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Revisiting the dynamics of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asia

dc.contributor.authorBohorquez, Patricio
dc.contributor.authorJimenez-Ruiz, Pedro J.
dc.contributor.authorCarling, Paul A.
dc.date.accessioned2023-11-29T07:36:56Z
dc.date.available2023-11-29T07:36:56Z
dc.date.issued2019-07-09
dc.description.abstractIn this work, we present a whole system model of megafloods from catastrophic ice-dam failure in the late Pleistocene that comprises the study of the dynamics of the glacial lake, the propagation of the flood wave downstream of the dam, and an approximation to the ice breach process. The ice-dam incision rate was simply considered an unknown constant, which was varied systematically to best fit the maximum altitude of the simulated water surface and the paleostage indicators in the downstream valley during the transient megaflood. Hence, the hydrograph resulting from the breach of the ice dam was not prescribed but was an output of the paleohydraulic reconstruction. By considering two possible configurations of the breach in the ice dam, i.e. full or partial removal of the ice, we constrained the incision rate in the narrow range of 28 − 42 m ⋅ h−1. Two connected glacial lakes, Kuray and Chuja, released 95% of the stored water volume (i.e., 564 km3) in 33.8 hours. A peak discharge of 10.5 M m3 ⋅ s−1 was required to form numerous giant bars and run-up deposits in the Chuja and Katun valleys. The peak streamflow occurred after 11 h when 45% of the available lake volume had been evacuated from the Kuray and Chuja basins. Further verification of the reconstructed megaflood was achieved by studying the computed hydraulic conditions during the lake draining that justify the existence and orientation of several fields of subaqueous gravel-dunes in the glacial lake. Complex spatiotemporal patterns during the recession stage of the flood built most of the fields of bedforms. In terms of nondimensional parameters, the Froude and Shields numbers that formed the dune fields were similar to those observed in large sandy rivers, but the flow was undoubtedly unsteady and two-dimensional. We conclude by noting that the extensions of the simulated area cannot be cropped or analysed by independent parts in order to predict the formation of the most relevant geological records due to the unsteady, two-dimensional nature of the flow motion and the development of backwater effects in the drainage network. Lastly, the paleohydrological reconstruction of a megaflood has helped not only to infer the dynamics of the event but also to retrodict the mean parameters of the ice-dam failure mechanism.es_ES
dc.description.sponsorshipThis work was supported by the Spanish Ministry of Science, Innovation and Universities (MICINN/FEDER, UE) under Grant SEDRETOCGL2015-70736-R. P.R.J. was supported by the European Social Fund and the University of Jaén.es_ES
dc.identifier.citationBohorquez P., Jimenez-Ruiz P.J., Carling P.A. Revisiting the dynamics of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asia. Earth-Science Reviews, 197: 102892, 2019. https://doi.org/10.1016/j.earscirev.2019.102892es_ES
dc.identifier.issn0012-8252es_ES
dc.identifier.other10.1016/j.earscirev.2019.102892es_ES
dc.identifier.urihttps://doi.org/10.1016/j.earscirev.2019.102892es_ES
dc.identifier.urihttps://hdl.handle.net/10953/1348
dc.language.isoenges_ES
dc.publisherElsevieres_ES
dc.relation.ispartofEarth-Science Reviews 2019; 197: 102892es_ES
dc.rights.accessRightsinfo:eu-repo/semantics/openAccesses_ES
dc.subjectLake drainagees_ES
dc.subjectMegafloodes_ES
dc.subjectGiant gravel duneses_ES
dc.subjectAltai Mountainses_ES
dc.subjectPaleohydrologyes_ES
dc.titleRevisiting the dynamics of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asiaes_ES
dc.typeinfo:eu-repo/semantics/articlees_ES
dc.type.versioninfo:eu-repo/semantics/acceptedVersiones_ES

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Bohorquez P., Jimenez-Ruiz P.J., Carling P.A. Revisiting the dynamics of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asia. Earth-Science Reviews, 197: 102892, 2019. https://doi.org/10.1016/j.earscirev.2019.102892

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