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Rationale: Embedding resins are widely used to fix carbonates for high‐precision sample preparation and high‐resolution sampling. However, these embedding materials are difficult to remove after sample preparation and are known to affect the accuracy of carbonate stable isotope analyses. Nevertheless, their impact on clumped isotope analysis, which is particularly sensitive to contamination artifacts, has so far not been tested. The observation that running resin‐containing samples decreased the reproducibility of clumped isotope values for internal laboratory carbonate standards and increased the external standard deviation (SD 0.061–0.088‰) compared to the long‐term observations (0.034‰), prompted us to set up an experiment to test the influence of resin addition on instrument performance. Methods: Here we analyzed the stable and clumped isotope composition of a pure calcium carbonate standard (ETH‐4) mixed with three types of embedding resins in 2:1 and 1:1 proportions. Our aim was to assess how resin addition affects isotope analyses. Results: We found that none of the stable isotopic values were significantly different. The δ13C values were −10.22 ± 0.07‰ (mean ± SD) for pure ETH‐4, while the δ13C values of ETH‐4 mixed with embedding resins in 2:1 and 1:1 proportions were −10.21 ± 0.06‰ and −10.18 ± 0.06‰, respectively (p > 0.05). The δ18O values were −18.82 ± 0.11‰ for pure ETH‐4 versus −18.81 ± 0.09‰ and −18.82 ± 0.08‰ for 2:1 and 1:1 ETH‐4:resin mixtures, respectively (p > 0.05). Given the large uncertainty in our results, we did not find significant differences between different mixtures in the carbonate clumped isotope values (Δ47), with 0.458 ± 0.107‰, 0.464 ± 0.086‰, and 0.417 ± 0.089‰ in pure ETH‐4 and ETH‐4 with 2:1 and 1:1 resin mixtures, respectively (p > 0.05). However, a resin‐related bias in the results might be masked by the large uncertainty. The measured ETH‐4 values in our study are similar to the InterCarb values (δ13C = −10.20‰, δ18O = −18.81‰, Δ47 = 0.450‰, InterCarb‐Carbon Dioxide Equilibrium Scale). However, the external SD of Δ47 in sessions measuring ETH‐4 with resins is higher than in sessions without deliberate resin addition for the same measuring period. Conclusions: We find that the potential contamination from the resin addition leads to a larger variability for Δ47 values in sessions measuring ETH‐4 including resins. We therefore recommend purification of embedded samples using a contamination trap with Porapak prior to analysis, if possible, or avoiding resins during sample preparation and workup, as well as monitoring the measurement quality during and after sessions with samples containing embedding resins. [ABSTRACT FROM AUTHOR]

Terrestrial snails are sensitive to climate changes and their shell's oxygen isotope composition (δ18O shell) is widely used in studies of paleoclimate reconstructions. However, the interpretation of δ18O shell remains complex due to the combined effects from different factors such as precipitation δ18O (δ18O p), relative humidity (RH), and temperature. Furthermore, no systematic studies have addressed the transformation of oxygen isotope signals from rainfall to the aragonite shell via snail body water. Here we present the results of Cathaica fasciola body water δ18O (δ18O BW) and its content, which were sampled every two days throughout the growing season in 2021 in Xi'an. Meanwhile, the soil water δ18O (δ18O SW), δ18O p , rainfall amount, RH and temperature were also simultaneously monitored, and two high-resolution (at ∼0.3 mm interval) δ18O shell series were obtained from two live snails collected in September and October 2021, respectively. These data reveal that the δ18O BW mimic the variations of δ18O p , and they are positively correlated (r2 = 0.84) for precipitation events and the correlation coefficient only increases slightly (r2 = 0.88) when RH is included in the multivariate analysis. During non-precipitation intervals, there is an obvious negative correlation between δ18O BW and RH. Moreover, the variations of two δ18O shell series are broadly consistent with the theoretically calculated δ18O shell from δ18O BW /δ18O p at seasonal scale. Collectively, this study demonstrates that δ18O p is the first-order control on the seasonal variations of δ18O BW and δ18O shell , while RH play its role during non-precipitation periods. Importantly, this study lays good foundation for reconstructing terrestrial seasonal distribution of precipitation and extreme rainfall events using fossil shells in the geological past. • Precipitation δ18O paced the seasonal variations of snail body water δ18O. • Relative humidity plays its role on body water δ18O during non-rainfall periods. • High-resolution snail shell δ18O recorded seasonal precipitation δ18O signals. [ABSTRACT FROM AUTHOR]

• δ13C of minute land snail shell could record the local vegetation signals. • Shell δ13C has the potential to be a reliable precipitation proxy. • Spatially scattered shell δ18O reflects the dominant control of precipitation δ18O. Land snails are abundant and well preserved in loess-paleosol sequences on the Chinese Loess Plateau (CLP) and are often regarded as valuable climatic indicators in paleoclimate reconstruction. To date, many stable isotope investigations have been carried out on land snail shells (e.g., δ13C shell and δ18O shell) from diverse geographical and climatic regions. However, few studies have been conducted on modern minute land snails (2–10 mm) on the CLP, and their climatic significance has not been adequately understood. Here, we present new δ13C shell and δ18O shell data from four minute modern land snails (Pupilla aeoli , Gastrocopta armigerella , Opeas striatissimum , Vallonia tenera), and analyses of their correlations with climatic factors (growing season temperature, precipitation and relative humidity) were conducted to examine their climatic significance across the CLP. The results show that δ13C shell can record local vegetation information and has the potential to be a reliable precipitation proxy. Interestingly, δ18O shell exhibits spatially scattered values in the studied region, and these data yielded poor correlations with various climatic parameters, such as precipitation amount, temperature and relative humidity. Given the similar spatial characteristics of observed precipitation δ18O (δ18O p), these phenomena may support the dominant control of δ18O p on δ18O shell. [ABSTRACT FROM AUTHOR]

The Kyzylkum Desert, as a transition area of different dust source in Central Asia, provides and reserves a large amount of dust transported by different atmospheric circulation systems, affecting Uzbekistan and downwind East Asia. However, there remains very few investigations about sediment sources and control factors of the desert. We hereby first present a provenance study on the Kyzylkum Desert, utilizing detrital zircon U‐Pb ages of samples composed of desert sand, alluvial sediments from Amu Darya River and piedmont of Southwest Tianshan Mountains. The results reveal that the Southwest Tianshan Mountains contribute the majority of the Kyzylkum desert sand, and the river system, dominated by Syr Darya, controls the sediment provenance of the desert. Moreover, little contribution from the Kyzylkum and Nurata segments indicates that wind erosion on the bedrocks is weak. However, the aeolian process is still crucial but deposit and storage of dust are determined by local topography. Plain Language Summary: The Arid Central Asia is commonly considered one of the most important dust sources in the world. The Kyzylkum Desert, located in the center of the multiple dust sources in Central Asia, provides and receives a large amount of dust, affecting Uzbekistan and downwind East Asia. However, research on sediment sources and control factors in the area is under debate. We investigate the potential provenance, spatial variability, and transport patterns of sand in the Kyzylkum Desert using detrital zircon U–Pb geochronology on 10 sediment samples. The results reveal that the Southwest Tianshan Mountains contribute the majority of the Kyzylkum desert sand, however, the proximal provenances also have a significant influence on the formation of the desert. The geomorphologic history shows that, the river system, dominated by Syr Darya, controls the sediment provenance of the Kyzylkum Desert. The wind displays little influence on the rework and recycle process of Kyzylkum Desert, indicated by inhomogeneous composition between northwest and southeast desert. The unmixing model results show evidence of sediments from the Kyzylkum Desert transported to the piedmont areas, but the transport and deposition of dust are primarily controlled by topography. Key Points: Detrital zircon U‐Pb dating indicates that the Southwest Tianshan Mountains are the primary sediment source of the Kyzylkum DesertThe river system controls the sediment provenance of the Kyzylkum DesertTopography determines reserve positions of the aeolian sand and dust from Central Asian deserts [ABSTRACT FROM AUTHOR]

Lake Qinghai is sensitive to climatic changes because of its pivotal location between mid-latitude Westerlies and the low-latitude East Asian monsoon. An 18.6 m long drilling core (1Fs) from Lake Qinghai provides new information on the hydroclimatic dynamics since the last glacial period. Here, we present the results of bulk mineral assemblages of this core. X-ray diffraction (XRD) results showed that the bulk minerals of the core sediments consist of major clastic minerals (e.g., quartz, feldspar, muscovite), carbonates (e.g., calcite, aragonite, dolomite), and minor clay minerals (e.g., chlorite). Quartz as an exogenous detrital mineral in lake sediments, its abundance is related to lake level changes resulting from regional climate changes via fluvial/aeolian transportation. Aragonite was precipitated from water solutions or chemical alteration of pre-existing minerals or biogenic mediation, closely related to lake hydroclimate change. Mineral assemblages revealed remarkable stepwise hydroclimatic changes. High quartz content and low calcite without aragonite suggested a cold-wet climate condition under predominant westerlies during the last glacial period from 35 to 25.3 ka. Afterward, quartz decreased and aragonite occasionally appeared, indicating an unstable hydroclimatic condition during the last deglaciation. Since the Early Holocene (11.9–8.2 ka), predominant minerals shifted from terrigenous quartz to authigenic carbonates, suggesting an increasing lake level, possibly due to intensified Asian summer monsoon with increased effective moisture. Aragonite became the primary carbonate mineral, implying a warming and humid hydroclimate environment with a relatively higher lake-level. During the Middle Holocene (8.2–4.2 ka), aragonite showed a decreasing trend indicating a higher lake level with weak evaporation. During the Late Holocene since 4.2 ka, there were lower quartz and aragonite, suggesting a deep lake with a weak summer monsoon. Our quartz and carbonate minerals record provided essential clues to reconstruct hydroclimate change in Lake Qinghai since the last glacial period. [ABSTRACT FROM AUTHOR]

A variety of proxies has been studied to document paleoclimatic changes in arid Central Asia (ACA). However, biological archives, which can be directly related to climatic conditions, are still scarce in this region. Here we report records of the total count fossils (TCF) of terrestrial mollusks, organic carbon isotopes (δ13C org) and loss on ignition (LOI), since the last deglaciation in the Talede and XRBLK loess sections in Xinjiang, eastern Central Asia. Prior to the Holocene, the records show rare fossils with relatively low LOI and more positive δ13C org , indicating low biomass/organic carbon content under dry conditions which were unfavorable for the survival of snails. In contrast, TCF increased abruptly at the beginning of Holocene, coincident with a prominent increase in LOI and a marked negative shift in δ13C org. Furthermore, TCF increased gradually to its maximum and δ13C org became progressively negative with constant high LOI from the early to late Holocene. The variations imply a trend towards wetter environment, with optimal moisture (precipitation/relative humidity) conditions occurring in the late Holocene. Overall, this Holocene moisture evolution history could be attributed to the variations of Westerlies strength modulated by the latitudinal temperature gradient and the insolation-related evaporation should also be concerned. • First terrestrial snail records from the loess profiles in Central Asia. • The TCF is a reliable humidity/moisture indication of interglacial in ACA. • The progressively wetting trend is more acceptable in ACA since the Holocene. [ABSTRACT FROM AUTHOR]

Extreme rainfall events cause tremendous threats to people's lives and economic well-being. Given the short time span of instrumental records, reconstructing the full range of past rainfall variability using available proxies is impossible when trying to unravel the history and underlying mechanisms of extreme precipitation events. However, this work is usually limited by the temporal resolution of current paleoclimate records. Here we demonstrate that the ultra-high resolution measurements of δ18O of terrestrial snail shells of Cathaica fasciola (Draparnaud, 1801) can be used to reconstruct the rainfall variability on weather time scales. Broadly, the modern daily time resolution snail shell's δ18O profile shows a negative trend from late March to September in 2020, which resembles the variations of monitored δ18O and amount of precipitation. Meanwhile, six abrupt negative deviations were observed in the δ18O profiles and these deviations matched well with the instrumental precipitation events for the same period. The high correlation of shell's δ18O with rainfall amount during the six precipitation events indicates that the ultra-high resolution δ18O records of gastropod shells have the potential to qualitatively record local synoptic rainfall events. Our study highlights that the terrestrial gastropod shell could provide daily to weekly geochemical proxies and has the potential to be used as an ultra-high resolution archive for characterizing terrestrial paleoweather, such as extreme precipitation events. [ABSTRACT FROM AUTHOR]

The climate instability (millennial-scale rapid climatic oscillations) during the last glacial period has been a hot issue in Quaternary paleoclimate cycle, however, the driving mechanism and involved areas are still unclear. Previous reports mainly came from Green ice cores, North Atlantic deep-sea sediments and loess, stalagmites, lake records in the East Asian monsoon area, however, evidences from the Asian interior arid regions are scarce. Central Asia is distant from oceanic moisture sources and the climate is dominated by the Westerlies and the Subtropical High. Late Pleistocene loess sediments sporadically distributed at the pediments, terraces and basins provide us an opportunity to verify the existence of millennial-scale climatic fluctuations in Central Asia and understand the relations between high-low latitude climate. During the last decades, we have carried lots of loess investigations in Central Asian mainly around the Tienshan Mountains including Xinjiang in China, Kazakhstan, Kyrgyzstan and Tajikistan. In this paper, we report the preliminary results of loess investigations, and divide the loess distribution in Central Asia into three zones, which correspond to different hydrothermal combination conditions; and coupled with previous literatures, we review the progress of paleoclimate study of loess especially chronology in Central Asia, analyze problems of the last glacial climate events in Central Asia, and discusses its process and mechanism. Up to now, paleoclimatic proxies like grain size, mineralogy and geochemistry confirmed that that there are indeed millennial-scale rapid oscillations during the last glacial period in Central Asia, but they are inconsistent in age and variability. These rapid changes may be related to the following aspects: (a) contraction and expansion of the ice sheet in the high latitudes region of North Atlantic, (b) changes in the intensity and extent of the Siberian high pressure which further lead to the variance in wind dynamics, (c) and the north-south migration of the mid-latitude westerlies. The solar radiation is not the main driving factor for the rapid changes in Central Asia. [ABSTRACT FROM AUTHOR]

Intrashell oxygen isotope (δ18Os) analyses of terrestrial snails have been carried out over two decades. However, the intraspecies/interspecies differences are not yet well understood. Here, we conducted a high‐resolution intrashell δ18Os study on 43 shells from Cathaica fasciola and Bradybaena ravida, and 1449 δ18Os data were obtained. These large amounts of data demonstrate the reproducibility of intrashell δ18Os. Our results suggest that C. fasciola and B. ravida have similar growing seasons mainly from March to October in the studied region. The ecological habits of the two species could explain the distinctive variations in their δ18Os sequences. Therefore, our study may interpret the discrepancy between the studies of land snail species and the stable/clumped isotopes of their shells. Moreover, the calculated average growth rate is ∼290 μm/day (from 250 to 330 μm/day) for nonadult C. fasciola. Thus, the use of snail shells for reconstructing high‐resolution terrestrial climate changes is promising. Plain Language Summary: Land snails are sensitive to climatic and environmental changes. Therefore, the oxygen isotopic composition of snail shells (δ18Os) has often been used to study environmental changes. Researchers started to collect multiple samples from a single shell for δ18Os analyses about two decades ago. However, it is still unclear whether high‐resolution intrashell δ18Os results are repeatable and whether the influences of different individuals/species may exist. To address these issues, we collected 43 snail shells from Cathaica fasciola and Bradybaena ravida. In total, 1449 δ18Os data were obtained. The large amount of data showing similar variations in the intrashell δ18Os from different shells demonstrates the repeatability. Accordingly, our data suggest that the two species have similar growing seasons, mainly from March to October, although their ecological habits are different. In addition, the ecological habits of these two species could explain the subtle differences in their δ18Os. Taken together, our study could resolve the discrepancy between previous work on land snail species and stable/clumped isotopes. Furthermore, the estimated average growth rate is ∼290 μm/day (from 250 to 330 μm/day) for nonadult C. fasciola. Overall, snail shells are promising records for exploring high‐resolution terrestrial climate changes in the future. Key Points: The intrashell δ18Os of land snails is reproducible, which mainly records the δ18O of precipitationCathaica fasciola and Bradybaena ravida have different ecological habits but similar growing seasonEcological habits could explain the discrepancy between studies of land snail species and stable/clumped isotopes [ABSTRACT FROM AUTHOR]

We collected 143 loess optically stimulated luminescence (OSL) ages between 10 ka and 30 ka from Central Asia (CA), and analyzed their probability density functions (PDFs). The PDFs show dust accumulation was greater during the late Last Glacial Maximum (LGM) (23–19 ka) than that during the early LGM (26.5–23 ka). The temporal variability of dust accumulation of CA loess is generally similar to that of Chinese Loess Plateau (CLP) loess, following precession. In contrast, dust accumulation in Greenland was stronger during the early LGM than that during the late LGM, following obliquity. Supported by numerical modeling experiments and our newly dating OSL ages, we conclude dust accumulation in CA and CLP during the LGM was controlled by Siberian High forced by precession, while dust accumulation in Greenland was closely related to both intensity of summer westerlies forced by obliquity, and to intensity of dust emissions at source forced by precession. Plain Language Summary: The dust accumulation in ice cores is often regarded as a direct record of the changing atmospheric dust loading reflecting the aridity of dust source regions. However, the underlying mechanism has not been well understood due to the lack of evidence from dust source regions. Here, we collected 143 optically stimulated luminescence (OSL) ages between 10 ka (ka means 1,000 years) to 30 ka from Central Asia (CA) loess to build the probability density functions (PDFs). The PDFs revealed a stronger dust accumulation occurred during the late LGM than that during the early LGM. The variation pattern of dust accumulation of CA loess is generally similar to that of the Chinese Loess Plateau (CLP) loess, in phase with precession. In contrast, Greenland presents that stronger dust accumulation occurred during the early LGM rather than during the late LGM. The variation pattern of dust accumulation during the LGM in Greenland followed obliquity. Supported by numerical modeling experiment and our newly dating OSL ages, we assumed dust accumulation during the LGM in the CA and CLP was controlled by the Siberian High forced by precession. In contrast, dust accumulation in Greenland was closely related to both the intensity of summer westerlies forced by obliquity and dust emission driven by Siberian High forced by precession. Key Points: Asynchronous variations of dust accumulation at midlatitude Asia and Greenland during the Last Glacial Maximum (LGM)Dust accumulation in Asia during the LGM was controlled by Siberian High forced by precessionDust accumulation in Greenland is related to westerlies forced by obliquity and source dust emissions forced by precession [ABSTRACT FROM AUTHOR]

Central Asia loess deposits can yield detailed records of aridification across the Asian interior, as well as the atmospheric circulation. In this study, we presented grain size, heavy mineral assemblage, rock magnetism and anisotropy of magnetic susceptibility of a loess section in the Tacheng Basin in Xinjiang region, NW China. The results of anisotropy of magnetic susceptibility indicated that a near-surface SE wind prevailed in the Tacheng area since Marine Isotope Stage (MIS) 3, while a near-surface SW prevailing wind developed during MIS3b. We inferred that the change of wind direction was due to glacial advance during MIS3b. Combining the result of anisotropy of magnetic susceptibility with grain size, heavy mineral assemblage data and previously published low-field mass susceptibility revealed that dust transported by the near-surface SW wind had a greater ability to enhance magnetic susceptibility and higher amphibole/epidote ratio. Additionally, a strong Siberian High during Heinrich Event (H)5 at ca. 48 ka blocked the advection of moisture into the region via mid-latitude westerlies, causing glacial recession and the weakening of the prevailing SW wind. Our study has implications for identifying changes in paleo-wind direction and dust source, which can aid understanding of the influence of westerlies and the Siberian High on dust accumulation, as well as their interactions. [ABSTRACT FROM AUTHOR]

Loess deposits as a unique terrestrial archive of paleo-dust contribute to understanding the wide-scale and long-term dust transport from source to sink. This study provided diagnostic constraints on the sources of clay-sized particles in the Chinese Loess Plateau (CLP) loess by expanding the potential dust source areas with the Kyzylkum Desert and the Central Asian loess. Based on the grain sizes and the particle-size-specific trace elements, we characterized the major provenance and the sedimentary process of the Kyzylkum Desert sands. The results indicate the main derivation of Kyzylkum Desert sands from the Tian Shan-derived sediments, with limited large-scale mixing. The desert was thought to be a sink region, instead of an important dust source, which was supported by its weak genetic links to the Central Asian loess. With integration of the published data set about trace element and Sr Nd isotopic composition and our results, combined with the simulation results, we revealed that the Badain Jaran and Tengger deserts in northwestern CLP, rather than the Taklimakan and Kyzylkum deserts further west, played an important role in supply of the clay-sized particles for the CLP loess. The findings implied that the fine particles were primarily related to the East Asian winter monsoon, instead of the high-level westerly airstreams. In this context, we attributed the asynchronous timing of enhanced dust accumulation during the last glacial maximum (LGM) over Greenland and North Pacific (early LGM) and on the CLP (late LGM) to the differences in the major dust sources and in the atmospheric circulation systems. • Kyzylkum Desert makes negligible contribution to the Central Asian loess. • Origin of clay-sized components in the CLP loess is systematically characterized. • The findings of this study help to improve understanding of the Asian dust cycle. [ABSTRACT FROM AUTHOR]

Central Asia (CA) is one of the main loess regions in the world and provides important information for the understanding of paleoclimate and paleoenvironmental changes. However, the spatio-temporal variability of the loess distribution is still not fully understood. Combining previous studies with our recent field investigations, we focus on the spatial distribution and ages of loess sediments in CA. Loess sediments are mainly distributed on the windward piedmonts of Central Asian high mountains, e.g. the Tianshan Mountains, Kunlun Mountains, and river terraces, with distinct pedogenic characteristics. The distribution of loess sediments is not only related to atmospheric circulations and regional climate but also closely related to landforms. Based on field observations and the pedogenic environment, we recommend that the loess distribution should be divided into three subregions (Western CA, Northern CA, and Eastern CA), which are approximately coincident with the 60% and 30% winter-half year's precipitation percentage contours, and also correspond to three loess depocenters with thicknesses over 200 m. Paleomagnetic, luminescence dating and AMS 14C geochronology indicated that most of the loess outcrops have developed since the last interglacial-glacial period; although CA loess sediments can span the entire Quaternary period and even extend into the Pliocene. AMS 14C can provide reliable ages for the last 25–30 kyr. Quartz OSL and K-feldspar post-infrared infrared stimulated luminescence (pIRIR) dating techniques, based on well-bleached natural environmental materials, can provide reliable ages younger than 80 ka. The luminescence ages of older samples may be underestimated due to signal saturation problems. Dating of deposits at some elevated locations in CA shows rapid and discontinuous deposition, implying that caution is required in the interpretation of proxies and paleoenvironment. Spatial-temporal distributions of Central Asian loess luminescence ages indicate different clusters in different loess subregions, but generally the periods of strong dust activity occurred during cold glacial periods or stadials. New dating techniques should be developed to enable high-resolution paleoclimate reconstruction. • We investigate the spatio-temporal distributions of loess in Central Asia. • Loess distribution should be divided into three subregions. • Loess deposited from Early Quaternary to Holocene, mostly since last glacial. • Loess sediments are rapid and discontinuous deposition in somewhere. • Local disparities should be considered in paleoclimate interpretation. [ABSTRACT FROM AUTHOR]

Loess deposits are widely distributed along the mountain piedmonts of Central Asia. The transport processes and origins of Central Asian loess sediments remain poorly understood. Here we investigate the origin and formation of loess along the northern piedmont of the Tian Shan based on trace element (including rare earth element) ratios and multidimensional scaling analysis. Our results indicate that the loess has undergone weak chemical weathering. Using a selection of geochemical fingerprinting techniques based on Pearson correlation and Kruskal–Wallis H tests, we establish a genetic link between alluvial-proluvial fans/plains, deserts, and loess along the Tian Shan piedmont in northern Kyrgyzstan and southern Kazakhstan. The unsorted sediments on the piedmont slopes and alluvial-proluvial plains are common sources for both deserts and loess to the north of the Tian Shan. Dune sediments are not the main source of the fine-grained loess. Origin and formation of Central Asian loess is strongly dependent on local topographic context and wind dynamics. Only once loess provenance and formation has been understood across both space and time can reliable interpretations of palaeoclimatic proxies in these deposits be made. • Tian Shan loess has experienced minimal post-depositional alteration. • Loess deposits in the North Tian Shan are mainly nearly-sourced. • Alluvial-proluvial fans/plains feed both the deserts and loess. • Central Asia deserts comprise a small proportion of the Tian Shan loess. • Heterogeneous sources of loess should be considered in palaeoclimatic study. [ABSTRACT FROM AUTHOR]