Search

During the Ediacaran–Cambrian transition, a series of stratal continuous and well-preserved siliceous rock and phosphorite assemblages developed in Qingzhen, Guizhou Province, China, facilitating research on the biological evolution, marine chemistry, and palaeoecological environment of this period. Therefore, we investigated the paleontology, trace and rare earth elements, total organic carbon, total sulfur content, and Zn isotopes of the phosphorus-bearing rock series in the Taozichong Formation of the Cambrian period in Qingzhen. Geochemical analysis reveals that the sedimentary rocks in this area were formed in the oxygen-rich seawater environment and were not affected by high-temperature hydrothermal activity. The upwelling ocean current provided abundant rare earth elements and other nutrient elements, as well as conditions for the prosperity of biota in Qingzhen. In addition, the δ66Zn value (−0.21‰–0.41‰ range and 0.17‰ mean) in the Qingzhen phosphorous rock series was much lower than that in seawater, indicating a strong level of biological productivity. The variation trend of δ13C, δ18O, and δ66Zn exhibited four stages and three obvious drift events. The results suggest that climate change during this period led to the intermittent flourishing and extinction of organisms, which triggered the negative drift of δ13C and δ18O in the ocean, resulting in a coordinated response of δ66Zn. The unique ecological environment of the Taozichong Formation in Qingzhen also provides favorable conditions for the population continuation of Ediacaran-type benthic soft-bodied metazoon dominated by discoid fossils, Shaanxilithes, worm fossils, and sponge fossils in the Cambrian strata, as well as participation in the global biological explosion events. The study area provides new insights for rebuilding the global Ediacaran–Cambrian ecosystem during the transition period. [ABSTRACT FROM AUTHOR]

Large infrastructure projects play a crucial role in regional development but can also negatively impact cultivated-land protection. This study focuses on the role of local governments in land-use conflicts and the rebalancing of land-use structures during large infrastructure construction. Using the construction of a reservoir in the Huaihe River as a case study, the research examines the evolution of government attention and the process of township local governments promoting land-use adjustment. The findings reveal that local governments go through a process of "Create–Reinforce–Adjust–Delivery" in their attention to reservoir construction to maximize their interests. Attention fluctuates in terms of reservoir construction, cultivated-land protection, and immigration-development assistance. Biased land-use decisions were made at different stages, leading to four stages of rebalancing efforts: "Generation–Challenge–Marked effect–Continuous negative impact". This process provides insights into land-use decision-making and the rebalancing of land-use structure. The study suggests that the superior government should guide local governments to enhance attention to cultivated-land protection through laws and policies, while local governments should focus on the quality protection of cultivated land and mitigate the negative impact of rebalancing efforts. [ABSTRACT FROM AUTHOR]

Deprivation and dependence are the main signs of poverty, and elimination of both constitutes a major means of poverty alleviation. The foremost goal of China's targeted poverty alleviation strategy (TPAS) and the sustainable livelihood analysis framework (SLAF) was thus the elimination of deprivation and dependence. Together, TPAS and SLAF form a poverty alleviation mechanism that provides an opportunity to conduct a systematic analysis of TPAS implementation that achieved world‐renowned results in poverty alleviation. In this study, we comprehensively compare the changes in households and villages in a poor county before and after the implementation of TPAS; furthermore, we use a multilevel model to analyze the mechanism behind the functioning of the "Household‐Village" multilevel structure in the poverty alleviation process. The TPAS implemented a comprehensive livelihood system for poor households, whereby multidimensional deprivation was eliminated by supplementing livelihood capitals. Acquisition‐oriented assistance policies were offered to different groups to build customized paths of poverty alleviation, which ultimately helped poor households break through poverty and achieve sustainable livelihoods. This study highlights the close connection between the various components of the livelihood system, provides new research ideas for the study of China's TPAS and presents a reference template for the promotion of China's poverty alleviation programs. [ABSTRACT FROM AUTHOR]

In this paper, the artificial neural network (ANN) model was used to evaluate the degree of intensive urban land use in Nanjing City, China. The construction and application of the ANN model took into account the comprehensive, spatial and complex nature of urban land use. Through a preliminary calculation of the degree of intensive land use of the sample area, representative sample area selection and using the back propagation neural network model to train, the intensive land use level of each evaluation unit is finally determined in the study area. Results show that the method can effectively correct the errors caused by the limitations of the model itself and the determination of the ideal value and weights when the multifactor comprehensive evaluation is used alone. The ANN model can make the evaluation results more objective and practical. The evaluation results show a tendency of decreasing land use intensity from the core urban area to the periphery and the industrial functional area has relatively low land use intensity compared with other functional areas. Based on the evaluation results, some suggestions are put forward, such as transforming the mode of urban spatial expansion, strengthening the integration and potential exploitation of the land in the urban built-up area, and strengthening the control of the construction intensity of protected areas. [ABSTRACT FROM AUTHOR]

Urbanization reflects the overall behavior of human society; thus, characterization of its associated spatial and temporal trends has been extensively researched. This study examines the process of urban expansion in the Huaihe River Basin (HRB) which is a key transition region within China’s urban system. In order to grasp the urban expansion process in different temporal sequences objectively, rapidly, and accurately, we used remote sensing data to assess the urban expansion in time and space. Urban expansion rules were defined for the urban area, urbanization intensification, extended dynamic degree, and spatial pattern. The research findings show that the urban area expansion speed was at medium level throughout the entire HRB and within each province. Presently, the formation of a whole urban agglomeration or urban system is not complete in the HRB; urban expansion in the HRB displayed space-time disequilibrium tendencies during 1998–2013. [ABSTRACT FROM AUTHOR]

This paper draws upon smart growth theory to provide an analytical framework of "smart identification" for industrial land to be readjusted. Huai'an city, Jiangsu province, China, is selected as a case example for the developed framework. Unlike the identification method of efficiency orientation for stock industrial land, which emphasizes the core goal of input and output of production factors per unit area, the smart identification framework covers the five dimensions of industrial policy, urban planning, socioeconomic benefits, transportation convenience, and environment protection. The framework pays more attention to the characteristics of high-quality socioeconomic development, including innovation-driven, coordinated, and sustainable development. Industrial land blocks are used as the research unit. A total of 1,552 industrial land blocks are identified for readjustment, covering an area of 4,008.7 hm2 and accounting for 54.3% of the total industrial land area in Huai'an city; this shows that considerable potential exists for adjustment. We argue that the evaluation index selection of intensive industrial land use and the method by which industrial land is identified for readjustment is influenced by the stage of socioeconomic development. The smart identification method is more consistent with the connotation of high-quality development, and more conducive to revealing the current demand and change law of industrial land against the background of industrial transformation and upgrading, which is of great significance with regard to promoting the intensive use and spatial optimization of industrial land. [ABSTRACT FROM AUTHOR]

The article focuses on a study that investigates geochemistry characteristics of Nibao super large gold deposits from Guizhou Province, China and its geologic significance. The study reveals that hydrothermal precipitation prompted the initial formation of Nibao gold deposits and subsequent low-temperature hydrothermal processes resulted in gold remobilization in ore-forming materials. Also the study shows that the Nibao gold deposits have sedimentary hydrothermal alteration characteristics.

[Display omitted] • Distinct Δ199Hg values of several tuff layers suggest that their magma sources can be different. • Volcanisms triggered the Late Ordovician and end-Guadalupian mass extinctions. • Hg isotopes as a useful proxy in revealing the type of volcanism in geological history. Mercury (Hg) anomalies in sedimentary records are a newly developed proxy of large volcanism in the geological past. Tuff layers host abundant volcanic ash and record key information on the type of volcanic emission (e.g., arc volcanism and large igneous province eruptions). Here, we measured the Hg isotopic compositions of several tuff layers in South China. Tuff samples in the Late Ordovician Wufeng Formation and the Middle Triassic Guanling Formation mostly show positive Δ199Hg values of – 0.01 to 0.10‰ and – 0.06 to 0.16‰, respectively, suggesting arc volcanism occurred during these two periods. Tuff samples in the Middle Permian Dachang Layer mostly show near-zero Δ199Hg values (– 0.08 to 0.00‰), suggesting volcanism was driven by the Emeishan large igneous province eruption. Results of this study verify Hg isotopes as a useful proxy in revealing the type of volcanism in geological history. [ABSTRACT FROM AUTHOR]

[Display omitted] • High Hg anomalies in the Zunyi Mn deposit coincidence with ELIP eruption. • Trace elements in the Zunyi deposit suggest changes in the land–ocean-climate system. • ELIP eruption triggered the formation of Middle Permian Mn deposits in South China. South China hosts a large number of Middle Permian marine sedimentary Mn deposits (MSMDs) coeval to the eruption of the Emeishan Large Igneous Province (ELIP). The linkage between these MSMDs and ELIP eruption remains unclear. Here, we observed anomalously high Hg concentrations and Hg/TOC ratios, and a shift of Δ199Hg to near-zero at the base of the Middle Permian Zunyi MSMD. These results suggest ELIP eruption as a possible driving force for the deposition of the Zunyi MSMD. Principal component analysis (PCA) of trace element concentrations of the Zunyi MSMD samples revealed three clusters of trace elements. Cluster A elements (Cr, Zn, Mo, Sb, and Tl) are anomalously high at the basal of the Zunyi MSMD, confirming ELIP as a driver for the formation of this deposit. Cluster B elements (Ba, Rb, and Cu) are high in the entire deposit, supporting elevated oceanic productivity. A stepwise increase in Cluster C elements (Li, Ga, Sn, Zr, Nb, Hf, Ta, and W) concentrations in the Zunyi MSMD suggests enhanced terrestrial weathering. We infer that the ELIP eruption triggered an increased input of terrestrial nutrients to the ocean, causing increased oceanic productivity and rising dissolved O 2 levels in the surface water of the middle Permian ocean in South China, favoring Mn deposition and MSMDs formation. [ABSTRACT FROM AUTHOR]

• Mass independent fractionation of Hg isotopes is observed in the Ediacaran-Cambrian sediments. • Variable Δ199Hg values reflect changing marine and terrestrial metal sources as a function of paleo-depositional setting. • Positive Δ199Hg values in the Early Cambrian V rich black shales suggest Hg of seawater origin. A broad spectrum of marine sediments, including metalliferous black shales, stratiform barite, phosphorite and sapropelite (combustible shale) was widely deposited during the Ediacaran-Cambrian transition on the Yangtze Platform. The source of metals in the metalliferous black shales and the trigger for ocean dynamics during this critical period remain controversial. We analyzed Hg isotopes in late Ediacaran to Early Cambrian carbonaceous sedimentary rocks from the basinal Sansui section, South China, and observed Hg concentrations of 102–103 ppb, which is high but within the global range of black shales. The late Ediacaran carbonaceous chert shows near-zero Δ199Hg values (−0.05–0.09‰), which can be interpreted as input of terrestrial Hg or volcanic Hg. However, the transgressive near-coastal setting supports the terrestrial origin. The Early Cambrian V rich black shales display positive Δ199Hg values (0.03–0.18‰), which are similar to those observed in polymetallic Ni-Mo-rich sulfidic black shales (0.10–0.22‰) and phosphorites (0.13–0.24‰) in the stratigraphically equivalent Maoshi and Zhijin sections, respectively. These positive Δ199Hg values suggest that Hg was of dominantly seawater origin in a restricted basin setting. The variable Δ199Hg values of the rock spectrum reflect the dynamic interplay of marine and terrestrial metal sources as a function of paleo-depositional setting within the transgressive–regressive system on the continental margin of the Ediacaran-Cambrian Yangtze platform. [ABSTRACT FROM AUTHOR]

Self-rated health status (SRHS) reflects individuals' social environment, and the difference between urban and rural areas in China further highlights the impact of social environment on health. This paper aimed to systematically analyze and compare the impact mechanism of the SRHS of urban and rural residents from multiple dimensions, i.e., time, space, and scale. Drawing on data from the Chinese General Social Survey (CGSS) and China Statistical Yearbook, we used spatial, cross, and HLM analyses. Results indicate that: (1) From 2010 to 2017, the overall SRHS level of Chinese residents gradually declined; the gradient pattern of east, middle, and west became more marked, and the health level in rural areas generally fell behind that of urban areas. (2) The focus of SRHS moved toward mental health, and people's perceptions of the social environment gradually became a key factor affecting health. (3) In the long term, the gradient allocation of medical service resources could narrow the gap between urban and rural areas to comprehensively improve regional health levels., Competing Interests: The authors declared no potential conflict of interest with respect to the research, authorship, and/or publication of this article.