Magnitude and frequency in proglacial rivers: a geomorphological and sedimentological perspective

Marren, Philip M.

doi:10.1016/j.earscirev.2004.12.002

Cited by 169 publications

(195 citation statements)

References 114 publications

Supporting

Mentioning

190

Contrasting

Unclassified

Order By: Relevance

“…Indeed, many of the facies recognised within Lithofacies A and B have also been recognised within a range of glacial environments (Maizels, 1997;Marren, 2005;Lang & Winsemann, 2013). Within the following section, a palaeoenvironmental model for the Lleiniog sequence is presented and discussed.…”

Section: 1mentioning

confidence: 99%

“…Of further significance is the occurrence of syn-depositional reverse faulting within Lithofacies B suggestive of conduit wall modification by compressive stresses operating within the glacial bed or basal ice. However, individual sediment facies characteristic of upper or transitional flow regimes have also been recognised within englacial outwash sediments (Delaney, 2001(Delaney, , 2002 and proglacial glacier outburst flood or jökulhlaup deposits (Lord et al, 1987;Maizels, 1997;Marren, 2005). An alternative 'englacial' origin is rejected here because of the overall high-degree of lateral bedding continuity which is often absent from englacial deposits due to post-depositional deformation produced by lowering during mass-wastage (cf.…”

Section: 1mentioning

confidence: 99%

“…Proglacial glacial outburst flood deposits comprise an extensive range of sediments driven by source proximity and the shape of the flood hydrograph (Clarke, 2003;Benn & Evans, 2010). However, at a meso-to smallscale, deposits are frequently characterised by complex facies associations and bounding surface geometries which reflect marked and rapid shifts in energy regime, sediment supply and turbulence (Maizels, 1992(Maizels, , 1993(Maizels, , 1997Marren, 2005;Russell et al, 2005;Duller et al, 2008;Marren et al, 2009). This meso-to small-scale architectural and sedimentological complexity is not apparent in the sequences at Lleiniog.…”

Section: 1mentioning

confidence: 99%

See 2 more Smart Citations

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

View full text Add to dashboard Cite

Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal / proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies attributed to subglacial meltwater activity record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream.

show abstract

Section: 1mentioning

confidence: 99%

Section: 1mentioning

confidence: 99%

Section: 1mentioning

confidence: 99%

See 1 more Smart Citation

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

View full text Add to dashboard Cite

show abstract

“…In sedimentological analyses, descriptions of braided river gravels have tended to emphasize the sedimentary structure and sedimentological detail with little direct analysis of grain size sorting except for limited vertical sections, trenches or cores using direct physical grain measurement or indirect grain size methods such as imagebased automatic sizing (Storz-Peretz and Laronne, 2013a). Analyses have typically focused on facies patterns and sedimentary structure, but several have mentioned that there is little vertical trend in grain sizes in braided river gravels (e.g., Bluck, 1979;Sambrook Smith, 2000;Heinz et al, 2003;Lunt and Bridge, 2004;Guerit et al, 2014;Marren, 2005;StorzPeretz and Laronne, 2013b). Similarly, physical models of aggraded braided gravel alluvium show patches and threads of distinct facies but no clear trend in grain size (e.g., Moreton et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Grain sorting in the morphological active layer of a braided river physical model

2015

View full text Add to dashboard Cite

Abstract.A physical scale model of a gravel-bed braided river was used to measure vertical grain size sorting in the morphological active layer aggregated over the width of the river. This vertical sorting is important for analyzing braided river sedimentology, for numerical modeling of braided river morphodynamics, and for measuring and predicting bedload transport rate. We define the morphological active layer as the bed material between the maximum and minimum bed elevations at a point over extended time periods sufficient for braiding processes to rework the river bed. The vertical extent of the active layer was measured using 40 hourly high-resolution DEMs (digital elevation models) of the model river bed. An image texture algorithm was used to map bed material grain size of each DEM. Analysis of the 40 DEMs and texture maps provides data on the geometry of the morphological active layer and variation in grain size in three dimensions. By normalizing active layer thickness and dividing into 10 sublayers, we show that all grain sizes occur with almost equal frequency in all sublayers. Occurrence of patches and strings of coarser (or finer) material relates to preservation of particular morpho-textural features within the active layer. For numerical modeling and bedload prediction, a morphological active layer that is fully mixed with respect to grain size is a reliable approximation.

show abstract

“…Consequently, jö kulhlaup landforms and sediments have been described, interpreted and classified. Thus conceptual models of jö kulhlaup flow dynamics, flow rheology and the control of jö kulhlaup magnitude and frequency on proglacial geomorphology and sedimentology, have been developed (Maizels, 1993(Maizels, , 1997Maizels and Russell, 1992;Rushmer et al, 2002;Marren, 2005;Rushmer, 2006, in press;Russell et al, 2006).…”

Section: Introduction and Rationalementioning

confidence: 99%

GPR-Derived Sedimentary Architecture and Stratigraphy of Outburst Flood Sedimentation Within a Bedrock Valley System, Hraundalur, Iceland

Carrivick

Pringle

Russell

et al. 2007

JEEG

View full text Add to dashboard Cite

Jö kulhlaups and lahars are both types of outburst flood that commonly comprise a glacial meltwater and volcaniclastic sediment mix, and have discharges that are typically several orders of magnitude greater than perennial flows. Both types thus constitute a serious threat to life, property and infrastructure but are too powerful and too short-lived for direct measurements of flow characteristics to be made. Consequently a variety of indirect methods have been used to reconstruct flow properties, processes and mechanisms. Unfortunately, limited observations of sedimentary architecture and stratigraphic relationships are hampering our ability to discriminate fluvial magnitude-frequency regimes and fluvial styles of deposition, particularly those produced by rapidly-varied flows. This paper therefore uses Ground Penetrating Radar (GPR) to obtain quantitative data on subsurface sedimentary character of high-magnitude outburst flood sediments, including architecture and stratigraphy, from a bedrock-valley system in north-central Iceland. Basement pillow lava and subaerial lava flows are characterised by chaotic and hummocky GPR reflectors with a lack of coherent structure. They also feature an upper rough surface as evidenced by concentration of hyperbolae point sources. Unconsolidated sedimentary units are interpreted due to occur where laterally-persistent horizontal and sub horizontal reflectors occur. Deposition produced spatially diverse sediments due to rapidlyvaried flow conditions. Observations include prograding and backfilling architecture, intercalated slope material and fluvial sediments, and multiphase sedimentary deposition. We suggest that these outburst flood sediments were initially deposited by traction load of coarsegrained material on prograding bedforms, and subsequently by drop-out from suspension of finer-grained material. The latter phase produced laterally extensive tabular sedimentary architectures that in-filled pre-existing topography and masked the complexity of bedrock forms beneath. Existing qualitative concepts of high-magnitude fluvial deposition within a topographically confined bedrock channel are therefore now refined with quantitative data on sediment architecture and thus on flow regimes.

show abstract

Magnitude and frequency in proglacial rivers: a geomorphological and sedimentological perspective

Cited by 169 publications

References 114 publications

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Grain sorting in the morphological active layer of a braided river physical model

GPR-Derived Sedimentary Architecture and Stratigraphy of Outburst Flood Sedimentation Within a Bedrock Valley System, Hraundalur, Iceland

Contact Info

Product

Resources

About