Effects of peat on the shapes of alluvial channels: examples from the Cumberland Marshes, Saskatchewan, Canada

Smith, Norman D.; Pérez‐Arlucea, Marta

doi:10.1016/j.geomorph.2004.01.006

Cited by 27 publications

(21 citation statements)

References 20 publications

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“…Specifically, the presence of a well-vegetated floodplain, levees, organicrich deposits, and abundant splays suggests that this fluvial system resembled Nanson and Knighton's (1996) Type 1B organo-clastic fluvial system. These bodies are similar to ancient anastomosed river deposits in the Joggins Formation (Falcon-Lang et al 2004;Rygel and Gibling 2006), St. Mary's River Formation (Nadon 1994), and Willwood Formation (Kraus and Gwinn 1997), as well as modern anastomosed river systems in Canada and Australia (Smith and Putnam 1980;Gibling et al 1998;Smith and Pérez-Arlucea 2004).…”

Section: Descriptionsupporting

confidence: 54%

The Pennsylvanian Springhill Mines Formation: sedimentological framework for a portion of the Joggins Fossil Cliffs UNESCO World Heritage Site

Rygel

Sheldon

Stimson

et al. 2014

atgeol

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This is the first detailed study of the coastal exposure of the Springhill Mines Formation within the Joggins Fossil Cliffs World Heritage Site. A 16.9-m-thick interval of dark laminated mudrocks and sharpbased sandstones at the base of our section is reassigned to the top of the Joggins Formation. This interval records a rapid, presumably widespread flooding event and the temporary establishment of a marginalmarine to brackish bay. The overlying 697 m of strata represent deposition in poorly drained and well-drained environments, and are assigned to the Springhill Mines Formation. Strata reflecting poorly drained environments contain green and grey mudrocks, thin coals, sheet sandstones, and channel bodies interpreted to have been deposited in coastal swamps and low-lying parts of a floodplain. Intervals reflecting well-drained conditions contain reddish brown mudrocks, sheet sandstones, and channel bodies interpreted to have been deposited on a vegetated floodplain that was periodically exposed to oxidizing conditions. Strata reflecting poorly drained conditions are thick and abundant in the lower half of the formation and well-drained intervals become thick and more abundant in the upper half. The shift in facies abundance is accompanied by an interpreted evolution in fluvial style from predominantly anastomosed channels (below 376 m) to sheet-like channel bodies (376-449 m) and ultimately to predominantly meandering-channel bodies (449-697 m). The formation-scale changes in drainage conditions and fluvial style records decreased halokinetic subsidence and aggradation of the alluvial surface as sediments shed from the Caledonia Highlands prograded into this part of the basin. rÉSUMÉ Il s'agit de la première étude détaillée sur l' exposition du littoral de la formation de Springhill Mines au sein du site du patrimoine mondial des falaises fossilifères de Joggins. Un intervalle de 16,9 m d' épaisseur de pélites feuilletées foncées et de grès à base nette situé au bas de la section a été rattaché au sommet de la formation de Joggins. Cet intervalle est le résultat d'une inondation rapide et probablement de grande envergure ainsi que de la formation temporaire d'un marginal marin dans une baie saumâtre. La couche sous jacente de 697 m de strate représente un dépôt dans des milieux mal drainés et bien drainés. Ces milieux se trouvent dans la formation de

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Section: Descriptionsupporting

confidence: 54%

The Pennsylvanian Springhill Mines Formation: sedimentological framework for a portion of the Joggins Fossil Cliffs UNESCO World Heritage Site

Rygel

Sheldon

Stimson

et al. 2014

atgeol

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“…There are other possible mechanisms as well. One is differential compaction beneath paired levees (van Asselen and Stouthamer, 2008), especially since most of the avulsion belt overlies easily compacted peat deposits representing the floodplain surface prior to the 1870s avulsion (Smith et al, 1989;Morozova and Smith, 2003;Smith and Pérez-Arlucea, 2004). Another possibility is the varied erosional and depositional effects of ice drives and ice jams on channel and floodplain morphology (Smith, 1979(Smith, , 1980Smith and Pearce, 2002), which have occurred frequently in the Saskatchewan River, though have become less effective in recent years due to effects of hydroelectric power dams.…”

Section: Discussionmentioning

confidence: 99%

Elevation adjustments of paired natural levees during flooding of the Saskatchewan River

Smith

Pérez‐Arlucea

Edmonds

et al. 2009

Earth Surf Processes Landf

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Natural levees control the exchange of water between an alluvial channel and its floodplain, but little is known about the spatial distribution and evolution of levee heights. The summer 2005 flood of the Saskatchewan River (Cumberland Marshes, east-central Saskatchewan) inundated large areas of floodplain for up to seven weeks, forming prominent new deposits on natural levees along main-stem channels. Measurements of flood-deposit thickness and crest heights of 61 levee pairs show that the thickest deposits occur on the lower pre-flood levee in 80% of the sites, though no clear relationship exists between deposit thickness and magnitude of height difference. Only 16% of the pairs displayed thicker deposits on the higher levee, half of which occurred at sites where relatively clear floodbasin waters re-entered turbid channels during general flooding. Difference in crest elevation (ΔE) between paired levees is approximately log-normally distributed, both before and after the flood, though with different mean values. Supplemental observations from tank experiments indicate that during near-bankfull flows, temporally and spatially variable deposition and erosion occur on levees due to backwater effects associated with nearby channel bars and irregular rises of the channel bed forced by channel extension. During floods, preferential deposition in lows tends to even out crest heights. Figure 6. Plot of pre-flood versus post-flood ΔE showing tendency for thicker flood deposits to occur on lower levees and overall reduction of ΔE (i.e. most points lie above line of equality). Only 10 sites show thickest deposits on the higher levee, five of which occurred where turbid flood water overlaid only one levee due to channelward intrusion of clear water from the adjacent floodbasin (circled dots).

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“…The Muskeg Lake splay (indicated with a star) was initiated around 1953. The upstream part of the 1870s avulsion belt has changed little since 1982 (Smith and Pérez-Arlucea, 2004). GC, Gun Creek; MR, Mossy River; OC, Old Channel.…”

Section: Regional Settingmentioning

confidence: 99%

Depositional development of the Muskeg Lake crevasse splay in the Cumberland Marshes (Canada)

Toonen

Asselen

Stouthamer

et al. 2015

Earth Surf Processes Landf

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Crevasse splays are common geomorphological features in alluvial and deltaic floodplains. Although crevasse splays can develop into full avulsions, thereby transforming large areas of floodbasins, little is known about their sedimentary and geomorphological development at the decadal scale and their avulsion potential. We used aerial photography and lithological cross‐sections to reconstruct crevasse‐splay formation in the largely unmanaged floodplain of the Saskatchewan River in the Cumberland Marshes (Saskatchewan, Canada). Based on surface geomorphology and subsurface deposits, various stages of crevasse‐splay development were described which were linked to both external forcing and internal morphodynamics. Initial splay deposition, following a levee breach during a large flood, occurred as a broad but relatively thin sandy sheet in a down‐basin direction in the receiving backswamp area. In a next phase, these primary crevasse‐splay deposits blocked local down‐basin flow, thereby forcing the crevasse‐splay channel in a direction perpendicular to the parent channel and original floodbasin gradient. This created an asymmetrical splay sequence composition, which differs in appearance from more commonly observed dendritic crevasse splays. It is concluded that sedimentation patterns in the splay have been influenced by inherited effects of previously formed deposits. Feedbacks of the original floodbasin gradient and earlier stages of splay formation are suggested as prominent mechanisms in creating the current morphology, orientation, and architecture of its deposits. Copyright © 2015 John Wiley & Sons, Ltd.

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Effects of peat on the shapes of alluvial channels: examples from the Cumberland Marshes, Saskatchewan, Canada

Cited by 27 publications

References 20 publications

The Pennsylvanian Springhill Mines Formation: sedimentological framework for a portion of the Joggins Fossil Cliffs UNESCO World Heritage Site

The Pennsylvanian Springhill Mines Formation: sedimentological framework for a portion of the Joggins Fossil Cliffs UNESCO World Heritage Site

Elevation adjustments of paired natural levees during flooding of the Saskatchewan River

Depositional development of the Muskeg Lake crevasse splay in the Cumberland Marshes (Canada)

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