| Titre | Planform sinuosity of Proterozoic rivers: a craton to channel-reach perspective
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| Auteur | Ielpi, A; Ghinassi, M; Rainbird, R H ; Ventra, D |
| Source | Fluvial meanders and their sedimentary products in the rock record; par Ghinassi, M (éd.); Colombera, L (éd.); Mountney, N P (éd.); Reesink, A J H (éd.); International Association of Sedimentologists,
Special Publication 48, 2018 p. 81-118, https://doi.org/10.1002/9781119424437.ch4 |
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| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20180397 |
| Éditeur | John Wiley & Sons, Ltd |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1002/9781119424437.ch4 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Nunavut; Territoires du Nord-Ouest |
| SNRC | 76I; 76J; 76K; 76L; 76M; 76N; 76O; 76P; 77; 78B; 78C; 86I; 86J; 86K; 86L; 86M; 86N; 86O; 86P; 87; 88A; 88B; 88C; 88D; 96I; 96J; 96O; 96P; 97A; 97D; 97H; 98A; 98D |
| Région | Banks Island; Canadian Arctic; Victoria Island; Coronation Gulf; Dolphin and Union Strait; Grand lac de l'Ours; Scotland; Northern Highlands |
| Lat/Long OENS | -124.0000 -104.0000 74.0000 66.0000 |
| Lat/Long OENS | -6.5833 -4.5000 58.6667 56.8333 |
| Sujets | paléodrainage; sinuosité; milieu sédimentaire; accretion; systèmes fluviaux; processus fluviaux; chenals de cours d'eau; paramètres d'écoulement canalisé; méandres; télédétection; imagerie par satellite;
géologie du substratum rocheux; lithologie; roches sédimentaires; dépôts fluviaux; paléocourants; végétation; bancs arqués; structures sédimentaires; hydrographes; bancs; Bassin d'Amundsen ; Bassin d'Elu ; Laurentie; Formation de Kuujjua ;
Supergroupe de Shaler ; Formation de Nelson Head ; Groupe de Rae ; Formation d'Applecross ; Groupe de Torridon ; Formation de Bay Of Stoer ; Groupe de Stoer ; Formation d'Ellice ; directions du paléodrainage; barres alluviales; sédimentologie;
géophysique; Précambrien; Protérozoïque |
| Illustrations | représentations schématiques; images satellitaires; graphiques; tableaux; croquis; modèles; cartes de localisation; diagrammes stratigraphiques; photographies; coupes transversales; graphiques en
étoile; diagrammes à secteurs; histogrammes; organigrammes |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Bouclier à Selwyn du corridor de Mackenzie |
| Diffusé | 2018 11 26 |
| Résumé | (disponible en anglais seulement)
Lacking evidence for fluvial lateral?accretion elements in early Palaeozoic systems has been ascribed to an absence of binding by rooted vegetation on subaerial
landscapes. Transposing this thesis to earlier geological times, it has been proposed that, likewise, Precambrian landscapes could not have sustained highly sinuous fluvial networks. This paradigm has been hardly ever tested for the Proterozoic, a
shortcoming addressed here through review of selected outcrop data and remote sensing of modern sinuous channel?flow configurations. Five sedimentary rock units deposited on Laurentia between 1.6 to 0.7 Ga record diverse palaeogeographic and tectonic
settings and yield evidence of lateral accretion and planform sinuosity in fluvial channels over a full range of developmental stages. In the absence of vegetation, multiple processes interacted at craton to channel?reach scales, setting conditions
favourable for self?sustained lateral accretion and thus sinuosity. Discharge modulation in perennial channels is interpreted to have had an overriding role, owing to craton?scale catchments capable of sustaining year?round flows or favourable
climate settings. Steady sediment supply and local channel?bank strengthening limited braiding, allowing for narrow hydraulic profiles with flow configurations favourable to lateral accretion. Less than 15% of current literature on Proterozoic
fluvial rocks reports reliable directional data on palaeoflows and stratal accretion, a bias that undermines literature compilations aimed at gauging the relevance or insignificance of pre?vegetation lateral accretion. Fluvial deposits aggraded on
unvegetated landmasses prior to the late Ordovician can only be assessed when comprehensive information on palaeoflow and bar accretion becomes available. The authors thus underline that a lack of evidence for early Palaeozoic lateral-accretion sets
should not be used to support the inference that meandering fluvial planforms were a rare occurrence in earlier geological times. |
| GEOSCAN ID | 313622 |
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