Timing of Holocene Lake Highstand in Jinchang Paleolake from the Northeast Tibetan Plateau Foreland

Lake shoreline beach ridges and their sediments have often been investigated as paleoenvironmental indicators in arid northern China. Robust chronology is crucial to utilize this archive for paleoenvironmental reconstruction and interpretation. In this study, we reported a robust chronology for the highest wave-built beach ridge around Jinchang paleolake at the northeast (NE) margin of the Tibetan Plateau, using a combined quartz and K-feldspar luminescence dating technique, together with radiocarbon dating. The consistent quartz and K-feldspar ages suggested the sufficient reset of luminescence signals before deposition for the investigated sediments. Both kinds of luminescence ages were in agreement with three independent ¹⁴C ages, further corroborating the robustness of these obtained luminescence ages. Our results demonstrated that the investigated beach ridge was formed around 8.5–6.9 ka, suggesting a distinct period of lake highstand which has been identified in other lakes nearby. This highstand event may implicate an increased regional moisture condition, which is likely caused by the increased Asian summer monsoon precipitation.