Proglacial megaflooding along the margins of the Laurentide Ice Sheet

Kehew, Alan E.; Lord, Mark; Kozlowski, Andrew L.; Fisher, Timothy G.

doi:10.1017/cbo9780511635632.007

Cited by 32 publications

(30 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pleistocene outburst fl oods by dam failure are also described from Scandinavia (Elfström, 1987), the Hindukush Mountains (Cornwell, 1998), Siberia (Grosswald and Rudoy, 1996), and the Altai Mountains (Butvilovsky, 1993;Rudoy, 1998Rudoy, , 2002. Pleistocene ice-dammed lakes drained by spillways are, for example, the Baltic Sea (Strömberg, 1992;Brunnberg, 1995), the continental-scale lake(s) in Siberia (Arkhipov et al, 1995;Grosswald, 1998Grosswald, , 1999, and local lakes along the Laurentide Ice Shield (e.g., Kehew and Lord, 1987) or at the margin of the Scandinavian Ice Shield (Thome, 1983;Klostermann, 1992;Herget, 2002). From several other Pleistocene glaciations the occurrence of ice-dammed lakes is evident, but the drainage process is unknown or not the subject of the investigation, for example, in Siberia (Mangerud et al, 2001), Scotland (Benn, 1989;Gordon, 1993;Brazier et al, 1999), or Germany (Müller, 1964;Gassert, 1975;Pilger, 1991;Schlaak, 1993;Junge, 1998).…”

Section: Occurrence and Distributionmentioning

confidence: 99%

Reconstruction of Pleistocene ice-dammed lake outburst floods in the Altai Mountains, Siberia

Herget¹

2005

Reconstruction of Pleistocene Ice-Dammed Lake Outburst Floods in the Altai Mountains, Siberia

132

View full text Add to dashboard Cite

In the Siberian Altai Mountains, where the sources of the River Ob are located, ice-dammed lake outburst fl oods, so-called jökulhlaups, occurred in Pleistocene times. Valley glaciers extended within the upper Chuja River catchment and dammed the river upstream of the village of Aktash, which generated ice-dammed lakes in the intramountainous Kuray and Chuja Basins. Indicated by shorelines and ice-rafted boulder deposits, the maximum lake level reached an altitude of 2100 m above sea level, which reveals a maximum lake volume of 607 km 3 . The failure of the ice dam caused outburst fl oods, which left traces by giant bars, fl uvial gravel dunes, and boulder deposits. Run-up sediments deposited in front of local obstructions along the valley slopes indicate a maximum depth of fl ow of 400 m above the valley bottom. Like the giant bars, they consist of characteristic relatively fi ne suspension gravels. Occasionally, secondary lakes are formed in tributary valleys that were blocked by giant bar deposits. The alternation of lacustrine deposits and suspension gravels in the tributary Injushka valley near Inja village give evidence for at least three large outburst fl oods. Age estimations by a variety of dating methods, such as luminescence methods, exposure dating, and accelerator mass spectrometry radiocarbon applied on different fl ood features and lake sediments, indicate that the outburst fl oods occurred between 40 ka and 13 ka. This estimation should be taken as preliminary, as problems occurred with the different dating techniques, resulting in partly contradictory results. This study focuses on the paleohydraulic reconstruction of the fl ood rather than describing fl ood-related features in detail. Seven different approaches are applied to estimate the discharge of the fl oods. Several new methods are developed within the study, partly based on previous approaches carefully considering the hydraulic background. Data for paleohydraulic estimations are obtained during repeated fi eld trips by observations, surveys, and sedimentological investigations in Chuja and Katun valleys. Peak discharge is estimated by the elevation of the surfaces of the giant bars indicating the depth of fl ow and additionally by the run-up sediments, which reveal information about the velocity head of the fl ood fl ow along the valleys. A value of 10 × 10 6 m 3 /s is estimated for peak discharge, which is considerably less than previous estimations derived. Dimensions of gravel dunes and obstacle marks obtain information of fl ow conditions during the decreasing fl ood. The application of regression formulae between drained lake volume and peak discharge, an established method to estimate discharges of jökulhlaups, and estimation of fl ow velocity considering fl ow *herget @giub.uni-bonn.de on May 27, 2015 specialpapers.gsapubs.org Downloaded from 2 J. Herget competence indicated by transported boulders yield problems as the magnitude of the outburst fl oods and the size of the boulders are beyond the level of experience.Based on the...

show abstract

Section: Occurrence and Distributionmentioning

confidence: 99%

Reconstruction of Pleistocene ice-dammed lake outburst floods in the Altai Mountains, Siberia

Herget¹

2005

Reconstruction of Pleistocene Ice-Dammed Lake Outburst Floods in the Altai Mountains, Siberia

132

View full text Add to dashboard Cite

show abstract

“…Along the palaeo-margin of the Laurentide ice sheet in central and eastern North America, the floodwater 566 pathways show largely erosional streamlined islands, with only limited depositional gravel bars (Lord and 567 Kehew, 1987;Kehew et al, 2009). Whilst the similarity with the English Channel is stronger than the 568 previously described examples; there are clear differences in the number and distribution of the erosional 569 remnants.…”

mentioning

confidence: 95%

“…In the central and eastern North American examples, they seem "more crowded", with 572 "as much island as channel" along many stretches. Isolated erosional remnants do occur within box-shaped 573 channels like in the English Channel, but they are relatively minor (Kehew et al, 2009). Possibly part of the 574 reason is the different bedrock lithologies.…”

mentioning

confidence: 99%

Streamlined islands and the English Channel megaflood hypothesis

Collier

Oggioni

Gupta

et al. 2015

Global and Planetary Change

View full text Add to dashboard Cite

“…In Europe IMVs occur across the North European Plain from Russia to the North Sea. The term IMVs is also used in North America (Goudie, 2004;Kehew et al, 2009) and in New Zealand (Soons, 1964), but in these countries the meaning is slightly different -in New Zealand IMVs are described as valleys that roughly parallel the ice edge, utilising pre-existing ice-free valleys, while North American IMVs usually are referred to as spillways and are connected with megafloods (Kehew et al, 2009). The term proglacial spillway, connected with megafloods, is employed in Latvia (Zelčs & Markots, 2004;Zelčs et al, 2011) as well.…”

Section: Introductionmentioning

confidence: 99%

Factors controlling sedimentation in the Toruń-Eberswalde ice-marginal valley during the Pomeranian phase of the Weichselian glaciation: an overview

Pisarska‐Jamroży

2015

Geologos

View full text Add to dashboard Cite

During the Pleistocene the Scandinavian ice sheet drained huge quantities of sediment-laden meltwaters. These meltwaters supplied ice-marginal valleys that formed parallel to the front of the ice sheet. Not without significance was the supply of ice-marginal valleys from extraglacial rivers in the south. Moreover, periglacial conditions during and after sedimentation in ice-marginal valleys, the morphology of valley bedrocks, and erosion of older sediments played important roles in the depositional scenarios, and in the mineralogical composition of the sediments. The mechanisms that controlled the supply and deposition in ice-marginal valleys were analysed on the basis of a Pleistocene ice-marginal valley that was supplied by northern and southern source areas in the immediate vicinity. Investigations were conducted in one of the largest ice-marginal valleys of the Polish-German lowlands, i.e., the Toruń-Eberswalde ice-marginal valley, in sandurs (Drawa and Gwda) supplied sediments and waters from the north into this valley, and on extraglacial river terraces (pre-Noteć and pre-Warta rivers), formed simultaneously with the sandurs and ice-marginal valley (Pomeranian phase of Weichselian glaciation) supplied sediments and waters from the south into this valley. A much debated question is how similar, or different, depositional processes and sediments were that contributed to the formation of the Toruń-Eberswalde ice-marginal valley, and whether or not it is possible to differentiate mostly rapidly aggraded sandur sediments from ice-marginal valley sediments. Another question addresses the contribution of extraglacial feeding of the Toruń-Eberswalde ice-marginal valley. These matters were addressed by a wide range of analyses: sediment texture and structure, architectural elements of sediments, frequency of sedimentary successions, heavy-mineral analysis (both transparent and opaque heavy minerals), analysis of rounding and frosting of quartz grains, and palaeohydrological calculations. Additionally, a statistical analysis was used. The specific depositional conditions of distribution of sediments in ice-marginal valley allow to distinguish new environment of ice-marginal valley braided river. The spectrum of depositional conditions in the Toruń-Eberswalde ice-marginal valley and their specific palaeohydraulic parameters allow to distinguish three coexisting zones in the ice-marginal valley braided-river system: (1) deep gravel-bed braided channel zone with extensive scours, (2) deep sand-bed braided channel zone with transverse bars, and (3) marginal sand-bed and gravel-bed braided channel zone with diamicton and breccia deposition, which were characterised in detail. Some of the results have been published previously, which is why they are discussed in the present paper within the context of new data.

show abstract

Proglacial megaflooding along the margins of the Laurentide Ice Sheet

Cited by 32 publications

References 72 publications

Reconstruction of Pleistocene ice-dammed lake outburst floods in the Altai Mountains, Siberia

Reconstruction of Pleistocene ice-dammed lake outburst floods in the Altai Mountains, Siberia

Streamlined islands and the English Channel megaflood hypothesis

Factors controlling sedimentation in the Toruń-Eberswalde ice-marginal valley during the Pomeranian phase of the Weichselian glaciation: an overview

Contact Info

Product

Resources

About