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TitlePlanform sinuosity of Proterozoic rivers: a craton to channel-reach perspective
AuthorIelpi, A; Ghinassi, M; Rainbird, R HORCID logo; Ventra, D
SourceFluvial meanders and their sedimentary products in the rock record; by Ghinassi, M (ed.); Colombera, L (ed.); Mountney, N P (ed.); Reesink, A J H (ed.); International Association of Sedimentologists, Special Publication 48, 2018 p. 81-118,
Alt SeriesNatural Resources Canada, Contribution Series 20180397
PublisherJohn Wiley & Sons, Ltd
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut; Northwest Territories
NTS76I; 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
AreaBanks Island; Canadian Arctic; Victoria Island; Coronation Gulf; Dolphin and Union Strait; Great Bear Lake; Scotland; Northern Highlands; Canada; United Kingdom of Great Britain and Northern Ireland
Lat/Long WENS-124.0000 -104.0000 74.0000 66.0000
Lat/Long WENS -6.5833 -4.5000 58.6667 56.8333
Subjectssedimentology; geophysics; paleodrainage; sinuosity; depositional environment; accretion; fluvial systems; fluvial processes; stream channels; channel flow parameters; meanders; remote sensing; satellite imagery; bedrock geology; lithology; sedimentary rocks; fluvial deposits; paleocurrents; vegetation; point bars; sedimentary structures; hydrographs; banks; Amundsen Basin; Minto Inlier; Brock Outlier; Duke of York Inlier; Cape Lambton Inlier; Elu Basin; Coppermine Homocline; Laurentia; Kuujjua Formation; Shaler Supergroup; Nelson Head Formation; Rae Group; Applecross Formation; Torridon Group; Bay of Stoer Formation; Stoer Group; Ellice Formation; Elu Basin Group; paleodrainage directions; alluvial bars; Precambrian; Proterozoic
Illustrationsschematic representations; satellite images; plots; tables; sketches; models; location maps; stratigraphic charts; photographs; cross-sections; rose diagrams; pie charts; histograms; flow charts
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Shield to Selwyn
Released2018 11 26
AbstractLacking 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.

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