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It is generally accepted that the glacial‐interglacial variations of the East Asian winter monsoon (EAWM) are controlled by the volume of the Northern Hemisphere ice sheets (NHIS), but the fact that they exhibit different evolution patterns during glacial inceptions is often overlooked. By generating an independent chronology framework and integrating multi‐proxy records from the loess sections on the central Chinese Loess Plateau, here we show that the rapid intensifying of the EAWM during glacial inceptions reflects millennial perturbations in the large‐scale atmospheric circulation in East Asia in response to insolation‐triggered abrupt North Atlantic cooling. This climate teleconnection between North Atlantic and East Asia is found to be particularly effective only when the NHIS reaches a critical large size. Our integrated multi‐proxy records thus highlight the key role of ice volume in modulating the response of the EAWM to insolation‐triggered North Atlantic cooling during the interglacial‐glacial transitions. Plain Language Summary: The strength of the East Asian winter monsoon is thought to be dynamically linked to the volume of the Northern Hemisphere ice sheets during the Quaternary glacial‐interglacial cycles. Nevertheless, paleoclimatic records generally indicate a rapid shift in the East Asian winter monsoon intensity in the mid‐way of the gradual build‐up of the Northern Hemisphere ice sheets, meaning that our current understanding of the East Asian winter monsoon dynamics remains elusive. By generating an independent chronology framework and integrating multi‐proxy records from the loess sections on the central Chinese Loess Plateau, here we show that the rapid intensifying of the East Asian winter monsoon during glacial inceptions, previously demonstrated as a direct response to the build‐up of the Northern Hemisphere ice sheets, actually reflects millennial perturbations in the large‐scale atmospheric circulation in East Asia caused by insolation‐triggered abrupt North Atlantic cooling when Northern Hemisphere ice sheets reach a critically large size. Our results thus offer new insights into how the climate teleconnections between high‐ and middle‐latitudes of the Northern Hemisphere have controlled the East Asian winter monsoon during glacial inceptions. Key Points: Microcodium 87Sr/86Sr record captures the cooling trend in East Asia at the interglacial‐glacial transitionsDecoupled evolution of East Asian winter monsoon and temperature occurred during glacial inceptionsIce volume modulates the response of East Asian winter monsoon to insolation‐triggered North Atlantic cooling during glacial inceptions [ABSTRACT FROM AUTHOR]

Earth's climate system has experienced substantial millennial‐scale oscillations characterized by abrupt changes superimposed on orbital‐scale changes. However, the dynamic connection between millennial and orbital timescales remains elusive. Here, we provide a summer monsoon precipitation δ18O record spanning from ∼8 to ∼60.5 ka based on the oxygen isotopic composition of microcodium from loess deposits on the Chinese Loess Plateau. This record shows distinct precessional variations (23 ka) punctuated by prominent millennial‐scale oscillations. It is generally consistent with speleothem δ18O and other loess‐based records, reflecting the East Asian summer monsoon changes. More importantly, our result also shows that large increases in the magnitude of millennial‐scale variability correspond to the Northern Hemisphere summer insolation minimum. We propose that precession‐induced low‐latitude summer insolation modulates the amplitudes of millennial‐scale summer monsoon variability by changing the mean monsoon state during the last glaciation. Plain Language Summary: Understanding the dynamic connections between different timescales is crucial to predicting future climate variability. Here, we provide a summer monsoon precipitation δ18O record based on the oxygen isotopic composition of microcodium from loess deposits on the Chinese Loess Plateau, showing that large increases in the magnitude of millennial‐scale variability correspond to Northern Hemisphere summer insolation minimum. We propose that low‐latitude summer insolation modulates the amplitudes of millennial monsoon variability during the last glaciation. Our work provides clues for deciphering the dynamic connections between orbital and millennial timescales. Key Points: A summer precipitation δ18O record on the Chinese Loess Plateau during the last glaciation was reconstructed based on microcodium δ18OThe record shows distinct precessional variations punctuated by millennial‐scale oscillations, consistent with other monsoon recordsThe magnitude of millennial‐scale East Asian summer monsoon variability was found to be modulated by low‐latitude insolation during the last glaciation [ABSTRACT FROM AUTHOR]

Records of Asia Summer Monsoon (ASM) from the Chinese loess and the speleothem display distinct features. The very different proxies that were applied to the two archives may be responsible for this discrepancy. A direct comparison between the speleothem and the loess records under the same proxy system of rainwater δ 18 O may help to resolve this puzzle. Here we show that the calcified microcodium in the loess deposits may record the oxygen isotopic composition of the summer rainwater. A microcodium based δ 18 O record covering the past 140 kyrs was generated, which shows similar magnitude of the overall variation to that of the speleothem records. However, much weaker precession variability was registered in the microcodium record during the last interglacial period. Instead, the microcodium δ 18 O record is more consistent with the widely used summer monsoon proxy of magnetic susceptibility in the loess deposits with clear glacial-interglacial pattern. This similarity may originate from the low sedimentation rate of the interglacial paleosol layer that preferentially record the peak ASM signals on the precession band. It is also possible that the orbital variability of ASM between the North China and South China is inherently different with more ice-volume related influence in the north. A longer microcodium δ 18 O record in sequences of higher sedimentation rate and a reliable record of summer rainfall may help to resolve these possibilities. [ABSTRACT FROM AUTHOR]

Abstract: Eolian deposits of loess on the Chinese Loess Plateau are investigated to decipher the influence of sequentially changed monsoon climate on silicate weathering process. Detailed hydrochloric acid dissolution experiments are applied to establish a sensitive proxy for silicate weathering. Combined elemental and mineralogical studies show that the minerals which are susceptible to incipient chemical weathering can be totally dissolved in hot hydrochloric acid (80°C, 3mol/L) after 4h, while other stable minerals are nearly unaffected. Thus, the hydrochloric acid dissolvable fractions (ADF) of loess and paleosol are more sensitive than bulk samples in the weathering reaction. Since Mg is tend to be leached out from the ADF while Al is conserved during the incongruent weathering, Mg/Al ratio of the ADF (Mg/AlADF) could indicate the weathering intensities of the Mg-bearing minerals, mainly chlorite. The Mg/AlADF of the modern soils on the Chinese Loess Plateau is closely correlated to the local precipitation amounts, suggests that the intensity of summer monsoon is a key factor in the weathering of Mg-silicate. The silicate weathering intensity of the loess-paleosol deposits of past 130Kyrs shows strong procession cycle of ∼ 23Kyrs coupled by glacial-interglacial variation. The ∼ 23Krys cycles are coherent to the variations of the intensity of summer monsoon, while the ∼ 100Kyrs glacial-interglacial variation may relates to the changes in winter monsoon. Phased intensification of East Asian summer monsoon, and thus enhanced silicate weathering and atmosphere CO2 drawdown, in response to the uplift of Tibetan Plateau, may be another mechanism relating the late Cenozoic tectonics to global cooling. [Copyright &y& Elsevier]

The East Asian summer monsoon (EASM) is a major component of the global climate yet, the causes for the past spatiotemporal variability of EASM rainfall, its interactions and impacts remain unresolved. Here we use the Sr–Nd isotopes and rare earth elements composition of dust in a peat record from northeast (NE) China to investigate the relationship between aeolian dust, the East Asian monsoon and Westerly Jet (WJ) over East Asia since the Late Pleistocene (14 cal ka BP). The NE drylands of China dominate the dust fraction (Hunshandake, Horqin; 44–88%) with a contribution from the deserts of NW China (Badain Jaran, Tengger, Taklamakan; 10–44%), suggesting an influence of the WJ. Dust deposition varied during the Holocene, displaying a minimum between 8.0 and 6.0 cal ka BP and two peaks at 5.8–3.8 and 1.7–0.3 cal ka BP. Changes in dust flux are opposite to the East Asian winter monsoon intensity profile, suggesting a limited influence of the winter monsoon. The EASM appears to have played a more significant role in the dust cycle, with increasing dust fluxes corresponding with lower EASM precipitation. Variations in dust flux from NE drylands display shifts reflecting changes in EASM precipitations and dune activity along the EASM margin, where the dust originates from. To account for the influence of the WJ, we propose that the meridional position and intensity of the WJ also affected dust emission in the drylands' region. A more northward position of the WJ allows the EASM front further north, generating more precipitations over the NE drylands, reducing the extent of arid areas, and resulting in less dust emission from dune activity, while the opposite occurs with a strong, more southerly WJ. Anthropogenic activities are likely to have had an increasing impact on the dust cycle over the late Holocene. Nevertheless, the presence of inconsistencies in records, coupled with a simultaneous decline in climatic conditions (mainly precipitations) during the same timeframe, hinders the precise assessment of the influence of human activities on dust emissions in the region. • Aeolian dust in Hani peatland originate mainly from the northeast drylands. • Deserts of the north margin of the Tibetan Plateau also contribute significantly. • Dust deposition follows the general pattern of the East Asian summer monsoon (EASM). • WJ path changes influence EASM dynamics and desert surface conditions in NE China. • EASM-WJ interactions control dust dynamics at the margin of the EASM system. [ABSTRACT FROM AUTHOR]

Projecting future changes in effective precipitation under global warming, which requires constraints on both the precipitation and evapotranspiration, is still challenging in the semi‐arid region of East Asia. Here we present proxies, based on Sr/Ca and 87Sr/86Sr of soil carbonate, to reconstruct the evolution of both effective precipitation and temperature from a high‐resolution loess profile in the East Asian monsoon marginal area covering the last interglacial period as a geological analog for future conditions. We find that intervals with a stronger summer monsoon are characterized by lower effective precipitation during Marine Isotope Stage (MIS) 5 due to a larger increase in evapotranspiration than in monsoonal precipitation in response to higher temperature. The greater response of the effective precipitation to temperature than summer monsoon intensity during MIS 5 thus suggests the risk of further aridification in the semi‐arid region of East Asia under climate warming. Plain Language Summary: The potential shortage of water resources in the semi‐arid regions of East Asia under climate warming may pose serious social issues in this highly‐populated area. Projecting changes in water resources in this region requires knowledge of how both monsoonal precipitation and evapotranspiration would respond to a warming climate. Here we present records of effective precipitation and temperature from the East Asian monsoon margins during Marine Isotope Stage (MIS) 5 when a similar degree of warming to future projections has been documented globally. The results show that warm intervals during MIS 5 were characterized by strong summer monsoon conditions but low effective precipitation, indicating greater response of evapotranspiration than monsoonal precipitation to climate warming. Our results thus suggest the possibility of water shortages in the future semi‐arid region of East Asia. Key Points: Microcodium Sr/Ca ratio is a proxy for effective precipitation while microcodium 87Sr/86Sr is sensitive to local temperatureEvolution of both effective precipitation and temperature during Marine Isotope Stage (MIS) 5 has been reconstructedEffective precipitation in the East Asian monsoon margins is controlled by both temperature and monsoonal precipitation amount during MIS 5 [ABSTRACT FROM AUTHOR]

Deciphering the sources of eolian dust on the Chinese Loess Plateau (CLP) is fundamental to reconstruct paleo-wind patterns and paleo-environmental changes. Existing datasets show contradictory source evolutions of eolian dust on the CLP, both on orbital and tectonic timescales. Here, the silicate Sr and Nd isotopic compositions of a restricted grain size fraction (28-45 μm) were measured to trace the source evolution of the CLP since ~2.7 Ma. Our results revealed an unchanged source on orbital timescales but a gradual source shift from the Qilian Mountains to the Gobi Altay Mountains during the past 2.7 Ma. Both tectonic uplift and climate change may have played important roles for this shift. The later uplift of the Gobi Altay Mountains relative to the Qilian Mountains since 5 ± 3 Ma might be responsible for the increasing contribution of Gobi materials to the source deserts in Alxa arid lands. Enhanced winter monsoon may also facilitate transportation of Gobi materials from the Alxa arid lands to the CLP. The shifting source of Asian dust was also reflected in north Pacific sediments. The finding of this shifting source calls for caution when interpreting the long-term climate changes based on the source-sensitive proxies of the eolian deposits. [ABSTRACT FROM AUTHOR]

Minerals and rocks have distinct Sr87/86Sr and 143Nd/144Nd ratios, depending on their geological origin and ages, and these isotope ratios are less altered than elemental composition during transport in the atmosphere or after deposition as sediments, thus stable isotopes of Sr and Nd have great potential as tracers for provenance and transport of materials. During the hypergene process, Sr isotope ratios of sediments are controlled by their parent rocks, particle sizes and chemical weathering. In general, the higher the Sr isotope ratios of parent rocks, and/or the more the fine-grained fractions, and/or the stronger the chemical weathering, thus the higher the Sr isotope ratios of sediments. On the contrary, there are lower Sr isotope ratios of sediments. Nd isotope ratios of sediments, independent of their particle sizes and chemical weathering, are only associated with parent rocks. For the provenance of the Chinese Loess Plateau, different reseachers drew discordant and even contradictory conclusions by using the method of Sr-Nd isotopic tracing. From the previous Nd isotope data, it is considered that the Tarim Basin, deserts in the central and west parts of Inner Mongolia and the Tibetan Plateau are the main sources of the Chinese Loess Plateau, and are also manufacturers for eolian dust of the Far East regions, together with the Chinese Loess Plateau. Sr isotope ratios of eolian dust are solely affected by wind sorting and weathering-pedogenesis due to its homogeneous composition in the Chinese Loess Plateau. Wind sorting is related to the East Asian winter monsoon but weathering-pedogenesis is mainly associated with the East Asian summer monsoon. Studies on Sr isotopic compositions of the loess-paleosol sequence suggest that 87Sr/86Sr ratios in acid-soluble materials are an index for chemical weathering intensity of the Chinese Loess Plateau, indicating the East Asian summer monsoon variations, whereas 87Sr/86Sr ratios in acid-insoluble materials are significantly controlled by particle sizes, and can be used as a proxy indicator reflecting the East Asian winter monsoon variations. Variations of 87Sr/86Sr ratios in acid-insoluble materials in the past 2.6Ma further demonstrate that the East Asian winter monsoon gradually strengthened since the beginning of the Quaternary period. This result agrees with the prior conclusion that climate gradually cooled since the onset of the Quaternary Ice Age. [ABSTRACT FROM AUTHOR]