Magnetic susceptibility, geochemical data from SDL section

The Miocene Climatic Optimum (MCO) disrupted long-standing cooling trend with a significant temperature rise due to elevated greenhouse gases. However, the dynamics of hydrological circulation and orbital influences during this epoch in eastern Asia remain underexplored. Employing magneto-cyclostratigraphic chronology, we analyzed samples from a 120-meter-thick section in inland Asia. Our findings highlight the profound influence of two orbital cycles on the MCO: the dominant 405-kyr eccentricity and the subtler 173-kyr obliquity band. These patterns shifted the summer movement of the Intertropical Convergence Zone in East Asia, impacting northward moisture transport. Notably, we identified six drought events correlating with global phenomena like Antarctic cooling events and the Monterey Excursion. Enhanced by latitudinal insolation gradients, our results provide insights into climate variations on both regional and global scales, with implications for past and potential future scenarios.中新世气候适宜期（Miocene Climatic Optimum, MCO）因温室气体浓度升高引发显著升温，打破了长期持续的气候变冷趋势。然而，东亚地区该时期的水文循环动力学特征与轨道尺度影响机制仍有待深入探究。本研究采用磁旋地层年代学（magneto-cyclostratigraphic chronology）方法，对亚洲内陆一处120米厚的沉积剖面样品开展分析。研究结果显示，两类轨道周期对中新世气候适宜期存在显著调控作用：占主导地位的40.5万年偏心率周期，以及影响相对较弱的17.3万年轨道斜率周期。上述轨道周期驱动了东亚地区热带辐合带（Intertropical Convergence Zone）的夏季位移，进而影响了水汽向北输送过程。值得注意的是，本研究识别出6次干旱事件，其与南极变冷事件、蒙特雷偏移（Monterey Excursion）等全球气候现象存在显著相关性。本研究结果结合纬度日射梯度的增强效应，揭示了区域与全球尺度的气候演变规律，可为理解过去及未来潜在的气候情景提供科学参考。