Lake Van

International audienc

Influences of Climate and Tectonic on the Middle to Late Holocene Deltaic Sedimentation in Lake Hazar, Eastern Turkey

Analyses of two piston cores from Lake Hazar together with high-resolution seismic data provide unique evidence of complex interaction of tectonics and lake level changes during the mid-to-late Holocene. This period is associated with stacked shelf-edge deltaic units at the mouth of the Kurk double dagger ayA +/- River at the western extreme of the lake. Despite the general dry climate during the middle Holocene (between 8.2 and 5.1 cal ka BP), transgressive and landward retreating deltaic successions developed due to the deepening of the lake that induced by transtentional activity of the East Anatolian Fault Zone. The arid climate during 5.1-2.6 cal ka BP is supported by the multi-proxy analyses of the cores. This period coincides with the late Bronze age deforestation, which probably provided the sediment supply by soil erosion for the deltaic deposition at the mouth of the paleo-Kurk double dagger ayA +/- River. On the other hand, the flooding of the youngest deltaic unit in the lake took place under a general wet climate after 1.4 cal ka BP. The seismic architecture and the core sedimentology indicate that the existing hydrological regime with the latest deltaic deposition started 2.6 cal ka BP was accompanied by a hyperpycnal mixing

Environmental effect and genetic influence: a regional cancer predisposition survey in the Zonguldak region of Northwest Turkey

The Cretaceous-Eocene volcano-sedimentary units of the Zonguldak region of the western Black Sea consist of subalkaline andesite and tuff, and sandstone dominated by smectite, kaolinite, accessory chlorite, illite, mordenite, and analcime associated with feldspar, quartz, opal-CT, amphibole, and calcite. Kaolinization, chloritization, sericitization, albitization, Fe-Ti-oxidation, and the presence of zeolite, epidote, and illite in andesitic rocks and tuffaceous materials developed as a result of the degradation of a glass shards matrix, enclosed feldspar, and clinopyroxene-type phenocrysts, due to alteration processes. The association of feldspar and glass with smectite and kaolinite, and the suborientation of feldspar-edged, subparallel kaolinite plates to fracture axes may exhibit an authigenic smectite or kaolinite. Increased alteration degree upward in which Al, Fe, and Ti are gained, and Si, Na, K, and Ca are depleted, is due to the alteration following possible diagenesis and hydrothermal activities. Micromorphologically, fibrous mordenite in the altered units and the presence of needle-type chrysotile in the residential buildings in which cancer cases lived were detected. In addition, the segregation pattern of cancer susceptibility in the region strongly suggested an environmental effect and a genetic influence on the increased cancer incidence in the region. The most likely diagnosis was Li-Fraumeni syndrome, which is one of the hereditary cancer predisposition syndromes; however, no mutations were observed in the p53 gene, which is the major cause of Li-Fraumeni syndrome. The micromorphology observed in the altered units in which cancer cases were detected may have a role in the expression of an unidentified gene, but does not explain alone the occurrence of cancer as a primary cause in the region