Seminar

A growing body of paleohydrological evidence has suggested out-of-phased patterns of Holocene moisture evolution in westerly-dominated arid central Asia (ACA) and monsoonal Asia, but water isotope records in the two regions, e.g., δ18O and δD, surprisingly share strong similarity. This study particularly focuses on the ACA region, where water isotope compositions are subject to complex processes, such as temperature, precipitation, evaporation and meltwater input, thus obfuscating their hydroclimate significance. As lipid compound-specific δD of short to mid- chain and long chain n-alkanes/n-fatty acids could reflect individual conditions of lake water and terrestrial source water respectively, their difference represents isotopic alteration within lakes, likely associated with evaporation and hence moisture variations at a regional scale. Here, I plan to investigate δD records of sedimentary leaf waxes over the Holocene epoch from different lakes in ACA (e.g., Lake Sayram, Lake Hurleg and Lake Embtyty). Together with available proxy records generated from the same sediment cores and existing water isotope records in surrounding areas, my PhD project aims to i) reveal the key factors that control water isotopic variations and ii) to explore the relationship between water isotope records and moisture evolution in ACA.