Beschreibung
Lake Van is the fourth largest terminal lake in the world (volume 607 km3, area 3570 km2, maximum depth 460 m), extending for 130 km WSW-ENE on a high plateau in eastern Anatolia, Turkey. The annually-laminated sedimentary record of Lake Van promises to be an excellent palaeoclimate archive because it potentially yields a long and continuous continental sequence that covers several glacial-interglacial cycles (ca. 500 kyr). Therefore, Lake Van is a key site within ICDP for the investigation of the Quaternary climate evolution in the Near East. The geochronological precision on a decadal or even annual scale will allow comparisons not only with astronomical cyclicity but also signals below the frequency of Milankovitch cycles, such as North Atlantic Oscillation, which may have also affected the past climate system of the eastern Mediterranean region. As a closed and saline lake, Lake Van react very sensitively to lake level changes caused by any alterations in the hydrological regime in response to climate change. We also intend to determine the concentrations of atmospheric noble gases in the pore waters of the long IDCP cores to geochemically reconstruct - for the first time ever - lake levels and salinity on time scales of 1 - 100 kyr. Hence, the long cores from Lake Van will allow determination of the in-situ terrestrial He gradient as a function of depth within a sediment column of several hundred meters. These data will provide the first direct insights about the transport of terrestrial He trough the uppermost crust. Tephra layers, documented in the short cores and also expected in the deep drilling of Lake Van sediments, will allow reconstructing larger volcanic events and environmental impacts. The short cores from Lake Van show also strong evidence of earthquake-triggered microfaults, interpreted as seismites. Similar features are expected to be found in the deeper sections. The unique setting of Lake Van, which records simultaneously the volcanic as well as the earthquake history, will also allow establishing possible coincidence between larger earthquakes and volcanic events. We propose to use GLAD800 to drill a series of sites in Lake Van to recover sedimentary sequences alog a transect. Based on the high resolution seismic data and multidisciplinary scientific work on cores collected in 2004, we propose to drill five primary sites. Alternate sites and secondary sites have also been identified.