Sedimentary processes in Lake Van, Turkey - correlation of high resolution seismic records with physical properties data
Zusammenfassung der Projektergebnisse
Lake Van in Eastern Anatolia (Turkey) is the fourth largest terminal lake in the world with a surface area of 3,574 km², a volume of 607 km³, a maximum depth of 450 m, and a maximal length of 130 km WSW-ENE. Annually laminated sediments for major parts of the sedimentary succession in Lake Van harbor an excellent high-resolution paleoclimate archive. Moreover, the lake basin developed in a tectonically active region. Two large active stratovolcanoes, Süphan (4,058 m asl) and Nemrut (2,948 m asl), grew just west and north of the lake. Hundreds of tephra layers interbedded with nonvolcanic sediments provide a basic stratigraphic and temporal framework of the sedimentary fill. Considering the statements above, Lake Van was chosen for scientific drilling in the framework of the International Continental Drilling Program (ICDP) aiming to recover long paleoclimate and paleoseismic archives. Two sites (Ahlat Ridge and Northern Basin) were successfully drilled in the summer of 2010 based on seismic data collected during a pre-site survey in 2004. Over 800 km of multi-channel seismic reflection profiles in combination with ICDP drilling data from Lake Van provide important insights into the seismic stratigraphic evolution of the lake basin. The basis for combining both data sets was the calculation of synthetic seismograms. The results show good correlations in both Ahlat Ridge and Northern Basin sites. Strong marker horizons correlate well with prominent tephra layers. The seismic stratigraphic framework of the lake has allowed to construct 17 isopach maps and corresponding depositional system maps. The sedimentary history of the Tatvan Basin includes two distinct intervals: From 550 ka to 30 ka, the Tatvan Basin was filled predominantly by mass-flow deposits sourced in the highlands along the southern edge of the basin chiefly triggered by ongoing tectonic activity. On the morphologically elevated ridges, such as the Ahlat Ridge drill site, lacustrine sediments and tephra layers predominate, as these locations were sheltered against mass flows and turbidity currents due to their elevated positions. From 30 ka to the Present, tectonic activity along the basin margins appears to have slowed down and mass-flow deposition in the basin decreased considerably. This rather quiet period was interrupted by a recent, minor tectonic pulse that resulted in a mass flows along the base of the southern margin. Sedimentation rates in the Northern Basin are ca. 3.5 times higher than on Ahlat Ridge; sedimentation at the Northern Basin site is dominated by volcaniclastic turbidites. This is probably due to the fact that the Northern Basin is closer to the volcanoes. The Northern Ridge may have acted as a structural barrier for carrying volcaniclastic turbidites into the deep Tatvan Basin and on Ahlat Ridge. Overall, the sedimentation patterns in the basins and ridges are mainly controlled by tectonic and volcanic activity at the peripheral regions of the lake.
Projektbezogene Publikationen (Auswahl)
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(2010) Sedimentary processes in Lake Van, Turkey: seismic pre-site survey and planned activities during the upcoming Lake Van Drilling Project. IODP-ICDP Colloquium, 09-11 March 2010, Frankfurt
Krastel, S., Winkelmann, D., Cukur, D., Litt, T.
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(2011) Sedimentary processes in Lake Van: first results from a joint interpretation of seismic and drilling data. 1. PALEOVAN Post Drill Science Meeting, 05-06 September 2011, Zurich
Cukur, D., Krastel, S., Winkelmann, D.
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(2011) Sedimentary processes in Lake Van: First results from a joint interpretation of seismic and drilling data. European Geosciences Union (EGU) General Assembly, 04-08 April 2011, Vienna
Cukur, D., Krastel, S., Winkelmann, D., Wonik, T., Litt, T.
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(2011) Sedimentary processes in Lake Van: First results from a joint interpretation of seismic and drilling data. IODP-ICDP Colloquium, 14-16 March 2011, Munster
Cukur, D., Krastel, S., Winkelmann, D., Wonik, T., Litt, T.
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(2011), A 500,000-year-long sediment archive drilled in eastern Anatolia. Eos Trans. AGU, 92(51), 477
Litt, T., Anselmetti, F. S., Cagatay, M. N., Kipfer, R., Krastel, S., Schmincke, H.-U., and Sturm M.
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(2011). Earthquake-related microdeformations of the Lake Van sediments. 5th International Limnogeology Congress, August 31- September 3 2011, Konstanz
Stockhecke, M., Anselmetti,FS., Cukur, D., Krastel, S., Sturm, M.
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(2012) 500,000 Years of Environmental History in Eastern Anatolia: The PALEOVAN Drilling Project. Scientific Drilling, 4, 18-29
Litt, T., Anselmetti, F. S., Baumgarten, H., Beer, J., Cagatay, N., Cukur, D., Damci, E., Glombitza, C., Haug, G., Heumann, G., Kallmeyer, J., Kipfer, R., Krastel, S., Kwiecien, O., Meydan, A. F., Orcen, S., Pickarski, N., Randlett, M. E., Schmincke, H.-U., Schubert, C. J., Sturm, M., Sumita, M., Stockhecke, M., Tomonaga, Y., Vigliotti, L., Wonik, T.
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(2012) Lake Level Changes of Lake Van over the Last 400 ka: Evidence from Deltas in Seismic Reflection Data and ICDP Drilling. European Geosciences Union (EGU) General Assembly, 22-27 April 2012, Vienna
Damci, E., Cagatay, M. N., Krastel, S., Ogretmen, N., Cukur, D., Ulgen, U. B., Erdem, Z., Litt, T., Anselmetti, F. S. und Eris, K. K.
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(2012) Sedimentary evolution of Lake Van (Eastern Turkey) reconstructed from high resolution seismic investigations. International Journal of Earth Sciences, 102 (2), 571-585
Cukur, D., Krastel, S., Demirel-Schlüter, F., Demirbag, E., Imren, C., Niessen, F. and Toker, M.
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(2012) Structural and stratigraphic analysis of the Lake Van, Eastern Turkey : an integration of high resolution seimic and drilling data. IODP/ICDP Kolloquium 2012, March 07-09 2012, Kiel
Cukur, D., Krastel, S., Winkelmann, D., Litt, T.
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(2012) Structural and stratigraphic analysis of the Lake Van, Eastern Turkey: An integration of high resolution seismic and drilling data. European Geosciences Union (EGU) General Assembly, 22-27 April 2012, Vienna
Cukur, D., Krastel, S., Winkelmann, D., Litt, T.
