气候变化和人类活动影响下黄河远端泥北支粒度组分变化及其区域沉积效应

受限于海洋动力条件的复杂性，基于陆架泥质沉积重建的古气候或古环境一直存在争议。为此，本文在北黄海地区沿沉积物输运路径采集3根柱样，通过沉积物粒度及其端元组分和基于器测数据的东亚冬季风指数和黄海暖流强度，分析了不同泥区沉积物粒度端元组分对冬季风暴和黄海暖流变化的响应机理和强度，揭示了上述变化在不同区域产生的沉积效应。结果表明，近百年以来黄河远端泥北支的沉积物组分变化受到了自然因素和人类活动的共同影响。1980年以后，人类活动对黄河沉积物入海通量及其组成的影响开始增强，并掩盖了自然演化信息。而1980年以前，不同泥区的不同端元组分对冬季风暴和黄海暖流的响应机理和强度存在差异，具有显著的区域沉积效应：粗端元组分受冬季风暴强度变化主导，能够反映山东半岛北岸跨锋面物质输运强度的变化；细端元组分受到黄海暖流强度变化主导，反映沉积物从北黄海西部泥区到辽东半岛东岸泥区的输运过程。上述结论说明，虽然粒度是表征古气候和古环境变化的重要标志物，但应根据不同泥区沉积物来源和沉积动力环境的特点，谨慎选择敏感端元组分，正确地使用粒度指标。

Variations in grain size composition and regional sedimentary effects in the north branch of Huanghe River distal mud induced by climate changes and human activities

Paleoclimate and paleoenvironment reconstruction based on shelf mud deposits remain controversial due to the complexity of coastal dynamic conditions. In this paper, three sediment cores distributed along the sediment transport path in the North Yellow Sea were collected, and the sediment grain size composition, end member, winter storms and Yellow Sea Warm Current strength variation were also analyzed. Based on above analysis, the response mechanism and intensity of different sediment grain size end member to winter storms and Yellow Sea Warm Current were discussed, and sedimentary effect in different regions caused by the above changes was also revealed. The results show that sediment composition in the north branch of Huanghe River distal mud is dominated by the natural condition and human activity over the past 100 years, respectively. Due to the impact of human activities on the sediment flux and composition of the Huanghe River into the sea began to enhance since 1980, and the natural evolution information was destroyed. In addition, through comparing sediment end member of different cores along the sediment transport pathway, the discrepancy in response mechanism and intensity of different end member to winter storms and the Yellow Sea Warm Current were observed before 1980, which reflected significant regional sedimentation effect. Further analysis demonstrated that, the coarse-grained end member is dominated by the winter storm, reflecting intensity of cross-front transport from the north Shandong Peninsula; and the fine-grained end member is controlled by the Yellow Sea Warm Current, representing the long distance transport from the offshore mud patch of the western North Yellow Sea to the eastern coast of the Liaodong Peninsula. Above conclusions indicated that, the sediment grain size is a robust tool for paleoclimate and paleoenvironment reconstruction; however, the utility of sensitive grain size should be based on sediment source and the characteristics of the sediment hydrodynamic environment analysis, and selection of the sensitive grain size and its implication should be careful.