dc.identifier.uri |
http://dx.doi.org/10.15488/10793 |
|
dc.identifier.uri |
https://www.repo.uni-hannover.de/handle/123456789/10871 |
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dc.contributor.author |
Lang, Jörg
|
|
dc.contributor.author |
Le Heron, Daniel P.
|
|
dc.contributor.author |
Van den Berg, Jan H.
|
|
dc.contributor.author |
Winsemann, Jutta
|
|
dc.date.accessioned |
2021-04-23T09:02:55Z |
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dc.date.available |
2021-04-23T09:02:55Z |
|
dc.date.issued |
2021 |
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dc.identifier.citation |
Lang, J.; Le Heron, D.P.; Van den Berg, J.H.; Winsemann, J.: Bedforms and sedimentary structures related to supercritical flows in glacigenic settings. In: Sedimentology 68 (2021), Nr. 4, S. 1539-1579. DOI: https://doi.org/10.1111/sed.12776 |
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dc.description.abstract |
Upper-flow-regime bedforms, including upper-stage-plane beds, antidunes, chutes-and-pools and cyclic steps, are ubiquitous in glacigenic depositional environments characterized by abundant meltwater discharge and sediment supply. In this study, the depositional record of Froude near-critical and supercritical flows in glacigenic settings is reviewed, and similarities and differences between different depositional environments are discussed. Upper-flow-regime bedforms may occur in subglacial, subaerial and subaqueous environments, recording deposition by free-surface flows and submerged density flows. Although individual bedform types are generally not indicative of any specific depositional environment, some observed trends are similar to those documented in non-glacigenic settings. Important parameters for bedform evolution that differ between depositional environments include flow confinement, bed slope, aggradation rate and grain size. Cyclic-step deposits are more common in confined settings, like channels or incised valleys, or steep slopes of coarse-grained deltas. Antidune deposits prevail in unconfined settings and on more gentle slopes, like glacifluvial fans, sand-rich delta slopes or subaqueous (ice-contact) fans. At low aggradation rates, only the basal portions of bedforms are preserved, such as scour fills related to the hydraulic-jump zone of cyclic steps or antidune-wave breaking, which are common in glacifluvial systems and during glacial lake-outburst floods and (related) lake-level falls. Higher aggradation rates result in increased preservation potential, possibly leading to the preservation of complete bedforms. Such conditions are met in sediment-laden jökulhlaups and subaqueous proglacial environments characterized by expanding density flows. Coarser-grained sediment leads to steeper bedform profiles and highly scoured facies architectures, while finer-grained deposits display less steep bedform architectures. Such differences are in part related to stronger flows, faster settling of coarse clasts, and more rapid breaking of antidune waves or hydraulic-jump formation over hydraulically rough beds. © 2020 The Authors. Sedimentology published by John Wiley & Sons Ltd on behalf of International Association of Sedimentologists |
eng |
dc.language.iso |
eng |
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dc.publisher |
Hoboken, NJ : Blackwell |
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dc.relation.ispartofseries |
Sedimentology Early View (2020) |
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dc.rights |
CC BY 4.0 Unported |
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dc.rights.uri |
https://creativecommons.org/licenses/by/4.0/ |
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dc.subject |
Antidune |
eng |
dc.subject |
chute-and-pool |
eng |
dc.subject |
cyclic step |
eng |
dc.subject |
glacifluvial delta |
eng |
dc.subject |
ice-contact fan |
eng |
dc.subject |
jökulhlaup |
eng |
dc.subject |
Deposits |
eng |
dc.subject |
Hydraulic jump |
eng |
dc.subject |
Lakes |
eng |
dc.subject |
Scour |
eng |
dc.subject |
Sediments |
eng |
dc.subject |
Depositional environment |
eng |
dc.subject |
Facies architecture |
eng |
dc.subject |
Free-surface flow |
eng |
dc.subject |
Glacial lake outburst flood |
eng |
dc.subject |
Melt-water discharges |
eng |
dc.subject |
Preservation potential |
eng |
dc.subject |
Sedimentary structure |
eng |
dc.subject |
Supercritical flow |
eng |
dc.subject |
Sedimentology |
eng |
dc.subject.ddc |
550 | Geowissenschaften
|
ger |
dc.title |
Bedforms and sedimentary structures related to supercritical flows in glacigenic settings |
|
dc.type |
Article |
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dc.type |
Text |
|
dc.relation.essn |
1365-3091 |
|
dc.relation.issn |
0037-0746 |
|
dc.relation.doi |
https://doi.org/10.1111/sed.12776 |
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dc.bibliographicCitation.issue |
4 |
|
dc.bibliographicCitation.volume |
Early View |
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dc.bibliographicCitation.volume |
68 |
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dc.bibliographicCitation.firstPage |
1539 |
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dc.bibliographicCitation.lastPage |
1579 |
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dc.description.version |
publishedVersion |
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tib.accessRights |
frei zug�nglich |
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