中布容事件（约430 ka）之后全球冰期—间冰期气候振幅显著增大。为深入研究该事件前后东亚季风气候变率及河湖相沉积演化对东亚季风气候变化的响应，对渭河盆地23GL 钻孔记录的过去1.18 Ma 以来河湖相—风成相的磁化率变化机理进行了探讨；综合黄土高原古气候记录，研究了MIS 12~10 期间钻孔磁化率揭示的东亚夏季风降水变化，并对其进行周期分析。结果表明，浅湖环境中低磁化率与粗碎屑输入较低和成岩过程中强磁性矿物可能发生还原性溶解有关；滨湖环 境中磁化率总体升高，且异常高的磁化率峰值与古湖萎缩使得钻孔位置更加接近岸边有关，这进而导致强磁性粗碎屑颗粒增加；河流沉积物中磁化率波动与不稳定的沉积环境及氧化—还原条件有关。周期分析表明，东亚夏季风降水受岁差主导的夏季日照驱动。MIS 12 期间东亚地区发生了2 次（451 ka 和460 ka）明显的季风降水减少事件；中布容事件前后浅湖—滨湖—河流环境的演化与MIS 12 晚期至MIS 9 期间季风降水减少、长冰期和较高蒸发的综合作用有关。

Abstract：The Mid-Brunhes Event (MBE, ~430 ka) marks a pronounced amplification of global glacialinterglacial climate amplitude and a fundamental reorganization of the Earth system. Palaeoclimatic proxies from the Chinese Loess Plateau indicate that Marine Isotope Stage (MIS) 13a, immediately preceding the MBE, was the warmest and wettest interglacial of the Middle–Late Quaternary in East Asia, whereas global marine and other terrestrial archives consistently identify the post-MBE MIS 11c as the humid and thermally optimal interglacial worldwide. To investigate the variability of the East Asian monsoon climate and the response of fluvial-lacustrine sedimentary sequences to East Asian monsoon climate change across the event, we analyzed the mechanisms governing down-core variations in volumetric magnetic susceptibility (κ, 10-5 SI) preserved in the lacustrinefluvial-aeolian succession preserved of borehole 23GL from the Weihe Basin over the past 1.18 Ma. By integrating previously published paleoclimate proxies from the loess-paleosol sequence of the Chinese Loess Plateau, we investigated variations in East Asian summer monsoon (EASM) precipitation as recorded by κ during MIS 12~10 and analyzed their orbital periodicities. Results show that the low κ in the shallow-lake setting is related to (i) the low input of coarse debris flux and (ii) possible reductive dissolution of ferrimagnetic minerals during early diagenesis. In the littoral settings, the κ values are systematically higher; exceptional κ peaks coincide with lake-level fall that shifted the depositional site closer to the paleo-shoreline, thereby increasing the flux of ferrimagnetic coarse detritus. In fluvial settings, high-amplitude κ variability is primarily controlled by unstable sedimentary environments and variable oxidation-reduction conditions associated with intermittent subaerial exposure. Within the overlying aeolian sequence, κ clearly defines two intervals: (i) a low- κ interval (~30~12 ka) correlative with the MIS 2 loess sub-layer L1L1, and (ii) a high-κ paleosol layer S0 (<12 ka) formed during the Holocene. Spectral analysis of the κ series for the 500~320 ka window reveals a statistically significant precession cycle (~20 ka), demonstrating that EASM precipitation is paced by precession-dominated boreal summer insolation. During MIS 12, two pronounced precipitation minima occurred at ~460 ka and ~451 ka across East Asia—expressed in the core as 30- to 50-cm-thick sand beds that coincide with high κ and meangrain-size values. The transition from shallow-lake to littoral-lake and finally to fluvial settings across the MBE is attributed to the combined effects of (i) the reduced EASM precipitation from late MIS 12 to MIS 9, (ii) the longer glacial stages after the MBE, and (iii) the enhanced evaporation during the extended MIS 11c interglacial.