Lake sediments on the Tibetan Plateau are important natural archives for studying past climate and environment changes. A precise sediment core chronology is a fundamental prerequisite for reconstructing past climate and environment changes. However, radiocarbon dates on bulk carbon in lake sediment cores are subject to “old carbon” reservoir effects, which can cause problems when trying to establish depth-age relations for sediment cores, especially those from the Tibetan Plateau (TP). Here we present a varve chronology that spans the last ~ 2000 years, from Jiang Co, on the central TP. Clastic-biogenic varves in Jiang Co sediments are comprised of two laminae, a coarse-grain and a fine-grain layer, observed by petrographic microscope and Electron Probe Micro Analyzer. The varve chronology is supported by ²¹⁰Pb and ¹³⁷Cs dating and was used to estimate the radiocarbon reservoir ages for the past ~ 2000 years. The thickness percentage of the coarse-grain layer within a single varve was used as a proxy for summer precipitation amount, as coarse grains are transported mainly by runoff. During the past 2000 years, the precipitation record inferred from Jiang Co sediments shows centennial-scale fluctuations that are consistent with other records from the region. The varve chronology from Jiang Co provided a valuable opportunity to estimate the “old carbon” reservoir effect in Jiang Co and reconstruct past precipitation on the Tibetan Plateau.

青藏高原湖泊沉积物是研究过去气候和环境变化的重要自然档案。精确的沉积岩核年代学是重建过去气候和环境变化的基本前提。然而，湖泊沉积物芯中散装碳的放射性碳日期受“老碳”储层效应的影响，这在试图建立沉积物芯的深度-年龄关系时会产生问题，尤其是青藏高原 (TP) 的沉积物芯。在这里，我们展示了一个跨越过去 ~ 2000 年的 varve 年表，来自中央高原的江错。江错沉积物中碎屑生物成因由岩相显微镜和电子探针显微分析仪观察，由粗粒层和细粒层两层组成。varve 年表由²¹⁰支持Pb 和¹³⁷ Cs 测年，用于估计过去 ~ 2000 年的放射性碳储层年龄。由于粗粒主要通过径流输送，因此使用单个变种内粗粒层的厚度百分比作为夏季降水量的代表。在过去的 2000 年中，从江错沉积物中推断出的降水记录显示出与该地区其他记录一致的百年尺度波动。江错的瓦斯年代学为估计江错的“老碳”储层效应和重建青藏高原过去的降水提供了宝贵的机会。