| Titre | Early Carboniferous syn-rift sedimentation in the Sverdrup Basin (Yelverton Pass area, northern Ellesmere Island, Arctic Canada): a solution to the Okse Bay problem |
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| Auteur | Beauchamp, B; Alonso-Torres, D; Piepjohn, K; Thériault, P; Grasby, S E |
| Source | Circum-Arctic structural events: tectonic evolution of the Arctic margins and trans-Arctic links with adjacent orogens; par Piepjohn, K (éd.); Strauss, J V (éd.); Reinhardt, L (éd.); McClelland, W C
(éd.); Geological Society of America, Special Paper vol. 541, 2018 p. 1-30, https://doi.org/10.1130/2018.2541(13) |
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| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20170173 |
| Éditeur | Geological Society of America |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1130/2018.2541(13) |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| SNRC | 340C/09; 340C/10; 340C/15; 340C/16; 340D/05; 340D/06; 340D/10; 340D/11; 340D/12; 340D/13; 340D/14; 340D/15; 340E/02; 340E/03; 340E/04; 340E/05; 340F/01; 340F/02; 340F/08 |
| Région | Yelverton Pass; île d'Ellesmere; Canadian Arctic Archipelago |
| Lat/Long OENS | -83.0000 -75.2000 82.3333 81.3333 |
| Sujets | Carbonifère inférieur; stratigraphie systématique; palynologie systématique; antécédents géologiques; antécédents tectoniques; décrochement horizontal; antecedents de sedimentation; sédimentation;
affaissement; intrusions; bassins; evolution du bassin; clastes; faciès clastiques; lithofaciès; lithologie; origine; roches mères; régions émettrices; transport des sediments; dispersion des sédiments; micropaléontologie; microfossiles; palynologie;
palynomorphes; datation radiométrique; datation au uranium-plomb; datations au zircon; géologie du substratum rocheux; caractéristiques structurales; failles; fosses d'effondrement; géologie du socle; lithostratigraphie; corrélations
stratigraphiques; paléogéographie; Bassin de Sverdrup ; Formation de Borup Fiord ; Formation d'Okse Bay ; Orogène Ellesmerien; Laurentie; Orogène Franklinien; Bassin Franklinien; Formation de Canyon Fiord ; Formation de Nansen ; Formation d'Otto
Fiord ; Formation d'Emma Fiord ; Formation d'Hare Fiord ; Formation de Belcher Channel ; Orogenèse d'Eurekan ; stratigraphie; tectonique; sédimentologie; paléontologie; géochronologie; géologie structurale; Phanérozoïque; Paléozoïque; Carbonifère;
Pennsylvanien; Mississippien; Dévonien |
| Illustrations | cartes géolscientiques généralisées; cartes de localisation; diagrammes; coupes transversales; tableaux; photographies; histogrammes; graphiques; corrélogrammes; modèles 3D |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Terrane Pearya, Ellesmere nord de l'ouest de l'Arctique |
| Diffusé | 2018 12 21 |
| Résumé | (disponible en anglais seulement)
The unit previously mapped as the lower Upper Devonian Okse Bay Formation in the Yelverton Pass area of northern Ellesmere Island, considered indicative of
syn-orogenic foreland (Devonian clastic wedge) basin deposition along the apex of the Ellesmerian Orogen, is in fact Early Carboniferous (Serpukhovian) in age and belongs to the Borup Fiord Formation of the successor Sverdrup Basin. The principal
lines of evidence in favor of the original Okse Bay formational assignment were: (1) the presence of late Middle (Givetian) or early Late (Frasnian) Devonian palynomorphs; (2) a set of lithofacies presumably different from that of the Borup Fiord
Formation; and (3) an angular unconformity between the so-called Okse Bay strata and overlying Pennsylvanian carbonates of the Nansen Formation. Here we demonstrate that the Devonian palynomorphs were eroded from the Devonian clastic wedge,
transported for some distance, and deposited into the Sverdrup Basin in the Early Carboniferous. We also show that the units mapped as Okse Bay and Borup Fiord formations share the same clastic lithofacies assemblages, albeit in different
proportions. We report the presence of Early Carboniferous palynomorphs in the uppermost part of a section assigned to the Okse Bay Formation, and show that detrital zircons contained in the middle part of the Okse Bay Formation yield dates as young
as 358 Ma, thus demonstrating that the rocks that contain them are considerably younger than the assumed youngest age (Frasnian) based on palynology. We conclude that the Okse Bay Formation is the same unit as the Borup Fiord Formation and should be
remapped as such. Both units are part of the same unconformity-bounded syn-rift Serpukhovian sequence that was rotated and differentially eroded prior to the widespread Pennsylvanian transgression.
The Serpukhovian sequence comprises three
lithofacies assemblages: meandering stream clastic, braided stream/alluvial fan clastic, and shallow marine carbonate. These lithofacies assemblages were deposited as part of a differentially subsiding rift system likely bounded to the south by one
or more master listric faults and associated footwall uplift, and to the north by hanging wall ramp uplift. The Serpukhovian sequence comprises three fourth-order sequences, each interpreted as corresponding to a rift pulse. Relatively coarse
terrigenous sediments derived from the erosion of the Franklinian basement (Laurentia margin) and the Devonian clastic wedge entered the rift basin at a high angle through broad alluvial fans and braided river systems. These streams fed into a
NE-flowing basin-axial meandering system, which met a shallow sea to the northeast. An additional source of sediments is Crockerland to the north, including syn- to post-Ellesmerian intrusions that shed detrital zircons of latest Devonian age once
sufficient unroofing of these had occurred during the Serpukhovian. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Ces travaux examinent l'âge des unités géologiques dans le nord de l'île d'Ellesmere et soutiennent que l'âge qu'on leur avait attribué
jusqu'ici est erroné. Les conséquences de ce changement sont les suivantes : 1) les cartes géologiques de la région doivent être révisées pour que la géologie de la région soit exacte et 2) ces résultats indiquent qu'il faut procéder à une nouvelle
corrélation circumarctique pour évaluer l'âge des unités similaires. Ces résultats pourraient aussi changer le modèle actuel au sujet des débuts de la formation du bassin Sverdrup, importante région pétrolifère du Canada. |
| GEOSCAN ID | 305831 |
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