Climate change characteristics in the Qinghai-Tibetan Plateau (QTP) exhibit spatial differences. These differences are due to different large circulation systems, comprising Asian summer monsoons and mid-latitude Westerlies. However, the paleoclimate pattern at the transition zone between the two systems existing since the Late Glacial remains unclear. We present a 13,000-year high-resolution record of climate change and monsoon effects in the source region of the Yangtze River at the modern limit of the Indian Summer Monsoon (ISM) influence, which lies in the interaction zone with the Westerlies. Multi-proxy records—such as grain size (GS), total inorganic carbon (TIC) and element geochemistry—suggest four stages of paleoclimate change since the Late Glacial: 1) relatively cold in the Late Glacial, 2) warm-wet conditions in the early Holocene, 3) cool-dry conditions in the mid- and late Holocene and 4) a warming and wetting trend over the last 2000 years. Correspondingly, the lake experienced a shallow-water phase in the Late Glacial and a deep-lake phase during the Holocene. The cold Younger Dryas (YD) event occurred from 12.7 to 11.0 cal. kyr BP in the core, with extremely low total organic carbon (TOC) and coarse GS. In contrast, the Holocene Megathermal occurred between 10.0 and 9.1 cal. kyr BP, as recorded by the TOC maxima, which had a finer grain size. In this study, the TIC (plus the XRF-Ca and Ca/Si ratio) reflected the combined effects of biochemical processes (e.g., algal photosynthesis) and hydrological changes (e.g., precipitation, evaporation and runoff). Comparisons between regional records and reconstructed paleoclimate indexes suggested that the studied area's effective moisture pattern mostly followed fluctuations in the ISM-dominated region. The monsoonal circulation drove the paleoclimate variations on the central QTP since the Late Glacial, mainly controlled by enhanced summer insolation until the mid-Holocene. Further, the effective moisture variation was influenced by the August insolation (increased evaporation), on which the Westerlies effect (related to intensely cold air) and the meltwater runoff were later superimposed. Recently, the hydro-climatic conditions have acquired a temperate-humid status in the study area, which likely approaches that in the early Holocene's late phase. Therefore, the paleoclimate pattern of the source region of the Yangtze River exhibits a transitional nature (phase) between two circulation regions during the Holocene.

青藏高原的气候变化特征表现出空间差异。这些差异是由于不同的大型循环系统，包括亚洲夏季风和中纬西风。然而，自晚冰期以来存在的两个系统之间的过渡带的古气候模式仍然不清楚。在印度洋夏季风（ISM）影响的现代极限（位于与西风的相互作用带）中，我们呈现了长江源地区气候变化和季风影响的13,000年高分辨率记录。自晚冰期以来，多代理记录（例如粒度（GS），总无机碳（TIC）和元素地球化学）建议了古气候变化的四个阶段：1）晚冰期相对寒冷，2）温湿条件下。早期全新世 3）全新世中期和晚期的凉爽干燥条件，以及4）过去2000年的变暖趋势和湿润趋势。相应地，该湖在晚冰川期经历了浅水期，而在全新世期间经历了深湖期。寒冷的年轻树妖（YD）事件发生于12.7至11.0 cal。核心中的yr BP，具有极低的总有机碳（TOC）和粗GS。相反，全新世超热发生在10.0到9.1卡之间。如TOC最大值所记录的kyr BP，其晶粒尺寸更细。在这项研究中，TIC（加上XRF-Ca和Ca / Si比）反映了生化过程（例如藻类的光合作用）和水文变化（例如降水，蒸发和径流）的综合作用。区域记录和重建的古气候指数之间的比较表明，研究区 其有效水分模式主要跟随ISM主导地区的波动。自晚冰川期以来，季风环流推动了中央QTP的古气候变化，主要受夏季日照增强直到全新世中期的控制。此外，有效的水分变化受八月日照（蒸发增加）的影响，随后将Westerlies效应（与强烈的冷空气有关）和融水径流叠加在一起。最近，研究区的水文气候条件已达到温带湿润状态，这可能接近全新世晚期。因此，在全新世期间，长江源区的古气候模式在两个环流区域之间表现出过渡性质（相）。