Meat and Hide: Subsistence and Survival in the IUP of Southern Siberia, Mongolia and North China

  The early Permian deglacial warming is the critical period in the last icehouse to greenhouse transition in the Phanerozoic and provides an opportunity to investigate the interactions among terrestrial ecosystem evolution, regional tectonics, and climatic perturbations during climate warming. This climate change has been documented by climate modelling and geological proxies, however, its effect on fluvial sediment dispersal remains unknown. During this period, there were a southwardly diachronous aridification in North China. We here employ detrital provenance data to track the changes in continental-scale drainage system and fluvial sediment supply in southern North China. Combing detrital zircon U-Pb age and sandstone petrographic data from the early Permian sedimentary successions in southern North China defined three major sources in the Qinling orogenic belt (P1) to the south, the uplifted Paleoproterozoic-Archean basement in the northern North China margin (P2) and in the Inner Mongolia Orogen (P3) to the north. In the high-resolution chronostratigraphic framework established for North China, we use DZ mixing modeling method to quantitatively estimate the relative sediment contributions of source regions to the early Permian southern North China basin. Our modeling results suggest that the relative contribution of northly sourced detritus (from P2 and P3) increased from ~4 % in the late Gzhelian to early Asselian (ca 301−297 Ma) to ~95 % in the late Asselian to Sakmarian (ca 297−290 Ma), then declined to ~70 % in the early Artinskian (ca 290−286 Ma), finally returned to ~95% in late Artinskian (ca 286−284 Ma), whereas the estimated relative sediment contribution of the these northerly sources remained in high, stable level (~95 %) for the corresponding successions in northern North China .The increase in northerly derived sediment fraction in southern North China through the Asselian-Sakmarian can be interpreted in terms of the enhanced erosion associated with the tectonic evolution of Central Asian Orogenic Belt which caused uplifting in the northern margin of North China. In contrast, the subsequent reduction in the Artinskian is abnormal considering the persistent tectonic activities in the northern margin of North China. It can be linked instead to the climate aridification in the northern North China and resultant decrease in fluvial sediment supply from the northerly sources to the southern North China. This work highlighted the regulation of hydroclimatic change on low-latitude fluvial sediment supply during the early Permian deglacial warming.  

Carboniferous-Permian high-resolution conodont biostratigraphy and paleoclimate change in North China

Reversal of soil moisture constraint on vegetation growth in North China

Heatwaves of different spatial types can cause various impacts. Based on the spatial heatwave intensity, 47 North China heatwaves from 1961 to 2019 could be classified into two categories: the S‐type with a centre in the south and the N‐type in the north. There were more N‐type events (36) than the S‐type (11). Observational analysis indicated that under atmospheric circulations favourable to North China heatwaves (e.g. the enhanced continental high), there is a linkage between the sea ice concentration (SIC) changes in the Barents‐Kara Sea (BKS) and these two types of heatwaves. Relative to high BKS SIC, the reduction of SIC would strengthen the cyclonic circulation over the Siberian‐BKS, which could coordinate with the continental high to enhance the cyclonic over the Jianghuai region. A cyclonic‐anticyclonic‐cyclonic pattern is present over the BKS‐North China‐Jianghuai. The cyclonic circulation over the Jianghuai region would push the continental high northerly, resulting in the heatwave centre to the north. It would also cause favourable conditions for precipitation over southern North China, reducing temperatures and raising soil moisture, not conducive to the heatwave. Therefore, the heatwave intensity in southern North China would weaken and the heatwave centre would locate in the north, making the N‐type. Conversely, when the BKS SIC increases, the upper cyclonic over the Siberian‐BKS would not get strengthened, indicating entire North China would be controlled by continental high, and the heatwaves would be southerly relative to the N‐type, namely the S‐type. A series of numerical experiments using NCAR CAM5.3 confirm the above observational results, whereby if the BKS SIC reduces (increases), the North China heatwave is likely to be the N‐type (S‐type).

The relationship between vegetation on the Tibetan Plateau (TP) and summer (June–August) rainfall in China is investigated using the normalized difference vegetation index (NDVI) from the Earth Resources Observation System and observed rainfall data from surface 616 stations in China for the period 1982–2001. The leading mode of empirical orthogonal functions analysis for summer rainfall variability in China shows a negative anomaly in the area from the Yangtze River valley to the Yellow River valley (YYR) and most of western China, and positive anomalies in southern China and North China. This mode is significantly correlated with summer NDVI around the southern TP. This finding indicates that vegetation around the southern TP has a positive correlation with summer rainfall in southern China and North China, but a negative correlation with summer rainfall in YYR and western China. We investigate the physical process by which vegetation change affects summer rainfall in China. Increased vegetation around the southern TP is associated with a descending motion anomaly on the TP and the neighboring area to the east, resulting in reduced surface heating and a lower Bowen ratio, accompanied by weaker divergence in the upper troposphere and convergence in the lower troposphere on the TP. In turn, these changes result in the weakening of and a westward shift in the southern Asian High in the upper troposphere and thereby the weakening of and an eastward withdrawal in the western Pacific subtropical high. These features result in weak circulation in the East Asian summer monsoon. Consequently, enhanced summer rainfall occurs in southern China and North China, but reduced rainfall in YYR.

The planform rotation of river basins has been used as a marker of crustal strain and been used to assess the style and rates of on‐fault deformation. We use the geometry of river basins to evaluate horizontal deformation associated with the South China–North China relative block motion in the east Qinling mountains. The long‐time average slip rates of the Luonan fault and Shangdan fault are constrained as 0.31 mm/year and 0.3–0.6 mm/year, respectively. According to the latest GPS, we believe that a minor portion of the crustal strain of relative block motion between North China and South China was partitioned into the east Qinling strike‐slip fault system, leaving a major portion of deformation to be accommodated by southern North China (SNC). We conclude that the eastward extrusion of South China cannot explain the present deformation of the entire eastern China, and more attention should be paid into the SNC.

The Late Palaeozoic period is known for containing coal-bearing strata on both land and in the sea, and for its potential influence on sea levels due to glaciation, particularly in North China. However, our understanding of the processes behind coal accumulation during this time is limited due to lack of a reliable timeframe. In our research, we analysed the cyclical patterns in the Late Palaeozoic Taiyuan Formation using data from natural gamma-ray (GR) measurements from two boreholes (ZJC33 and XJC04) in the Huainan Coalfield in southern North China. Our analysis revealed distinct cycles in the Taiyuan Formation, with lengths of approximately 8.6 m, 2.5–1.7 m, and 1.1–1.0 m, which we identified as related to long eccentricity, short eccentricity, and obliquity based on correlation coefficient (COCO) analysis. We have constructed a floating ~5.3 Myr for the Taiyuan Formation. We have established an absolute astronomical time scale of 301.13 Ma to 295.83 Ma for the Taiyuan Formation. This was done using the volcanic ash age of 301.13 million years (with an error margin of ± 0.20 million years) at the bottom of the Taiyuan Formation as a reference point. The results indicate a significant correlation between coal seam development in the Taiyuan Formation and the minimum of the 405-kyr cycle, suggesting that orbitally forced variations in terrestrial clastic input may have been the dominant control on coal accumulation. This study is important for understanding the orbital factors influencing climate evolution and coal sedimentation during the Carboniferous-Permian period.

The spring soil moisture and the summer rainfall in eastern China

Previous studies suggest that the atmospheric and shallow seawater oxygen levels during the mid‐Proterozoic may have remained persistently unbalanced due to the low atmospheric oxygen levels and that, under these conditions, the oxygen concentrations of shallow seawater would largely reflect local oxygenation caused by primary productivity. As a result, in a microbialite‐rich setting, it may be difficult to differentiate oxygenation caused by local primary productivity from overall oxygenation of the surface environment. To address this issue, we conducted an integrative study of the ∼1.44 Ga stromatolitic carbonates of the Fengjiawan Formation in the Xiong’er Basin, southern North China, using techniques of sedimentology, mineralogy and geochemistry. The results show that the Fengjiawan Formation is dominated by water‐column precipitated carbonate mud (now dolomitized), pointing to moderately oxidized marine conditions. A significant and stable negative Cerium (Ce) anomaly (as low as 0.42) is identified in a long interval (>50 m in thickness) of this formation. This Ce anomaly is lower than the minimum values both recorded in the Great Oxidation Event (GOE; minimum 0.76) and in the Neoproterozoic Oxygenation Event (NOE; minimum 0.52), suggesting a significant oxygenation process rather than an oxygen oasis. Some intervals in this formation show I/(Ca + Mg) values higher than the Precambrian background value of 0.5 μmol/mol, providing a further support for shallow seawater oxygenation. This study, together with the enhanced oxygenation identified in the time‐equivalent Tieling Formation, indicates a multi‐basin oxygenation event in North China at ∼1.44 Ga.

The emissions of reactive nitrogen (Nr) from cropland links the pedosphere and atmosphere, playing a crucial role in the Earth’s nitrogen cycle while significantly impacting regional climate change, air quality, and human health. Among various Nr species, nitrogen oxide (NO) and nitrous acid (HONO) have garnered increasing attention as critical precursors to surface ozone (O3) formation due to their participation in photochemical reactions. While most studies focus on Nr emissions from soils, the specific contributions of cropland Nr emissions considering planting activities to regional O3 pollution remain insufficiently investigated. This study applied the enhanced process-based agroecological model (FEST-C*) coupled with the air quality (CMAQ) model to quantify cropland Nr emissions and assess their contributions to regional O3 formation across China in June 2020. The simulated results indicated that the fertilizer-induced total Nr emission was estimated at 1.26 Tg in China, with NO emissions accounting for 0.66 Tg and HONO emissions for 0.60 Tg. North China was identified as a hotspot for cropland Nr emissions, contributing 43% of the national total. The peak emissions of cropland NO and HONO occurred in June, with emissions of 169 and 192 Gg, respectively. Cropland Nr emissions contributed approximately 8% to the national monthly mean MDA8 O3 concentration, with localized enhancements exceeding 9% in agricultural hotspots in summer. North China experienced the largest MDA8 O3 increase, reaching 11.71 μg m−3, primarily due to intensive fertilizer application and favorable climatic conditions. Conversely, reductions in nighttime hourly O3 concentrations were observed in southern North China and northern Southeast China due to the rapid titration of O3 via NO. In this study, the contributions of cropland Nr emissions to MDA8 O3 concentrations across different regions of China have been further constrained. Incorporating cropland Nr emissions into the CMAQ model improved simulation accuracy and reduced mean biases in MDA8 O3 predictions. This study offers a detailed quantification of the contribution of cropland Nr emissions in regional ozone formation across China and highlights the critical need to address cropland NO and HONO emissions in air quality management strategies.

The Chuanlinggou Formation in the northern North China preserves the world's earliest multicellular eukaryote microfossils. Here we present a high‐precision zircon U–Pb CA–ID–TIMS age of 1,641.7 ± 1.2 Ma for a tuff layer within the black shales of the Chuanlinggou Formation. The new age is similar to those obtained for black shales from the Cuizhuang Formation in the southern North China, and the Barney Creek and Fraynes formations in the North Australia, indicating synchronous deposition of large volumes of black shales across both the North China and North Australia at ca. 1640 Ma. Global correlations and analysis of the spatial distribution of ca. 1640 Ma black shales and large igneous provinces (LIPs) and associated magmatic rocks in paleogeographic reconstruction reveal a spatiotemporal link between the ca. 1640 Ma LIPs and black shales. The widely distributed ca. 1640 Ma LIPs and black shales in Columbia supercontinent can provide a natural marker for the Statherian/Calymmian boundary at 1,640 Ma.

Heterogeneity of pore structure of late Paleozoic transitional facies coal-bearing shale in the Southern North China and its main controlling factors

Carboniferous–Triassic subduction in the Qinling orogen

Based on a newly developed daily precipitation dataset of 740 stations in China and more robust trend detection techniques, trends in annual and seasonal total precipitation and in extreme daily precipitation, defined as those larger than its 95th percentile for the year, summer, and winter half years, have been assessed for the period 1951–2000. Possible links between changes in total precipitation and frequency of extremes have also been explored. The results indicate that there is little trend in total precipitation for China as a whole, but there are distinctive regional and seasonal patterns of trends. Annual total precipitation has significantly decreased over southern northeast China, north China, and over the Sichuan Basin but significantly increased in western China, the Yangtze River valley, and the southeastern coast. In western China, precipitation increase has been observed for both cold and warm seasons. However, trends differ from one season to another in eastern China. Spring precipitation has increased in southern northeast China and north China but decreased significantly in the midreach of the Yangzte River. The summer precipitation trend is very similar to that of annual totals. Autumn precipitation has generally decreased throughout eastern China. In winter, precipitation has significantly decreased over the northern part of eastern China but increased in the south. The number of rain days has significantly decreased throughout most parts of China with northwest China being an exception. Meanwhile, precipitation intensity has significantly increased. This suggests that the precipitation increase in western China is due to the increase in both precipitation frequency and intensity. In eastern China, the impact of reduced number of rain days seems to be more dominant in the north while the influence of enhanced intensity prevails in the south. Over regions with increasing precipitation trends, there have been much higher than normal frequency of precipitation extreme events. For example, significant increases in extreme precipitation have been found in western China, in the mid–lower reaches of the Yangtze River, and in parts of the southwest and south China coastal area. A significant decrease in extremes is observed in north China and the Sichuan Basin. Trends in the number of extremes and total precipitation from nonextreme events are generally in phase. An exception is southwest China where an increase of extreme events is associated with a decrease in total nonextreme precipitation.

Enhanced continental weathering and large igneous province induced climate warming at the Permo-Carboniferous transition