Kinematics, age of deformation, and regional significance of the Cayoosh Creek fault, Lillooet, British Columbia
Notice bibliographique
Résumé
The Cayoosh Creek fault, located in the eastern Coast Belt of the Canadian Cordillera, is a low-angle fault truncated by the Marshall Creek fault to the east and the Phair Creek fault to the west. The Marshall Creek and Phair Creek faults are associated with the regionally significant Yalakom and Fraser-Straight Creek fault systems. The upper plate of the Cayoosh Creek fault contains Mississippian to lower Middle Jurassic units of the Bridge River Complex which overlie Middle Jurassic to Lower Cretaceous rocks of the Cayoosh Assemblage. The hangingwall is typically prehnite-pumpellyite to lower greenschist facies, whereas footwall rocks record mid- to upper greenschist grade metamorphism. While the older-over-younger relationship implies contraction, the juxtaposition of low over high metamorphic grade suggests normal faulting. This study seeks to associate the kinematic history and age of deformation of the Cayoosh Creek fault with that of the regional fault systems. Three phases of deformation have been documented in the study area. D1 is represented by related southwest vergent isoclinal folds and foliation (S1). A shallow northeast-dipping mylonitic foliation (S2), and northwest-trending folds and lineations define D2. Peak metamorphism during D2 is constrained to 500°-550° C and 1.8-2.9 kilobars. Steep to upright axial planes of northwest-southeast trending open and gentle folds define a possible third deformational event (D3). Zircons from a post-kinematic dike, a D2 synkinematic dike, and locally deformed granite were dated using U-Pb radiogenic isotopes. Results yielded ages of 47.0 +/- 0.2 Ma, 47.8 +/- 0.1 Ma, and 48.8 +/- 0.1 Ma respectively. The D1 fabrics record mid-Cretaceous (?) southwest-directed contraction and emplacement of Bridge River Complex over Cayoosh Assemblage. The penetrative D2 fabrics are the result of 10-12 kilometers of top-towards the northwest extension on the Cayoosh Creek fault. D2 largely occurred between 48.8-47.0 Ma, but may have commenced earlier. D3 fabrics may have been related to progressive D2 deformation. The Cayoosh Creek fault is integrally related to the dextral strike-slip fault systems on the Coast Belt- Intermontane Belt boundary. Orogen-parallel extension and translation were the dominant means of accommodation during Early to Middle Eocene oblique-convergence on the plate margin. The Cayoosh Creek fault—as well as the Tatla Lake metamorphic complex, Mission Ridge area, and Ross Lake shear zone—lies within a belt of high metamorphic grade and low-angle ductile deformation that coincides with the axis of the Eocene magmatic arc. The likely cause of regional extension was gravitational collapse of an overthickened and thermally weakened crust, and a shift in relative plate motions. Significant deformation on the Cayoosh Creek fault had diminished by 47.0 Ma but regional strike-slip faulting in the arc-axial belt continued into the Oligocene. [Scientific formulae used in this abstract could not be reproduced.]
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,000 |
| 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 ».