Western Shandong Research Articles

Characteristics and Source Analysis of Ozone Pollution in Tianjin from 2013 to 2022

This study has analyzed ozone pollution in Tianjin from 2013 to 2022, focusing on the relationships between ozone distribution, meteorological conditions, and precursor substances. A method for identifying high-value areas of ozone precursors using the Ozone Sensitivity Factor (FNR) has been introduced. Results show that the average ozone concentration in Tianjin has been 100.608 µg/m3, with an annual growth rate of 2.84 µg·m⁻3·yr⁻¹. Tianjin has ranked among the top provinces and urban agglomerations in China for both ozone concentration and growth rate. Ozone levels have peaked in summer, followed by spring, autumn, and winter, while the growth rate has been highest in spring. This indicates that ozone pollution extends from summer into spring and autumn. An analysis of six ozone pollution events reveals significant regional transmission impacts from northern Hebei and Inner Mongolia, contributing over 30%, with additional significant contributions from southern and southwestern Hebei and western Shandong. In terms of controlling ozone precursors, high-HCHO-value areas have been identified. The correlation between areas of high HCHO values and ground-level ozone concentrations was 0.56339 during the ozone season and 0.2214 during the non-ozone season, both of which improved identification accuracy to varying degrees, suggesting that targeting precursor emissions in these areas could enhance pollution mitigation efforts.

Underplating-induced trans-crustal melting and maturation of Neoarchean continental crust in the North China Craton

A global change in granitoid compositions from early predominantly sodic tonalite-trondhjemite-granodiorites (TTGs) to later TTGs and more potassic granites occurred during the late Archean, coupled with a major period of crustal maturation. However, the detailed relationship between granitoid chemical evolution and the maturing crustal process remains enigmatic. Successive granitoid magmatism including late Neoarchean TTGs and high-K granites occurred in the Western Shandong Province granite-greenstone belt (WSP) of the North China Craton and thus preserves crucial clues of the crustal maturation process. In this study, petrology, whole-rock geochemistry, and zircon U-Pb and Lu-Hf isotopes are reported for the late Neoarchean TTG gneisses, monzogranites, and minor metabasaltic to andesitic rocks from the WSP. The ca. 2560−2540 Ma TTG gneisses show low MgO, K2O/Na2O, but high (La/Yb)N, Sr/Y, and absence of Eu anomalies, indicating their derivation from partial melting of the thickened lower mafic crust. The ca. 2530−2500 Ma monzogranites are characterized by systematically high SiO2 and K2O/Na2O, but low MgO and Sr/Y, and moderately negative Eu anomalies, revealing they were formed by intracrustal reworking of local TTGs and sedimentary rocks in the middle to upper crust. Geochemical variations of these crustal-derived granitoids suggest that they were formed by melting at gradually higher crustal levels with the melt zone moved gradationally from the eclogite stability field into the plagioclase stability field. The ca. 2530−2500 Ma calc-alkaline metabasaltic to andesitic rocks sourced from metasomatized mantle outline roles of mantle-derived magma underplating in contributions of heating and trans-crustal melting magmatism. The long-term melting processes facilitated the upward movement of volatiles and heat-producing elements from deep to shallow crustal levels, and introduced K-enriched monzogranites into the upper crust, leaving a refractory, strengthening, and tectonically stable lower crust. Secular compositional evolution of crustal-derived granitoids reveals that continuous crustal reworking drove lithosphere differentiation and paved the way for the maturation of the Archean continental crust.

Vertical high-velocity structures and seismic activity in western Shandong Rise, China: Case study inspired by double-difference seismic tomography

Abstract In this article, we collected the seismic phase arrival data (115°–120°E, 34°–39°N) of 2,833 local natural earthquakes above magnitude 1.0 recorded by 128 seismograph stations provided by the China Earthquake Networks Center covering the period from January 2008 to October 2023. We extracted the first arrival P- and S-wave arrival time data and obtained 26,351 P- and 26,349 S-wave absolute arrival times and 99,627 P-differential and 99,625 S-differential arrival times. Then, we determined 3-D P and S wave velocity structures under the Luxi region by using the double-difference tomography method. The results show lateral heterogeneities under the Luxi region, and the distribution of surface basins and uplift zones is associated with seismic velocities within the crust. The vertical section shows the widespread presence of vertical high-velocity bodies within the crust of the Luxi region, indicating seismological evidence of mantle upwelling in the region. Meanwhile, our imaging results also clearly indicate the presence of a significant low-velocity anomaly at depths of 13–17 km, which corresponds to the presence of a high-conductivity layer at that depth obtained from electromagnetic bathymetry. The transition zone between high and low velocities exists at a depth of 7–13 km, which plays an important role in the transfer of lithospheric stresses from the deep to the shallow part of the lithosphere. Combined with the results of the previous deep seismic wave velocity structure, petrology, and geological investigations, the deep dynamical background of the formation of slip tectonics and seismic mechanism in the Luxi area can be attributed to the go-slip activity of the Tan-Lu fault Zone, the subduction of the Pacific Plate, and the magmatism generated by mantle upwelling.

Leaf–Soil C:N:P Stoichiometry and Homeostasis Characteristics of Plantations in the Yellow River Floodplain in Western Shandong, China

The concentrations and ratios of plants C, N, and P serve as important indicators of ecological processes. However, how plant and soil C:N:P relationships and ratios change with forest stand types remain unclear. Here, we analyzed the ecological stoichiometric characteristics by measuring leaf and soil organic C, total N, and P contents in four stand types in Liaocheng, including Populus tomentosa Carrière pure forest, Populus tomentosa–Robinia pseudoacacia L. mixture forests, Platanus orientalis L. pure forest, and Salix matsudana Koidz. pure forests. We find that (1) The N and P leaf contents varied significantly across the four forest stands, with Populus tomentosa–Robinia pseudoacacia mixture forests having higher P levels. Platanus orientalis pure forests had lower C and N but higher P levels compared to others. (2) Uncoupled cycling of P in leaf–soil systems due to environmental influences, but C and N elements showed coupled cycles in some forest stands. (3) Populus tomentosa pure forests, Populus tomentosa–Robinia pseudoacacia mixture forests, Platanus orientalis pure forests are limited by N, and Salix matsudana pure forests are limited by both N and P elements. Overall, environmental factors, in addition to species variations, influence the C, N, P, and C:N:P ratios in leaves and soils of different forest stand types. Enhancing conservation and efficient use of N and P elements is crucial for sustainable plantation forest management to promote optimal growth in the region.

Determination of the banded iron formation sources in the Lanling area of Western Shandong of the North China Craton through rare earth element testing

Determination of the banded iron formation sources in the Lanling area of Western Shandong of the North China Craton through rare earth element testing

Preliminary Exploration of the Monetization of Land Tax in the Mid-Ming Dynasty's Western Shandong Region from an HGIS Perspective

Transportation and retention are among the most important elements of the fiscal system during the Ming Dynasty, categorized as types of tax allocations used in the collection of the land tax, reflecting the fiscal relations between central and local governments. Thus, transportation and retention are central to the fiscal operations of the Ming Dynasty. This paper compiles fiscal data from the Western Shandong Region during the Ming Dynasty and discusses the transportation, retention, and the monetization issues of the land tax during the Wanli Reform. Using Geographic Information Systems, the spatial visualization of the traditional and new land tax transportation quotas was performed, revealing that the new tax regime is heavily constrained by the original quotas.

Analysis of the Coupling Coordination between the Ecosystem Service Value and Urbanization in the Circum-Bohai-Sea Region and Its Obstacle Factors

In light of the tremendous pressure for improving urbanization levels and expanding construction land on ecosystems, regional sustainable development is premised on the coordinated development of the ecological environment and urbanization. This paper focuses on the Circum-Bohai-Sea Region and assesses the ecosystem service value (ESV) and urbanization level using the equivalence factor and entropy-weighted TOPSIS methods. Based on these assessments, it examines the coupling coordination between the ESV and urbanization as well as the obstacles to this coordination, utilizing the coupling coordination degree model, spatial autocorrelation model, and obstacle model. The results revealed several key findings. First, the Circum-Bohai-Sea Region experienced a continuous improvement in the urbanization level from 2005 to 2020, which presented a “center–periphery” spatial pattern. Overall, the ESV exhibited an N-shaped trend, namely, initially increasing, then decreasing, and then rapidly increasing. The ESV per unit of area exhibited a spatial difference, with the boundary of Baoding and Cangzhou as the dividing line. The ESV per unit of area in the northern parts was higher than that in the southern parts. Second, the degree of the coupling coordination between the ESV and urbanization exhibited an inverted U-shaped trend, initially increasing and then slightly decreasing. It also exhibited significant spatial heterogeneity, with the degree of the coupling coordination in the northern parts being higher than that in the southern parts and that in the central parts being higher than those in the eastern and western parts. Additionally, the ESV showed a significant spatially positive correlation with urbanization. H-H clusters were predominantly found in central and southern Liaoning Province, while L-L clusters were primarily located in southern Hebei Province and western Shandong Province. Third, the obstacle factors remained stable during the study period. The top five obstacles in the ESV system were the water resource supply, nutrient cycling maintenance, raw material production, aesthetic landscape, and food production. Moreover, the top five obstacles in the urbanization system were the number of college students per 10,000 people, population density, number of health technical personnel per 10,000 people, per capita road area, and proportion of secondary and tertiary industry output values.

Petrogenesis of the Early Cretaceous Tietonggou Diorite and Its Geological Implications

The Tietonggou pluton is mainly composed of gabbroic diorite and diorite. The petrology, zircon U-Pb age, and geochemistry of the Tietonggou diorite have been studied to determine its petrogenesis and metallogenic significance. The diorite samples have 56–58 wt% SiO2 and 11–14 wt% Al2O3 and are peraluminous and sodic (Na2O/K2O = 1.29–2.07). All the samples are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs; e.g., Rb, Ba, and Sr) but depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs; e.g., Zr, Nb, and Ta), suggesting subduction-related affinities. The rocks have narrow ranges of (206Pb/204Pb)t (18.5–19.0), (207Pb/204Pb)t (15.71–15.75), and (208Pb/204Pb)t (38.4–39.0) ratios, respectively. Zircons from the Tietonggou diorite yielded a weighted average U-Pb age of 132.86 ± 0.92 Ma (MSWD = 0.48), whilst those from the nearby Laowa diorite yielded 129.72 ± 0.61 Ma (MSWD = 1.05). This suggests that the rocks represent Early Cretaceous plutons, coeval with the peak lithospheric thinning in eastern North China Craton (NCC). The magma likely originated from partial melting of the enriched lithospheric mantle and was contaminated by ancient lower NCC crustal materials. Our study clarifies the tectonic background of the Tietonggou pluton and provides support for the study of the genesis of Fe–skarn deposits in western Shandong.

Magmatic Intrusion during the Yanshanian Period and Multi-Mineral Enrichment Mechanisms in the Eastern Margin of the North China Craton

The mineralization within the North China Craton (NCC) is intricately linked to Mesozoic large-scale extension in eastern China and is a consequence of a unified geodynamic tectonic background. Despite previous attempts to elucidate the relationship between large-scale mineralization and magmatic activity in the NCC, a lack of systematic research has hindered the identification of connections among deposits with inconsistent metallogenic ages. This study focuses on the coal measures of the Huanghebei Coalfield (HHBC) in western Shandong, presenting a regional magmatic–hydrothermal metallogenic system with a genetic connection. It delves into the intricate interplay between the multi-mineral enrichment mechanism, metallogenic regularity, and the NCC’s destruction. The findings reveal that: (1) Various stages of magmatic intrusion during the Yanshanian period significantly influenced the Late Paleozoic coal measures in the HHBC. The coal measures exhibit distinct ranks, ranging from medium-rank bituminous C to A and high-rank anthracite C, resulting in noticeable differences in gas generation among different coal ranks. The shale between the coal seams C5 and C7 emerges as excellent with a good hydrocarbon-generating capacity during the middle-maturity stage. (2) The “Intrusion along the rock layer type” proves most conducive to shale gas enrichment, while the “laccolith type” is more favorable for shale gas enrichment compared to “dike type” intrusions, which have a limited impact on shale gas enrichment. (3) The mineralization process of CBM, shale gas, and iron ore is influenced by Yanshanian-period magma. The enrichment degree of CBM and shale gas exhibits an inverse correlation with the distance from the magmatic intrusion. Iron deposits demonstrate a close association with the magmatic intrusion, with enhanced enrichment along the rock layer. The results indicate that the destruction of the NCC triggered intense metasomatism in the deep cratonic fluids, serving as the primary driving mechanism for large-scale mineralization during the Yanshanian period. Magmatic intrusions bring hydrothermal fluids conducive to mineralization, and the heat release from these intrusions promotes thermal evolution, hydrocarbon generation, and the enrichment of organic-rich strata.

Petrogenesis of Late Mesozoic trachydacites in the Jiaolai Basin, Eastern China: Implications for the destruction of the North China Craton

The North China Craton has witnessed a large-scale lithospheric thinning event in the Mesozoic. The volcanic rocks of the Qingshan Group formed during the destruction of the North China Craton, therefore retaining important information to the deep processes in this region. Zircon U-Pb dating and geochemical analyses have been carried out on volcanic rocks of the Qingshan Group collected from southeastern margin of the Jiaolai Basin. In combination with previously published data on the volcanic rocks of the Qingshan Group, the newly acquired data show that: (1) the volcanic rocks of Qingshan Group in Mashan have SiO2 content of 62.82 ∼ 66.3 wt% and total alkali content (K2O + Na2O) of 7.64 ∼ 9.34 wt%. According to TAS diagram, they belong to trachydacite which experienced strong fractionation between LREEs and HREEs with depletion of HFSEs and enrichment of LILEs. (2) The crystallization age of trachydacite in Mashan is 116.4 ± 2.3 Ma (MSWD = 1.9, n = 9). The magma originated from the partial melting of the ancient lower crust and the enriched lithospheric mantle metasomatized by the fluids/melts released from the subducted slab of the Yangtze Craton. (3) The formation age of magmatic rocks in western Shandong is generally earlier than that in eastern Shandong, while the lower crust delamination in western Shandong preceded that in eastern Shandong. The occurrence of magmatism in eastern Shandong is probably attributed to the delamination process in western Shandong as well as the ongoing tectonic activities along the Tan-Lu fault zone. The lithospheric thinning of the North China Craton was mainly controlled by the change of the subduction angle of the Paleo-Pacific plate, and is probably influenced by the continuous activity of the Tan-Lu fault zone in eastern Shandong.

Petrogenesis of ~2.7 Ga metabasalts in the Tai'an area of western Shandong and its constraint on the tectonic evolution of Neoarchean granite-greenstone belt

Petrogenesis of ~2.7 Ga metabasalts in the Tai'an area of western Shandong and its constraint on the tectonic evolution of Neoarchean granite-greenstone belt

Magmatic‐hydrothermal evolution and mineralization mechanisms of the Wangjiazhuang Cu (‐Mo) Deposit in Zouping Volcanic Basin, Shandong Province, China: Constraints from Fluid Inclusions

AbstractWangjiazhuang Cu (‐Mo) deposit, located within the Zouping volcanic basin in western Shandong Province, China is the only one with economic value found in the area so far. In order to expound the metallogenetic characteristics of this porphyry‐like hydrothermal deposit a detailed fluid inclusion study has been conducted employing the techniques of representative sampling, fluid inclusion petrography, microthermometry, Raman spectroscopy, La‐ICP‐Ms analysis of single fluid inclusions, as well as cathode fluorescence spectrometer analysis of host mineral quartz. The deposit contains mainly two types of orebodies, i.e. veinlet‐dissemination‐stockwork orebodies in the K‐Si alteration zone and pegmatitic‐quartz sulfide veins above them. In addition, minor breccia ore occurs locally. Four types of fluid inclusions in the deposit and altered quartz monzonite are identified: L‐type one‐ or two‐phase aqueous inclusions, V‐type vapor‐rich inclusions with V/L ratios greater than 50‐90%, D‐type multiphase fluid inclusions containing daughter minerals or solids and S‐type silicate‐bearing fluid inclusions containing mainly muscovite and biotite. Ore petrography and fluid inclusion study has revealed a three‐stage mineralization process driven by magmatic‐hydrothermal fluid activity as follows. Initially a hydrothermal fluid separated from the parent magma infiltrated into the quartz monzonite, resulting in its extensive K‐Si alteration as indicated by silicate‐bearing fluid inclusions trapped in altered quartz monzonite. This is followed by the early mineralization, the formation of quartz veinlets and dissemination‐stockwork ores. During the main mineralization stage due to the participation and mixing of meteoric groundwater with the magmatic‐sourced hydrothermal fluid the cooling and phase separation caused deposition of metals from the hydrothermal fluids. As a result the pegmatitic‐quartz sulfide‐vein ores formed. In the late mineralization stage, decreasing in fluid salinity has led to the formation of L‐type aqueous inclusions and chalcopyrite‐sulfosalt ore. Coexistence of V‐type and D‐type inclusions and their similar homogenization temperatures but different homogenization modes suggest that phase separation or boiling of the ore‐forming fluids once took place during the early and the main mineralization stages. The formation P‐T conditions of S‐type inclusions, and the early and the main mineralization stages are estimated as ca. 156 ∼ 182 MPa and 450 ∼ 650 °C, 350‐450 °C, 18‐35 MPa and 280‐380 °C, 8‐15 MPa, respectively based on the microthermometric data of the fluid inclusions formed at the individual stages.

Analysis of coupling coordination and obstacle factors between tourism development and ecosystem services value: A case study of the Yellow River Basin, China

The rapid development of tourism has caused a series of impacts on the ecosystem. Although studies on the relationship between tourism development (TD) and the ecological environment are rich, few scholars have focused on the coupling coordination between them from the perspective of ecosystem services value (ESV). Given this research gap, we evaluated the levels of TD and ESV in 78 cities of the Yellow River Basin (YRB), China based on statistical and land-use data. Then, the coupling coordination degree (CCD) model, exploratory spatial data analysis (ESDA), the spatial variogram model, and the obstacle degree model were used to analyze the spatiotemporal evolution of coupling coordination between TD and ESV and its obstacle factors. The results show the following: (1) The comprehensive TD level shows an upward trend and presents significant spatial differentiation characteristics. The total ESV of the YRB shows a fluctuating upward trend, and the average ESV presents the spatial pattern of uplift in the middle reaches. (2) The comprehensive CCD of the YRB has gradually improved, but the gap between cities has widened. The global spatial autocorrelation of CCD is significantly positive, and the spatial variability has gradually increased. An “uplift area” in southern Shaanxi always exists and has gradually expanded to Shanxi and western Henan, while eastern Henan and western Shandong become a “subsidence area”. The coupling coordination level has changed from uncoordinated to coordinated in most counties, but the problem of TD and ESV imbalance generally exists. (3) For the whole basin, TD is always the main obstacle factor at the system layer, and tourism scale and tourism economic benefit are the most significant obstacles at the category layer. At the city level, the proportion of cities where TD is the main obstacle factor exceeds 80% by 2019. Specifically, insufficient tourism scale and low tourism economic efficiency restrict the improvement of CCD in most cities. This research provides valuable references for studying the coupling coordination relationship between TU and ESV in big river basins worldwide.

Macroalgal fossil Longfengshania from the Tonian Shiwangzhuang and Jiuliqiao formations in western Shandong and northern Anhui, North China

Longfengshania is among the few examples of Pre-Cryogenian macroscopic fossils with an unambiguous eukaryotic affinity. It has received great attention since this genus is the earliest known Pre-Cryogenian macroalga with blade, stipe, and holdfast differentiation. However, compared to other macrofossils, such as Chuaria and Tawuia, reported occurrences (lithostratigraphic units) of Longfengshania are limited in Tonian strata, restricting the assessment of paleogeographic distribution of Longfengshania and therefore hindering our understanding of its paleoecological role in the Tonian oceans. Here, we describe two new localities of Longfengshania, including the Tonian Shiwangzhuang Formation (∼850–720 Ma) in western Shandong and Jiuliqiao Formation (∼950–720 Ma) in northern Anhui, North China. Specimens of Longfengshania from the Shiwangzhuang and Jiuliqiao formations are smaller than specimens from other localities, which has been interpreted as adaptations to relatively stronger hydrodynamic conditions. Biometric and principal component analyses suggest that most other species of Longfengshania actually fall within the morphospace range of the type species L. stipitata and therefore a re-examination on previously reported specimens and a taxonomic revision for this genus are needed in future study.

Region selection and efficiency improvement for apple production using an indicator system based on cost-effective factors

ABSTRACTBalanced and coordinated allocation of production factors is crucial for promoting the apple industry. We constructed a cost-ecological 21-indicator system for apple production in China based on labour cost, opportunity cost, fertilizer machinery input, natural resource, meteorological factor, ecological pressure and topography. The Hurst Index was used to analyse spatial changes in apple production in 617 counties of six provinces from 1999 to 2019. Grey correlation and TOPSIS models were adopted for optimal region selection and efficiency improvement. The areas supporting significant and sustained growth in apple production were concentrated in the eastern edge of Gansu, the northern, central and southern parts of Shaanxi, the western and central parts of in Henan, the northern, central and southern parts of Shanxi, the northern, central and southern parts of Hebei and the western, central and eastern parts of Shandong, covering 197 counties. Fertilizer machinery input was the key factor to improving apple production efficiency in Hebei, Shandong, Shanxi and Henan. The optimal regions were distributed in northern and southern Hebei, eastern and western Shandong, central and southern Shanxi, western Henan, central and northern Shaanxi and northeastern and southern Gansu. Compared with Shandong, the optimal factor allocation in Shaanxi is particularly favourable for optimal region selection, and the development momentum is remarkable despite a small county scale. Apple production has expanded westwards and northwards both between and within provinces over the past 21 years.

Geochemistry, U-Pb zircon geochronology, and Fe isotopes of the Shanzhuang banded iron formation in the North China Craton: Implications for genesis and depositional environment

The Shanzhuang banded iron formation (BIF) occurs in the Shancaoyu Formation, Taishan Group, in the western Shandong Province (WSP), eastern North China Craton (NCC). We constrained the Shanzhuang BIF depositional age of ∼2.50 Ga based on the zircon U-Pb dating of the leptynite interlayers and the cross-cutting metagranitoid. After deposition, the Shanzhuang BIF was subsequently metamorphosed into amphibolite facies at 2.50–2.45 Ga. According to different mineral assemblages, the Fe ores can be divided into three types: magnetite + quartz ± hornblende (type-1 ore), magnetite + quartz + hornblende + garnet ± hematite (type-2 ore), and quartz + hematite ± magnetite ± hornblende (type-3 ore). In the Post-Archean Australian Shale (PAAS)-normalized rare earth element and yttrium (REY) patterns, the three ore types show consistent flat REY curves. All ore types have moderate ƩREY concentrations (27.24–143 ppm), (La/Yb)N values of 0.29–2.31, significant positive Eu anomalies (1.05–3.47), slightly negative or positive Ce anomalies (0.87–1.26), slightly positive Y anomalies (1.16–1.48), and no apparent fractionation between light REEs (LREEs) and heavy REEs (HREEs), indicating mixing of hydrothermal fluid and seawater. The similar REY patterns and heavy Fe isotopes (0.47–1.02‰) of the three ore types suggest a certain amount of continental detritus was incorporated during the precipitation of the Fe phases in the Neoarchean-Paleoproterozoic oceans. The post-depositional metamorphism did not significantly affect the original REY geochemical signature of the BIF. The Shanzhuang BIF ores are not highly pure chemical sediments, but the type-1 ore is relatively pure and more representative of the original sedimentary composition. By contrast, the type-3 ore tends to have higher δ56Fe ratios (0.74–1.02‰) but lower δEu (1.27–1.97‰), implying substantial post-depositional hydrothermal alteration. The Shanzhuang Fe deposit is an Algoma-type BIF, and the surrounding rock consists of pyroclastic materials. Our model indicates that the Shanzhuang BIF was probably deposited in a redox stratified paleo-ocean environment.

Associations of time in bed and sleep timing with dementia and cognitive decline among Chinese rural‐dwelling older adults: A cohort study

AbstractBackgroundThe longitudinal associations of time in bed (TIB) (a composite indicator of sleep duration, latency, and fragmentation) and sleep timing (a marker of circadian rhythms) with dementia and cognitive decline in older adults are unclear.MethodThis population‐based cohort study used data from 1982 participants in the Shandong Yanggu Study of Aging and Dementia, who were aged ≥60 years, free of dementia, and living in the rural communities in western Shandong Province, China. At the baseline (2014) and follow‐up (2018) examinations, sleep parameters were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale. Global cognitive function was measured using the Mini‐Mental State Examination (MMSE). Dementia was diagnosed following the DSM‐IV criteria, and the NIA‐AA criteria for Alzheimer disease (AD). Data were analyzed using restricted cubic splines, Cox proportional‐hazards models, and general linear models.ResultDuring the mean follow‐up of 3.7 (standard deviation = 0.3) years, dementia was diagnosed in 97 participants (68 with AD). Restricted cubic spline curves showed J‐shaped associations of sleep duration, TIB, and rise time with dementia risk, and a reverse J‐shaped association with mid‐sleep time. When continuous sleep parameters were categorized into tertiles, the multivariable‐adjusted hazard ratio (HR) of incident dementia was 1.69 (95%CI 1.01‐2.83) for baseline sleep duration >8 hours (vs. 7‐8 hours), 2.17 (1.22‐3.87) for bedtime before 9PM (vs. 10PM or later), and 2.00 (1.23‐3.24) for mid‐sleep time before 1AM (vs. 1‐1.5AM). Early bedtime and mid‐sleep time were significantly associated with incident AD (multivariable‐adjusted HR range: 2.25‐2.51; P<0.05). Among individuals who were free of dementia at follow‐up, baseline long TIB, early bedtime and mid‐sleep time, early and late rise time, and prolonged TIB and advanced mid‐sleep time from baseline to follow‐up were associated with greater decline in MMSE score (P<0.05). These associations with cognitive decline were statistically evident mainly among men or participants who were aged <75 years.ConclusionLong TIB and early sleep timing are associated with an increased risk of dementia and AD, and their associations with greater cognitive decline are evident only among young‐old people and men.

Early Precambrian mafic dykes in western Shandong province, North China Craton: constraints on the chronology, genetic model and tectonic significance

AbstractIn the Late Neoarchaean, the lithosphere of the North China Craton (NCC) experienced a strong extensional event, which is of great significance for understanding the evolution of the continental crust in the Precambrian. In this study, a suite of mafic dykes from Shandong province in the northeastern NCC were investigated to determine the nature, timing and source of rift-related magma activities using zircon U–Pb data, whole-rock geochemistry and Nd–Hf isotopes. Zircon U–Pb dating of four dolerites by laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) yielded weighted mean 207Pb/206Pb ages in the range 2509 ± 6.1 to 2537 ± 6.2 Ma (2σ, 95 % confidence interval). The mafic dykes are classified as alkaline rocks based on their K2O + Na2O contents (6.78–7.21 wt %) and belong to the shoshonitic series according to their K2O contents (3.23–3.36 wt %). The dolerites show low concentrations of light rare earth elements ((La/Yb)N between 7.17 and 8.55), positive Eu anomalies (Eu/Eu* between 1.12 and 1.27), positive Ba, K, Pb, Sr, Eu, Dy and Lu anomalies, and depleted U, Nb, Pr, Ta, P, Nd and Ti anomalies. The dykes are characterized by low initial (87Sr/86Sr)i (∼0.6969), positive εNd(t) values (0.2–0.8) and εHf(t) values (0.5–8.6) and relatively old mean Nd and Hf model age (2.73 Ga). Collectively, the data suggest that the mafic dykes were derived from the partial melting (10–20 %) of an isotope-depleted garnet–lherzolite mantle source that was hybridized through interaction with subducted lower crustal material. The parental magmas of these dykes underwent a certain number of crustal contaminations during magma ascent. The mafic magmatism represented in the form of the dyke swarms is considered to be a response to widespread lithospheric extension which affected the NCC at c. 2.5 Ga during the Neoarchaean.

The Interaction between Anthropogenic Activities and Atmospheric Environment in North China

To quantify the interaction between anthropogenic activities and the atmospheric environment in North China, spatiotemporal characteristics, transmission, source apportionment and a health risk assessment of the elements were analyzed in regional and background atmospheric research stations during a period of 2017. This study found that the concentration of PM2.5 and 16 elements in the regional station was 1.5 and 2.8 times higher, respectively, than that in the background station. Under the combined influence of human activities and the dusty weather in Spring, the concentration of 16 elements in the regional station was up to 3 times that in the background station. In terms of the transmission of PM2.5, the potential source regions of PM2.5 in North China were mainly the central and southern parts of Beijing-Tianjin-Hebei (BTH), as well as parts of northern Henan and western Shandong. The source apportionment of the elements proved that the elements in North China were mainly derived from soil dust (29.9–68.2%), followed by traffic (8.8–26.3%), with coal combustion and oil consumption accounting for 5.8–24.5% and 4.1–12.9%, respectively. Although the proportion was not the largest, traffic posed the highest health risk to people, which should draw the attention of the relevant authorities.

Sequence-paleogeography and coal accumulation of the Late Carboniferous – Early Permian paralic successions in western Shandong Province, northern China

The coal-bearing strata of the Late Carboniferous to the Early Permian in western Shandong Province, northern China, were deposited within a range of paralic facies associations spanning from marine offshore carbonate shelf to fluvial and delta, which constituted a general paralic cratonic setting. In this paper, the sedimentary characteristics, sequence stratigraphy, paleogeography, and coal accumulation of the Benxi, Taiyuan and Shanxi formations of the Moscovian to Sakmarian age are studied by using data of outcrops, borehole cores, and geophysical loggings. A total of 14 different lithofacies are identified, with lithologies including sandstones, siltstones, mudstones, and bioclastic limestones, and grouped into fluvial, delta, tidal bar-lagoon, and offshore shelf facies associations. Furthermore, the key sequence boundaries represented by regional unconformity, incised valley erosional surface, switching surface of transgressive direction, stratigraphic color change surface marking the abrupt change of environment, and paleosol horizon have been recognized. Based on these sequence boundaries, three third-order sequences (S1, S2, S3 in ascending order) and corresponding lowstand, transgressive, and highstand systems tracts are subdivided. S1 corresponds to the Benxi Formation and the lower part of Taiyuan Formation, S2 corresponds to the middle and upper parts of Taiyuan Formation, and S3 corresponds to the Shanxi Formation. The lithofacies paleogeography maps of three sequences are reconstructed based on the contours of a variety of lithological parameters including strata thickness, limestone thickness, limestone percentage content, coarse (sandstone)/fine (siltstone and mudstone) ratio, and total coal thickness. S1 and S2 were developed with the offshore carbonate shelf paleogeographic units and the tidal bar – lagoon paleogeographic units, and S3 was developed with delta and fluvial units. In general, the western Shandong experienced transgression in the S1, transgression direction switching between S1 and S2, transgression again in S2, and then regression in the S3 during the Late Carboniferous to the Early Permian. Most significant coal accumulation occurred in the S3, followed by S1 and then S2. The coal accumulation centers of S1 were mainly distributed in Liaocheng, Feicheng, Jining regions in the west of the western Shandong where the tidal bar and lagoon were developed, those of S2 were mainly distributed in Tai'an, Jining and Tengzhou regions in the central part of the western Shandong, where the lagoon and tidal flat were developed, and those of S3 were mainly distributed in Heze, Jining, Tengzhou and Zaozhuang regions of the southern part of the western Shandong where the delta environment was developed. Overall, the high accommodation setting of S1 and S2, represented by the Benxi and Taiyuan formations, favors thick coal accumulation in the early TST, while the low accommodation setting S3, represented by the Shanxi Formation, favors thick coal accumulation in the middle and late TST. The research results of this study can be used in the evaluation of the favorable areas for the exploration and development of the deep-buried coal and CBM resources in western Shandong Province.