U-Pb and Lu-Hf LA-ICP-MS detrital zircon and structural investigations in the Abitibi subprovince, Canada, with implications for Archean geodynamic processes and deformation behavior along gold-bearing, crustal-scale faults
Notice bibliographique
Résumé
This work presents investigations based in the south-central Abitibi subprovince of Ontario and Quebec, Canada, which place constraints on a sequence of Neoarchean geodynamic and structural processes, including crustal growth and amalgamation with the rest of the Superior Province, and the formation of orogenic gold deposits along regional deformation zones.Archean geodynamic processes were primarily investigated by multi-isotope U-Pb and Lu-Hf laser ablationinductively coupled plasmamass spectrometry (LA-ICP-MS) analysis of detrital zircon grains from successor basins.Three temporally distinct successor basin groups are recognized: the ~2690-2685 Ma Porcupine assemblage, the ~2685-2682 Ma Pontiac subprovince, and the ~2680-2670 Ma Timiskaming assemblage.All samples contain abundant Neoarchean grains (~85-95% of the individual sample populations), while the remaining grains yielded Mesoarchean ages.The Neoarchean grains likely reflect predominately local sources.Since no Mesoarchean rocks occur in the Abitibi and Pontiac subprovinces, and based on comparison with published zircon ages from the Superior Province,Mesoarchean grains are interpreted as derived from an orogenic hinterland to the NNW that developed during regional amalgamation.The older Porcupine assemblage contains ~5% Mesoarchean zircon, while Pontiac subprovince and Timiskaming assemblage samples contain ~18% and ~13%, respectively.This suggests hinterland sources were more prevalent during the late stages of collision, probably as a result of progressive uplift and denudation of the hinterland.The paired Lu-Hf isotopic analyses support this interpretation of provenance and further indicate that the majority of grains (~96%) have compositions consistent with derivation from a modern MORB depleted mantle (mMORB-DM) reservoir.This occurrence of mMORB-DM-like signatures in detrital zircon grains that were sourced from multiple disparate crustal domains suggests that a modern-style depleted mantle reservoir was not only well established, but widely occurring by the Mesoarchean.The observed pattern of lateral accretion of crustal domains that grew from a mMORB-DM-like reservoir, the transport of detritus across terrane boundaries, and the progressive uplift and denudation of a hinterland are most consistent with the operation of plate tectonic processes during Neoarchean construction and amalgamation of the southern Superior Province.During the late stages of accretion, deformation became increasingly localized along regionally extensive, crustal-scale fault zones, including the Larder Lake Cadillac deformation zone (LLCdz) in the Kirkland Lake area of Ontario.New field mapping and map compilation indicates that a series of spaced brittle-ductile deformation zones occur in a broad, >6 km area to the north of the LLCdz.Detailed structural mapping and analysis further indicate that the location of late-stage brittle-ductile deformation, fluid flow, and iv gold mineralization was likely controlled by early brittle deformation zones characterized by breccia.Therefore, undiscovered gold deposits may be hosted by deformation zones farther from the LLCdz than previously recognized and that fault-related breccia bodies may provide an indicator for nearby prospective structures in both the Kirkland Lake area and in similar structural settings of all ages, worldwide.
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 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| 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 ».