Sedimentary evolution of Lake Van (Eastern Turkey) reconstructed from high-resolution seismic investigations

Deniz Cukur*, Sebastian Krastel, Filiz Demirel-Schlüter, Emin Demirbağ, Caner Imren, Frank Niessen, Mustafa Toker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)

Abstract

This paper presents results of a multi-channel seismic reflection survey at Lake Van and provides constraints on the sedimentary evolution of the lake. The geophysical data of the lake confirm the existence of three physiographic provinces: a shelf, a slope, and a deep, relatively flat basin. The most prominent features identified on the shelf and slope are clinoforms, submerged channels, as well as closely spaced lake floor depressions, reflecting a highly variable lake-level history. The morphological depressions are interpreted as resulting from subaquatic erosion by channelized, sediment-laden currents into horizontally bedded fan sediments. Submerged channels on the eastern shelf are interpreted as meandering-slope channels, probably as a consequence of a lake-level fall that exposed the shelf area. Clinoforms on the Eastern fan may represent relict deltas formed during stationary or slightly rising lake-level intervals. Merging subsurface imaging interpretation with morphological studies of exposed sediments reveals lake-level fluctuations of several hundreds of meters during the past ca. ~550 ka. The lake has three prominent basins (Tatvan, Deveboynu, and the Northern basin) separated by basement ridges (e. g., the Northern ridge). The seismic units in the Tatvan and Northern basins are dominated by alternations of well-stratified and chaotic reflections, while the Deveboynu basin subsurface consists mainly of chaotic units. The chaotic seismic facies are interpreted as mass-flow deposits, probably triggered by earthquakes and/or rapid lake-level fluctuations. The moderate-to-high-amplitude, well-stratified facies seen in the deeper parts of the basins are interpreted as lacustrine deposits intercalated with tephra layers. The occurrence of a clinoform in the deepest part of the lake suggests a major flooding stage of Lake Van more than ~400 ka ago. Seismic profiles from the deepest part of the lake basin show remarkably uniform and continuous stratigraphic units without any major erosional feature following the flooding event, indicating that the lake was never completely dry afterward and therefore significantly older than previously suggested.

Original languageEnglish
Pages (from-to)571-585
Number of pages15
JournalInternational Journal of Earth Sciences
Volume102
Issue number2
DOIs
Publication statusPublished - Mar 2013

Funding

Acknowledgments We would like to thank Prof. Sefer Örcen and his team from Yüzüncü Yil University (Van) for the possibility to use the university boat and logistic support. The boat crew is thanked for their untiring commitment, which made the cruise a great success. Two anonymous reviewers are acknowledged with thanks for their constructive comments and suggestions. The IHS Kingdom® software was used for seismic data interpretation and mapping. Financial support was provided by the Deutsche Forschungsgemeinschaft (Project KR2222-9).

FundersFunder number
Deutsche ForschungsgemeinschaftKR2222-9

    Keywords

    • Clinoform
    • Lake Van
    • Lake-level fluctuations
    • Mass-flow
    • Seismic data
    • Seismic facies

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