| Titre | Pliocene landscape evolution inferred from the Iperk Sequence, offshore Banks Island, NWT |
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| Auteur | Stashin, S; Gosse, J; Smith, I R ; Csank, A |
| Source | ArcticNet, ASM2019 Annual Science Meeting: abstracts/ArcticNet, ASM2019 Réunion scientifique annuelle : abstracts/ArcticNet, ASM2019 Annual Science Meeting: abstracts; 2019 p. 248-249  Accès ouvert |
| Liens | Online - En ligne (complete volume - volume complet, PDF, 2.80
MB)
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| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190315 |
| Éditeur | ArcticNet |
| Réunion | ASM2019 - ArcticNet Annual Science Meeting; Halifax, NS; CA; décembre 2-5, 2019 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Territoires du Nord-Ouest; Région extracotière du nord |
| SNRC | 98 |
| Région | Banks Island |
| Lat/Long OENS | -141.0000 -124.0000 76.0000 71.0000 |
| Sujets | Holocène; Pléistocène; Néogène; Pliocène; Miocène; antécédents géologiques; érosion; antecedents de sedimentation; paléoclimats; paléoenvironnement; milieu sédimentaire; marges continentales; plate-forme
continentale; levés géophysiques; levés sismiques marins; levés de reflexion sismiques; échantillons carrotés; lithostratigraphie; corrélations stratigraphiques; interpretations structurelles; Séquence d'Iperk ; Formation de Beaufort ; Archipel
Arctique Canadien; Bassin de Canada ; géologie marine; sédimentologie; stratigraphie; géologie structurale; géophysique; Sciences et technologie; Nature et environnement; Phanérozoïque; Cénozoïque; Quaternaire; Tertiaire |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux L'ouest de l'Arctique-Beaufort-nord du Yukon |
| Diffusé | 2019 12 01 |
| Résumé | (disponible en anglais seulement)
During the Pliocene (5.3-2.6 Ma), global mean surface temperatures were approximately 2°C warmer than present. However, Arctic Pliocene local mean annual
temperatures were at least 22°C warmer than today, due to a shallower latitudinal temperature gradient. We hypothesize that a thick Miocene-Pliocene regolith was readily available for erosion during global cooling in the Piacenzian, which lead to a
Pan-Arctic mobilization and deposition of quartz-rich sand. The mostly Pliocene Beaufort Formation (BFm) provides a well-preserved record of dramatic landscape change during that subtle (2°C) global cooling. Today the BFm outcrops along the western
Canadian Arctic Archipelago where fluvial deposits formed a contiguous coastal plain and westward thickening (up to 3 km) clastic wedge across the continental shelf and into the Canada Basin. The Miocene-Holocene Iperk Sequence (IpS), interpreted in
seismic data and identified in marine petroleum exploration cores from the Beaufort Sea shelf, contains some fluvial and marine sediments that may be coeval with the BFm. Quantifying how these northern landscapes respond to large-scale climate
deterioration is critical to understanding the first-order controls on sediment flux and regional marine alkalinity. For the first time, a lithostratigraphic correlation of the onshore-offshore stratigraphy has been achieved using newly available
climatological and chronological constraints to help evaluate the scale of landscape response to the Piacenzian climate change. Distinct geophysical facies and unconformities observed in high resolution marine seismic reflection data from ION
Geophysical Technologies form the basis for subdividing the IpS into five Pliocene sub-units and a Pleistocene-Holocene sequence. The sub-unit volume changes appear to scale with contemporaneous onshore catchment-wide average erosion rates observed
in BFm and equivalent onshore units. Our results also indicate that Pliocene shorelines lie between 30 and 90 km offshore from Banks Island. Furthermore, there is no evidence of coastline-parallel faulting in M'Clure Strait which supports the
hypothesis that at least some waterways of the Northwest Passage may have been climatogenic (owing to fluvial and glacial incision) instead of tectonogenic grabens. We discuss the implications of these data in relation to major transgressive
sequences and landscape evolution during a period of significant climate change. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette recherche examine les enregistrements sismiques extracôtiers de l'île Banks comme moyen d'interpréter les changements climatiques et
environnementaux survenus au cours d'une période de changements climatiques rapides dans l'Arctique canadien, dus aux conditions chaudes du Pliocène (il y a 5,3 à 2,6 millions d'années) et aux conditions plus fraîches du Pléistocène. (moins de 2,6
millions d'années) et l'apparition des premières glaciations. |
| GEOSCAN ID | 321058 |
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