Dust activity in inland China shapes global dust cycling and affects terrestrial and marine ecosystems alongside human well-being. Climate change and human activities are widely acknowledged as major drivers of dust activity. However, the specific pathways through which these factors shape dust activity remain poorly understood. Here, we analyzed Holocene sediment grain-size data from five Holocene loess–paleosol sections in the Hexi Corridor and western Chinese Loess Plateau, including one new section and four previously dated sections. The results show a gradual decrease in dust activity from the early to middle Holocene, followed by an increase since ∼2.2 ka (the Qin–Han dynasties). Modern data from recent decades indicate that cultivated land area dominates dust emissions in semi-arid regions, with wind and precipitation as secondary and tertiary factors, respectively, whereas no significant relationships are observed in semi-humid areas. From the early to middle Holocene, when the influence of human activity was negligible, increased winter temperatures weakened the East Asian winter monsoon (EAWM) and hence the dust activity. After the Qin–Han dynasties, changes in the land ownership system and innovations in tools promoted the agricultural development, resulting in a gradual increase in the human population and cultivated area, which contributed to the intensification of dust activity. Supported by modern observations, we propose that human-induced agricultural expansion played a critical role in intensifying dust activity since the Qin–Han dynasties, regardless of whether the EAWM strengthened or weakened. Overall, our findings provide robust support for understanding present and future dust dynamics across inland China.

As the world's highest and largest plateau, the Tibetan Plateau (TP) exerts a crucial influence on regional and global eco-environmental evolution. Soil organic carbon isotopes (δ13Corg) serve as a valuable proxy for reconstructing C3/C4 vegetation dynamics under varying climatic conditions. However, the paleovegetation history inferred from δ13Corg and its climatic controls on the TP remain poorly understood. This study investigated two Holocene aeolian sections (SGX and HZ) in the Yarlung Zangbo River Basin (YZRB) on the southern TP to conduct the first in-depth exploration of δ13Corg variations and the estimate C3/C4 plants relative abundances. Modern collected surface soil analyses reveal a strong positive correlation between δ13Corg values and mean annual temperature (R=0.55, P<0.001) under mixed C3/C4 vegetation. Besides, both sections recorded mixed C3/C4 vegetation since the early Holocene, with estimated C4 plants relative abundance peaking at 20.2% and 20.0%, respectively in the middle Holocene. Spatiotemporally, in the marginal zone of the Indian Summer Monsoon (ISM), the increase of C4 plants recorded in the SGX section responded to a Holocene warming trend regulated by retreated ice volume and rising greenhouse gases. By comparison, in the ISM-dominated region, the elevated C4 plants in the middle Holocene documented in the HZ section cannot disentangle the influence of insolation-regulated precipitation, thus reflecting the synergistic effect of temperature and precipitation. Our results indicate the presence of C4 plants in the high-altitude areas and emphasize the climatic forcing factors regulate the spatiotemporal evolutionary patterns of Holocene vegetation change in the TP.

Aeolian deposits across the Yarlung Zangbo River Basin on the southern Tibetan Plateau record the landscape and atmospheric evolution of Earth’s Third Pole. The complex mountain-basin system exhibits nonlinear responses to climate forcing, complicating the interpretation of its high-altitude environmental dynamics. Investigating the magnetic enhancement mechanism of aeolian deposits offers an opportunity to decipher climate signals. Our analysis of three aeolian sections from the basin indicates that magnetic minerals are predominantly low-coercivity ferrimagnetic minerals, and grain sizes fine from upper to lower reaches due to climate shifts from arid to humid. Magnetic enhancement in the upper reaches primarily originates from dust input, while dust input and pedogenesis contribute variably over time in the middle and lower reaches. Similar complex patterns occur in the Ili basin, a mountain-basin system in northwestern China. They differ from the Chinese Loess Plateau, where long-distance-transported dust is well-mixed and the pedogenic enhancement model is applied, and desert peripheries where short-distance dust is transported and the dust input model is applied. We summarize the magnetic enhancement mechanisms in various settings and offer a new framework for applying magnetic techniques in paleoclimate reconstruction within global mountain-basin systems, which highlights the need for caution in interpreting their magnetic susceptibility records.

The southern Tibetan Plateau (sTP) is an important source of global dust emissions and is also a region with a high concentration of human activities. Therefore, distinguishing climatic drivers of dust activity from anthropogenic influences is challenging. In this paper, we analyze a high-resolution aeolian sequence in the Yarlung Zangbo River basin on the sTP, which provides direct evidence of past dust accumulation. Quartz optically stimulated luminescence and radiocarbon dating indicate that this sequence accumulated during the early to middle Holocene, when human activity had a negligible influence on dust activity. We use grain size parameters including the sorting coefficient, residual grain size, grain size components determined by end-member modeling, and dust accumulation rate to reconstruct the history of natural dust storm activity. The results indicate a gradual decrease in dust storm activity from the early to middle Holocene. Combining modern meteorological data with climate simulations indicates that dust storm activity was co-regulated by the Qiangtang Plateau high (QPH) and the Indian summer monsoon (ISM). From the early to middle Holocene, with the gradual weakening of the QPH and ISM, both the near-surface wind intensity and the supply of dust materials decreased, which contributed to the decrease in dust storm activity. Overall, our findings provide new insights into the natural forcing mechanisms behind Holocene dust storm activity in this high-altitude region.

The southern Tibetan Plateau (TP) is a crucial component of the “Asian Water Tower,” whose moisture dynamics influence both the terrestrial ecosystems and welfare of a large human population across Asia. However, the pattern of its moisture evolution and interactions with atmospheric circulation remain unclear, limiting our understanding of the current and future hydroclimatic changes. Here, we present geochemical, environmental magnetic, and color proxy records derived from a well-dated, high-resolution aeolian sedimentary record. Based on detailed evaluation of the environmental proxies and integrating data from other aeolian records, we investigated the spatial heterogeneity of moisture modes and their atmospheric responses. Our findings reveal two distinct Holocene moisture evolutionary modes in the southern TP, with their boundary delineated by the Shannan wide-valley, which roughly coincides with the southernmost northern boundary of the modern monsoon. In the western region, moisture was co-influenced by the mid-latitude Westerlies (MLW) and the Indian summer monsoon (ISM), characterized by higher moisture during the early Holocene due to strong ISM precipitation. This was followed by a sharp decrease in moisture and then a gradual increase from the middle Holocene onward, under the influence of an enhanced winter MLW. In contrast, the moisture mode in the eastern region was predominantly influenced by the ISM and shows a general decreasing trend. Using climate simulations, we project a future scenario where, as the winter MLW weakens and the ISM strengthens, moisture in the southern TP will experience a decreasing trend in the west and an increasing trend in the east.

The precipitation delivered by the East Asian summer monsoon (EASM) has significantly influenced the ecological environment, climate, and economy of China. However, the mechanisms responsible for the spatiotemporal pattern of EASM precipitation remain unclear. We present a new Holocene loess-paleosol record from the Hexi Corridor on the EASM margin. Environmental magnetic parameters (chi lf, chi fd, chi ARM/SIRM, and chi fd/HIRM) indicate that precipitation was low during 14-8 ka and then increased to a maximum during 4-2 ka. Integrated with published records, our results reveal a distinct geographical gradient in the timing of the Holocene precipitation maximum: an early Holocene peak in eastern Inner Mongolia, a mid-Holocene peak in the central and eastern Chinese Loess Plateau (CLP), and a late Holocene peak in the western CLP and central Hexi Corridor. In addition to these zonal differences, we also observed a longitudinal difference in the timing of the Holocene precipitation peak, which occurred later in the southern region than in the northern region. Combined with existing paleoclimate and climate simulation results we propose that this spatial difference in the timing of the Holocene precipitation peak reflects the movement of the EASM rainfall belt related to the westward extension and northward shift of the western Pacific subtropical high. Overall, our findings provide evidence for the location of the westernmost boundary of EASM influence and offer a unified explanation for regional differences in EASM precipitation and its timing.

Land cover change (LCC) plays a critical role in shaping the distribution of regional landscape ecological risk (LER). This study investigates the spatiotemporal evolution of LER and its influencing factors in the Hexi Corridor from 2000 to 2020 by leveraging multi-source data, ecological risk assessment models, and optimal parameter geographical detectors. The results showed that the (1) Farmlands expanded from 14221 km2 to 15787 km2, and built-up areas increased from 1163 km2 to 1758 km2. The main land cover types transferred out were unused land (1849.73 km2), grassland (700.09 km2), and desert (359.82 km2), while the primary types transferred in were farmland (1807.63 km2), grassland (581.05 km2), and built-up areas (598.61 km2). (2) The proportions of areas with medium, relatively high, and high landscape ecological risk are relatively large. In 2020, they accounted for 21.15 %, 33.43 %, and 22.21 %, respectively. Relatively High-risk areas decreasing from 86424 km2 to 82693 km2. It shows a positive correlation at the spatial scale. (3) In the single-factor detection, annual mean precipitation, NDVI, and annual mean surface temperature are the main factors influencing the changes in LER. The interaction between annual mean precipitation and NDVI is the main reason for the evolution of LER. These findings offer valuable scientific support for developing differentiated ecological protection strategies and promoting sustainable development in the Hexi Corridor.

Aeolian deposits on the Tibetan Plateau (TP) and its surroundings provide crucial source materials for the Asian dust cycle, which significantly affects Asian and global ecosystems and climate. However, it is unclear how the dust dynamics of the TP and its surroundings are linked to Earth's climate system. To address this issue, we examined the grain size and accumulation rate of six Holocene aeolian sections on the southern TP (a new, well-dated high-resolution section, two relatively low-resolution sections, and three published sections) and combined them with equivalent aeolian sedimentary records from eastern arid central Asia. The results suggest that dust activity in both regions decreased during the early to middle Holocene and then increased in the late Holocene. We hypothesize that the primary drivers of Holocene dust activity in both regions are similar. Cold-season insolation, as the primary driving factor, combined with ice volume and atmospheric CO2 concentration, collectively controlled the regional temperature, which determined the near-surface wind intensity via its influence on the TP High and Siberian High, respectively, thus ultimately controlling the regional dust activity. In this context, we project that dust activity on the TP and its neighboring areas will decrease under warm scenarios in the 21st century. Overall, our findings provide an extensive overview of the past, present, and future scenarios of Asian dust activity, especially of the TP dust.

The sustainable development of arid regions is significantly constrained by the availability of water resources, which play a crucial role in this context. It is necessary to deeply investigate and analyze the hydrochemical characteristics and major ion sources. This study, which was based on data from 183 water samples collected from the Jinghe River Basin, provided a comprehensive analysis of the river water hydrochemistry. The results show that the average TDSs (total dissolved solids) was measured at 49.8 mg·L−1. HCO3− (82.4%) and Ca2+ (77.1%) were the ions present in the highest abundances. The river water was classified as the HCO3−-Ca2+ hydrochemical type. The Gibbs diagrams indicated that the ion composition was primarily influenced by rock weathering. Additionally, the Na-normalized molar ratio diagrams suggested that the chemical composition was primarily governed by the weathering and dissolution of silicate rocks, while the carbonate rock dissolution played a lesser role. This study demonstrates a critical aspect of water resources quality evaluation, which is of great significance for the sustainable development, utilization and environmental protection of regional water resources.

The aeolian deposits on the southern Tibetan Plateau (TP) are one of the most important environmental archives preserved at the highest altitudes worldwide, containing extensive information about both the current and past landscapes and environments of Earth's Third Pole. Over the past three decades, these deposits have attracted considerable attention in Quaternary paleoclimate research. Nevertheless, our understanding of these high-altitude aeolian deposits is significantly less than that for similar deposits in the low-altitude regions of the Eurasian continent. To better comprehend this important archive, it is essential to integrate knowledge from various perspectives. However, there is a lack of consensus regarding their formation, distribution, chronology, provenance, and paleoclimatic history across different timescales. Here, based on our recent field investigations and new data, along with previously published data, we present the results of a systematic analysis of aeolian deposits on the southern TP. Our principal results and findings are: (1) We present up-to-date maps of the aeolian deposits, consisting of an overview map of the overall spatial distribution, and six high-resolution regional maps highlighting details of the depositional areas. Loess and sand dunes have accumulated within the six subdomains, following the global pattern of dust accumulation along rivers in arid and semi-arid regions. (2) Based on paleomagnetic and ESR dating, the oldest aeolian sediments were formed during the middle Pleistocene. The probability density of 220 OSL and AMS 14C ages reveals that 98.7 % of the young sediments accumulated since the last interglacial, with the majority (66.4 %) forming during the Holocene. A comparison of age clusters with records of ice volume, temperature, precipitation, vegetation, and paleolakes revises previous hypotheses regarding the factors influencing dust deposition, emphasizing the dominant control of climate change. (3) The aeolian sediments are of local origin and their sources remained relatively stable over time. Quantitative analysis of 48 samples using geochemical fingerprinting showed that the aeolian sediments are a mixture of various clastic materials derived from upstream areas, with the predominant contribution from sand dunes (58.7 %). (4) We examined the climatic evolution of this region and its driving mechanisms during the middle to late Pleistocene and the Holocene. This analysis suggests that changes in cold and warm season insolation were the primary external drivers of moisture and dust activity on both orbital and sub-orbital scales. The winter mid-latitude Westerlies and the Indian summer monsoon, which are influenced by these seasonal insolation variations, regulated the moisture evolution, while the near-surface winds, primarily driven by cold season insolation and influenced by ice volume and oscillations in North Atlantic climate, played a significant role in modulating dust activity. Accordingly, we present a comprehensive conceptual model to illustrate the theoretical framework of aeolian sedimentary landscapes and their impacts and responses to regional and global climate changes. Overall, this review contributes to an improved understanding of the late Quaternary evolution of dust deposition and the environment on the southern TP.

Aeolian deposits on the southeastern Tibetan Plateau (SETP) can provide evidence of how prehistoric humans were influenced by climatic and environmental changes in high-altitude regions. We present the results of multi- proxy analyses of a middle-late Holocene aeolian section in the SETP, together with the probability density of the ages of various cultural sites within and around the study area. Quartz optically stimulated luminescence dating provides a reliable chronology for this section, and analyses of geochemical elements, color and grain size are used to reconstruct the pattern of climate change during the middle-late Holocene. The results suggest a trend of gradually decreasing moisture from the middle Holocene (similar to 6 ka) onwards, followed by a slight increase at similar to 2 ka, which is supported by TraCE-21 ka simulation results. These changes were closely related to variation in the Indian summer monsoon (ISM) caused by decreasing Northern Hemisphere summer insolation and an increase in the Atlantic Meridional Overturning Circulation. The variations in dust activity are inversely related with moisture and there was a significant decrease in dust activity after similar to 2 ka. The drought conditions during the 4.2 ka event recorded within the section appear to be a continuation of the trend of middle-late Holocene climatic deterioration, which is superimposed on a weakening trend of the ISM. The permanent human occupation of the study area after similar to 2 ka corresponded to an interval of mild and wet climate when dust activity was relatively weak. An observed correlation between the intensity of human activity and dust storms suggests that the enhancement of human activities played a significant role in increasing the occurrence of dust storms. Overall, our results provide new insights into human-environmental interactions in the SETP.

Aeolian activity on the Tibetan Plateau (TP) has profound effect on the Asian and global climate. In the southern TP, loess deposition widely occurred associated with the massive glaciers and large rivers, recording the interplay history among the aeolian activity, atmosphere, and cryosphere. However, the initiation age of the loess and the factor controlling the loess formation are still controversial. Here, three drilling cores were retrieved from Linzhi area, in the eastern Yarlung Zangbo River Basin of the southern TP, which reached the bedrock and documented the loess development in the southern TP. Based on the optically stimulated luminescence, electron spin resonance, paleomagnetism dating and relative paleointensity correlation, the basal age of the drilling core was constrained at 584 ka revealing the onset of significant aeolian activity on the southern TP. Synthesize this study and previous work on the loess age across the TP, three stages were identified, namely 3600, 2800-2700, and 1200-600 ka, with the age trending younger from north to south. Extensive loess development on the TP occurred between 1200 and 600 ka, which was mainly ascribed to the global cooling during the mid-Pleistocene Transition. During this time, the ampler glaciers extent significantly expanded, westerly displaced southward and the wind intensity also intensified on the TP, which resulted in the enhancement of dust generation, arid and windy condition, leading to the loess preservation and development on the TP. Moreover, numerous evidences suggested that the glaciers on the TP may significantly developed since 800 ka, then enlarged at 500-600 ka, which may lead to the massive dust/loess input to the TP, Chinese Loess Plateau and north Pacific Ocean.

Spatiotemporal changes in the Holocene climate of the arid region of China were principally caused by shifts in the intensity and location of the East Asian summer monsoon (EASM). However, our knowledge of these EASM variations is limited, especially since the middle Holocene. We investigated two aeolian sedimentary sections (the Linxia/LX and Gulang/GL sections) on the western Chinese Loess Plateau (CLP), to explore the variations in the intensity and location of the EASM and their impact on the regional environment and human cultural development during the middle to late Holocene. The longitudes of these two loess sections are similar, but the GL section is located on the northern edge of the CLP, in the eastern Hexi Corridor, and it is situated further north than the LX section. The chronologies of both sections are based on accelerator mass spectrometry C-14 dating, and environmental magnetic parameters and grain size end-members were used to reconstruct their moisture histories. The results suggest that the climate at the LX section was relatively dry before 3.5 ka, after which it became wetter. In contrast, at the GL section, the climate was also relatively dry before 3.5 ka, with the wettest conditions occurring during 3.5-2 ka, but subsequently there was an abrupt shift to a dry climate. We suggest that these spatiotemporal patterns reflect the westward movement and rapid southward retreat of the EASM and the linked monsoon rainfall belt. TraCE-21 ka climate simulation results support our inference. We also found that, compared with other ancient cultures in the eastern Hexi Corrido, sites of the Shajing culture, dated to similar to 2.4-2.8 ka, are predominantly located in areas that are arid at the present-day, and relatively distant from rivers. We suggest that this distribution pattern reflected the occurrence of a humid climate during the period of the Shajing culture, thus demonstrating the impact of the EASM on cultural development in this region.

In the context of the rural revitalization strategy, an accurate grasp of the spatial differentiation characteristics and influencing factors of rural settlements in underdeveloped arid inland river basins is urgently required. Taking the Shiyang River Basin as an example, rural settlements from 2000 to 2019 were examined via visual interpretation using satellite remote sensing data and official statistical data. Following the logic of “state characteristics—evolutionary patterns—influence factors—layout optimization”, the average nearest index, the gravity-center migration model, spatial statistical analysis, and other methods were used in combination with GIS. The spatiotemporal pattern evolution characteristics of rural settlements in the past 20 years were analyzed. The results revealed the following: (1) The distribution pattern of rural settlements in the study area is sheet-like and strip-shaped. The projects in the southeast are mostly distributed in a patchy pattern with high density, while the characteristics in the west and north are exactly opposite. The objects in the south are distributed in an alluvial area of rivers, while settlements in the north are located in an oasis area. (2) From 2000 to 2019, the scale of rural settlements in the Shiyang River Basin, where there is a simultaneous occurrence of newly-built and disappearing phenomena, shows an expansion trend that first increased quickly and then slowed down. Spatially, rural settlements in the basin show a clustering trend toward the southwest. (3) The distribution characteristics of rural settlements are close to water and roads, and they are greatly influenced by urban–rural integration and ecological migration. The results will provide a scientific basis for accelerating the modernization of rural areas and the construction of new rural areas according to local conditions.

青藏高原南部雅鲁藏布江(雅江)流域位于印度板块和欧亚板块碰撞产生的缝合带,是地球系统科学研究的热点地区.该区域中更新世以来的风成沉积物不仅是揭示青藏高原气候变化与大气环流演化的重要窗口,而且有助于深入认识构造、气候及地表景观之间的内在联系,然而我们对于该区域风成沉积物的空间格局、沉积模式及其环境效应至今仍然缺乏系统的认识.本文在大量野外考察和已有研究结果基础上,结合典型沉积物样品的综合分析,对雅江流域风成沉积体系进行了梳理,绘制了《雅江风成沉积空间分布图》,包括1幅序图和6幅区域分布图,其中风沙和黄土沉积呈斑块状分布,二者通常相伴而生.黄土与沙丘、河流砂等松散沉积物之间存在密切的物质联系,区域内的风成沉积以自循环过程为主,记录了区域气候的空间差异.河谷沉积物在接受有限的远源粉尘输入的同时,在高空西风的作用下向全球贡献粉尘物质.中更新世以来的粉尘活动受控于构造运动和全球气候变化的耦合,而全新世粉尘活动受河谷环境影响表现较为复杂,区域气候变化受中纬度西风和印度夏季风的协同作用影响.

SUMMARY The relationship between climate and the magnetic properties of surface soils on the Chinese Loess Plateau (CLP) have been widely used to provide the basis for palaeoclimatic reconstruction, based on the underlying loess/palaeosol sequences. To date, however, there are few investigations of variations in the magnetic properties of surface soils on the Tibetan Plateau (TP), especially on the southern TP. Therefore, it remains unclear whether magnetic properties could be used as proxies for palaeoclimatic reconstruction in the region. In this study, environmental magnetic parameters and bulk sediment grain-size measurements were made on a set of surface samples from the Yarlung Zangbo River Basin (YZRB), on the southern TP, and their environmental significance was evaluated. The results reveal spatial differences in the magnetic properties of the surface soils, likely caused by regional climatic factors. The input of primary magnetic minerals is the driver of the magnetic properties of the samples from the western (Gar-Saga) part of the YZRB, where the magnetic variations are controlled by the influence of wind intensity on the local source material. However, the samples from the eastern region (Gongga-Nyingchi) are significantly affected by the topographic and sedimentary conditions, and there is no relationship between the magnetic properties and climate. The samples from the central part of the study area (Saga-Gongga) show obvious signs of a pedogenic influence on magnetic properties and ultrafine superparamagnetic (SP) and single domain (SD) ferrimagnetic minerals dominate the magnetic susceptibility. Combined with the variation of grain size, this implies the influence of wind intensity and pedogenesis contribute to the magnetic enhancement. However, the pedogenic intensity closely related to precipitation and temperature could offer the possibility of using sedimentary magnetic properties for palaeoclimatic reconstruction. Furthermore, the existence of a distinct pedogenic alteration boundary in the Saga area is consistent with the location of the Indian summer monsoon, which may be the dominant control on the pedogenic intensity.

Aeolian deposits in the Yarlung Zangbo River (YZR) valley in the southern Tibetan Plateau (TP) have recorded the evolution of past climate and atmospheric circulation in the "Asian water tower" region. However, the paleoclimatic history of the region remains controversial, largely because of ambiguous proxy environmental indicators. Here, we conducted the first detailed investigation of the environmental magnetic properties of two Holocene aeolian sedimentary sequences in the valley. Combined with geochemical and sediment granulometry data, we clarify the magnetic enhancement mechanisms and the paleoclimatic implications of the magnetic parameters. The results reveal spatial differences in magnetic properties, which makes sense in relation to the climatic gradient in this region. Due to the stronger Indian summer monsoon (ISM), ferrimagnetic and imperfect antiferromagnetic minerals (both coarse and fine-grained) dominate the sedimentary magnetic properties in the middle reaches of the YZR, suggesting both detrital and pedogenic origins. Hence, although both wind activity and pedogenesis cause the observed magnetic enhancement, magnetic parameters sensitive to the presence of fine magnetic grains can be used as paleo-moisture and/or temperature proxies. With decreasing ISM precipitation, the sedimentary magnetic properties in the upper reaches of the YZR are dominated by coarse ferrimagnetic grains, indicating the dominant influence of detrital input. Hence, the variations in sedimentary magnetic properties are caused by changes in paleo-wind intensity, given the constant material source. Accordingly, we propose a conceptual model that explains the spatiotemporal variations in dust accumulation and magnetic properties in this region. Our results provide a sound basis for understanding the sedimentary magnetic properties and their application in paleoclimatic reconstruction in the southern TP.

Knowledge of past changes in the Westerlies is important for understanding the climatic and environmental evolution of Central Asia. Here, we use high-resolution grain size records from several loess deposits in Central Asia to study the spatial pattern of the Westerlies during an interval of high global ice volume during the Last Glacial Maximum. During Heinrich event 2 (H2), the Westerlies strengthened in southern Central Asia, as indicated by the high accumulation rate of dust transported by the Westerlies, while it decreased in northern Central Asia. Our grain size record, combined with climate modeling results, suggest that the main axis of the Westerlies strengthened and moved southward to southern Central Asia during Heinrich events, especially H2. Comparison with other climate records from East Asia indicates that a southward shift of the Westerlies may influence the extension of the downstream East Asian Summer monsoon rain belt into north and northwest China. Thus, the position and strength of the mid-latitude Westerlies need to be considered in future studies of the Asian monsoon.

Understanding the origin of the stable carbon isotope composition of the organic matter ( delta C-13(org) ) in surface soil is critical for using delta C-13(org) in geological archives to reconstruct environmental and climatic changes. However, the relationship between soil delta C-13(org) and climatic factors varies in different climatic regimes, resulting in uncertainties in climatic reconstructions. We measured the delta C-13(org) of 79 surface soil samples collected from the upper and middle reaches of the Yarlung Zangbo river basin (YZRB), southern Tibetan Plateau, in order to explore their spatial variations and environmental implications. The soil delta C-13(org) values range from -28.1%0 to -15.2%0, with an average of -22.8%0 and a modal value of around ???25%0 to ???23%0. Higher ??13Corg values occur in the central part of the YZRB (Lazi-Nedong) and lower delta C-13(org) values occur in the western (Gar-Lazi) and eastern (Nedong-Bomi) parts. The variations in soil delta C-13(org) are significantly correlated with altitude (with a boundary at similar to 3500 m a.s.l.). The co-variation of temperature and precipitation is responsible for the effect of al-titude on soil ??13Corg, with temperature (mainly warmest season temperature) being the main controlling factor above 3500 m a.s.l., and precipitation the main factor below 3500 m a.s.l.. Higher absolute values of the regression coefficients for the relationships between soil delta C-13(org) and altitude (-5.1%0/km) and with mean annual temperature (+0.56%0/degrees C) above 3500 m may be due to the higher proportion of C4 plants in the central part of the YZRB, making it necessary to avoid the influence of C4 plants when using soil ??13Corg to reconstruct altitude or temperature. However, soil delta C-13(org) may be useful for precipitation reconstruction below 3500 m a.s. l., where C3 plants dominate.