CB. Although the ages of rifting for either NR or the deeply buried graben complex are not well constrained, their subparallel orientation suggests this northeast direction is a preferred tectonic fabric either inherited prior to or created during the rifting and opening of the basin.
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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 | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».