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As the second largest dust source on the globe, the tectonic and climatic evolution of continental Asia has an important impact on regional and global climate change. The West Pacific is the main sediment sink for eolian dust transported eastward from the Asian interior. Clay minerals, as the major fine-grained weathering products of continental rocks, can be readily transported by wind or currents over long distances and thus have been widely used in the reconstruction of paleoclimate and weathering history. However, the overall evolutionary tendency and response mechanism of clay mineral records over large spatial and long timescales across Asia remain unclear. Here, two continuous and high-resolution clay mineral records since 30 Ma were reconstructed from sediments at Deep Sea Drilling Program (DSDP) Sites 292 and 296 in the Philippine Sea. Clay minerals and Sr-Nd isotope compositions were used to constrain provenance and reconstruct the drying history of the dust source region since the Oligocene. The results show that the clay-sized detrital sediments in the Philippine Sea are a mixture of Asian eolian dust and volcanic materials from the West Pacific arcs. Based on the clay mineral compositions and eolian flux, we reveal that the Asian interior has been continuously drying since the late Oligocene and that stepwise enhanced aridification occurred at approximately 20, 14, 7, and 3 Ma. Compared with other regions of the world, the relative contents of illite and chlorite increased more dramatically in Asia during the late Cenozoic, and the inconsistency became more obvious at approximately 20 Ma. Since 3 Ma, illite and chlorite have increased consistently across the globe. Combined with the Asian tectonic and climatic history, we suggest that the increase in illite and chlorite from Asia between 20 and 3 Ma was mainly in response to the uplift of the Himalayan-Tibetan Plateau, whereas after 3 Ma, it was primarily controlled by global cooling driven by the expansion of the Arctic ice sheet. [ABSTRACT FROM AUTHOR]

Despite the importance of the westerlies to the global climate system, we still know little about their long‐term evolution and possible orographic controls during the late Cenozoic because of the lack of sedimentary records with precise chronological control. Eolian deposition in the North Pacific preserved past information about the westerlies, the major wind system delivering Asian dust to the Pacific. A continuous, high‐resolution eolian flux record since 23 Ma was reconstructed from sediments at Deep Sea Drilling Project Site 296 in the North Pacific. Combined with dust flux at Ocean Drilling Program Site 1208, variations in their difference indicated a northwards shift of the westerlies during 23‒9 Ma and a relatively stable state since then. We suggest that Tibetan uplift since the early Miocene began to drive the poleward shift of the westerlies until 9 Ma, after which the westerlies remained relatively stable over Asia on million‐year timescales. Plain Language Summary: The Northern Hemisphere Westerly wind is a significant component of planetary‐scale atmospheric circulation and has a large impact on regional and global climate change. Although numerous modern observations and orbital time‐scale studies of the Westerly wind have been conducted, we still know little about its evolution on million‐year time‐scales, which may modulate the overall amplitude of short‐term variations. Eolian deposition in the North Pacific has preserved precious information about the westerlies in the past. A continuous and high resolution eolian flux record dating from 23 Ma was reconstructed from sediments at Deep Sea Drilling Project Site 296 in the Northwest Pacific. Combined with dust records at Ocean Drilling Program Site 1208 to the east, we constrain how the path and strength of the Northern Hemisphere Westerlies have changed since the early Miocene. The two eolian records indicate a northwards shift of the westerlies between 23 and 9 Ma and a relatively stable state since then. We suggest that stepwise uplift of the Tibetan Plateau since at least the early Miocene began to drive the northwards shift of the Northern Hemisphere Westerlies until about 9 Ma, after which the westerlies remained relatively stable over Asia‐North Pacific on million‐year timescales. Key Points: We reconstruct the eolian flux record in the North Pacific since 23 Ma at high resolutionThe Northern Hemisphere Westerlies shifted northward between 23 and 9 Ma and have remained relatively stable since thenTibetan uplift drove the northward shift of Northern Hemisphere Westerlies in the early late Miocene [ABSTRACT FROM AUTHOR]

Shelf mud is an important sink for fluvial sediment, and it is sensitive to variations in river discharge and ocean circulation, which are significantly influenced by climate change. However, the evolution of shelf mud in response to climate change during the Holocene is poorly understood. Here, we present high‐resolution sedimentary records of heavy minerals and mass accumulation rates (MARs) from the East China Sea shelf to study the response mechanisms of the Holocene shelf mud supply, transport, and sedimentation to the climate‐driven variations in fluvial discharge and ocean currents. The results indicate that the shelf mud primarily originates from the Changjiang (Yangtze) River and has been mainly transported by wind‐driven longshore currents in suspension since approximately 8.0 ka. A comparison of the MARs with several shelf mud sedimentation‐rate records and climate changes during the Holocene on millennial timescales showed that strong (weak) precipitation in the river basin, which is positively linked with Asian summer monsoon and El Niño‐driven storms, could intensify (weaken) the fluvial sediment supply, thereby increasing (decreasing) the shelf mud deposition flux. On multicentennial timescales, changes in the relative intensities of different ocean currents due to climate oscillations during the Holocene could generate frequent migrations of the current shear front (a hydrodynamic barrier), which has trapped an abundance of suspended materials on the shoreward side and resulted in rapid mud sedimentation (~2.3 g/cm2/year) at different sites during different periods. Therefore, our study highlights that the Holocene shelf mud evolution responds sensitively to climate changes on different timescales. Key Points: The Changjiang River mud has been mainly carried southward by wind‐driven longshore currents since 8.0 kaHolocene shelf mud supply is modulated by precipitation from summer monsoons and El Niño‐related stormsHolocene rapid shelf mud sedimentation is directly linked with climate‐driven migrations of ocean currents [ABSTRACT FROM AUTHOR]

The Kuroshio Current (KC) is the northward branch of the North Pacific subtropical gyre (NPG) and exerts influence on the exchange of physical, chemical, and biological properties of downstream regions in the Pacific Ocean. Resolving long-term changes in the flow of the KC water masses is, therefore, crucial for advancing our understanding of the Pacific's role in global ocean and climate variability. Here, we reconstruct changes in KC dynamics over the past 20 ka based on grain-size spectra, clay mineral, and Sr–Nd isotope constraints of sediments from the northern Okinawa Trough. Combined with published sediment records surrounding the NPG, we suggest that the KC remained in the Okinawa Trough throughout the Last Glacial Maximum. Together with Earth-System-Model simulations, our results additionally indicate that KC intensified considerably during the early Holocene (EH). The synchronous establishment of the KC “water barrier” and the modern circulation pattern during the EH highstand shaped the sediment transport patterns. This is ascribed to the precession-induced increase in the occurrence of La Niña-like state and the strength of the East Asian summer monsoon. The synchronicity of the shifts in the intensity of the KC, Kuroshio extension, and El Niño/La Niña-Southern Oscillation (ENSO) variability may further indicate that the western branch of the NPG has been subject to basin-scale changes in wind stress curl over the North Pacific in response to low-latitude insolation. Superimposed on this long-term trend are high-amplitude, large century, and millennial-scale variations during last 5 ka, which are ascribed to the advent of modern ENSO when the equatorial oceans experienced stronger insolation during the boreal winter. [ABSTRACT FROM AUTHOR]

Abstract: Changes in paleoenvironments over the last 17,500yr have been documented by a high-resolution clay mineralogy and grain–size records of Core KNG5 from the northern slope of the South China Sea. Our results indicate that clay minerals are mainly from the Pearl River from 17,500 to12,500calyr BP, and the South China Sea modern current system began to form since 12,500calyr BP, as a result, Taiwan turns to be the major contributor of clay minerals after 12,500calyr BP. Two grain-size populations with high variability through time were identified in the 13–28μm and 1–2.2μm grain-size intervals. The 1–2.2μm grain-size population are mainly controlled by provenance supply and current transport. The 13–28μm grain-size fraction could be controlled mainly by the sea-level change. The 1–2.2μm grain-size population record demonstrates that East Asian Summer Monsoon intensity generally follows changes in insolation and that the response is similar for a large area of China and other northern low-latitude records, implying the globality of the monsoon evolution since Holocene. The anomalous environmental conditions in the northern South China Sea may imply intensified ENSO activity during the late Holocene. [Copyright &y& Elsevier]

The heavy mineral composition and sensitive grain size changes from core SS4 retrieved from the mud wedge on the East China Sea inner shelf have been studied for better understanding provenance variations in the sediment and climate changes during the last ~1500 yr. High dolomite content and occurrence of ubiquitous polysynthetic mica indicate that the sediments in core SS4 were mainly derived from the Yangtze River, while the relatively high epidote content represent the contribution of small local rivers from Zhejiang and Fujian provinces. The substantial decrease in the epidote/hornblende ratio since ~730 yr BP manifests a decline in the relative contribution of sediment from the small local rivers to the core. We propose that the changes in drought/flood conditions in response to the East Asian winter monsoon (EAWM) and human activities might have been mainly responsible for changes in sedimentary characteristics. During 1400–730 yr BP, the core sediments were characterized by relatively finer sensitive grain size and high epidote/hornblende ratio, due to a possibly weaker EAWM (i.e., less Yangtze River-derived sediment transported by the southward coast current). This time interval coincides with the Sui-Tang Warm Period (1400–1130 yr BP) in China and the Medieval Warm Period (1000–730 yr BP) on a broader regional scale. The prolonged warm periods were, however, interrupted by three short cold phases at 1350–1280 yr BP, 1130–1000 yr BP and 870–750 yr BP, characterized by coarse sensitive grain size and decreased epidote/hornblende ratio. Between 360 and 150 yr BP, the sensitive grain size significantly coarsened, which corresponded to the Little Ice Age. Our new findings suggest that sedimentation processes of mud wedge formation are responsive to natural environmental change and human activity. ∙ Provenance and climate changes have been detected in the East China Sea ∙Significant changes in the ratio of epidote/hornblende indicate source variations ∙The contribution of small local rivers has declined since 730 yr BP ∙Climate-driven drought/flood conditions and human activities are the main causes ∙The alternation of the warm and cold period is well recorded by heavy minerals [ABSTRACT FROM AUTHOR]

AMS14C dating and grain-size analysis for Core DD2, located at the north of the Yangtze River-derived mud off the Zhejiang-Fujian coasts in the inner shelf of the East China Sea, provide us a high-resolution grain-size distribution curve varying with depth and time. Data in the upper mud layer of Core DD2 indicate that there are at least 9 abrupt grain-size increasing in recent 2000 years, with each corresponding very well with the low-temperature events in Chinese history, which might result from the periodical strengthening of the East Asian Winter Monsoon (EAWM), including the first-revealed maximum temperature lowering event at around 990 a BP. At the same time, the finer grain size section in Core DD2 agrees well with the Sui-Tang Warming Period (600–1000 a AD) defined previously by Zhu Kezhen, during which the climate had a warm, cold and warm fluctuation, with a dominated cooling period of 750–850 a AD. The Little Ice Age (LIA) can also be identified in the core. It starts around 1450 a AD and was followed by a subsequent cooling events at 1510, 1670 and 1840 a AD. Timing of these cold events revealed here still needs to be further verified owing to some current uncertainty of dating we used in this study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Al/Si ratios can be used to correct CIA values to avoid the influence of grain-size sorting. • CIA values decreased during the YD, 8.2 ka, and 4.2 ka cold events during the Holocene. • Chemical weathering could be enhanced due to shelf exposure when the sea level is low. • Chemical weathering shelf sediments could rapidly respond to abrupt climate events. Chemical weathering of shelf sediments is important in driving the global elemental cycle and climate to maintain the earth's habitability. However, the response mechanism between chemical weathering of shelf sediments and climate and sea-level changes is still unclear. This study focuses on core ECMZ located in the mud area of the East China Sea (ECS) inner shelf. The results indicate that the mechanisms controlling chemical weathering in the sediment of the ECS inner shelf differ at different timescales. On the orbital time scale, the Chemical Index of Alteration (CIA) indicates that the intensity of chemical weathering in sediments during the deglacial period was significantly higher than that during the Holocene. This was caused by shelf exposure during low sea-level periods when the sediments were fully exposed and the residence time in the weathering zone was long, leading the shelf sediments to undergo consistent and complete weathering under supply-limited conditions. In comparison, during cold events on the millennium-centennial time scale, such as Younger Dryas, 8.2 ka, and 4.2 ka, chemical weathering was weaker (lower CIA values) due to accelerated erosion as a result of lower temperatures and higher precipitation, which shortened the rocks' residence in the weathering zone, resulting in the control of chemical weathering shifted from supply factors to kinetic ones, such as temperature and precipitation. Our findings suggest that on the orbital time scale, glacial shelf exposure could enhance chemical weathering, thereby reducing atmospheric CO 2 ; on the millennium-centennial time scale, chemical weathering could rapidly respond to abrupt climate events. [ABSTRACT FROM AUTHOR]

Marine authigenic pyrite sulfur isotope (δ34S pyr) is one of the most important proxies for reconstructing remarkable changes of Earth's surface in deep time. Recent observations of unexpectedly large δ34S pyr variations in Quaternary sediments complicate the application of this isotopic proxy, and a mechanistic understanding of such variabilities is needed. In this study, we measured multiple sulfur isotopic compositions of pyrite in well dated sediments spanning the last 7500 years from the East China Sea (ECS) inner shelf to study the mechanism how Holocene climate controls pyrite sulfur isotopic compositions. We found that variabilities of pyrite multiple sulfur isotopes, δ34S pyr and Δ33S pyr (ranging from −38.3‰ to 2.3‰ and from −0.01‰ to 0.21‰, respectively) are significantly correlated with large fluctuations of sedimentation rates (0.03–2.09 cm/yr). In tandem with box model calculations and compiled data, the large δ34S pyr variations up to 40‰ are primarily ascribed to fluctuated anaerobic oxidation of methane coupled sulfate reduction (AOM-SR). Further analyses suggest that heightened distillation of interstitial sulfate, likely propelled by high methane flux coupled with increased sedimentation rates, can produce such negatively correlated δ34S pyr -Δ33S pyr pattern and large variations in δ34S pyr. Possible changes in isotope fractionation factors caused by varied cell-specific sulfate reduction rates result in a maximum δ34S pyr variation of <20‰ and therefore play a minor role in the large variation in δ34S pyr (>40‰). The major and minor isotopic compositions of pyrite align with sulfide produced through pure sulfate reduction, indicating little evidence of additional oxidative sulfur cycling. Sedimentation rates in the ECS are controlled by the East Asian winter monsoon that influences the sediment transport capacity from longshore currents on a multicentennial timescale, and also by the coupled East Asian summer monsoon that affects the sediment availability from the Yangtze River on a millennial timescale. Holocene climate changes alter sediment supplies at the ECS and therefore play a vital role in controlling multiple sulfur isotope compositions of sedimentary pyrite in this region. This study has the potential to provide new insights into δ34S excursions in seawater sulfate that occurred during periods of notable acceleration in sedimentation rates throughout the geological history. • ∼40‰ and 0.22‰ variations in δ34S and Δ33S of pyrite were observed in Holocene sediments. • AOM-SR account for the large sulfur isotope variations. • AOM-SR were dominated by sedimentation rate. • Climate changes regulate sulfur isotopes depending on sedimentation rate. [ABSTRACT FROM AUTHOR]

Carbon and sulfur preserved in estuary and shelf sediments play a critical role in controlling sediment diagenesis related to the global biogeochemical cycle. Their ratio (C/S = 2.8) in mud sediments has been widely used to distinguish freshwater from marine environments; however, this ratio can be influenced by depositional evolution, physical reworking, and other sedimentological parameters. We present a new C/S ratio data set from surface sediments of five rivers (Aojiang, Feiyunjiang, Jiaojiang, Oujiang, and Qiantangjiang Rivers), as well as core sediments offshore of the Oujiang Estuary (core EC2005, 60 m), to discuss how the evolution of the depositional environment influenced carbon and sulfur preservation since the last deglaciation. To this aim, we measured the contents of total organic carbon (TOC), total sulfur (TS), and carbonate in the collected samples. Our results demonstrate that a C/S ratio of 2.8 can effectively separate freshwater environments (river sediments and core sediments deposited before 13.1 ka), suggesting the initial impact of sulfate-enriched seawater on carbon and sulfur perseveration at ~13.1 ka. However, the TS content is independent of the TOC content after 13.1 ka, implying that pyrite sulfur is derived not only from organoclastic sulfate reduction (OSR) but also from sulfate-driven anaerobic oxidation of methane (AOM) under anoxic diagenetic conditions. In the shallowest core section (shallower than 5 m; < 1.5 ka), the C/S ratios gradually increase from 1 to 2.8, which corresponds to an interval with sulfide reoxidation under suboxic conditions caused by strong physical reworking. When the sediment is buried to a certain depth (deeper than 5 m; > 1.5 ka), a high sedimentation rate is conducive to an AOM reaction, resulting in the generation of a large amount of pyrite and finally causing the minimum value of the C/S ratio to be approximately 1. However, during the transitional period of 13.1–11.0 ka, sediments deposited in the tidal environment show overlap with those deposited in the marine shelf environment, and C/S ratios decrease from >10 to ~1. In addition, we propose that C/S and C/N ratios could be combined to reveal the depositional evolution from terrestrial to marine environments, which is sensitive to sea level and climatic changes. Therefore, our new findings suggest that the sedimentation process can modulate the diagenetic path of mud sediments (e.g., OSR versus AOM), and geochemical indicators of environmental evolution should be carefully used in combination with sedimentological parameters in shallow depositional environments. • We present a set of C/S data record from the East China See inner shelf since 16 ka. • C/S ratios could effectively distinguish between marine and freshwater environments. • The sedimentary process could affect the diagenetic process of authigenic pyrite. • C/S and C/N ratios could indicate the evolution of sedimentary environment. [ABSTRACT FROM AUTHOR]

Previous studies have proposed that the two-phase structure of Heinrich Stadial 1 (HS1) is a ubiquitous feature. However, few studies have focused on the internal structure of HS1 over a tropical domain; thus, the interhemispheric ocean-atmosphere teleconnections during HS1 are poorly defined. Here, we present high-resolution sedimentological, geochemical, and palaeoceanographic records from the core CG2 in the southern South China Sea (SCS), off the northern Sunda Shelf. The core continuously spans 9.0–22.0 ky BP. The records suggest two episodes of increased monsoon rainfall during the pre-HS1 (∼19.0–18.0 ky BP) and in the early HS1 (17.5–16.1 ky BP), along with a weaker monsoon rainfall during the late HS1 (16.1–14.7 ky BP). In contrast, a lower precipitation over the Flores Sea occurred during the early HS1, off the southern Sunda Shelf, followed by an enhanced precipitation runoff during the late HS1 (Muller et al., 2012). Notably, these two different precipitation phases characterise a southward Intertropical Convergence Zone (ITCZ) shift over the Sunda Shelf during HS1. These changes are also consistent with other monsoon records, as well as other available data from the tropical to high latitudes of both hemispheres, supporting the global scope of the twofold HS1. We propose that the two episodes of intense monsoon rainfall over the northern Sunda Shelf during the pre-HS1 and the early HS1 observed in our study are closely linked to two different melting events associated with European ice sheet (EIS) retreat. We further propose that the subsequent maximum Atlantic meridional overturning circulation (AMOC) reduction and the migration of the ITCZ to its southernmost position during the late HS1 are tightly connected with the destabilization of the marine-terminating ice-streams of the Laurentide ice sheet (LIS) in the North Atlantic. Tropical positive feedbacks during HS1, in turn, should have played an important role in sustaining the AMOC reduction and Northern Hemisphere (NH) stadial conditions, by continuously lowering the salinity of the low-latitude currents in the Atlantic Ocean. In addition, the tropical ITCZ appears to have been a key bridge in promoting interhemispheric climate connections, by which North Atlantic cooling was rapidly linked to increased Southern Ocean surface westerlies. This, in turn, drove upwelling and CO 2 ventilation from the Southern Ocean, and thereby facilitated deglacial warming. Finally, these findings show that tropical climate variation is an important component of deglacial climate changes; understanding how it responds to millennial events like HS1 may help us better understand global teleconnections. • The tropical hydroclimate in the Sunda Shelf area presents a two-phase structure during HS1. • Intense monsoon rainfall during pre-HS1 and early HS1 coincide with EIS melting episodes. • The two-step AMOC slowdown acts to rapidly push the tropical ITCZ southward. • The tropical ITCZ is a bridge in promoting north-south climate connections during HS1. [ABSTRACT FROM AUTHOR]

Changing sediment provenance and related paleoenvironmental evolution since marine isotope stages (MIS) 3 have been investigated based on accelerator mass spectrometry (AMS) 14C and optically stimulated luminescence (OSL) dating of core CSDP-01, recovered from the western South Yellow Sea (SYS). Based on our results, sea level fluctuations and monsoonal climate variations are identified as the principal factors driving these changes. Sea level fluctuations determined the accommodation space in the shelf area, while the monsoonal climate controlled the sediment supply capacity from river to sea. Mineral and Sr Nd isotopic records reveal the major contribution of the paleo-Changjiang River (Yangtze River) to the study core area during the early-mid MIS 3, which likely defined the northern limit of the paleo-Changjiang delta at that time. High sediment supply and limited accommodation space led to the development of sediment-fed systems on the SYS shelf, resulting in a high preservation potential for thick-stacking and overlapping deltaic sediments. Along with deltaic progradation, core sediment provenance gradually transformed from the paleo-Changjiang River to the paleo-Huanghe River (Yellow River) near the late MIS 3, implying that the paleo-Huanghe River likely emptied into the SYS and built a large delta during the MIS 3 interval. A strong summer monsoon during the early MIS 1 interval was favorable for the Changjiang to deliver abundant sediments to the study core area. A weak summer monsoon during the mid-late MIS 1 when the coastline had retreated to nearly its present-day position decreased the Changjiang and Huanghe supply to the study area. Low sediment supply and sufficient accommodation space gave rise to the development of sediment-starved systems during this period. ɛNd values fluctuated between the Changjiang and Huanghe sources at that time, suggesting that sea bed erosion materials are the main sediment contribution to the study area. In general, sedimentary evolution in the western SYS since MIS 3 is a good example of river-sea interaction in the marginal seas of Southeast Asia, in which sea level and monsoonal climate changes should play an important role. • We present mineral and Sr Nd isotopic records of core CSDP-01 since MIS 3. • Paleo-Changjiang delta built during MIS 3 distributed over a broad area. • Paleo-Huanghe River emptied into the SYS and built a large delta during MIS 3. • Sediment-starved systems have developed in the SYS during the mid-late MIS 1. • Sea level and monsoonal climate play an important role in the river-sea interaction. [ABSTRACT FROM AUTHOR]

Reconstructing the Plio-Pleistocene sedimentary history of the Yellow Sea, is important for understanding the long-term influence of the Yellow River (Huanghe) and/or Yangtze River (Changjiang) on the Asian marginal seas and to further constrain any links between river development, regional paleoenvironmental change, tectonic deformation and/or global climate change. Here we present the first high-resolution clay mineral record combined with Sr-Nd isotopic compositions from a 300-m long sediment core recovered in the western South Yellow Sea. Our study suggests that large-scale transgression in the Yellow Sea occurred after ∼0.8 Ma, possibly related to tectonic subsidence of eastern China coast and the Min-Zhe Uplift. In contrast, the sedimentary environment of Bohai and Yellow Seas was mainly dominated by fluvial/lacustrine deposits at 3.5–0.8 Ma. Provenance analysis suggests a major change in sediment provenance from the Yangtze River to the Yellow River at ∼0.8 Ma, which corresponds to the timing of the final integration of the Yellow River in its present form. At the same time the major channels of the Yangtze River migrated from the South Yellow Sea to the modern Yangtze River delta due to the subsidence of east China coast. The consistence in timing of the provenance transition and large-scale regional marine transgression suggests that tectonic deformation, rather than climate change, is the first-order control on the evolution of the Yellow and Yangtze Rivers and sedimentary environmental change in the Bohai and Yellow Seas. • A major change in sediment provenance in South Yellow Sea from the Yangtze River to Yellow River occurred at 0.8 Ma. • Large-scale transgression in the Yellow Sea began at 0.8 Ma, possibly related to subsidence of the Min-Zhe Uplift. • Tectonic deformation, rather than climate change, is the major control on the evolution of the Yellow and Yangtze Rivers. [ABSTRACT FROM AUTHOR]

Abstract Eolian dust deposition is crucial to paleoclimate reconstructions of dust source areas and may have played an important role in the climate during the mid-Pleistocene transition (MPT). Here, we present the radiogenic Sr and Nd isotopic composition and excess barium (Ba xs) of a sediment core that was recovered from the Parece Vela Basin (PVB) in the northwestern Pacific. The new record indicates that these detrital sediments are primarily composed of dust from western and central Chinese deserts and volcanic materials from the islands in and around the PVB. A two end-member Sr isotope model was applied to distinguish Asian dust from volcanic materials and to reconstruct the mass accumulation rates (MARs) of dust over the last 2.1 Myr. Starting at ~1.2 Myr, the dust MARs doubled relative to those in the Early Pleistocene, which was coupled with the frequent congruence of minimum eccentricity and low obliquity. We argue that the congruent minimum eccentricity and low obliquity may have triggered the climate change before and during the MPT and resulted in the aridity of East Asia and increased dust input. The coupling of dust MAR, Ba xs MAR and atmospheric CO 2 concentration and their rapid increase since the MPT strongly suggest that the internal positive feedback of dust input might be another mechanism behind dust input to the PVB since the MPT. Highlights • Eolian dust in the Parece Vela Basin derived from western and central Chinese deserts • Dust flux in the Parece Vela Basin significantly increased since the mid-Pleistocene • Earth orbital variation and dust feedback forced more dust input in the Parece Vela Basin since MPT [ABSTRACT FROM AUTHOR]

High resolution multi-proxy records, including geochemical and grain-size data from detrital sediments of IODP Site U1429 in the northern Okinawa Trough, provide reliable evidence for constraining sediment source and transport processes. They also allow silicate weathering and erosion controlled by sea-level change and East Asian summer monsoon evolution since 34 ka to be reconstructed. Provenance proxies indicated that sediments in the northern Okinawa Trough were mainly supplied by the Yellow River middle reach at ~ 34–8 ka. The low sea level and proximity of paleo-Yellow River mouth to the northern Okinawa Trough were the causes of the dominant Yellow River input. After ~ 8 ka, a retreated Yellow River mouth coupled with the blocking effect of the Kuroshio Current and its branches, together with strong East Asian summer monsoon precipitation resulted in relatively strong sediment input from Kyushu to the northern Okinawa Trough. Meanwhile, Yellow River upper reach supplied more sediments to the study site than that during the ~ 34–8 ka. On glacial-interglacial scale, silicate weathering proxies indicate that the core sediment was more weathered during the last glacial and deglacial than that in the modern Yellow River. We attribute this to the increased upper reach sediment input, which supplied more weak weathered sediment to the study site during the Holocene. Besides, composite effect of weathering during glacial and deglacial sediment production and additional weathering upon subaerial exposure of shelf deposits during low sea-level stage, as well as older weathered sediments reworking during sea-level rise could also account for this weathering regime. On multi-millennial scale, from ~ 34 to 18.5 ka, silicate weathering was mainly controlled by the East Asian summer monsoon, with a cooling and drying climate associated with weakened summer monsoon activity. This is consistent with the reduced alteration of sediments eroded from the Yellow River basin. From ~ 18.5 to 8 ka, strong reworking of older weathered sediments overwhelmed the East Asian summer monsoon in controlling silicate weathering, which induced a continuous increase in chemical alteration of the sediments during this period. [ABSTRACT FROM AUTHOR]

The emergence and expansion of terrestrial C 4 vegetation represent the most striking evolutionary adaptation of ecosystems to climate change during the Cenozoic. However, the long-term history of terrestrial C 4 ecosystem expansion in East Asia remains poorly documented, and its links to tectonic and/or climate changes remain unclear due to the complexity of its forcing factors. Here, we reconstruct the long-term evolution of terrestrial C 3 –C 4 plants biomass in South China since the late Eocene using continuous records of the stable carbon isotopic compositions (δ13C) of black carbon extracted from sediments at International Ocean Discovery Program (IODP) Site U1501 in the northern South China Sea (SCS). This study reveals remarkable stepwise expansions of C 4 plants in South China at ∼20 Ma and 15 Ma with a gradual expansion trend at 7–4 Ma. We demonstrate that stepwise drying (long-term weakening of the East Asian summer monsoon and simultaneous strengthening of the East Asian winter monsoon), as well as the enhanced seasonality of precipitation, is responsible for the ecological evolution in South China since the early Miocene. Our black carbon records, combined with previous studies, indicate a coupled evolution of East Asian drying, vegetation shifts and global cooling. We suggest that the major Asian topography framework was established before the middle Miocene, and global cooling overwhelmed tectonic controls of the long-term evolution of the East Asian monsoon thereafter. This study highlights that both Tibetan uplift and global cooling have played a significant role in the long-term evolution of regional climate and vegetation. • Stepwise expansion of C 4 plant in South China occurred at 20 Ma, 15 Ma and 7–4 Ma. • Stepwise drying and enhanced seasonality of precipitation induced C 4 plant expansion in South China. • Both Tibetan uplift and global cooling played a significant role in evolution of East Asian monsoon. [ABSTRACT FROM AUTHOR]

Thermocline conditions in the tropical western Pacific are closely linked to regional- and basin-scale hydrological variation and may have played a critical role in global climate evolution on various timescales. However, long-term changes in thermocline hydrology in the subtropical northwestern Pacific and their connection to the tropical Pacific remain unclear. Based on planktonic foraminiferal Mg/Ca and δ18O, we reconstructed the temperature and salinity of thermocline water since the last deglaciation, using core OKI02 from the Okinawa Trough (OKT) in the subtropical northwestern Pacific. The results indicated a discrepancy in evolution of both temperature and δ18O between the thermocline and surface water over the past 19 ka. Unlike for surface water, changes in thermocline hydrology correlated with changing conditions in the tropical western Pacific, indicating a close relationship between these regions since the last deglaciation. Thermocline temperature and salinity gradients between the OKT and the tropical western Pacific increased from ∼16.5 to 10 ka BP, reached their maximum values at approximately 10 ka BP, and then decreased from the Early Holocene to present. Variations in temperature and salinity gradients correlated with changes in the El Niño–Southern Oscillation (ENSO) over the past 19 ka, which were coupled with equatorial summer insolation variations. We suggest that the ENSO-like process, forced by equatorial summer insolation, regulated thermocline dynamics in the subtropical northwestern Pacific Ocean since the last deglaciation, by influencing the strength of the Kuroshio Current. • TWT changes were different from those of SST in OKT for the past 19 ka • Thermocline conditions in OKT linked to hydrological climate variations in the tropical western Pacific through the KC • ENSO state could have controlled the thermohaline variations in the OKT • Reduced TWT and salinity gradients between the tropical western Pacific and OKT since the Early Holocene [ABSTRACT FROM AUTHOR]

Atmospheric CO 2 and global climate are closely coupled. Since 800 ka CO 2 concentrations have been up to 50% higher during interglacial compared to glacial periods. Because of its dependence on temperature, humidity, and erosion rates, chemical weathering of exposed silicate minerals was suggested to have dampened these cyclic variations of atmospheric composition. Cooler and drier conditions and lower non-glacial erosion rates suppressed in situ chemical weathering rates during glacial periods. However, using systematic variations in major element geochemistry, Sr–Nd isotopes and clay mineral records from Ocean Drilling Program Sites 1143 and 1144 in the South China Sea spanning the last 1.1 Ma, we show that sediment deposited during glacial periods was more weathered than sediment delivered during interglacials. We attribute this to subaerial exposure and weathering of unconsolidated shelf sediments during glacial sealevel lowstands. Our estimates suggest that enhanced silicate weathering of tropical shelf sediments exposed during glacial lowstands can account for ∼9% of the carbon dioxide removed from the atmosphere during the glacial and thus represent a significant part of the observed glacial–interglacial variation of ∼80 ppmv. As a result, if similar magnitudes can be identified in other tropical shelf-slope systems, the effects of increased sediment exposure and subsequent silicate weathering during lowstands could have potentially enhanced the drawdown of atmospheric CO 2 during cold stages of the Quaternary. This in turn would have caused an intensification of glacial cycles. [ABSTRACT FROM AUTHOR]

We present a multi-proxy geochemical analysis of core KNG5 retrieved from the northern South China Sea slope spanning the last 13.0 ka BP to assess the response of weathering and erosion processes in the Southwestern Taiwan River basin to climate change. A provenance analysis indicates that the core sediments were primarily derived from the Southwestern Taiwan River, and can be used to reconstruct the erosion and/or weathering history of this river basin. The chemical index of alteration, the plagioclase index of alteration, Rb/Sr, Al/Ti, principle component 1, and K/Al combined with terrigenous mass accumulation rates and the proportion of clay exhibit sharp excursions from 12.0 to 5.5 ka, peaking at 10.0 ka, which suggests strong chemical weathering and physical erosion during the Early-Mid Holocene, the period of the maximum summer monsoon. Abrupt falling weathering trends during 5.2 and 3.5 ka BP correlate with a weaker monsoon. After 3.5 ka BP, a stable lower weathering trend to the present day was evident, indicating the deposition of less weathered sediments in the slope when the monsoon rainfall was weakening. A good correlation between our proxy records of chemical weathering and variations of the monsoon intensity in South China emphasizes that variation in monsoon intensity is most likely the primary drive of the intensity of weathering and erosion in Southwestern Taiwan River sediments over the last 13.0 ka BP. Finally, we concluded that geochemical parameters can be used as reliable proxies for climate variation on a millennial-centennial time scale in such areas as Taiwan, where weathering-limited regimes exist. [ABSTRACT FROM AUTHOR]

Reconstructing the Cenozoic sedimentary history of the Bay of Bengal (BoB) is significant for understanding the evolutionary history of South Asian river systems and the links between river development, tectonic deformation and global climate change. Here, we present the first long-term clay mineral record combined with Sr-Nd isotopic compositions from a 200-m-long sediment core from Ocean Drilling Program (ODP) Site 758 in the southern BoB to establish past variations in sediment sources and river evolution that have occurred since the late Eocene. Provenance analysis suggests that the contribution of the Himalayan source materials from the Irrawaddy and Brahmaputra Rivers to the study site became more important and stable since 22 Ma and 8 Ma, respectively. This new evidence indicates that the Brahmaputra and Irrawaddy Rivers were possibly initiated in the early Miocene (~22 Ma). Considering the timing of major tectonic and climatic evolution in South Asia, we conclude that the two phases of tectonic uplift of the Himalayan orogen that occurred in the early and late Miocene were the primary controls on river development in South Asia and provenance changes in the southern BoB. Global cooling and Indian drying after the late Miocene could also have strengthened Himalayan erosion and contributed more illite and chlorite to the South Asian margin. • First long-term clay-sized sediment record of Himalayan erosion from the Bay of Bengal since the last 37 Ma. • South Asian river system (Brahmaputra and Irrawaddy Rivers) might have initiated and established at the early and late Miocene, respectively. • Himalayan uplift exerts primary controls on river evolution in South Asia since the early Miocene. [ABSTRACT FROM AUTHOR]