Tephrochronological Synchronisation of the Dead Sea and Lake Van ICDP sediment records in the eastern Mediterranean for the last 130 kyrs (TephroMed)

该项目旨在精确同步的长ICDP沉积物芯从死海和湖货车，以提供一个强大的年代学基础，调查假定的区域水文气候差异在地中海东部。对于死海和湖货车沉积物记录的独立年表的基础上不同的相对和绝对测年技术已经建立，然而，遭受相当大的测年不确定性，特别是超出放射性碳的时间尺度。这妨碍了对这些关键的古气候记录进行详细的比较和整合，以研究区域气候差异。我们将利用最近的进展，在寻找cryptotephra（宏观上看不见的火山玻璃碎片）的沉积物记录，已被证明是一个合适的工具，区域同步，即使相关的火山爆发的精确日期是不可用的。我们的目标是寻找玻璃碎片在死海ICDP核心周围的主要气候转变在末次冰期/间冰期循环，并通过主要和微量元素化学与玻璃碎片从选定的主要可见火山灰层在湖货车记录。在一项初步研究中，我们可以证明来自安纳托利亚的火山玻璃在死海沉积物中的含量比预期的要丰富得多。到目前为止，与全新世早期和冰川晚期Erciyes Dag（安纳托利亚中部），Süphan和Nemrut（安纳托利亚东部）火山爆发的地球化学相关性是成功的。这使得死海火山灰与安纳托利亚火山喷发的相关性非常有希望，即使由于大量的安纳托利亚火山喷发具有相似的地球化学性质，这可能不可能适用于死海的所有火山灰层位。我们将应用玻璃碎片形态学以及主要和微量元素地球化学的相关性。除了Dead Sae和Lake货车岩心的直接联系外，我们还试图通过与合作伙伴的合作，通过与安纳托利亚近端沉积物和其他湖泊沉积物记录中的玻璃化学的相关性，确定火山中心以及可能的主要火山灰层位的确切喷发。我们进一步尝试与我们在英国的合作伙伴正在进行的Leverhulme项目中在死海附近的黎凡特考古遗址中发现的火山灰相关。即使来自意大利和希腊火山中心的隐火山岩在死海沉积物中非常罕见，我们也将研究与这些来源的可能相关性。最终，基于火山灰的同步死海和湖货车ICDP核心将提供一个坚实的基础，测试两个核心的独立的年龄模型，并减少目前的测年不确定性。最后，这两个关键的古气候记录的同步将允许在时间上量化和更好地了解地中海东部的区域水文气候差异。

This project aims at precise synchronisation of the long ICDP sediment cores from the Dead Sea and Lake Van in order to provide a robust chronological fundament to investigate the assumed regional hydroclimatic differences in the eastern Mediterranean. For both the Dead Sea and Lake Van sediment records independent chronologies based on different relative and absolute dating techniques have been established which, however, suffer from rather large dating uncertainties especially beyond the radiocarbon time scale. This prevents from a detailed comparison and integration of these key palaeoclimatic records in order to investigate regional climatic differences. We will make use of recent advances in the search for cryptotephra (macroscopically invisible volcanic glass shards) in sediment records that have been demonstrated as a suitable tool for regional synchronisation even if a precise dating of the correlating volcanic eruptions is not available. We aim at searching for glass shards in the Dead Sea ICDP core around major climatic transitions during the last glacial/interglacial cycle and correlate these through major and trace element chemistry with glass shards from selected major visible tephra layers in the Lake Van record. In a pilot study we could prove that volcanic glass from Anatolian sources is much more abundant in the Dead Sea sediments than expected. So far, a robust geochemical correlation with early Holocene and late Glacial eruptions of the Erciyes Dag (central Anatolia), Süphan and Nemrut (eastern Anatolia) volcanoes was successful. This makes correlations of Dead Sea tephra with Anatolian volcanic eruptions very promising, even if that presumably will not be possible for all tephra horizons in the Dead Sea due to the large number of Anatolian eruptions with similar geochemistry. We will apply glass shard morphology as well as major and trace element geochemistry for correlations. In addition to the direct link of the Dead Sae and Lake Van cores, we attempt to determine the volcanic centres and where possible the exact eruption of major tephra horizons through correlation with glass chemistry from proximal deposits and other lacustrine sediment records in Anatolia through collaboration with partners. We further attempt correlation with tephra found in archaeological sites in the Levant near the Dead Sea in an ongoing Leverhulme project by our partners in the UK. Even if cryptotephra from Italian and Hellenic volcanic centres is comparably rare in the Dead Sea sediments, we will investigate possible correlations with these sources. Ultimately, a tephra-based synchronisation of the Dead Sea and Lake Van ICDP cores will provide a solid base for testing the independent age models of both cores and reduce present dating uncertainties. Finally, the synchronisation of these two key palaeoclimatic records will allow to temporally quantify and better understand regional hydroclimatic differences in the eastern Mediterranean.