Muscovite^(40)Ar/^(39)Ar isotopic dating of pegmatite veins in the Bieyesamas rare metal deposit in the Altay Mountain,Xinjiang,northwestern China

1.Objective The Altay Orogenic Belt in Xinjiang,China is located in the west of the Central Asian Orogenic Belt and in the transition zone between the Siberian Plate and the Kazakhstan-Junggar Plate,extending approximately 500 km in northern Xinjiang,China(Fig.1a).The Altay Orogenic Belt has undergone two-way accretion of the Paleozoic crust and the Meso-Cenozoic intracontinental orogeny,leading to the formation of large numbers of intermediate-acid intrusions.More than 100000 pegmatite veins have been discovered in the intermediate-acid intrusions,and they constitute an important rare metal metallogenic belt of China(Fig.1b).

A new small baurioid therocephalian from the Lower Triassic Jiucaiyuan Formation, Xinjiang, China

Several therocephalian species,mainly represented by cranial material from the late Permian,have been reported from China in recent years.Here we describe a tiny new baurioid therocephalian,Jiucaiyuangnathus confusus gen.et sp.nov.,from the Jiucaiyuan Formation,Xinjiang,China.The new taxon is represented by a partial snout with occluded partial lower jaw and two postcranial skeletons.Although juvenile in stage,the new species is diagnosed by the following features:round pit in middle of lateral surface of maxilla;lacrimal contact nasal;fossa for dentary tooth on the posterior end of the premaxilla,lateral to the anterior choana;two small vertical triangular ridges extending dorsally and ventrally on the vomerine anterior portion,and bordering a thin vomerine foramen laterally;anterior projection of the lateral part of the frontal on the nasal;symphyseal region of the dentary projected anteriorly;5 upper premaxillary teeth,upper and lower canines absent,diastema between the last premaxillary upper incisor and first maxillary tooth present,no diastema separating anterior from posterior dentition in the mandible,10 maxillary teeth and 12 dentary teeth,posterior postcanine expands mesiodistally,having a main large cusps and tiny anterior and posterior accessory cusps in line;neural arches of the atlas fused by the neural spine,neural spine of the axis projected posteriorly,procoracoid foramen lies between procoracoid and scapula.Features of the dentition resembles those of the small baurioid Ericiolacerta parva from South Africa and Silphedosuchus orenburgensis from Russia.The specimens provide the rare opportunity to know in detail the postcranial skeleton of baurioids.

Spatiotemporal variation of land surface temperature and its driving factors in Xinjiang,China

Land surface temperature(LST) directly affects the energy balance of terrestrial surface systems and impacts regional resources, ecosystem evolution, and ecosystem structures. Xinjiang Uygur Autonomous Region is located at the arid Northwest China and is extremely sensitive to climate change. There is an urgent need to understand the distribution patterns of LST in this area and quantitatively measure the nature and intensity of the impacts of the major driving factors from a spatial perspective, as well as elucidate the formation mechanisms. In this study, we used the MOD11C3 LST product developed on the basis of Moderate Resolution Imaging Spectroradiometer(MODIS) to conduct regression analysis and determine the spatiotemporal variation and differentiation pattern of LST in Xinjiang from 2000 to 2020. We analyzed the driving mechanisms of spatial heterogeneity of LST in Xinjiang and the six geomorphic zones(the Altay Mountains, Junggar Basin, Tianshan Mountains, Tarim Basin, Turpan-Hami(Tuha) Basin, and Pakakuna Mountain Group) using geographical detector(Geodetector) and geographically weighted regression(GWR) models. The warming rate of LST in Xinjiang during the study period was 0.24℃/10a, and the spatial distribution pattern of LST had obvious topographic imprints, with 87.20% of the warming zone located in the Gobi desert and areas with frequent human activities, and the cooling zone mainly located in the mountainous areas. The seasonal LST in Xinjiang was at a cooling rate of 0.09℃/10a in autumn, and showed a warming trend in other seasons. Digital elevation model(DEM), latitude, wind speed, precipitation, normalized difference vegetation index(NDVI), and sunshine duration in the single-factor and interactive detections were the key factors driving the LST changes. The direction and intensity of each major driving factor on the spatial variations of LST in the study area were heterogeneous. The negative feedback effect of DEM on the spatial differentiation of LST was the strongest. Lower latitudes, lower vegetation coverage, lower levels of precipitation, and longer sunshine duration increased LST. Unused land was the main heat source landscape, water body was the most important heat sink landscape, grassland and forest land were the land use and land cover(LULC) types with the most prominent heat sink effect, and there were significant differences in different geomorphic zones due to the influences of their vegetation types, climatic conditions, soil types, and human activities. The findings will help to facilitate sustainable climate change management, analyze local climate and environmental patterns, and improve land management strategies in Xinjiang and other arid areas.

Spatial-temporal Coupling Analysis of Economic Development-Social Development-Government Governance in Xinjiang, China

High-quality development of ethnic minority areas is a key issue in China’s economic and social transformation.In order to explore the development trend and optimization path of high-quality development in ethnic minority areas,this study constructed a systematic evaluation index system of economic development,social development and government governance.The coupled coordination model was adopted to quantitatively analyze the spatio-temporal evolution characteristics of economic development,social development and government governance in Xinjiang from 2013 to 2020.The influencing factors of coupling coordination development of the three systems were identified by grey correlation analysis.The spatial-temporal pattern analysis results show that the coupling coordination degree of Xinjiang increased steadily,but the regional differences gradually expanded.The coupling coordination degree shows a stable structure with high center and low periphery,and a spatial pattern of low in southern Xinjiang and high in northern Xinjiang.The results of grey correlation analysis show that the grey correlation degree among economic development,social development and government governance in Xinjiang is above 0.78.The three systems of economic development,social development and government governance interact with each other,forming a complex system of high-quality development in ethnic minority areas.To promote highquality development in Xinjiang,it should take social stability and long-term stability as the overall goal,improve the quality of the production and living environment on the basis of economic development,enhance regional economic competitiveness,and take government governance as a means to optimize the environment for regional development.

Urban Spatial Carrying Capacity and Sustainable Urbanization in the Middle-east Section of North Slope of Kunlun Mountains in Xinjiang,China

Urban spatial carrying capacity is the comprehensive support capacity of natural resources for urban development,which is of great significance in guaranteeing the sustainable urbanization.The middle-east section of North Slope of Kunlun Mountains in Xinjiang,China,is characterized by harsh climate and sparse population,whereas it is important for the initiative of the new Silk Road Belt because of its important location.Cities in this area have begun to take shape,and the implementation of the Silk Road Belt Initiative will inevitably stimulate the urbanization in this area.The extent to which the cities in this area will be supported by natural resources and how to fulfill the requirements of sustainable socioeconomic development needs to be investigated.In view of this,the present study evaluated the urban spatial carrying capacity and discussed feasible approaches that could support the sustainable urbanization in this area.The results show that 97.59%of the study area belongs to the low and relatively low levels of spatial carrying capacity for urban construction,and the area of medium,relatively high and high levels is 1.12×104 km2,accounting for 2.41%of the total study area,mainly distributed in small clusters in the central alluvial fan oasis plains.Resource and environmental factors highly constrain urban construction,and low spatial matching of land and water resources,harsh climatic conditions and high risk of geological disasters are three major shortcomings.In addition,lagging transportation infrastructure construction and the resulting weak internal and external spatial connections also affect urban development.On this basis,the scientific arrangement of urban distribution,steady promotion of regional economic development based on local characteristics,further improvement of transportation infrastructure construction and strengthening the cooperation between the Xinjiang Production and Construction Corps and local governments are suitable approaches for sustainable urbanization in the study area.

Spatiotemporal variation of surface albedo and its influencing factors in northern Xinjiang, China

Surface albedo is a quantitative indicator for land surface processes and climate modeling,and plays an important role in surface radiation balance and climate change.In this study,by means of the MCD43A3 surface albedo product developed on the basis of Moderate Resolution Imaging Spectroradiometer(MODIS),we analyzed the spatiotemporal variation,persistence status,land cover type differences,and annual and seasonal differences of surface albedo,as well as the relationship between surface albedo and various influencing factors(including Normalized Difference Snow Index(NDSI),precipitation,Normalized Difference Vegetation Index(NDVI),land surface temperature,soil moisture,air temperature,and digital elevation model(DEM))in the north of Xinjiang Uygur Autonomous Region(northern Xinjiang)of Northwest China from 2010 to 2020 based on the unary linear regression,Hurst index,and Pearson's correlation coefficient analyses.Combined with the random forest(RF)model and geographical detector(Geodetector),the importance of the above-mentioned influencing factors as well as their interactions on surface albedo were quantitatively evaluated.The results showed that the seasonal average surface albedo in northern Xinjiang was the highest in winter and the lowest in summer.The annual average surface albedo from 2010 to 2020 was high in the west and north and low in the east and south,showing a weak decreasing trend and a small and stable overall variation.Land cover types had a significant impact on the variation of surface albedo.The annual average surface albedo in most regions of northern Xinjiang was positively correlated with NDSI and precipitation,and negatively correlated with NDVI,land surface temperature,soil moisture,and air temperature.In addition,the correlations between surface albedo and various influencing factors showed significant differences for different land cover types and in different seasons.To be specific,NDSI had the largest influence on surface albedo,followed by precipitation,land surface temperature,and soil moisture;whereas NDVI,air temperature,and DEM showed relatively weak influences.However,the interactions of any two influencing factors on surface albedo were enhanced,especially the interaction of air temperature and DEM.NDVI showed a nonlinear enhancement of influence on surface albedo when interacted with land surface temperature or precipitation,with an explanatory power greater than 92.00%.This study has a guiding significance in correctly understanding the land-atmosphere interactions in northern Xinjiang and improving the regional land-surface process simulation and climate prediction.

A Cross-sectional Survey Assessing Carriage of Streptococcus pneumoniae in a Healthy Population in Xinjiang Uygur Autonomous Region of China

The carriage rate and serotype distribution of Streptococcus pneumoniae（S.pneumoniae）in a healthy population in China remains unclear.In this study,we collected the oropharyngeal swabs from513 individuals in Xinjiang,China.Real-time PCR targeting the lytA gene and 12 serotypes were assessed to identify S.pneumoniae carriage.

Holocene Yellow Silt Layers and the Paleoclimate Event of 8200 a B.P.in Lop Nur,Xinjiang,NW China

Many yellow silt layers have been identified in the Holocene sediments in the last lake of Lop Nur (playa), Xinjiang, northwestern China. Statistics of drill-hole cores have revealed more than one hundred layers, which exhibit regularity in time sequence. Study has further verified that these yellow silt layers were deposited through eolian processes. The time-frequency distribution diagram shows an obvious peak occurring at about 8200 a B.P., which is consistent with the dry, windy and cold climate event occurring at 8200 a in other places around the world. Therefore, this event is regarded as a response to the global climate change.

Sequence Stratigraphy of the Desert System: A Case Study of the Lower Cretaceous in the Kuqa Basin in Xinjiang, Northwestern China

The Lower Cretaceous strata in the Kuqa Basin in Xinjiang are marked by a set of arid red beds. Several types of sedimentary fades can be identified in this set of arid red beds: mudstones of the plaza and intracontinental sebkha, aeolian sandstones, sandy conglomerates of the intermittent river, conglomerates of the pluvial fan, etc. These types of sedimentary facies constitute a typical desert system. Therefore, the Cretaceous strata in the Kuqa Basin provide a favorable condition for studies of sequence stratigraphic divisions of the desert system. With the rise and fall of the base level of the sedimentary basin, cyclicity is clearly revealed in stratigraphic records, which helps the identification of the third-order sequences. Based on the cyclicity in stratigraphic records, 5 third-order sequences can be found in the strata of the Early Cretaceous in the Kuqa Basin. These sequences comprise a second-order tectonic sequence. The primary feature of these third-order sequences is of an upward-fining sedimentary succession formed by a succession of 'coarse sediments of the alluvial system-fine sediments of the lake system'. The result of this study shows that aeolian sandstones are the best reservoirs of natural gas in the Cretaceous strata in the Kuqa Basin, and that the Kela-2 gas field is the first large gas field dominated by aeolian sandstone reservoirs in China.

Dynamic Variability in Daily Temperature Extremes and Their Relationships with Large-scale Atmospheric Circulation During 1960–2015 in Xinjiang, China

Climate changes are likely to increase the risk of numerous extreme weather events throughout the world.The objectives of this study were to investigate and analyze the temporal-spatial variability patterns of temperature extremes based on daily maximum(TX)and minimum temperature(TN)data collected from 49 meteorological stations in Xinjiang of China during 1960–2015.These temperature data were also used to assess the impacts of altitude on the temperature extremes.Additionally,possible teleconnections with the large-scale circulation pattern(the El Nino-Southern Oscillation,ENSO and Arctic Oscillation,AO)were investigated.Results showed that all percentile indices had trends consistent with warming in most parts of Xinjiang during 1960–2015,but the warming was more pronounced for indices derived from TN compared to those from TX.The minimum TN and maximum TX increased at rates of 0.16℃/10 yr and 0.59℃/10 yr,respectively during 1960–2015.Accordingly,the diurnal temperature range showed a significant decreasing trend of–0.23℃/10 yr for the whole study area.The frequency of the annual average of the warm events showed significant increasing trends while that of the cold events presented decreasing trends.Over the same period,the number of frost days showed a statistically significant decreasing trend of–3.37 d/10 yr.The number of the summer days and the growing season showed significant increasing trends at rates of 1.96 and 2.74 d/10 yr,respectively.The abrupt change year of each index was from the 1980 s to the 1990 s,showing that this periodic interval was a transitional phase between cold and warm climate change.Significant correlations of temperature extremes and elevation included the trends of tropical nights,growing season frequency,and cold spell duration indicator.This result also indicated the clear and complex local influence on climatic extremes.In addition,the relationship between each index of the temperature extremes with large-scale atmospheric circulation(ENSO and AO)demonstrated that the influence of ENSO on each index of the temperature extremes was greater than that of the AO in Xinjiang.

Spatio-temporal pattern and changes of evapotranspiration in arid Central Asia and Xinjiang of China

Accurate inversion of land surface evapotranspiration （ET） in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response of water resources. It is also important in the functional evaluation of regional water cycle and water balance, as well as the rational allocation and management of water resources. This study, based on model validation analysis at varied scales in fiwe Central Asian countries and China＇s Xinjiang, developed an appropriate approach for ET inversion in arid lands. The actual ET during growing seasons of the study area was defined, and the changes in water participating in evaporation in regional water cycle were then educed. The results show the simulation error of SEBS （Surface Energy Balance System） model under cloud amount consideration was 1.34% at 30-m spatial scale, 2.75% at 1-km spatial scale and 6,37% at 4-kin spatial scale. ET inversion for 1980-2007 applying SEBS model in the study area indicates： （1） the evaporation depth （May-September） by land types descends in the order of waters （660.24 ram） 〉 cultivated land （464.66 mm） 〉 woodland （388.44 mm） 〉 urbanized land （168.16 mm） 〉 grassland （160.48 mm） 〉 unused land （83.08 mm）; and （2） ET during the 2005 growing season in Xinjiang and Central Asia was 2,168.68x108 m3 （with an evaporation/precipitation ratio of 1.05） and 9,741.03x108 m3 （with an evaporation/precipitation ratio of 1.4）, respectively. The results unveiled the spatio-temporal variation rules of ET process in arid areas, providing a reference for further research on the water cycle and water balance in similar arid regions.

Status and distribution of ungulates in Xinjiang,China

Based on a long-term field investigation and other research results, we reviewed the status and distribution of ungulates in Xinjiang, China. The ungulates in Xinjiang included 19 ungulate species （30 subspecies） from 6 families and 2 orders. Among them, 3 species （2 subspecies） relate to Equidae （Per- risodactyla）, and 16 species （28 subspecies） are from 5 families of Artiodactyla. In this paper, we analyzed the conservation status of most rare and important 13 ungulate species. Firstly, we proposed the protec- tion of genetic diversity of Camelus ferus and the distribution areas of Moschus sifanicus, Procapra przewalskii and Saiga tatarica in Xinjiang. We found that Moschus sifanicus but not Procapra przewalskii distributed in Xinjiang. It was not clear whether the remnant populations of Saiga tatarica existed in Xinjiang and China-Kazakhstan border or not. We discussed that the protection level and rational use of Capra si- birica and enhancing protection level and enlarging monitoring and research projects for Pantholops hodgsoni and Gazella subgutturosa. And we would like to suggest Forestry Department to develop the captive breeding of Tibetan antelope for rational use. In addition, the captive breeding of Cervus elaphus in Xinjiang was reviewed. Local government should lessen strong control to Cervus elaphus because of many breeding centers＇ establishment.

A review of mineral systems and associated tectonic settings of northern Xinjiang,NW China

In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogenic Belt （CAOB）. The CAOB is a complex collage of ancient microcontinents, island arcs, oceanic plateaux and oceanic plates, which were amalgamated and accreted in Early Palaeozoic to Early Permian times. The establishment of the CAOB collage was followed by strike-slip movements and affected by intraplate magmatism, linked to mantle plume activity, best exemplified by the 250 Ma Siberian Traps and the 280 Ma Tarim event. In northern Xinjiang, there ale numerous and economically important mineral systems. In this contribution we describe a selection of representative mineral deposits, including subduction-related porphyry and epithermal deposits, volcanogenic massive sulphides and skarn systems. Shear zone-hosted Au lodes may have first formed as intrusion-related and subsequently re-worked during strike-slip deformation. Intraplate magmatism led to the emplacement of concentrically zoned （Alaskan-style） mafic-ultramafic intrusions, many of which host orthomagmatic sulphide deposits. A huge belt of pegmatites in the Altay orogen, locally hosts world-class rare metal deposits. Roll-front,

HPV Infection among Uygur Women in a Rural Area of Hetian Prefecture,Xinjiang Uygur Autonomous Region, China

It is not clear how HPV infection is prevalent among Uygur women in Xinjiang Uygur Autonomous Region, China and whether the distribution of HPV infection is related with cervical intraepithelial neoplasia （CIN） incidence among them. A study including 883 Uygur women were conducted from 2006 to 2007 in Hetian Prefecture, Xinjiang Uygur Autonomous Region, China.

Zircon U-Pb geochronology of the newly discovered Kulabiye Cu-Ni sulfidemineralized gabbroic complex,East Junggar Basin in Xinjiang,China

1.Objective As an important component of the southern Central Asian Orogenic Belt(CAOB),North Xinjiang in NW China is characterized by numerous Cu-Ni sulfide-bearing maficultramafic intrusions,and this region constitutes the secondlargest Cu-Ni metallogenic province in China.Zircon U-Pb chronology studies reveal that these intrusions predominantly formed in the Early Permian(300–270 Ma;Qin KZ et al.,2011).

Ore-Forming Mechanism of the Asikaerte Granitic Pegmagtite Beryllium Deposit in Xinjiang, China

Objective Granitic pegmatite has great significance for studying magmatic-hydrothermal evolution, which is the main formation mechanism of rare metal deposits. Conventionally, granitic pegmatite rare metal deposits are regarded as crystallization from H20-saturated granite magma that formed in the late fractional crystallization of granitic magma. However, some scholars recently believed that the liquid immiscibility of granitic magma promoted the formation of pegmatite deposits. The Asikaerte beryllium deposit in Xinjiang, China, bearing metallogenic belts from lower granite belt to upper pegmatite belt, could benefit us to understand the formation of pegmatite through analyzing fluid and melt inclusions data.

The Petrology and Geochemistry of Listwaenite in the Sartohay Ophiolitic Melange of West Junggar, Xinjiang, China

The west Junggar,located in the eastern part of Balkash-Junggar tectonic province,is a major component of the core of the Central Asian metallogenic region.This area is characterized by occurrences of ophiolitic mélanges,such as the Sartohay ophiolitic mélange in the NE and the Tangbale ophiolitic mélange in the west.As a hydrothermal alteration product of serpentinite in the Sartohay ophiolitic mélange,listwaenite lenses are gold-mineralized and crop out on surface in the ophiolitic mélange via weathering of exhumated hanging wall of fault zone.Listwaenite is mainly composed of magnesite,quartz,dolomite,and trace amounts of mariposite,chromian spinel,talc and sulfide.A vertical thermal gradient model for the hydrothermal alteration shows that serpentinite would first be transformed to talc schist,then into listwaenite as the ophiolite slices continued to rise along shear zone,with XCO2,oxygen and sulfur fugacity increase and temperature decrease.Both serpentine and magnetite were progressively destroyed during the transformation from serpentinite to talc schist,andcompletely vanished in listwaenite,while mariposite generated in weakly deformed to mylonitized listwaenite.Concentrations of most trace elements including high field strength elements and metallogenic elements,increasing from undeformed,through weakly deformed,to mylonitized listwaenite,show a positive correlation with deformation degree and content of apatite,rutile,monazite,zircon and sulfide in listwaenite.The shear zone served as pathways for percolation and accumulation of fluid and trace elements during the metasomatism from serpentinite to listwaenite.Compared to undeformed listwaenite,mylonitized listwaenite will be more favorable to be fractured and brecciated due to more intense shearing,which caused strong metasomatic reaction and then induced trace element-bearing mylonitized listwaenite.

Gravity and magnetic field characteristics and regional ore prospecting of the Yili ancient continent, West Tianshan, Xinjiang Uygur Autonomous Region, China

Gold,iron,copper,lead-zinc and other mineral exploration in West Tianshan,Xinjiang Uygur Autonomous Region,has made remarkable progress in recent years.However,due to the dispute on the tectonic division of West Tianshan,the ore-controlling factors and the regional metallogenic laws are controversial.The authors analyze regional gravity data and notice that the high-value region corresponds to the Yili ancient continent,thus the southeastern boundary of the Yili ancient continent is delineated.Comparative analysis of gravity,aeromagnetic and geologic data reveals that the Tulasu basin,where some medium to large epithermal gold deposits locate,lies above the Yili ancient continent;the Yili Carboniferous-Permian rift extends in E-W direction,numbers of copper deposits have been found in the mid-west section of the rift which lies above the Yili ancient continent,whereas few copper deposits have been discovered in the east section which is outside the Yili ancient continent.Accordingly,the Yili ancient continent may be rich in gold,copper and other metal elements;the metal-bearing hydrothermal solution moves up with the activity of magmatism,and deposits in the favorable places(the Tulasu basin and the Yili Carboniferous-Permian rift),forming numerous small and medium gold,copper deposits,as well as some large and super-large gold deposits.Therefore,the tectonic-magmatic hydrothermal zone above the Yili ancient continent should be the prospective area for epithermal gold and copper polymetallic deposits.

Aquatic beetle species and their distributions in Xinjiang, China

The species of aquatic beetles and their distributions in lotic and lentic habitats were investigated during July to August of 2005 and 2006 in Xinjiang Uygur Autonomous Region, China. A total of 66 species belonging to 7 beetle families （Dytiscidae, Gyrinidae, Haliplidae, Helophoridae, Noteridae, Hydraenidae, Hydrophilidae） are recorded, of which 16 are new records of aquatic beetles for China.

YANSHANIAN AND HIMALAYAN EVOLUTION OF THE WESTERN TARIM AREA(XINJIANG CHINA):FROM THE JURASSIC TROUGH UP TO THE NEOGENE AND QUATERNARY FLEXURAL BASIN

The Tarim Basin corresponds to a large sedimentary depression which separates (Yang et al.,1996)the Tianshan belt to the North from the Kunlun—Pamir belt to the South (Fig.1A).Its western part can be divided into the following structural units,from North to South (Fig.1B):①Foreland belts of Southern Tianshan.which involve Palaeozoic and Cenozoic sediments overlapping southward the Quaternary infilling of the basin (Dong Jia et al.,1998);②Bachu NW\|SE oriented Uplift of Central Tarim. where NE dipping reverse faults crossing Palaeozoic and Cenozoic series can be found (Hendrix et al.,1992);③SW depression of Tarim Basin. filled up with thick (up to 15000m),weakly deformed,post hercynian sediments;④Foreland belts of West Kunlun\|Pamir. made up of Precambrian,Palaeozoic,Mesozoic and Cenozoic materials overlapping northeastward the preceding unit(Qu et al.,1996).