资源环境科技发展态势分析平台

The late Holocene is generally regarded as an interval of monsoon recession and decreased precipitation in North China. However, the extent to which this affected the status of lakes in North China is unclear. In the study, we analyzed multiple proxies (delta C-13, magnetic susceptibility [chi(lf)], and exogenous element concentrations) from Lake Mayinghai, an undisturbed alpine lake in North China. We also compared the results with previously published paleoenvironmental records from the Chinese Loess Plateau. We aimed to determine the extent of the influence of variations in the East Asian summer monsoon (EASM) on the status of Lake Mayinghai during the late Holocene. The results demonstrate that negative delta C-13 values at Lake Mayinghai correspond to high sedimentary tree pollen content and high reconstructed precipitation, indicating that variations in delta C-13 likely reflect variations in vegetation and the EASM in North China. A comparison of the delta C-13 record with other proxies from the same core reveals an abrupt change in the EASM at similar to 3 kyr before present (BP), which is also evident in other regional climate records from the Chinese Loess Plateau. The rapid decline in EASM intensity at similar to 3 kyr BP is also consistent with changes in the status of Lake Mayinghai, Lake Gonghai, Lake Ganhai, and Lake Daihai, in that these lakes underwent an abrupt retreat after 3 kyr BP, demonstrating that the rapid decline in EASM intensity at similar to 3 kyr BP had a large impact on lake evolution in North China.