Environmental response to climatic and volcanic events in NE Anatolia during the last 20,000 years based on annually laminated sediments from Lake Van

2004年在400米深的凡湖(安纳托利亚)钻探的Tephra层将在结构、结构和成分上进行研究，以确定钻探地点和陆地上火山沉积之间的相关性。对历史上活跃的破火山口Nemrut火山上的等量矿床进行分析，将能够重建更大的火山事件(普林尼安陨石、火山碎屑流和侧翼坍塌)、岩浆演化和海啸等环境影响。火山玻璃与湖泊沉积物中碱性孔隙溶液的相互作用可能释放了与生物相关的元素。分析的重点是玻璃碎片和斑晶的激光-电感耦合等离子体质谱组成和40Ar/39Ar单晶测年。在毗邻湖泊的重大火山事件期间重建质量传递过程将有助于凡湖的火山灾害和风险评估。基于年度叠层湖相沉积的高分辨率孢粉分析应反映火山事件对古环境的影响。将分析火山和气候引起的植被变化之间的比较。火山喷发对植被的短期影响只能通过高分辨率地层学来追踪。凡湖的各种沉积物记录是这种方法的一个很好的档案。

Tephra layers drilled in 400 m-deep Lake Van (Anatolia) in 2004 will be studied structurally, texturally and compositionally for correlation between drill sites and with volcanic deposits on land. Analysis of equivalent deposits on the historically active caldera volcano Nemrut, the major supplier of tephra, will allow reconstructing larger volcanic events (Plinian fallout, pyroclastic flows and flank collapses), magma evolution and environmental impacts such as tsunamis. Interaction of volcanic glass with alkaline pore solutions in lake sediments is likely to have released biologically relevant elements. The analytical focus is on Iaser-ICP-MS composition of glass shards and phenocrysts and 40Ar/39Ar single crystal dating. Reconstruction of mass transfer processes during major volcanic events adjacent to the lake will aid volcanic hazard and risk assessment at Lake Van. High-resolution pollen analyses based on the annually laminated lacustrine sediments should reflect the impact of volcanic events on paleoenvironment. The comparison between volcanic and climatically induced vegetation changes will be analyzed. Short-term effects of volcanic eruptions on vegetation can only be traced by a high-resolution stratigraphy. The varved sediment record of lake Van is an excellent archive for this approach.