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Grassland provides multiple ecosystem services and plays a key role in preventing desert encroachment and maintaining oasis stability. In China, the area of cropland in oases has expanded significantly in recent decades, which results in a rapid increase in agricultural water demand and encroachment on grassland subsistence space. However, our knowledge about how the expansion of cropland affects oasis grasslands remains limited. We used machine learning, temporal segmentation of spectral trajectories, and maximum covariance analysis to generate an annual oasis grassland aboveground biomass (AGB) data set at 30‐m resolution from 1989 to 2021 based on multiple remotely sensed and ground observation data sets, and investigated the dynamics of grassland AGB under cropland expansion in oases. We found that overall oasis grassland AGB increased significantly (0.3 gm−2 yr−1, P < 0.01) during 1989–2021, but trends in AGB were not consistent across basins. In the Yellow River, Turpan Hami, Qaidam, and southern Altai Mountains River Basins, AGB was dominated by a significant increase. Conversely, in all basins in southern Xinjiang, AGB showed a decreasing trend due to the rapid cropland expansion. Spatially, cropland expansion and AGB dynamics were strongly coupled. In regions characterized by agricultural concentration, grassland AGB benefitted from resource spillover via edge effects. However, in downstream areas or those with a low proportion of cropland, where most grasslands are distributed, the relationship between the two shifted to a trade‐off. Our study provides a scientific basis for identifying priority areas for ecological restoration and for science‐based planning of the scale of cropland in oases. Plain Language Summary: The rapid expansion of cropland in China's oases inevitably increases agricultural water demand, leading to a gradual reduction in water resources available for grasslands. We assessed the dynamic trends of aboveground biomass (AGB) in oasis grasslands and revealed the impact of cropland expansion on grasslands. We found that although AGB had increased significantly across the region, AGB across all basins of southern Xinjiang showed a decreasing trend due to continuous cropland expansion. Cropland expansion negatively impacts grassland AGB in downstream areas of basins and in areas with a low proportion of cropland. These findings identify hotspots of vegetation loss in Chinese oases and underscore the necessity of science‐based planning of the cropland scale. Key Points: Aboveground biomass (AGB) decreased in 46.0% of grasslands in Chinese oases from 1989 to 2021The river basins in southern Xinjiang are hotspots of grassland AGB loss in Chinese oasesGrassland AGB was more strongly coupled with cropland expansion than with climate factors [ABSTRACT FROM AUTHOR]

The Three-North Shelterbelt Project is the largest ecological engineering initiative in China to date, distinguished by its immense scale, extended construction period, and widespread benefits for the population. The gross ecosystem product (GEP) serves as a crucial indicator for assessing ecological benefits. This study focuses on the Three Northern Protection Forest Project Area, utilizing GEP calculations for the years 2000 to 2020. This study evaluates variations in the production values of different ecosystem services to reflect the ecological conservation benefits of the restoration project. Additionally, it analyzes the spatiotemporal evolution and trends of the GEP calculations, offering data references and decision support for the enduring efficacy of ecological restoration projects. The findings are as follows. (i) Between 2000 and 2020, the GEP of the Three-North region exhibited significant growth with continuous enhancement of various ecosystem service functions; the most substantial rate of change was observed in the water conservation function, followed by carbon sequestration and oxygen release, soil retention, windbreak and sand fixation, flood regulation, and environmental purification functions. (ii) The per-unit area value of different ecosystem types generally increased; the forest ecosystem displayed the largest growth rate at 61.18%, followed by shrubland ecosystems at 49.84%. (iii) The spatial distribution of ecosystem service in the Three-North region displayed a clustering trend alongside notable spatial heterogeneity. High-high clustering zones were identified in areas such as the Tianshan Mountains, Altai Mountains, Qilian Mountains, and Greater and Lesser Khingan Mountains. Conversely, low-low clustering areas were scattered, forming patchy distributions in regions like the Tarim Basin, northern Qinghai-Tibet Plateau, and the Hexi Corridor. This study, by analyzing the gross ecosystem product of the Three-North Shelterbelt Project region, unveils the spatial distribution characteristics, trends, and variations in ecosystem service values over the past two decades. It provides data support and decision guidance for the long-term efficacy of future ecological conservation and restoration projects. This study incorporates the GEP accounting method into the assessment of the effectiveness of major conservation projects. Compared to the traditional methods of effectiveness assessment, this represents a significant exploration and innovation. [ABSTRACT FROM AUTHOR]

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Investigating the spatial and temporal changes in snow cover over mountain areas is significant for understanding the impact of regional climate variability. In this study, using cloud‐removed snow cover data, which are generated based on Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products, the spatiotemporal changes of snow cover fraction (SCF) and its relationship with temperature and precipitation changes from 2002 to 2020 were examined over Altai Mountains, China. The results demonstrate that the distribution and changes of SCF are highly spatiotemporally heterogeneous. Within a year, the maximum SCF occurs in January at 98.6%, and the minimum appears in July at 8.7%. The annual‐mean SCF shows an increasing trend at 0.09%·annum−1, owing to the significantly increasing SCF in the snow accumulation period at 0.5%·annum−1 and the decreasing SCF in the snow melting period at −0.2%·annum−1. The SCF distribution, as well as its interannual change, is greatly influenced by elevation. During the snow cover period, a positive linear correlation between SCF and elevation is found at 0.02%·m−1 (p <.01). The annual‐mean SCF decreases in the area below 1,200 m, whereas it increases in the area above 1,200 m. Accordingly, the elevation‐dependent SCF results in various SCF distributions on different slopes and watersheds. The SCF shows an apparent pattern in different aspects, with similar SCFs between the north and east aspects and between the west and south aspects but a difference between the northeast aspects and the westsouth aspects. The SCF is negatively correlated with air temperature (r = −0.74, p < 0.01) and positively correlated with precipitation (r = 0.74, p < 0.01). In addition, temperature shows a significant and larger correlation with SCF in both the snow accumulation and melting periods, indicating the major factor of temperature for the changes in SCF. [ABSTRACT FROM AUTHOR]

Background: Medicinal plants have always played an important role in the history of human health. However, the populations and sustainable use of medicinal plants have been severely affected by human activities and climate change. Little is known about the current conservation status and distribution pattern of medicinal plants. In this study, based on accurate geographical distribution information of 9756 medicinal plants, we identified diversity hotspots and conservation gaps, evaluated conservation effectiveness of nature reserves, and predicted suitable habitat areas for medicinal plants in China to provide scientific guidance for their long-term conservation and sustainable use. Results: A total of 150 diversity hotspot grid cells, mainly concentrated in central and southern China, were identified. These only accounted for 5% of the total distribution area but contained 96% of the medicinal plants of the country. The hotspot grid cells included all traditional hotspot areas, but we also detected three new hotspots, namely Mufu-Lushan Mountains, Tianshan-Altai Mountains, and Changbai Mountains. The current national and provincial nature reserves protect 125 hotspot grid cells, which harbor 94% of all medicinal plants. However, 25 hotspot grid cells, distributed in the Tianshan-Altai Mountains and Hengduan Mountains, are located outside the national and provincial nature reserves. An analysis of the predicted effects of climate change indicated that the suitable habitat areas will shift from southern to northern China, and that southern China will face a considerable loss of suitable habitat areas, while the east and west parts of China will encompass remarkably more suitable habitat areas in the future. Conclusions: The current conservation networks have achieved high conservation effectiveness with regard to medicinal plants; however, the conservation gaps we identified should not be neglected, and conservation planning needs to take into account the predicted shifts of some hotspots of medicinal plants due to climate change. [ABSTRACT FROM AUTHOR]

A thorough understanding of regional differences in change patterns of surface air temperature (SAT) at various spatial scales can help people cope well with global warming. In this study, a SAT change pattern recognition method was firstly established based on k-mean++ algorithm. By creating a clustering effect evaluation index (DBWk) to select the optimal cluster number k, the pattern of SAT change in 1960–2016 of China was recognized at national and regional scales. Results showed that China's SAT change patterns were grouped into 3 clusters, namely, Clusters I, II and III, at the national scale. These clusters were further divided into 3, 7, and 4 subclusters at the regional scale, respectively. The SAT change in Cluster I was intense, with a relatively cold period (1960–1987) and a relatively warm period (1988–2016). The SAT of Cluster II decreased slightly in the first phase (1960–1983), minimally increased in the third phase (1999–2016), but rose strongly in the second phase (1984–1998). The linear trend (LT) of SAT increase of Cluster III was high and statistically significant, especially in 1983–2016. The analysis of the SAT change pattern of subclusters showed that the SAT fluctuations of the Altai Mountains and Junggar Basin were the strongest. The Northern Qinghai–Tibet Plateau had the highest warming rate, and the LT of warming was statistically the most significant in China. [ABSTRACT FROM AUTHOR]

For a better understanding of the precipitable water in the arid northwestern China (NWC), we surveyed the water vapour variability on both sides of the alpine range crests based on the Tropical Rainfall Measuring Mission monthly precipitation data (TRMM 3B43). There were 12 target zones and 23 subzones in six mountain systems representatively selected according to alpine hydrogeomorphology. They were used for comparative analyses in time and space. Comparisons between the two sides of the range crests revealed that there is more precipitable water on the south slopes of the Qilian, Altun, Kunlun, and Altai Mountains, on the north slope of the Tian Mountains, and on the east slope of Helan Mountains. High correlations were detected between precipitable water for both sides of the range crests in target zones, while low correlations were found among precipitable water separately averaged in the Kunlun, Tian, and Qilian Mountains including both sides of the range crests. The proportion of precipitable water during the rainy season gradually increased from west to east along the mountains. Temporally, precipitation presented synchronous increases or decreases on the two sides of the range crests in most of the target zones during the time period from 1998 to 2016, and an overall increase in alpine annual precipitable water was found in the area, except for the decrease in the Altun and western Tian Mountains. The summer decay dominated the decrease in these two target zones, while strengthened conveyance was observed in other seasons, especially in spring and autumn, which compensated for, and led to, total increases in precipitable water in most of the target zones. All of the above findings were indicative of differences in vapour transport from outside areas into diverse alpine systems in the arid NWC, which could be schematically evidenced by the spatial patterns of monthly and annual water vapour conveyance retrieved from the TRMM precipitation data. [ABSTRACT FROM AUTHOR]

Voluminous Silurian-Devonian granitoids intruded a greywacke-dominated Ordovician accretionary wedge in the Chinese Altai. These granitoids are characterized by significant Nd-Hf isotopic decoupling, the underlying mechanism of which, so far, has been poorly understood. This issue is addressed in this study by the integration of our new and regional published geological and geochemical data. Geological studies indicated a close spatial relationship between the regional anatexis of the Ordovician wedge and the formation of the granitoids, which is characterized by a gradual textural evolution from the partial molten Ordovician wedge sedimentary rocks (the Habahe Group) to the granitoid bodies. Compositionally, these granitoids and the Ordovician Habahe Group rocks displayed close geochemical similarities, in the form of arclike trace elemental signatures as well as comparable Nd isotopic characteristics. Combined with regional available data, we suggest that the Silurian-Devonian granitoids originated from the immature and chemically primitive Habahe Group rocks. Since Nd and Hf isotopic data for the Habahe Group rocks show significant Nd-Hf isotopic decoupling, we propose that the Silurian-Devonian granitoids inherited the Nd and Hf isotopic signatures from their sources, i.e., the Habahe Group rocks. In other words, the Nd-Hf decoupling in the Habahe Group rocks is the primary causative factor leading to the prevailing Nd-Hf isotopic decoupling of the Silurian-Devonian granitoids in the Chinese Altai. [ABSTRACT FROM AUTHOR]

Peatlands can archive exceptional paleoenvironmental histories of dust delivery because of their uninterrupted and elevated accumulation rates, yet long-term records of dust deposition and its effect on peat accumulation are rare in the arid and semiarid Asian regions that can be major dust sources. We present here high-resolution Holocene peat accumulation and paleodust records from the Tielishahan (TLSH) and Halashazi (HLSZ) peatlands in the Altai Mountains of northwestern China. We find that although the two peatlands share common histories of external climate forcing and dust delivery, they have significantly different long-term rates of peat accumulations. Peat deposition initiated ~2 kyr earlier in the HLSZ peatland than in the TLSH peatland, exhibiting higher peat accumulation rates and greater mineral dust fluxes during the early Holocene, but it has constantly smaller values from the mid-Holocene to the present. The TLSH peatland has a higher peat accumulation rate and mineral dust flux during the early Holocene, lower values during the mid-Holocene, and increasing values during the latest Holocene. The elemental proxies in the two peat cores indicate that atmospheric deposition is the major factor in controlling delivery of mineral elements in HLSZ peatland, whereas elemental delivery in the TLSH peat record is affected by both the regional atmospheric dust flux and the water table under this sequence. We also find that peat accumulation is closely related to mineral dust deposition, as most Asian locations generally share similar patterns in long-term peat accumulation and dust deposition. We postulate that increased aridity in the dust sources of arid central Asia and stronger westerly winds induced by negative NAO variations are key drivers on greater dust deliveries. We further postulate that local factors, such as site-specific differences in permafrost thawing, the areas of the peatlands, and their hydrology are the main reasons for the asynchronous Holocene histories of these two neighboring peatlands. These local factors should be considered when interpreting long-term paleoclimate records from rates of peat accumulation and paleodust delivery. • High-resolution peat accumulation and dust records from two specific peatlands in the Altai Mountains, northwest China. • Evident difference in long-term peat accumulation and dust deposition between two peatlands. • Peat accumulation in the Altai Mountains is closely related to mineral dust delivery. • Specific features of different peatlands play important roles on long-term peat accumulation and dust deposition. [ABSTRACT FROM AUTHOR]

Based on pollen data of 274 samples from a 550-cm core at Kelashazi Peat in the southern Altai Mountains within China, we reconstructed the Holocene vegetation dynamics and climatic change. The pollen assemblages and the associated biome scores indicate that the vegetation in Kelashazi valley was dominated by alpine meadows during the early Holocene (before ~8.2 cal. kyr BP) and by taiga forests in the middle Holocene (~8.2-~5.6 cal. kyr BP) that was followed by an expansion of alpine meadows (~5.6-~3.2 cal. kyr BP). The pollen-based temperature index-indicated thermal maximum lasting from ~8.0 to ~5.6 cal. kyr BP was consistent with temperature stack for 60–30°N and the later onset warming at Kelashazi Peat was associated with the cooling influence of remnant ice sheets in the early Holocene. The pollen-based increasing moisture index curve from Kelashazi Peat is in a good agreement with the synthesized decreasing aridity index curve in low-elevation regions of the Altai Mountains and the surrounding areas during the data-overlapping period between ~12.0 and ~3.2 cal. kyr BP. The Holocene wetting trend at Kelashazi Peat might have resulted not only from the increasing trend of NAO-related winter precipitation but also from the increasing trend of AMO-modulated summer precipitation. • Holocene vegetation and climate changes was reconstructed in the southern Altai Mountains. • Thermal maximum was consistent with temperature stack for 60–30°N. • Moisture reconstruction is consistent with synthesized Holocene aridity index in low-elevation regions. • Holocene wetting trend have resulted from the increasing trends of NAO-related winter precipitation and AMO-related summer precipitation. [ABSTRACT FROM AUTHOR]

Based on numerical experiments undertaken with nine climate models, the glacier equilibrium line altitudes (ELAs) in western China during the last glacial maximum (LGM) are investigated to deepen our understanding of the surface environment on the Tibetan Plateau. Relative to the preindustrial period, the summer surface air temperatures decrease by 4–8°C while the annual precipitation decreases by an average of 25% across the Tibetan Plateau during the LGM. Under the joint effects of reductions in summer temperature and annual precipitation, the LGM ELAs in western China are lowered by magnitudes that vary with regions. The ELAs in the southern margin and northwestern Tibetan Plateau decline by approximately 1100 m; the central hinterland, by 650–800 m; and the eastern part, by 550–800 m, with a downward trend from southwest to northeast. The reduction in ELAs is no more than 650 m in the Tian Shan Mountains within China and approximately 500–600 m in the Qilian Mountains and Altai Mountains. The high-resolution models to reproduce the low values of no more than 500 m in ELA reductions in the central Tibetan Plateau, which are consistent with the proxy records from glacier remains. The accumulation zones of the Tibetan Plateau glaciers are mainly located in the marginal mountains during the LGM and have areas 2–5 times larger than those of the modern glaciers but still do not reach the central part. [ABSTRACT FROM AUTHOR]

Abstract A high-resolution pollen record in a peat sequence from the Altai Mountains of Xinjiang, China, allows reconstruction of the regional vegetation and climate changes that occurred during the Holocene. Pollen distributions from the sequence indicate that the vegetation community in the Altai Mountains region transitioned through five general phases: forest and desert steppe, wet steppe, desert steppe, steppe, and finally forest and desert steppe. These vegetative phases imply that the regional climate changed from a cold and dry early Holocene to a warmer and wetter early-mid Holocene and then to a cold and rather dry mid-Holocene that was followed by a cool and wet late Holocene and finally by warm and dry conditions for the last millennium. These regional changes in climate are roughly consistent with local changes previously reconstructed from organic geochemical paleoclimate proxies in the same peat sequence by Zhang et al. (2016), but with some minor but important differences that reflect local factors. Regional comparisons reveal that the Holocene climate changes in the Altai Mountains are generally consistent with those of most arid central Asian regions that are influenced mainly by westerlies. However, they are out-of-phase with the climate histories of regions controlled by the Asian monsoons, indicating that the Asian monsoons did not extend to the high-altitude mountain regions of arid central Asia during the Holocene. We postulate that the regional Holocene moisture variations have been mainly modulated by NAO variations that affected transport of water vapor from the North Atlantic Ocean by the westerlies. Moreover, local factors that include topography of the mountains and glacial meltwater events in the high-altitude regions also contributed to the climate changes in the Altai Mountains. In addition, air temperatures related to summer insolation of the Northern Hemisphere might have played an important role in modulating moisture in the region, but only after the local montane ice-sheets had disappeared by the mid-Holocene. Highlights • Pollen records from a peat sequence from Xinjiang Altai Mountains reveal Holocene vegetation changes. • Pollen-based reconstruction of Holocene climate changes in the Altai Mountains. • Comparisons of Holocene climate changes in Altai Mountains with arid central Asian and monsoonal Asian regions. • Explanations proposed for Holocene vegetation and climate changes in the Altai Mountains. [ABSTRACT FROM AUTHOR]

Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-term records of paleofloods in arid regions are scarce, thus preventing a thorough understanding of such events. In this study, a reconstruction of paleofloods over the past 300 years was conducted through an analysis of grain sizes from the sediments of Kanas Lake in the Altay Mountains of northwestern China. Results showed that grain parameters and frequency distributions can be used to infer possible abrupt environmental events within the lake sedimentary sequence, and two extreme flood events corresponding to ca. 1736-1765 AD and ca. 1890 AD were further identified based on canonical discriminant analysis (CDA) and coarse percentile versus median grain size (C-M) pattern analysis, both of which occurred during warmer and wetter climate conditions by referring to tree-ring records. These two flood events are also evidenced by lake sedimentary records in the Altay and Tianshan mountains. Furthermore, through a comparison with other records, the flood event from ca. 1736-1765 AD in the study region seems to have occurred in both the arid central Asia and the Alps in Europe, and thus may have been associated with changes in the North Atlantic Oscillation (NAO) index. [ABSTRACT FROM AUTHOR]

Though being considered strategically important in matters of national defense based on its abundance of natural resources, Northwest China is one of the most ecologically vulnerable areas in the country. As one of the region's important water sources, glaciers have gone through major changes due to climate change. An analysis of research results over the past 60 years reveals that the glaciers have been retreating in general to some degree in large river basins in Northwest China, but the rate of retreating varied largely among different regions, ranging from 0.01% • a-1 to 0.75% . a-1. Specifically, glaciers around the Lantsang River Basin and the Altay Mountains have bean retreating fastest. The retreat of glaciers has already caused an increase in runoff in mountainous areas of Northwest China. Meanwhile, increases in the frequency of glacial flash floods and in the flood discharge will further enhance the probability of glacial lake outburst floods and ensuing disasters. [ABSTRACT FROM AUTHOR]

Strong cold air outbreak tracking has been a key meteorological focal point over the years. With observational data and gridded datasets, we used the “three-dimensional wind speed trajectory inverse method” to trace cold air intrusion tracks that occurred during the winter half-years for the central and eastern parts of Inner Mongolia in 1970–2013. The results indicated that there were a total of 303 northwest and 32 westward tracks intruding from along the north end and southern side of the Altai Mountains, respectively, 118 northward tracks intruding from the two individual sides of the Yablonoi Mountains, and 16 occurrences of “other” tracks. The imminent circulation evolution pattern prior to outbreaks essentially causes three categories of cold air masses to undergo dramatic temperature increases, thereby reducing the impacts of source regional differences on the subject air masses. The measure of the annual frequency reduction in northwest tracks was determined to be 0.41 incidents every ten years, while other tracks’ annual frequencies increased, which essentially implies the probable increase of extreme cold in northeast and central China and an increase in the frequency of continuous cold weather exceeding a three-day span in southern China. [ABSTRACT FROM AUTHOR]

The location of the Altai Mountains at the limits of both the Pacific and Atlantic influences implies that this mountain range is an important climatic boundary. Based on pollen data of 188 samples of a 390-cm core from Narenxia Peat in the southern Altai with a chronologic support of 11 accelerator mass spectrometry (AMS) dates, we reconstructed the Holocene climatic change at Narenxia Peat. The reconstruction revealed five stages of climatic change: a cold and dry latest deglacial (prior to ~11,500 cal. yr BP), a warm and wet early-Holocene (~11,500 to ~7000 cal. yr BP), a considerably cooled and dried middle Holocene (~7000 to ~4000 cal. yr BP), a resumed warm and wet late-Holocene (~4000 to ~1200 cal. yr BP), and a relatively cool and dry latest Holocene (past ~1200 years). The reconstructions of mean annual temperature (MAT) and mean annual precipitation (MAP) from Narenxia Peat well resemble the reconstructions of North Atlantic Oscillations (NAO) and El Niño–Southern Oscillations (ENSO). The resemblance implies that the Holocene millennial-scale changes in MAT and MAP in the Altai might have been causally associated with the variations in NAO and ENSO. [ABSTRACT FROM AUTHOR]

The discharge of wastewater and waste rock in mining production activities is a significant hidden cause of soil heavy metal pollution. The accumulation of heavy metals in soil occurs through a variety of processes, and exposure to these metals can permanently damage the human body. Due to multiple factors, such as the formation causes, sources, and distribution trends of heavy metals in mineral resources, reasonably applying different machine learning methods to monitor and evaluate heavy metal pollution remains challenging. In this paper, we choose the copper mining area in the southern Altai Mountains of China as the study area, and 19 different types of spatial data are uniformly managed in a distributed database to improve monitoring efficiency. Furthermore, we propose a heavy metal pollution evaluation framework based on a stacked long short-term memory (LSTM) model, which considers spatial data correlations and extracts spatial clustering features. Information is screened through state updating in the framework, the short-term memory features of long sequences are extracted, and an effective prediction model is established. The results show that 26 of the 31 mining occurrences in the study area are in moderate- and high-pollution-risk grids, suggesting that the spatial distribution of copper mines is consistent with the predicted spatial distribution of pollution risk. Overall, these results show that using the optimized stacked LSTM model to integrate multisource geological features and mine the internal rules of feature information has a positive effect on improving the risk assessment of heavy metal pollution. [Display omitted] • Big data technology and multivariate high-resolution data were used for high-risk area identification. • An efficient deep learning-based method for the spatiotemporal modeling of heavy metal pollution. • A wide range of heavy metal pollution assessment results was obtained with a good performance. • Mineral exploration affected the distribution of heavy metal pollutants in soil. [ABSTRACT FROM AUTHOR]

Glacier retreat in high altitude areas triggered by anthropogenic warming exerts a profound impact on the ecology of glacier-fed lakes. In this paper, we report on the results of a multi-proxy analysis of a Lateglacial (13.3–11.3 cal kyr B.P.) core obtained from the glacier-fed Kanas Lake in the Altai Mountains, China, to understand the responses of aquatic ecosystems to meltwater influxes. Core intervals with high sand fractions and enriched silicon dioxide and zirconium (~11.5, 11.7, 11.8, 12.2 and 13.0 cal kyrs B.P.) reflect intense meltwater pulses from alpine glaciers. In the core, these pulses generally coincide with low abundance of littoral cladocerans, high abundance of planktonic Pediastrum , and high phosphorus concentrations. Our results suggest that intense meltwater influxes not only brought nutrients (nitrogen and phosphorus) into the lake and promoted phytoplankton growth, they also generated cold, turbid water masses and restricted the growth of benthic algae and invertebrates. Therefore, we infer that future anthropogenic warming may lead to significant changes in the structure and function of aquatic ecosystems in glacier-fed lakes worldwide. • We study the impact of Lateglacial meltwater influx on the aquatic ecology of Kanas Lake, China. • Intense meltwater influx delivered nutrients to the lake and promoted the phytoplankton growth. • Intense meltwater influx also generated turbid and cold waters and restricted the benthic organism growth. • Future anthropogenic warming may lead to significant changes in aquatic ecosystems of glacier-fed lakes worldwide. [ABSTRACT FROM AUTHOR]

The Chinese Altai, as an accretionary orogen developing from the Cambrian to Carboniferous, was modified by Permian deformation, metamorphism and magmatism in response to the collision with the East Junggar. The tectonic processes of the collision and the timing of related deformation and metamorphism are still enigmatic. Here we present new 40 Ar/ 39 Ar dating results for granitic gneisses and amphibolites exposed in the Qiongkuer Domain in two areas (Alahake and Fuyun) of the southern Chinese Altai. The amphiboles from both Aalaheke and Fuyun areas yield consistent 40 Ar/ 39 Ar plateau ages at 265.9 ± 1.7 Ma and 270.1 ± 3.1 Ma. In contrast, the biotites from two areas show distinct 40 Ar/ 39 Ar ages of 232.0 ± 2.1 Ma and 226.8 ± 1.7 Ma for the Alahake area, and 245.1 ± 1.5 Ma and 264.5 ± 2.2 Ma for the Fuyun area, respectively. Given that 40 Ar/ 39 Ar ages are younger than the Permian high temperature metamorphism at ∼299–277 Ma as constrained by metamorphic zircons in the Qiongkuer Domain, we interpret these 40 Ar/ 39 Ar ages to record the cooling history of two areas. Compatible amphibole ages in both areas indicate a similar exhumation age along the Qiongkuer Domain cooling through 550 °C at ∼270–265 Ma, which may have been associated with the development of the sinistral Erqis Shear Zone during the collision between the Chinese Altai and the East Junggar. The subsequent exhumation processes were variable in different areas of the Qiongkuer Domain as showed by the distinct biotite ages, which may indicate along-strike variation of cooling processes from 550 °C to 300 °C in the Qiongkuer Domain. [ABSTRACT FROM AUTHOR]

Peat brGDGTs (branched glycerol dialkyl glycerol tetraether lipids) have been proposed as an indicator of past temperature changes. However, recent Chinese peat brGDGTs-based Holocene temperature ranges, of >10 °C, are implausible as they are greater than the corresponding ranges obtained using other proxies. This indicates the possible role of additional factor(s) affecting peat brGDGTs, other than temperature. Here, we report the results of a comparative study of surface peat samples, from dry sites (without water cover when sampling) and water sites (with water cover when sampling), from three peatlands with contrasting environmental backgrounds in China. The results clearly demonstrate the influence of water conditions on the molecular distribution of peat brGDGTs. Specifically, the relevant methylation index (MBT′/MBT′ 5ME , which is proposed as a temperature indicator) of brGDGTs from the water sites is generally lower than that from the dry sites, which may be caused by the decoupling of water/air temperatures and/or different brGDGTs-producing bacterial communities controlled by the water conditions. Considering the long-term process of hydroseral succession from a water body (an analogue of a water site) to a peat bog (an analogue of a dry site), we estimate that around half of the range of the peat brGDGTs-based Holocene temperature record could result from long-term changes in hydrological conditions. If this effect is removed from the peat core MBT′ 5ME record, the residual range of the peat brGDGTs-based Holocene temperature record from the Narenxia peatland in the Altai Mountains, in arid inland China, is consistent with that of the quantitative pollen-based Holocene temperature record from the same peatland, highlighting the paleoclimatic significance of our findings. [ABSTRACT FROM AUTHOR]

• Tianshan and Junggar Mountains provide sediment for Gurbantunggut Desert; • Fluvial, northwest and south west wind caused sediment rework and mixing; • Sediment and topographic controlled sediment geochemistry heterogeneous. • Wind controlled sediment geochemistry spatial heterogeneous. The provenance of desert sands controls the formation and development of sand seas. However, the sediment provenance in the Gurbantunggut Desert, the second-largest desert in China, has been largely unknown. We collected samples from sand dune crests and nearby interdune lacustrine deposits in the desert's core regions, as well as from the beds of rivers originating in the surrounding mountains, and analyzed samples for rare earth elements and trace elements. The novelty of our research was to apply geochemistry properties of samples to explain how fluvial and aeolian system controlled aeolian sediment transport and reworking processes. In order to identify the sand provenance, we first calculated fingerprint indexes based on range tests for a variety of parameters, and applied multidimensional scaling to establish the similarities among samples. Range test indicated that Cu, Zn, As, Rb, Nb, Mo, In, Sn, Ls, Ce, Ta, Y/Nb, Sc/Y, Y/Nd, Sc/La, Σ REE , La n , and LREE can be used as the fingerprints indices. The elemental geochemical characteristics of samples were similar among Altain Mountains, and different with samples in the desert. However, elemental compositions were similar between Tianshan Mountains and Junggar Mountain and in the desert. We found that clastic materials from the Junggar Mountains and Tianshan Mountains were carried to low-lying areas of the Gurbantunggut Desert by rivers, whereas the areas with relatively high topography located along on the route blocked flowing water, and transport was instead by strong westerly winds and arrived by means of aeolian transport. The parent materials from surrounding mountains, river fluxes, and topographic elevation determined the proportions of sand from different sources, which varied among sites in the desert. Clastic material from the Altai Mountains could not be transported to the Gurbantunggut Desert because it was blocked by an elevated river terrace. [ABSTRACT FROM AUTHOR]

Abstract: The Kanas River originates on the southern slope of Youyi Peak, the largest center of modern glaciation in the Altai Mountains in Central Asia. Glaciers advanced and retreated repeatedly during Quaternary glacial–interglacial cycles in the Kanas River valley, and four moraine complexes and associated glaciofluvial deposits are preserved in the valley. Optically stimulated luminescence (OSL) dating has been used to determine ages of glaciofluvial deposits (sand lenses sandwiched between tills in moraines) using a single aliquot regenerative-dose (SAR) protocol. Based on dating results from this and previous studies (including 14C, electron spin resonance (ESR) and OSL dates) and geomorphic relationships, the innermost moraine complex was concluded to deposit during the Little Ice Age (LIA), the second (Akekule) moraine complex was deposited during the Neoglacial, the third (Kanas) moraine complex was deposited during the last glacial cycle (marine oxygen isotope stage (MIS) 2–4) and the outermost set of moraines is MIS 6 in ages (penultimate glaciation). The Kanas moraine complex could be divided into three subsets (III1, III2 and III3), with inferred ages of MIS 2, mid-MIS 3 and MIS 4, respectively, which is consistent with moraine records from other areas in Central Asia and climate reconstructions from the Guliya ice core. The glaciers in the Kanas valley at their maximum extents during the LIA, Neoglacial, last glaciation and penultimate glaciation were 13.8 km, 32 km, ∼100 km, and ∼120 km long, respectively. [Copyright &y& Elsevier]

Abstract: This paper reports whole-rock Sr–Nd and zircon U–Pb and Hf isotopic compositions, as well as major and trace element data, for the granodiorites and their mafic microgranular enclaves (MMEs) in the Tuokesalei area, northwestern Chinese Altai. The granodiorites are characterized by peraluminous compositions (A/CNK=1.01–1.45), with relatively high SiO2 (64.4 to 70.9wt.%) and low MgO (0.75 to 1.97wt.%) contents. These rocks possess low total rare earth element (REE) contents (67–187ppm) with weakly negative Eu anomalies and mantle-like whole-rock Nd–Sr isotopic compositions (εNd(t)=+2.5 to +4.5; (87Sr/86Sr)i =0.7038 to 0.7048) and zircon εHf(t) values (+5.93 to +12.9). The MMEs contain abundant magmatic amphiboles and needle-like apatites, have low SiO2 (51.7 to 54.3wt.%) and high MgO (2.86 to 3.75wt.%) and REE contents (162–298ppm), and are characterized by moderately negative Eu anomalies (Eu/Eu*=0.40–0.60) and slightly depleted to enriched LREE ((La/Nd)N =0.74–1.41) and flat HREE ((Gd/Yb)N =1.16–1.39) patterns. The MMEs have whole-rock Nd–Sr isotopic compositions (εNd(t)=+2.6 to +2.7, (87Sr/86Sr)i =0.7034–0.7050) similar to those of the host granodiorites. Their similarities in crystallization age, mineral assemblage and isotopic composition document that the MMEs may represent an early crystallized phase, which was broken into pieces and brought to the shallow level during the host magma ascent and emplacement. Their precursor magmas were probably derived from an oceanic lithospheric mantle, which was characterized by pronounced Nd–Ta depletions. Mineral compositions of MMEs suggest that amphibole was a major early fractional mineral, which effectively differentiated the mantle-derived basaltic liquids to silica-rich melts. Zircon U–Pb dating yielded an age of 313±5Ma for the host granodiorites and 313±13Ma for their MMEs. The geochemical data of this study records an important episode of magmatism in an environment transitional from a subduction-related regime to a post-tectonic extension. Results of this study suggest that the accretionary orogenic process did not completely terminate until the Late Carboniferous to Permian in this region. [Copyright &y& Elsevier]

Abstract: Numerous Pb–Zn and Fe ore deposits occur in the volcanic–sedimentary basins along the southern Chinese Altay Mountains. The mineralization of these deposits is hosted by Early–Middle Devonian volcanics and sedimentary rocks and is directly associated with skarns. The genesis of these deposits is uncertain or hotly debated. This study considers the Sawusi Pb–Zn deposit from the southern Chinese Altay. The host rock of the Sawusi deposit is rhyolitic crystal tuff with intercalated bands of Fe–Mn calcic carbonates and a small amount of rhyolite within the upper section of the Early Devonian Kangbutiebao Formation. On the basis of a field investigation, the petrographic features of the skarn were described. Detailed electron microprobe analysis was performed on the skarn minerals, and the O, H and C isotopic compositions of quartz and its fluid inclusions were determined. Petrographic observation revealed a progressively intensifying alteration from the tuff and its intercalated bands to the stratiform skarn characterized by alternate bands of dark garnet–biotite skarn and light grunerite–biotite skarn. Mineral–chemical analysis shows that the stratiform skarn of the Sawusi deposit consists mainly of spessartine, almandine, Mn-rich grunerite, biotite and Fe–Mn calcic carbonate minerals. A mass balance consideration of the cations in the skarn minerals suggests that the stratiform skarn formed through dimetasomatism between the tuff and intercalated bands of sedimentary Fe–Mn calcic carbonates; however, the scale of the metasomatism is limited to a few centimeters. Laser 40Ar/39Ar dating was performed on the skarn grunerite, yielding an isochron age of 412±15Ma. The 40Ar/39Ar age is identical, within analytical error, to the zircon U–Pb age (401±2.7Ma) of the rhyolite from the Kangbutiebao Formation that hosts the skarn and Pb–Zn mineralization, and the age (401±3.1Ma) of the Biesisala porphyry, Sawusi deposit. The O, H and C isotopic compositions show that the ore-forming fluid includes two components. One is H2O–CO2, which has volatilized from carbonate and dehydrated from tuff, and the other is meteoric-derived surface water carrying minor meteoric CO2 or organic matter-derived CO2. Therefore, the stratiform skarn and Pb–Zn mineralization of the Sawusi deposit are quite different from the contact-metasomatic skarn and related deposits, and suggest a volcanic exhalation–sedimentation origin instead. This study has broad relevance to the Pb–Zn and Fe deposits along the southern Altay Mountains in the areas of ore genesis study and ore prospecting. [Copyright &y& Elsevier]

Clematis sibirica, a woody vine occurring primarily under conifer forests, is widespread in northern Eurasia. In this study, we intend to illustrate how the taxon has responded in the area of the Tianshan and Altai Mountains of Central Asia to the Pleistocene climatic fluctuations. The chloroplast intergenic spacer psbA- trnH was sequenced for 125 individuals from 28 populations, and a total of eight chlorotypes were identified. The presence of definite phylogeographic structure was detected for the species ( NST > GST, P < 0.001), and phylogenetic analysis indicated that the eight chlorotypes were clustered into two divergent lineages. They split at approximately 550-690 ka BP, according to coalescence analysis, coincident with the Pleistocene maximum glacial stage in these mountains, which suggests the restriction of these lineages to separate refugia at that time. Spatial analysis of molecular variance likewise divided the sampled populations into two associations, an Altai and eastern Tianshan group (populations 1-17), and a western Tianshan group (populations 18-28). Low levels of genetic diversity and unimodal mismatch distributions were obtained for both of these groups, suggesting postglacial range expansions. During the course of these expansions, mountain ranges surrounding the Dzungarian Basin probably served as migration corridors. In addition, a contact zone was identified in the central Tianshan and eastern Altai Mountains between the two phylogeographic lineages. [ABSTRACT FROM AUTHOR]

Abstract: The Paleozoic granites in the Chinese Altai are important for the study of tectonic evolution and crustal growth in the Central Asian Orogenic Belt (CAOB). Four representative peraluminous granitic intrusions were selected for systematic studies of zircon U–Pb and Hf isotopic compositions and whole-rock geochemical and Nd–Sr isotopic analyses. These rocks have high ASI (Alumina Saturation Index, Al2O3/(CaO+Na2O+K2O)=1.01–1.46 molecular ratios), with 0.6–5.6wt.% of normative corundum, and are characterized by moderately negative Eu anomalies (Eu/Eu*=0.38–0.98) and strong depletion in Ba, Nb and Sr elements. Our data suggest that these intrusions were emplaced from 419 to 393Ma, consistent with a period of intensive magmatic activities and high temperature metamorphism in the Chinese Altai. While in situ zircon Hf isotopic analyses for these granites give predominantly positive εHf(t) values (+0.8 to +12.8), a few inherited zircons yield negative εHf(t) values from −12.5 to −1.53. The U–Pb age and Hf isotopic data of these inherited zircons are similar to that of the widespread metasediments. In addition, the peraluminous granitic rocks have near-zero or negative εNd(t) values (−3.3 to −0.5) and relatively high initial 87Sr/86Sr ratios (0.7079–0.7266), distinct from those of the I-type granites in the study region, but similar to the Early Paleozoic Habahe sediments. These isotopic compositions suggest that the newly accreted metasediments of Habahe Group may be the major source rock of the peraluminous granites. The geochemical compositions indicate that their precursor magmas were derived from a relatively shallow crustal level (P≤5kbar) and zircon saturation temperatures suggest that these granitic intrusions were emplaced at 672–861°C. The peraluminous granitic magmas were generated by dehydration melting of newly accreted materials, which were possibly brought to at least middle crustal depth by subduction-related processes in an active margin, and were subsequently molten by strikingly high ambient temperature probably caused by upwelling of the hot asthenosphere associated with ridge subduction in the Paleozoic. [Copyright &y& Elsevier]

Abstract: The Mengku iron deposit (110Mt at 44% Fe) in the eastern extension of the Rudnyi Altai mineral belt, Xinjiang, NW China, is hosted in an Early Devonian volcano-sedimentary sequence affected by prograde skarn formation (clinopyroxene, garnet, scapolite and albite) and retrograde alteration (actinolite, epidote, chlorite and apatite). Ore minerals are magnetite, with minor chalcopyrite, pyrrhotite and pyrite. Gangue minerals include predominantly diopside, andradite, epidote, chlorite, quartz and calcite. Fluid inclusions in garnet and clinopyroxene yield homogenization temperatures (Th) of 241–500°C, and salinities of 9.6–13.0wt.% NaCl equivalent. Fluid inclusions in quartz consist of two varieties: (1) liquid–vapor–solid inclusions with (Th) of 348–458°C and salinities of 38.2–57.1wt.%, and (2) two-phase inclusions with (Th) of 166–382°C and salinities of 9.6–13.0wt.% NaCl equivalent. Two-phase inclusions in calcite vary from 145 to 265°C, with salinities of 1.2–9.6wt.% NaCl equivalent. The fluid evolution progressed from high temperature and moderate salinity (prograde skarn stage) to moderate T and salinity (retrograde stage), to low T and salinity (sulfide stage). Stable isotope data of quartz and calcite (−84‰ to −110‰ δD, 5.5–7.0‰ δ18OSMOW, and −3.8‰ to −6.1‰ δ13CPDB) reflect late-stage interaction of meteoric water with granitic rocks. Skarn formation was likely related to a Late Devonian tonalite (378±7Ma, U–Pb zircon age). The geological and geochemical evidence suggests magnetite skarn formation from granite-related fluids which reacted with andesitic to mafic volcanics and their intercalated carbonate beds and lenses, contrary to earlier interpretations of the deposit as of synsedimentary-exhalative origin or related to iron–oxide magma. [Copyright &y& Elsevier]

SHRIMP U-Pb zircon dating of a granite in the Mengku iron district, Altay, Xinjiang, yielded an age of 400 ± 6 Ma (MSDW = 1.3), which is similar to the age (SHRIMP U-Pb zircon age 404 ± 8 Ma) of granite north of orebody No. 1 in the Mengku iron deposit. This indicates that the two plutons are of Early Devonian age. These plutons intruded the Kangbutiebao Formation, thereby constraining the age of the Kangbutiebao Formation to >404 Ma. The Mengku granite and granite north of the No. 1 orebody are characterised by high silica (SiO2 = 72.29-78.63%), Na enrichment (Na2O = 4.12-7.98%), elevated Th, La, Ce, Nd and LREE, depleted Nb, Ta, P and Ti, as well as moderate negative Eu anomalies (δEu = 0.38-0.65). The granites belong to the low-K (tholeiitic) series with Na2O/K2O = 6.36-196.25 and are metaluminous and slightly peraluminous with alumina oversaturation indices of 0.97-1.09. Sr-Nd isotopic analyses [εNd(t) = 1.04-2.17] indicate that the sources of the Mengku pluton are predominantly mantle-derived, contaminated with small amounts of crustal components. Chemical, isotopic and structural characteristics indicate that granites in the Mengku district originated in a continental-arc setting associated with plate subduction. [ABSTRACT FROM AUTHOR]

This article is a study of the Khoton-nor War of 1731, in which the Chinese army lost over 10,000 soldiers in defeat. The battle is regarded as the biggest military disaster in the Qing campaign in Mongolia. While many scholars have written on this war, none have used the comprehensive treatises on the Eight Banners (Baqi tongzhi) as a source of documentation. The author draws from records of bannermen from Heilongjiang, China, regarding the Khoton-nor War. The first part of the article describes the background to Manchu bannermen stationed in the Heilongjiang area and Yongzheng emperor’s decree in the preparation for war in 1728, when elite troops were first selected. The second part of the article describes the deployment of troops in the sixth month of 1731 and reasons for the Heilongjiang bannermens' defeat. The conclusion discusses the impact of the Khoton-nor War to the Heilongjiang banner.

Abstract: The Kanas River originates on the southern slope of Youyi Peak, the largest center of modern glaciers in Altai Mountains, China. Three sets of moraines and associated glacial sediments are well preserved near the Kanas Lake outlet, recording a complex history and landscape evolution during the Last Glacial. Dating the moraines allows the temporal and spatial glacier shift and climate during the Last Glacial to be determined, and then constrains when and how the Kanas Lake basin was formed. Dating of the glacial tills was undertaken by utilizing the optically stimulated luminescence (OSL) method. Results date four samples from the three sets of moraines to 28.0, 34.4, 38.1, and 49.9ka and one sample from outwash sediment to 6.8ka. The Kanas Lake basin is a downfaulted basin and was eroded by glacier before 28.0ka, and the glacial moraines blocked the glacier-melt water after the glacier retreat, which made the present-day Kanas Lake eventually form at least before 6.8ka BP. In Altai Mountains, the glacier advance was more extensive in Marine Isotope Stage (MIS) 3 than MIS 2, probably because the mid-latitude westerlies shifted northward and/or intensified during the MIS 3, resulting in a more positive glacier mass balance. Nevertheless, the Siberian High dominated the Altai Mountains in MIS 2, resulting in a relative decrease in precipitation. [Copyright &y& Elsevier]

Abstract: The mineralization ages reported in the past in the Altai Mountains, northern Xinjiang, China, not only are different, but also fall into the Hercynian epoch. This study has achieved 17 zircon fission track analysis results from different ore deposits. The zircon fission track ages range from 134±9Ma to 339±49Ma. We consider that the zircon fission track age could reveal the mineralization age based on an annealing zone temperature of 140–300°C and a retention temperature of ∼250°C for zircon fission tracks, and a metallogenetic temperature of 150–260°C in various ore districts. The mineralization age agrees with the regional tectonics. A total of four mineralization epochs have been identified, i.e., 339–312Ma, 255–234Ma, 218–174Ma and 158–126Ma, and these indicate occurrence of the mineralizations in the Indosinian and Yanshan epochs as well as the Hercynian epoch. [Copyright &y& Elsevier]

Abstract: The Altay orogenic belt (AOB), situated in the middle part of the Central Asian Orogenic Belt (CAOB), is one of the most important metallogenic belts in China. The Kangbutiebao Formation is a Late Paleozoic stratigraphic unit that hosts many important iron and Pb–Zn deposits. The Kangbutiebao Formation consists of intercalated volcanic and sedimentary rocks that have undergone regional greenschist to lower amphibolite facies metamorphism, and mainly outcrops in three NW-trending fault-bounded volcano–sedimentary basins, including the Maizi, Kelang, and Chonghuer basins. SHRIMP analyses of zircons from three metarhyolites of the Kangbutiebao Fm. in the Kelang Basin yield weighted mean 206Pb/238U ages of 412.6±3.5 Ma, 408.7±5.3 Ma and 406.7±4.3 Ma, respectively, which can be interpreted as the eruption age of the Kangbutiebao silicic volcanic rocks in the Kelang Basin. These ages indicate that the Kangbutiebao Formation was formed during the Late Silurian to Early Devonian. They also demonstrate that the deposits hosted in the Kangbutiebao Formation were formed after 412–407 Ma. They play a key role in understanding the Paleozoic tectonic evolution and metallogenesis of the southern margin of the Chinese AOB. [Copyright &y& Elsevier]

Abstract: The Chinese Altai orogen is a typical domain of the Central Asian Orogenic Belt and in previous syntheses was divided into six tectonic units (or terranes). In this paper, 41 new and 36 published whole-rock Nd and Sr isotopic data for granitoid intrusions and mafic dykes within units 2 and 3 of the central Altai and units 4 to 6 of the southern Altai were used for isotopic mapping. The age of the samples used is known from U–Pb zircon dating. ε Nd(t) values range from −4 to +2 in the central Altai units 2 and 3, and from +1.4 to +6 in the southern Altai units 4 and 5 and up to +8.4 in unit 6. Correspondingly, Nd model ages (T DM) decrease from 1.6–1.1 Ga in the central Altai to 1.0–0.5 Ga in the southern Altai, except for a continental fragment in unit 4. I Sr is elevated in the central units, decreasing to <0.705 in the southern units 5 and 6. These results demonstrate that the central Altai contains widespread old crustal components in its basement, whereas the southern Altai comprises a higher proportion of juvenile crust. When integrated with published U–Pb zircon ages, our data show that new crust grew southwards in the Chinese Altai. In addition, our data suggest that units 2 and 3 are a single tectonic unit, whereas the southern Altai (unit 4), which previously was regarded as a single young accretionary terrane, should be subdivided into two units: a younger arc and an older continental fragment. The granitoids in the Chinese Altai can be divided into syn- and post-/non-orogenic groups. The syn-orogenic granitoids have ca. 50–80% mantle-derived component, whereas the post/non-orogenic granitoids contain ca. 70–90%. The generation of syn- and post-/non-orogenic granitoids represents horizontal (lateral) and vertical crustal growth, which contributed ca. 18–28% and 7–8% respectively to the area of the Chinese Altai. This work shows that isotopic mapping is an effective approach to elucidate terrane composition in the Central Asian Orogenic Belt and thereby better constrain Palaeozoic crustal growth. [Copyright &y& Elsevier]

The chemical Th-U-total Pb isochron method (CHIME) has been applied to determine the ages of monazite grains from metasediments of greenscshist-amphibolite facies in the Altai orogen, northwest China. The area of distribution of these metamorphic rocks is divided into the Permian (261–268 Ma) central-western and Devonian (377–382 Ma) eastern units on the basis of their metamorphic ages. The Devonian CHIME ages are consistent with the Pb–Pb ages of granitoid in the eastern unit, and support the idea that emplacement of the granitoids was synchronous with regional metamorphism at deep levels. The Permian metamorphic ages (the present study) and igneous ages previously reported from the central-western unit can be interpreted in terms of subduction of crustal material and oceanic plate, and rapid exhumation. [ABSTRACT FROM AUTHOR]

Abstract: This study uses apatite fission track (FT) analysis to constrain the exhumation history of bedrock samples collected from the Altai Mountains in northern Xinjiang, China. Samples were collected as transects across the main structures related to Palaeozoic crustal accretion events. FT results and modeling identify three stages in sample cooling history spanning the Mesozoic and Tertiary. Stage one records rapid cooling to the low temperature part of the fission track partial annealing zone circa 70±10 °C. Stage two, records a period of relative stability with little if any cooling taking place between ∼75 and ∼25–20 Ma suggesting the Altai region had been reduced to an area of low relief. Support for this can be found in the adjacent Junngar Basin that received little if any sediment during this interval. Final stage cooling took place in the Miocene at an accelerated rate bringing the sampled rocks to the Earth''s surface. This last stage, linked to the far field effects of the Himalayan collision, most likely generated the surface uplift and relief that define the present-day Altai Mountains. [Copyright &y& Elsevier]

The composition of Kuerti mafic rocks in the Altay Mountains in northwest China ranges from highly geochemically depleted, with very low La, Ta and Nb and high &epsiv;Nd(t) values, to slightly enriched, arc lava-like composition. They display flat to light rare earth element (REE)-depleted patterns and have variable depletions in high field-strength elements (HFSE). These mafic rocks were most probably derived from a variably depleted mantle source containing a subduction component beneath an ancient intra-oceanic backarc basin. Together with the slightly older arc volcanic rocks in the Altay region, the Kuerti mafic rocks display generally positive correlations of their key elemental ratios (e.g., Th/Nb, La/Yb and Th/Yb). These indicate that the more mid-ocean ridge basalt (MORB) component was contained in these magmas, the less arc component was present in their mantle source. Therefore, we propose a two-stage melting evolution model to interpret the compositional evolution of the Kuerti mafic rocks and associated arc volcanic rocks. First, arc basaltic melts were extracted from the hydrated arc mantle wedge beneath Kuerti, leaving behind a mantle source that is variably depleted in incompatible trace elements. Then, mafic rocks were erupted during seafloor spreading in the Kuerti backarc basin from the upwelling asthenospheric mantle. The variably depleted mantle source produced mafic rocks with composition ranging from arc lava-like to more geochemically depleted than MORB. The recognition of Kuerti mafic rocks as backarc basin basalts (BABB) is consistent with the proposed tectonic model that an active backarc basin–island arc system along the paleo-Asian ocean margin was formed in the Altay region during Devonian–Early Carboniferous. New data further indicate that the final orogenic event in the Altay Mountains, i.e. the collision of the north and south continental plates in the region, most probably took place in Late Carboniferous and Permian. [Copyright &y& Elsevier]

• Radial growth pattern differed between high and low altitudes. • Radial growth was more sensitive to climate at low-altitude than high-altitude. • Radial growth will increase between 1800 and 1900 m a.s.l. in the future. Considering climate change, there is no consensus on the impact of global warming on forest growth. Therefore, it is crucial to investigate the effects of climate change on tree radial growth. However, in arid eastern central Asia, the large-spatial scale radial growth-climate relationship remains poorly understood. In this study, we collected radial growth data from 13 Siberian larch (Larix sibirica) plots along an altitudinal gradient (1100–2200 m a.s.l.) in the Altai Mountains, China. Principal component analysis (PCA), bootstrapped correlation, and linear regression were conducted to detect and quantify the effects of climatic factors on radial growth and to reveal the spatial variation in the radial growth-climate relationship. Results showed that chronologies were clustered into low- and high-altitude groups. In the low-altitude group, the self-calibrating Palmer Drought Severity Index (scPDSI) in current April showed a strong positive impact on radial growth, while the previous September mean temperature and diurnal temperature range in previous July both significantly negatively affected radial growth. These three climate variables explained 63% of radial growth variance. Among them, the scPDSI, with a relative importance of 63%, was the primary limiting factor. In the high-altitude group, the current January maximum temperature and previous July precipitation were significantly negatively correlated with radial growth, while the June minimum temperature was significantly positively correlated with radial growth. These three climatic factors together contributed to 38% variance in radial growth. Furthermore, the plot-specific relationship between climate variables and radial growth varied significantly with different altitudes. As the climate becomes wetting and warming in the Altai Mountains, our result suggests that the radial growth might benefit in an altitude between 1800 and 1900 m a.s.l., where temperature and precipitation were both positively correlated with radial growth. These findings will provide a basis for sustainable forest management under global climate change. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the chemical composition of Astragalus altaicus's roots collected from the Altay, in Xinjiang's Uyghur Autonomous Region, China. Methanol was extracted from 400 grams of air-dried roots of A. altaicus which was evaporated to get the total extracted compounds which was eluted in hydrocarbons. Spectrum analysis revealed that triterpenoid 3 is betulinic acid. Results revealed two types of steroids and a lupane triterpenoid in A. altaicus' roots.

Integrating traditional ecological knowledge (TEK) with remote sensing capabilities to monitor rangeland dynamics could lead to more acceptable, efficient, and beneficial rangeland management schemes for stakeholders of grazing systems. We contrasted pastoralists' perception of summer pasture quality in the Altai Mountains of Central Asia with normalized difference vegetation index (NDVI) metrics obtained from Terra Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor. The spatial relationship between satellite-based assessment of the grassland quality and on-the-ground evaluation by local herders was first assessed for a single year using 49, 1 × 1 km grassland blocks sampled in July 2013. Herder-derived forage value was positively and strongly (63% of variance explained) related to satellite-derived NDVI values (MODIS 1 km monthly data, MOD13A3) as well as field estimates of % vegetation cover (62% explained) and to a lesser degree to vegetation height (28% explained). Herders' multi-year perception (i.e., recall ability) was also contrasted with satellite observations of their herding areas over the period of 2006-2016 during which NDVI temporal anomaly explained >11% of variance in estimates of pasture quality recalled. Few herders in Kazakhstan could recall pasture conditions, most herders in Russia and China could but inconsistently (4 and 7% variation explained, respectively), whereas most herders in Mongolia could recall pasture conditions in strong agreement with NDVI anomaly (30% variation explained), patterns reflecting herders' regional dependence on herding as a livelihood. Corroboration of herder-derived estimates and satellite-derived vegetation indices creates opportunity for re-expression of satellite data in map form as TEK-derived indices more compatible with herder perceptions.

Abstract: Allele and haplotype frequencies of 12 Y-chromosomal short tandem repeats (STRs) included in the PowerPlex® Y Systems (Promega) were determined in a sample of 150 unrelated healthy male individuals of Chinese Tuvans living in the Altay region of Xinjiang Uygur Autonomous Region. Allele frequencies and gene diversity for each Y-STR locus were determined. The observed haplotype diversity value was 0.9708. The present results can be used as Chinese Tuvan genetic information resources in routine population study and forensic analysis. [Copyright &y& Elsevier]