Abstract
This study analyzed multi-channel seismic reflection data from Lake Van, Eastern Anatolia, to provide key information on the structural elements, deformational patterns and overall tectonic structure of the Lake Van basin. The seismic data reveal three subbasins (the Tatvan, northern and Ahlat subbasins) separated by structural ridges (the northern and Ahlat ridges). The Tatvan basin is a tilted wedge-block in the west, it is a relatively undeformed and flat-lying deep basin, forming a typical example of strike-slip sedimentation. Seismic sections reveal that the deeper sedimentary sections of the Tatvan basin are locally folded, gently in the south and more intensely further north, suggesting a probable gravitational “wedge-block” instability, oblique to the northern margin. The northern subbasin, bounded by normal oblique faults, forms a basin-margin graben structure that is elongated in a northeast-southwest direction. The east-west trending Ahlat ridge forms a fault-wedged sedimentary ridge and appears to offset by reverse oblique faults forming as a push-up rhomb horst structure. The Ahlat subbasin is a fault-wedged trough fill that is elongated in the west-east direction and appears as a horst-foot graben formed by the normal oblique faults. The northeast-southwest directed northern ridge is a faulted crestal terrace of a sublacustrine basement block. Its step-like morphology, in response to the downfaulting of the Tatvan basin, as well as its backthrusted appearance, indicates the normal oblique nature of the bounding faults. The lacustrine shelf and slope show distinctive stratigraphic features; progradational deltas, submerged fluvial channels, distorted and collapsed beddings and soft sediment deformation structures, characterizing a highly unstable nature of shelf caused by strong oblique faulting and related earthquakes. The faulting caused uplift of the Çarpanak spur zone, together with the northeastern Erek delta, deformation of deltaic structures and subsequently exposing the shelf and slope areas. The exposed areas are evident in the angular unconformity surface of the Çarpanak basement block with the northeastern Erek delta and thinned sediments. The uplift resulted in the asymmetric depositional emplacement of the southeastern delta that is controlled by a series of ramp anticlines/low angle reverse faults. The Deveboynu subbasin and Varis spur zone form wide fault-controlled depressions with thick sediments that are elongated in the north-south direction. These subbasins appear as a small pull-apart boundary formed by normal oblique faults at the western end of the southeastern delta.
Original language | English |
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Pages (from-to) | 165-178 |
Number of pages | 14 |
Journal | Journal of African Earth Sciences |
Volume | 129 |
DOIs | |
Publication status | Published - 1 May 2017 |
Bibliographical note
Publisher Copyright:© 2017 Elsevier Ltd
Funding
The authors acknowledge funding of the PaleoVan drilling campaign by the International Continental Scientific Drilling Program (ICDP), the Deutsche Forschungsgemeinschaft (DFG; Grants KR2222-9). From Yuzuncu Yil University (Van), we thank Prof. Umit Tolluoglu, Dean of the Faculty of Engineering and Architecture and his staff for the use of the university boat and logistics support. We are very grateful to the boat crew for their untiring commitment to the project. We much appreciate the help, constructive comments and suggestions from; Prof. Sebastian Krastel, the chief scientist and leader of ICDP seismic survey-PaleoVan project; Prof. Thomas Litt, the chief scientist of sedimentological survey, and Prof. A. M. Celal Sengor, the supervisor of the PhD thesis referred to in this paper. We thank our colleagues from the Istanbul Technical University, Eurasian Institute of Earth Sciences (Istanbul, Turkey) and from the Kiel University (Kiel, Germany) team for support during data collection and interpretation. Special thanks go to our captains, Mete Orhan and Munip Kanan, for their untiring commitment during the seismic data acquisition. The authors offer their greatest thanks to Editors and the two anonymous reviewers for their constructive comments and suggestions which helped to improve the manuscript. The Kingdom Suite® software, partly used for seismic data interpretation and mapping was provided by IHS Inc.
Funders | Funder number |
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Eurasian Institute of Earth Sciences | |
IHS Inc. | |
Kiel University | |
Deutsche Forschungsgemeinschaft | KR2222-9 |
Istanbul Teknik Üniversitesi |
Keywords
- Eastern Anatolia
- Lake Van
- Oblique faults
- Ridges
- Seismic data
- Strike-slip deformation
- Subbasins
- Unstable delta