Formation and evolution of sand deserts in Xinjiang,Northwest China：Ⅰ. Provenances of desert sands

Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transportation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large basins and thus largely increases the degree of sediment mixing, alternation and recycle between younger and older sediment sources, as well as the complexity and diversity of sand provenances.     

Formation and evolution of sand deserts in Xinjiang,Northwest China: I. Provenances ofdesert sands简

Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transpor- tation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large sediment mixing, alternation and recycle basins and thus largely increases the degree of between younger and older sediment sources, as well as the complexity and diversity of sand provenances.     

Spatial and temporal temperature variations in Xinjiang, China during 1961–2008

This study examines spatial and temporal changes in 16 extreme temperature indices at 37 weather stations in Xinjiang and their associations with changes in climate means during 1961–2008. Linear regression analyses reveal that significant increasing trends in temperature were observed over Xinjiang, with the rate of 0.13 °C/decade, 0.24 °C/decade, and 0.52 °C/decade for annual mean temperature, annual maximum, and minimum temperature, respectively. Annual frequency of cool nights (days) has decreased by -2.45 days/decade (-0.86 days/decade), whereas the frequency of warm nights (days) has increased by 4.85 days/decade (1.62 days/decade). Seasonally, the frequencies of summer warm nights and days are changing more rapidly than the corresponding frequencies for cool nights and days. However, normalization of the extreme and mean series shows that the rate of changes in extreme temperature events are generally less than those of mean temperatures, except for winter cold nights which are changing as rapidly as the winter mean minimum temperatures. These results indicate that there have been seasonally and diurnally asymmetric changes in extreme temperature events relative to recent increases in temperature means in Xinjiang.     

Spatial evolution and determinants of new infrastructure development in China北大核心CSCD

New infrastructure has become an important support for China's economic transformation and high-quality development in the new era. In order to investigate the temporal and spatial evolution of China's new infrastructure development and its driving factors, this study first constructed a comprehensive evaluation index of the development level of new infrastructure based on the provincial panel data from 2013 to 2020. Then, it used the technique for order of preference by similarity to ideal solution (TOPSIS) entropy method and spatial econometric model to measure the development level of new infrastructure and analyze its driving factors. The results show that: 1) The development level of China's new infrastructure has increased year by year, and there is a trend of balanced development among provinces. 2) There is great spatial heterogeneity in the development level of China's new infrastructure. The new infrastructure development level is much higher in the eastern region than the central, western, and northeastern regions. The overall temporal and spatial evolution pattern showed an east-west expansion trend, and the center of gravity continued to move to the southwest. 3) The development level of new infrastructure is affected by many factors, among which the economic development level, financial development level, innovation foundation, urbanization process, and population size are the key driving factors. By examining the evolution of the spatial pattern of China's new infrastructure development level and its influencing factors, this article may provide a decision-making reference for its optimal layout and development. © 2023, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.     

Spatiotemporal evolution and driving factors of urban-rural integration in China北大核心CSCD

Urban-rural integration (URI) is a new idea to guide the urban-rural transformation in China, and exploring the spatio-temporal characteristics and driving mechanism of URI in China is an urgent need to overcome the dilemmas of insufficient rural development and unbalanced urban and rural development. Based on the process framework of \"foundation-motivation-result\" of URI, an evaluation indicator system was constructed. The improved entropy evaluation model and the kernel density estimation method were used to quantitatively measure the spatiotemporal evolution characteristics of URI level of 31 provinces, autonomous regions, and municipalities in China's mainland from 2000 to 2020. This study further used the Geodetector to explore the heterogeneous evolution of driving factors for URI level in different regions of China. The main conclusions are as follows: 1) From 2000 to 2020, the URI level in China decreased first and then increased, showing a √-shaped trend, and its spatial differences narrowed. 2) The URI level in China presented a spatial pattern of high in the east and low in the west, divided by the Hu Huanyong Line. The high-value centers showed prominent polarization characteristics and presented a zonal aggregation trend. The medium-value areas were clustered but weakened,and showed a spreading trend from the eastern to the central and western parts. 3) At the national scale, the core influencing factors of URI level were population mobility, economic development level, urban-rural income gap, and educational supports, potential factors were the optimization of industrial structure and the opening-up level, and threshold effect existed in investment benefit and government intervention. At the regional scale, the core driving forces of URI level in China showed obvious spatial heterogeneity, and in 2020 they were economic development level, investment benefit, and government intervention in the eastern region, investment benefit, opening-up level, and urban-rural income gap in the central region, are educational supports, government intervention, and the optimization of industrial structure in the western region. The interaction of driving factors had far more influence on URI level in China than individual factors, and the interaction between traffic accessibility and other socioeconomic factors had been significantly enhanced. Research on the spatio-temporal evolution and mechanism of URI in China can provide theoretical basis for rural revitalization and high-quality urban and rural development. © 2023, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.     

The spatial morphological determining mechanism in a evolution of RBD and its typical scenic tourist city： The case study of Yangshuo County

在讨论游憩商业区（RBD）定义与深度访谈的基础上,通过形状指数、土地利用动态度等指标测度典型旅游城市阳朔县RBD的形成与发展,并对其影响因素与成长机制进行路径分析,研究表明：（1）阳朔RBD的形成源于旅游业的发展,西街是RBD演变的初始地。以西街为基础衍生出“十字”、“工字”、南北“日字”与网状结构的RBD形态。1979～2005年,阳朔RBD空间形态上经历了从线性状态向网状的空间形态变化,而土地利用类型的动态变化经历了较长时期的平稳扩展时期后,2003～2005年开始急速扩展。（2）在土地市场、地方政府政策、大型事件以及外部控制等多种因素的影响下,阳朔RBD的变化呈现短期均衡,这种均衡是“旅游投资一旅游产业规模”,“游客人数一旅游产业规模”正反馈,“消费预期一游客人数”、“旅游121碑一游客人数”、“旅游产业规模一地价”负反馈共同作用下旅游用地从西街向其外围拓展,并不断循环的结果。（3）在客观存在的竞标地租与利益群体的集体选择行为下,阳朔RBD呈现从西街开始向外围扩展并最终形成以其为中心的网状结构。由于RBD的边界尚未有权威的界定,其外部性也没有办法得到量化。     

Potential food deserts and food oases in a post-communist city: Access,quality, variability and price of food in Bratislava-Petržalka

Delimitation tools and definitions of food deserts have not been internationally unified so far. Such comprehension ambiguity may lead to variability in research methods as well as to terminology mismatch in the research. In general, assessment of accessibility of selected (large-scale) food stores network in a region is considered as a suitable tool to identify the food deserts, but this is certainly not the only approach. In our paper some other approaches (such as measuring quality, variability and food price) are assessed together with supermarkets and hypermarkets accessibility examination. Results gained by analyses based on various methodological approaches are then compared and confronted, which simultaneously allows us to compare the individual approaches. For our case study purposes, the largest housing estate in Slovakia's capital city was selected.     

The drivers and spatial distribution of economic efficiency in China’s cities

Journal of Geographical Sciences - This study analyzes cities in China at the prefecture level and above to calculate indices for “urban economic efficiency” (the relationship between...     

How is the precipitation distributed vertically in arid mountain region of Northwest China?

Precipitation in the arid region of Northwest China (NWC) shows high spatial and temporal variability,in large part because of the region's complex topography and moisture conditions.However,rain gauges in the area are sparse,and most are located at altitudes below 2000 m,which limits our understanding of precipitation at higher altitudes.Interpolated precipitation products and satellite-based datasets with high spatiotemporal resolution can potentially be a substitute for rain gauge data.In this study,the spatial and temporal proper-ties of precipitation in the arid region of NWC were analyzed using two gridded precipitation products:SURF_CLI_CHN_PRE_DAY_GRID_0.5 (CHN) and Tropical Rainfall Measuring Mission (TRMM) 3B43.The CHN and TRMM 3B43 data showed that in summer,precipitation was more concentrated in southern Xinjiang than in northern Xinjiang,and the opposite was true in winter.The largest difference in precipitation between mountainous areas and plains appeared in summer.High-elevation areas with high precipitation showed more stable annual precipitation.Different sub-regions showed distinctive precipitation distributions with elevation,and both datasets showed that the maximum precipitation zone appeared at high altitude.     

The poverty evolution of typical countries along the Belt and Road and implications from China’s poverty reduction experiences

Journal of Geographical Sciences - The world is facing a poverty crisis. Despite the great achievements that have been made in poverty alleviation over the past two decades, the extent of poverty...     

Measuring the spatiotemporal variation and evolution of transport network of China’s megaregions

Megaregion has become a prominent feature of modern China. Reflecting upon China’s recent path of transport infrastructure construction, this research examines the spatiotemporal characteristics of transport network development and its accessibility impacts in China’s ten megaregions from 1982 to 2010. Using historical transport network data and multiple national censuses (1982, 1990, 2000 and 2010), we computed two levels of indicators of megaregional transport network: megaregion level and county level, and analyzed the intra-megaregion and inter-megaregion disparities of transport network of the ten megaregions of China. Transport networks at the megaregion level are measured by three indicators: 1) transport network density; 2) infrastructure endowment per capita; and 3) size of transport network’s standard ellipse. Two accessibility indicators for measuring transportation network at the county level are calculated: weighted average travel time and potential accessibility. The research results show the following: 1) Road and rail network densities witnessed the greatest growth during the 2000–2010 period, and growth was more significant for railway network. 2) By 2010, average road endowments per capita in inland megaregions became higher than in coastal megaregions, while average rail endowments per capita in coastal megaregions became higher than in inland megaregions. 3) The sizes and directions of the standard deviational ellipses of road and rail network changed continuously during the study period. However the changes of road network ellipses were relatively small, while the changes of railway network ellipses were more significant. 4) Megaregions have all benefited significantly from transportation infrastructure improvement in the past few decades in terms of WATT and potential accessibility, but the three giant megaregions benefited most.     

Application of AdaBoost Algorithms in Fe Mineral Prospectivity Prediction: A Case Study in Hongyuntan–Chilongfeng Mineral District,Xinjiang Province,China

Natural Resources Research - Continuous resource supply is one of the key points to improve comprehensive national strength. Resource prediction models supportive of target delineation for...     

Prospectivity Mapping for Porphyry Cu–Mo Mineralization in the Eastern Tianshan,Xinjiang, Northwestern China

Natural Resources Research - In order to comprehensively utilize regional-scale geological, geochemical and geophysical datasets for future exploration of undiscovered porphyry Cu–Mo...     

Quantitative estimation and spatial reconstruction of urban and rural construction land in Jiangsu Province, 1820–1985

Land cover is the most evident landscape signal to characterize the influence of human activities on terrestrial ecosystems. Since the industrial revolution, the expansion of construction land has profoundly changed the status of land use coverage and changes. This study is proposed to reconstruct the spatial pattern of construction land (urban construction land and rural settlement land) for five historical periods over the past 200 years in Jiangsu Province with 200 m × 200 m grids on the basis of quantitative estimation. Urban construction land is estimated based on data about city walls, four gates along walls, and other socio-economic factors. Rural settlement land is calculated based on the rural population and per capita housing allowance. The spatial pattern of historical construction land is simulated based on the distribution of modern construction land in 1985 with a quantitative-boundarysuitability control method and thorough consideration over connectivity of different land use types. The study concludes that: (1) the amount of construction land in Jiangsu Province is estimated at 963.46 km² in 1820, 1043.46 km² in 1911, 1672.40 km² in 1936, 1980.34 km² in 1952 and 10,687.20 km² in 1985; and (2) the spatial distribution of construction land features the great proclivity to water bodies and main roads and the strong polarization of existent residence. The results are verified directly and indirectly by applying the trend verification of construction land changes and patterns, the correlation analysis between rural settlement land and local arable land, and quantitative accuracy test of the reconstructed construction land to actual historical survey maps covering four sample regions in 1936.     

Land Degradation in the Test Areas of China and Argentina：Observed P

叙述中国西北地区的黑河流域、塔里木盆地南缘和阿根迁西北的门多萨、圣地亚哥德埃斯特罗省等检验区的退化土地的类型、分布特征、影响因素及其相互关系。结合近百年来平原区气候变化有明显暖化和旱化,阿根廷半干旱区的降水波,和人口增长对土地利用压力的加大趋势,可以预测在人工绿洲外围和河流下游,尽管人类在优化绿洲建设和合理利用水资源等方面可以取得很大进步,但土地退化的趋势还会继续,因此必须加强对这些生态脆弱边缘土     

Spatiotemporal variations of maximum seasonal freeze depth in 1950s–2007 over the Heihe River Basin, Northwest China

Investigation on spatiotemporal variations of maximum seasonal freeze depth （MSFD） over the Heihe River Basin is of great importance for systematic understanding of regional climate and environmental change, ecological-hydrological processes, water resources assessment, construction and resource development. Based on soil and air temperatures at the meteorological stations of the China Meteorological Administration （CMA） over the Heihe River Basin, MSFDs time series are structured into a composite time series over the 1960-2007 period. Evaluating the averaged MSFD time series for 1960 2007 reveals a statistically significant trend of 4.0 cm/decade or a net change of-19.2 cm for the 48-year period over the basin. The MSFD had significantly negative correlation with mean annual air temperature （MAAT）, winter air temperature, mean annual ground surface temperature （MAGST）, degree days of thawing for the air （DDTa） as well as for the surface （DDTs）, and degree days of freezing for the surface （DDFs）. While there was significantly positive correlation between DDF,. and MSFD time series, MSFD was deeper and changed greatly in the Heihe River source area. It was shallower in the east-central basin and gradually deepened in other sections of the basin. The MSFD distribution pattern in 2003-2005 is consistent with that of averaged degree days of freezing for air （DDFa） in 1960-2007. However, the maximum of MSFD may not be accurate, because there is no long term observation data in the deep seasonally frozen ground regions near the lower boundary of permafrost. With increasing elevation, averaged DDFa increased at a rate of 51.6 ℃-day/100m, therefore, the MSFG and the date reaching MSFG became deeper and later, respectively.     

Geochemistry of waters and brines from the Salinas Grandes basin,Córdoba,Argentina. II. Gypsum dissolution-calcite precipitation,and brine evolution

Rivers and streams originating in the surrounding mountainous area are the major sources of salt in the Salinas Grandes basin (Córdoba, Argentina). These rivers infiltrate when they reach the sandflat or in the fringes of the mudflat, feeding springs which often form shallow lakes. Presently, the lakes are distant from the playa edge, thus allowing inflow waters to dissolve ancient (Pleistocene?) evaporite beds. In the sandflat environment, two dominant types of water have been recognized (SO ₄ ^2? -Cl^?-HCO ₃ ^? -Na⁺, and Cl^?-SO ₄ ^2? -HCO ₃ ^2? -Na⁺), both considered as original members of the brine in the saline complex. Two main sources of solutes were distinguished, one related to the waters supplied by the southern sector and another to waters of the eastern sector. As a result of the chemical evolution in the playa environment, all brines belong to the neutral type (Cl^?-SO ₄ ^2? -Na⁺). Following Hardie and Eugster's (1970) model, waters from the southern sector should evolve towards an alkaline brine (Cl^?-SO ₄ ^2? -HCO ₃ ^? -Na⁺), whereas those from to the eastern sector should evolve towards a neutral one (Cl^?-SO ₄ ^2? -Na⁺). A computer simulation was carried out to model the chemical evolution of source waters. The results obtained by this methodology showed the same dichotomy (alkaline vs. neutral) established by Hardie and Eugster's (1970) model. The deficit in alkalinity could not be explained by any of the mechanisms published until now. Gypsum dissolution is the most likely mechanism which accounts for the chemical evolution of the waters investigated. When such a process is included in the computations, the Ca²⁺ supplied by gypsum beds generates an increase in the ion activity product (aCa⁺²·aCO ₃ ^2? ) and produces a significant change in the 2Ca⁺²/(2CO ₃ ^2? +HCO ₃ ^? ) ratio, switching from values less than 1 to values greater than 1. This process determines the precipitation of calcite, and leads to a decrease in alkalinity, which in turn would explain the existence of a neutral brine in the saline complex. An intermediate salinity brine was detected in the mudflat, which, according to the model (Hardie and Eugster, 1970), should evolve towards a SO ₄ ^2? -free neutral brine (Cl^?-Na⁺-Ca²⁺). The absence of this type of brine may be explained through mixing processes.     

The causes and environmental effects of land use conversion during agricultural restructuring in Northeast China

1IntroductionLand use change has received lots of attention internationally (Turner etal., 1994). Understanding of the mechanism of land use change and its adverse effect on the environment is conducive to understanding of population, resources, environment and sustainable economic development on the global, national and regional scales. With the rapid rise in human population, human-induced changes in land use form an important component of regional environmental change. In China, to emphasi…     

Lake evolution and its implication for environmental changes in China during 1950–2000

Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an important role on the recent decades＇ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume （water level, depth and area） in the eastern and western lake regions of China during 1950-2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect.     

Lake evolution and its implication for environ-mental changes in China during 1950?2000

Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an im-portant role on the recent decades’ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume (water level, depth and area) in the eastern and western lake regions of China during 1950–2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect.