The Holocene paleoclimate of the Caucasus region is rather complex and not yet well understood: while existing studies are mainly based on pollen records from high‐altitude and humid lowland regions, no records are available from the semi‐humid to semi‐arid south‐eastern Caucasian lowlands. Therefore, this study investigated compound‐specific δ²H and δ¹³C isotopes of leaf wax biomarkers from Holocene floodplain soils in eastern Georgia. Our results show that the leaf wax δ²H signal from the paleosols mostly reflects changes in the moisture source and its isotopic composition. Depleted δ²H values before ~8 cal ka bp change towards enriched values after ~5 cal ka bp and become again depleted after ~1.6 cal ka bp. This trend could be caused by Holocene changes of the isotopic compositions of the Black and eastern Mediterranean Sea, and/or by varying contribution of both moisture sources linked with the North Atlantic Oscillation. The leaf wax δ¹³C signal from the paleosols directly indicates varying local water availability and drought stress. Depleted δ¹³C values before ~8 and after ~5 cal ka bp indicate wetter local conditions with higher water availability, whereas more enriched values during the middle Holocene (~8 until at least 5 cal ka bp) indicate drier conditions with increased drought stress.

中文翻译：

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从半湿润到半干旱的东南高加索低地的第一个全新世基于叶蜡同位素的古气候记录

高加索地区的全新世古气候是相当复杂的，尚未得到很好的理解：虽然现有研究主要基于高海拔和潮湿低地地区的花粉记录，但从半湿润到半干旱的东南部没有记录高加索低地。因此，本研究调查了化合物特异性δ ² H和δ ¹³叶蜡生物标记物的同位素Ç从全新世格鲁吉亚东部漫滩土壤。我们的结果表明，叶蜡δ ²从古土壤H信号大多体现在湿气源及其同位素组成的变化。耗尽δ ²〜8之前ħ值CALかbp的后〜5 CAL KA朝富集值变化bp的并在约1.6 cal ka bp后再次耗尽。这种趋势可能是由于黑海和东地中海同位素组成的全新世变化，和/或与北大西洋涛动有关的两种水分来源的不同贡献所致。叶蜡δ ¹³从古土壤C信号直接指示变化的局部水可用性和干旱胁迫。耗尽δ ^13个C值〜8之前和〜5 CALか后BP表示润湿剂具有更高的水可用性当地条件，而中间全新世更富集值（〜8，直到至少5 CAL KA BP）表示具有增加的干旱胁迫干燥的条件。