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Based on the global reanalysis data of the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research, the surface meteorological observation data, sounding data and satellite observation data, this paper comprehensively analyzes the evolution process and formation mechanism of a persistent severe dense fog process occurred on February 15–17, 2015 in Yancheng, eastern China. Through the numerical simulation experiment of Weather Research and Forecast (WRF) model, we further analyze the impact of sea-land breeze on the formation and burst reinforcement of fog. Results show that the precipitation caused by the southwesterly airflow in front of the upper-level trough and the low-pressure inverted trough are conducive to the formation of early rain fog, while the nighttime clear radiance under the control of surface cold high and the infiltration of weak cold advection are conducive to the formation and development of later radiation-advection fog. The WRF model simulates the fog evolution process, which is basically consistent with the actual fog area, and the simulation results are credible to a certain extent. The simulation results show that the establishment of sea breeze has an advection cooling effect on the near surface layer, which is conducive to the formation and development of the inversion layer on the near surface, providing stable stratification conditions for the formation and burst reinforcement of fog. On one hand, the strengthening of sea breeze circulation can continuously transport water vapor to the study area. On the other, the occurrence of ultra-low level jet is favorable for the accumulation of low-level water vapor. At the same time, the inversion intensity further strengthens, which is in favor of the burst reinforcement and long-term maintenance of fog. [ABSTRACT FROM AUTHOR]

Concurrent compound dry and hot events (CDHEs) amplified more damange on the ecosystems and human society than individual extremes. Under climate change, compound dry and hot events become more frequent on a global scale. This paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation, change in temperature and change in the dependence between precipitation and temperature. The attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model. A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river basins. It is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China, except for the upper and middle reaches of the Yangtze River. In West China, precipitation changes drove the increase in CDHEs in 18 river basins (23%), particularly in parts of North Xinjiang, Qinghai and Gansu. On the other hand, dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins (16%) of China with other factors, including parts of South China, East China and Northwestern China. Furthermore, changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs. [ABSTRACT FROM AUTHOR]

There are many types of atmospheric heat engines in land-air systems. The accurate definition, calculation and interpretation of the efficiency of atmospheric heat engines are key to understanding energy transfer and transformation of land-air systems. The atmosphere over the Qinghai-Tibet Plateau (QTP) in summer can be regarded as a positive heat engine. The study of the heat engine efficiency is helpful to better understand land-air interaction and thermal-dynamic processes on the QTP. It also provides a new perspective to explain the impact of the QTP on the climate of China, East Asia and even the world. In this paper, we used MOD08 and ERA5 reanalysis data to calculate the atmospheric heat engine efficiency, surface heat source and atmospheric heat source on the QTP in summer (May to September) from 2000 to 2020. The average atmospheric heat engine efficiency on the QTP in summer from 2000 to 2020 varies between 1.2% and 1.5%, which is less than 1.6%; the heat engine efficiency in summer is higher than that in June, July and August; the Qaidam Basin is the region with the highest atmospheric heat engine efficiency, followed by the western QTP. The mean surface heat source on the QTP in summer from 2000 to 2020 is 96.0 W m−2, the atmospheric heat source is 90.7 W m−2, and the release of precipitation condensation latent heat is the most important component of the atmospheric heat source on the QTP in summer. There is a strong and significant positive correlation between the atmospheric heat engine efficiency and the surface heat source on the QTP in summer. The precipitation con densation latent heat is the most important component of the atmospheric heat source in summer and can reflect the precipitation process. There is a strong and significant negative correlation between the atmospheric heat engine efficiency and the atmo spheric heat source on the QTP in summer. [ABSTRACT FROM AUTHOR]

As the only natural satellite of the earth, the Moon has always been the first choice for human exploration of the solar system. China's lunar exploration project (Chang'e project) was launched in 2004. At present, it has created a perfect end to the three phases of "orbiting, landing and returning". A series of remarkable research achievements have been made on the basic issues of current lunar scientific research, such as the Earth-Moon space environment, lunar surface material, morphology, geological structure, lunar subsurface and internal structure, and the origin and evolution of the Moon, further deepening the human understanding of the Moon. This paper briefly reviews the development process of China's lunar exploration project, summarizes the main research results and scientific understanding, and finally prospects to the future development of China's lunar and planetary exploration. [ABSTRACT FROM AUTHOR]

The latest Coupled Model Intercomparison Project Phase 6 (CMIP6) proposes new shared pathways (SSPs) that incorporate socioeconomic development with more comprehensive and scientific experimental designs; however, few studies have been performed on the projection of future multibasin hydrological changes in China based on CMIP6 models. In this paper, we use the Equidistant Cumulative Distribution Function method (EDCDFm) to perform downscaling and bias correction in daily precipitation, daily maximum temperature, and daily minimum temperature for six CMIP6 models based on the historical gridded data from the high-resolution China Meteorological Forcing Dataset (CMFD). We use the bias-corrected precipitation, temperature, and daily mean wind speed to drive the variable infiltration capacity (VIC) hydrological model, and study the changes in multiyear average annual precipitation, annual evapotranspiration and total annual runoff depth relative to the historical baseline period (1985–2014) for the Chinese mainland, basins and grid scales in the 21st century future under the SSP2-4.5 and SSP5-8.5 scenarios. The study shows that the VIC model accurately simulates runoff in major Chinese basins; the model data accuracy improves substantially after downscaling bias correction; and the future multimodel-mean multiyear average annual precipitation, annual evapotranspiration, and total annual runoff depth for the Chinese mainland and each basin increase relative to the historical period in near future (2020–2049) and far future (2070–2099) under the SSP2-4.5 and SSP5-8.5 scenarios. The new CMIP6-based results of this paper can provide a strong reference for extreme event prevention, water resource utilization and management in China in the 21st century. [ABSTRACT FROM AUTHOR]

Sulphate (SO42−) is a main component of PM2.5 in China. The chemical formation mechanisms of sulphate are complex, and many air quality models have been used to analyse these mechanisms. To improve the accuracy of Weather Research Forecast-Chemistry (WRF-Chem) on sulphate, an alternative method is proposed in this paper. Moreover, data assimilation is performed to adjust the chemical reaction rates of sulphate. Based on the original reactions, a new sulphate parameterisation scheme, which includes two hypothetical reactions and six undetermined parameters, was added. Based on the WRF-Chem/DART (Data Assistance Research Testbed) system, the near-ground concentrations of SO42−, SO2, NO2, O3 and particulate matter are assimilated to adjust the six parameters. After adjusting the parameters, the new scheme can effectively solve the underestimation of SO42− and overestimation of SO2. The simulation of SO42− improved as the mean bias changed from −13.1 µg m−3 to 3.5 µg m−3 while SO2 improved from 17.0 µg m−3 to 6.3 µg m−3. The temporal and spatial variation characteristics predicted by the new scheme are consistent with the theoretical research results, indicating that the complex mechanism of sulphate formation could be replaced by the temporal and spatial variation characteristics predicted by the new scheme and that the parameters can be adjusted by data assimilation. Furthermore, the reaction rates of the SO42− parameterisation scheme of the WRF-Chem model are improved in this study, and a new method for improving the accuracy of the air quality model is provided. [ABSTRACT FROM AUTHOR]

The Sichuan-Yunnan area is located at the southeastern margin of the Tibetan Plateau, where tectonic movement is strong with deep and large faults distributed in a staggered manner, which results in strong seismic activities and severe earthquake hazards. Since the 21st century, several earthquakes of magnitude 7.0 or above occurred in this region, which have caused huge casualties and economic losses, especially the 2008 Ms8.0 Wenchuan earthquake. At present, earthquake monitoring and source parameter inversion, strong earthquake hazard analysis and disaster assessment are still the focus of seismological researches in the Sichuan-Yunnan region. Regional high-precision 3D community velocity models are fundamental for these studies. In this paper, by assembling seismic observations at permanent seismic stations and several temporary dense seismic arrays in this region, we obtained about 7.06 million body wave travel time data (including absolute and differential travel times) using a newly developed artificial intelligence body wave arrival time picking method and about 100,000 Rayleigh wave phase velocity dispersion data in the period range of 5–50 s from ambient noise cross-correlation technique. Based on this abundant dataset, we obtained the three-dimensional high resolution Vp and Vs model in the crust and uppermost mantle of southwest (SW) China by adopting the joint body and surface wave travel time tomography method considering the topography effect starting from the first version of community velocity model in SW China (SWChinaCVM-1.0). Compared to SWChinaCVM-1.0, this newly determined velocity model has higher resolution and better data fitness. It is accepted by the China Seismic Experimental Site as the second version of the community velocity model in SW China (SWChinaCVM-2.0). The new model shows strong lateral heterogeneities in the shallow crust. Two disconnected low velocity zones are observed in the middle to lower crust, which is located in the Songpan-Ganzi block and the northern Chuandian block to the west of the Longmenshan-Lijiang-Xiaojinhe fault, and beneath the Xiaojiang fault zone, respectively. The inner zone of the Emeishan large igneous province (ELIP) exhibits a high velocity anomaly, which separates the two aforementioned low velocity anomalies. Low velocity anomaly is also shown beneath the Tengchong volcano. The velocity structures in the vicinity of the 2008 Ms8.0 Wenchuan earthquake, the 2013 Ms7.0 Lushan earthquake and the 2017 Ms7.0 Jiuzhaigou earthquake mainly show high Vp and Vs anomalies and the mainshocks are basically located at the transition zone between the high and low velocity anomalies. Along with the segmentation characteristics of seismic activity, we suggest that areas with significant changes in velocity structures, especially in active fault zones, might have a greater potential to generate moderate to strong earthquakes. [ABSTRACT FROM AUTHOR]

To achieve carbon peak targets, realize carbon neutrality vision, and tackle global climate change, China must improve the carbon emission performance at the city level. Based on the carbon emission performance of 191 prefecture-level cities in China from 1997 to 2017, this paper analyses the evolution characteristics of urban carbon emission performance from three aspects: the overall spatial and temporal evolution, the differences according to both region and city size, and the differences among clusters categorized by carbon emission performance at the city level. This paper also reveals the impact of the social and economic transition on China's carbon emission performance. The results show that: (1) The overall level of carbon emission performance of Chinese cities is low, and there is a downward trend during the study period. The differences in carbon emission performance among cities are convergent, but there is a wide gap between high and low values. (2) The carbon emission performance of cities in eastern coastal areas is higher than that in non-coastal areas cities. Large urban agglomerations and economically developed regions, such as provincial capitals, are the agglomeration areas of high urban carbon emission performance values. (3) The carbon emission performance level of cities with similar sizes will converge. At the same time, such changes will enhance the differences among carbon emission performances at the city level within the same region. (4) Cities that belong to high urban carbon emission performance clusters are mainly distributed in the eastern region. Such cities are classified into large cities, supercities, and megacities. Compared with low urban carbon emission performance clusters, cities in high urban carbon emission performance clusters show a higher proportion in the medium-high level and high level of carbon emission performance. Moreover, cities in high urban carbon emission performance clusters are more likely to improve theirurban carbon emission performance. (5) The economic agglomeration effect, industrial structure adjustment and carbon intensity reduction have a significant impact on improving urban carbon emission performance. Population agglomeration has an incremental effect, and the anticipated benefits of environmental regulation have yet to be fully realized. The impacts of different clusters and different regions are variable. Finally, this paper advances policy enlightenment according to its research findings. [ABSTRACT FROM AUTHOR]

The Banquan Basin is a pull-apart basin with the largest scale and the most prominent structure due to dextral slip of the Tanlu Fault Zone (TLFZ) in late Cenozoic. The depositional history of the basin records the start time and evolution of the right-lateral strike-slip movement of the TLFZ. This paper studies the sedimentary and tectonic evolution of the Banquan Basin by seismic reflection exploration, borehole detection and cosmogenic nuclide chronology. We analyze the coupling relationship between the pull-apart basin and the strike-slip fault and discuss the start time and tectonic significance of the right-lateral strike-slip of the TLFZ. Our study indicates that the Banquan Basin has undergone three evolutionary stages: weak rifting during the pre-pull-apart period, strong extension during the syn-pull-apart period and subsidence during the post-pull-apart period. This implies that the TLFZ, which controls the evolution of the basin, experienced an evolutionary process of weak activity, intensified activity and migration of activity toward the central basin. The sedimentary filling of the basin has strong response to the episodic pull-apart and extension of the basin. Lying upon the basement of the basin, a thin layer of Miocene mudstone slowly accumulated due to local rifting before the strong pull-apart event. Along with the dextral slipping and pull-apart process, the basin was filled with alluvial fan facies, fluvial facies and floodplain facies strata from bottom to top. The latest tectonic movement of the TLFZ in the North China Block in late Cenozoic was dominated by episodic dextral strike-slip motion, and this deformation pattern started at 4.01±1.27 Ma. The latest tectonic deformation in North China since late Cenozoic was governed by eastward extrusion and tectonic orogenesis of the eastern margin of the Qinghai-Xizang Plateau since late Miocene. The eastward thrusting of the Liupanshan fault zone and sinistral shearing of the Qinling fault zone led to the anticlockwise rotation and pushing of secondary blocks in North China, resulting in a planar bookshelf faulting and rotation pattern. This unique deformation pattern transferred eastwards to the North China Plain at ∼ Ma and the process continues to the present time. This planar bookshelf rotation, accompanied with regional sinistral strike-slip movement of the ∼EW-trending boundary fault zones to the north and south of the North China Block and dextral strike-slip motion of the NNE-trending boundary faults between secondary blocks, is likely to be the long-range effect of the strong extrusion of the eastern margin of the Qinghai-Xizang Plateau. [ABSTRACT FROM AUTHOR]

China has planned and built several world-class cascade high dams in Jinsha River, Dadu River, Lancang River, and Yarlung Zangbo River. The complex geological conditions in the reservoir area and numerous large-scale landslide bodies make the potential disaster risk of overflowing and cascade dam failure caused by landslide-generated tsunami under increasing severe situations. However, the study on describing and predicting the complex dynamic processes of generation, propagation, overflowing, wave setup, and the interaction between tsunami and lakeshore has not been systematically carried out. Based on the high-order Boussinesq-type equations, the development of the dynamic system of tsunamis in lakes coupled with the landslide process is realized using the finite volume method in this paper. To verify the accuracy and reliability of the study, the Xiluodu Reservoir is selected as the object to simulate the potential landslide-generated tsunamis. The factors such as the generation and propagation of tsunamis, dam overflowing, and wave setup in the downstream river are quantitatively evaluated and analyzed. The constructed landslide with a total volume of 24×106 m3 generates a near-field wave amplitude of about 28 m. The maximum wave run-up height is about 95 m, the volume of the dam overflowing water up to 2.13×106 m3, and the maximum wave height above the dam crest presents an M-shaped distribution. This LGWs event raises the downstream water level by nearly 40 m. The results show that the risk of landslide-generated tsunamis in the reservoir area in China cannot be ignored. The developed Boussinesq-type equations coupled with the landslide dynamics can simulate the whole process of generation, propagation, runup, and estimating the overflowing water volume of the tsunamis in the lake, laying a foundation for the quantitative risk assessment of tsunamis in lakes of high cascade dams in China. [ABSTRACT FROM AUTHOR]

Located on the southeast coast of China, Fujian is an important junction for the spread and migration of agriculture and populations from mainland Asia to Taiwan and the Island Southeast Asia. Research on the emergence of agriculture and its relationship with the regional environmental context is key to understanding the evolution of ancient human-land interactions in the coastal zone of China. This paper presents a detailed microfossil analysis of the Dapingding site, which is located in the lower reaches of the Min River on the southeast coast of China. We found a large number of phytoliths produced in rice stems and leaves from the cultural layers of this site, dated to 7,500 cal. a BP. In addition, we found rice husk impressions and rice phytoliths in the pottery sherds of these cultural layers. Among these phytoliths, rice bulliform phytoliths with ≥9 fish-scale patterns indicating the degree of rice domestication, accounted for 44%. This percentage is much higher than the established standard for wild rice bulliform phytoliths with fish-scale patterns, suggesting that rice cultivation had already occurred on the southeast coast of China approximately 7,500 years ago. Subsequently, the starting time of agricultural activity on the southeast coast of China was pushed from 5,000 to 7,500 years ago. Comparing the regional history of sea level and coastline changes in the early to mid-Holocene, we suggest that the emergence of early rice cultivation in Southeast China was associated with high sea levels in the mid-Holocene and the last transgression in the Fuzhou Basin. The 'Fuzhou Bay', formed by the retreating coastline and transgression driven by high sea levels, may have provided a sea channel for the southward movement of northern rice farmers. [ABSTRACT FROM AUTHOR]

Helium gas is a scarce but important strategic resource, which is usually associated with natural gas. Presently, only one extra-large helium-rich gas field has been found in China: the Hetianhe Gas Field in the Tarim Basin. This paper reports a new example, the Dongsheng Gas Field (DGF) in the Ordos Basin. In this study, 92 natural gas samples from the DGF were analyzed for helium content and isotope composition using isotope mass spectrometry. The natural gas samples were found to have an average helium content of 0.133%, with 65 (70.7%) of the samples having a helium content of 0.1% or more. Based on the proven natural gas reserves of the DGF, the proven geological helium reserves were calculated to be 1.96×108 m3, suggesting that it represents the first extra-large helium-rich natural gas reservoir to be hosted in tight sandstone in China. The 3He/4He ratios of 5 natural gas samples from the DGF are within the range of 3.03×10−8−3.44×10−8. Therefore, the helium in the gas field is thought to be of typical crustal origin and to have formed in the granitic basement that is rich in uranium and thorium. The accumulation of helium-rich natural gas was controlled by regional tectonic activities. Activity along the fault connecting the reservoir with the basement caused release of the helium gas, which entered the overlying strata along the fault and accumulated with conventional hydrocarbon gas. Based on the structural background and the distribution of helium source rocks in the Ordos Basin, the main helium source rocks with high exploration potential are located in deep strata within the north and middle parts of the basin. [ABSTRACT FROM AUTHOR]

Regional processes on land-water-air interface carbon (C) budget and balance that interconnect the land and sea are in fact C neutrality critical processes within the earth system. It is therefore essential to quantitatively analyze synergistic land-water-air interface C transport and C exchange processes to gain a deep understanding of the important role that terrestrial ecosystems play in "missing C sink". This paper systematically analyzes global land-water-air interface C migration processes as well as C budget changes and associated impact mechanisms. It also investigates the important role that these C budgets and C cycling processes play in inland water bodies, respective to C budgets at the land-water-air interface. Moreover, this study reveals the regulatory mechanisms of land-water-air interface C budgets and balances under a background of global climate change. It also quantitatively evaluates the status of China's regional land-sea-air interface C budgets as well as the C sequestration potential of its lake systems. Finally, this study concludes that the explicit quantification of anthropogenic activity impacts on land-water-air interface C transport and exchange processes is of great significance to global C balances and C neutrality. [ABSTRACT FROM AUTHOR]

The Middle Miocene Climate Transition (MMCT, ∼14 Ma) is the largest cooling event in the Cenozoic "Coolhouse", which significantly impacts the global chemical weathering pattern. In this paper, the responses of the MMCT global cooling event in the deep South China Sea were studied by clay mineral assemblages analysis of the oceanic red beds (ORB) at International Ocean Discovery Program (IODP) Expedition 368 Site U1502. The results show that the clay mineral assemblages of the ORB at Site U1502 are mainly composed of smectite (56–88%), illite (7–29%), and kaolinite (6–20%), without chlorite. The contents of these clay minerals and illite crystallinity show a four-stage variation pattern during early-middle Miocene (22.8−10.8 Ma). Smectite decreased from average 81% during 22.8–16.2 Ma and 16.2–14.4 Ma to average 67% during 13.8–10.8 Ma, with a rapid decrease of ∼14% during 14.4–13.8 Ma. On the contrary, illite and kaolinite increased rapidly by ∼8% and ∼6%, respectively, during 14.4–13.8 Ma. Illite crystallinity increased from average 0.18°Δ2θ during 22.8–16.2 Ma to average 0.19°Δ2θ during 16.2–14.4 Ma, and then decreased rapidly by ∼0.02°Δ2θ during 14.4–13.8 Ma. The provenance analysis of clay minerals shows that illite and kaolinite mainly originated from South China landmass due to physical erosion, while smectite mainly came from the Luzon arc as the product of chemical weathering. Therefore, smectite/illite ratio and illite crystallinity are used as proxies of chemical weathering intensity in the early-middle Miocene. High values of the ratio and the crystallinity represent the enhanced chemical weathering, whereas low values indicate the weakened chemical weathering or the strengthened physical erosion process. The smectite/illite ratio and illite crystallinity both decreased rapidly during 14.4–13.8 Ma, indicating the chemical weathering in the surrounding area of the South China Sea weakened rapidly, which we believe is the result of the MMCT event forcing. In addition, their values increased slightly during 16.2–14.4 Ma, which is in response to the relatively enhanced chemical weathering during the Middle Miocene Climate Optimum (MMCO). The variation pattern of clay mineral assemblages of the early-middle Miocene ORB in the South China Sea and its rapid transformation during the MMCT reveal that the Cenozoic cooling played a specific role in controlling the chemical weathering of the Earth's surface. [ABSTRACT FROM AUTHOR]

On May 22nd, 2021, an MS7.4 earthquake occurred near the Maduo county of the Qinghai Province, China, within the Bayan Har Block. Seismic activities have been intense in this block, thus whether the Maduo Earthquake will bring subsequent seismic hazards to its surrounding regions raises wide concerns. In this paper, we first calculated the Coulomb failure stress changes caused by the Maduo Earthquake on nearby faults, and estimated how much these faults are brought closer or further from their next failures based on their stressing rates. Next, we combined the Coulomb failure stress changes with the rate-state fictional law to estimate the seismicity rate in the study region in the next decade. A declustered catalogue before the Maduo Earthquake was adopted to calculate background seismicity rate, and rate-state parameters are constrained by fault slip rates. Our results show that the Maduo Earthquake increases stress accumulations in the northwestern portion of the Qingshuihe fault (0.02 MPa at maximum), the two ends of the Kunlun Mountain Pass-Jiangcuo fault (0.01 MPa at maximum), and the northwestern portion of the Maduo-Gande fault (on average ∼0.09 MPa), and seismicity rates are expected to increase near these faults. What is especially worth noting is the seismic hazard in the region extending from the eastern end of the Kunlun Mountain Pass-Jiangcuo fault to the Maqin-Maqu seismic gap on the Eastern Kunlun fault, which is calculated to have experienced a maximum stress increase of 0.67 MPa after the Maduo Earthquake. On the other hand, stress accumulations are reduced in the southern end of the Elashan fault, the Eastern Kunlun fault segment to the west of Maduo, and the northwestern portion of the Dari fault. Seismic hazards are expected to be low in these regions. For the study region as a whole, the probability of an M≥6 earthquake taking place in the next decade is estimated to be 59%, about twice the value calculated for the time period before the Maduo Earthquake. [ABSTRACT FROM AUTHOR]

The Qaidam Basin on the Qinghai-Tibet Plateau is well endowed with a variety of critical metals, such as Li and Rb. However, little is known about the distribution, source, and enrichment mechanisms of these elements. In this paper, we present results of systematic geochemical and H-O-B isotopic analyses of brines in the Tertiary and Quaternary sediments of the Qaidam basin. The results reveal that the paleobrines from oil-bearing anticlines at Dafengshan, Nanyishan, Youquanzi, Jiandingshan, and Jianshishan are significantly enriched in Li and Rb, whose contents are 81.1–128.9 mg L−1 and 4.5–29.2 mg L−1, respectively, reaching levels of economic significance. High Rb contents (up to 12.5 mg L−1) and well-endowment of Li also characterize the Dongtai, Xitai, Yiliping, and Senie salt lakes in the Qaidam Basin. The Tertiary paleobrine average in δD and δ18O at −40.7‰ and 2.84‰, respectively. The paleobrine with the highest Li and Rb has δD and δ18O values close to magmatic water. The δ11B values are lower than those of river water but close to those of geothermal fluids, suggesting that replenishment by deep magmatic hydrothermal fluid is most likely the key mechanism for the anomalous enrichment of these elements in the paleobrines, though evaporation and water-rock reactions have contributed to the critical metal mineralization. The anomalous enrichment of Li and Rb in modern salt lake brines is closely related to the input of volcanic geothermal water. The relatively high Li and Rb contents of intercrystalline brines in salt lakes of the western Qaidam Basin and the increase of Li and Rb contents with increasing depth were caused by upwelling of local paleobrines along the fault zones. [ABSTRACT FROM AUTHOR]

Grass carp (Ctenopharyngodon idella) is a cyprinid species, widely living in the freshwater on the plain area of East Asia. The fish has characteristic comb-like pharyngeal teeth, an adaptation to their typical vegetarian feeding habit. This paper deals with fossil pharyngeal teeth that related to grass carp, found from about 20 localities, ranging from the lower Oligocene to Holocene. Based on the morphology of the teeth, we established two new genera and species related to the genus Ctenopharyngodon (Dezaoia saintjaquensis, Eoctenopharyngodon liui) and two new species of Ctenopharyngodon (C. xiejiaensis and C. orientalis). The first recognized C. idella pharyngeal teeth were from the lower Pliocene of Yushe, Shanxi, and many others from 11 Pleistocene to Holocene localities. Judged from the materials and their occurrences, the grass carp may have originated from the western part of China during the early Oligocene. Throughout the Miocene, the grass-carp-like pharyngeal teeth were discovered from a vast area in China, indicating an appropriate atmosphere for the grass carp to develop, although the climate in the western part of China was possibly drier than that in the eastern part. From the beginning of the Pliocene, as the consequence of a considerable uplift of the Tibetan Plateau, the large rivers in East Asia finally formed, created favorable conditions for the Recent grass carp to thrive. Most teeth were collected in association with fossil mammals. Therefore, we are using the associated fossil mammals as the checking reference against which to test our interpretation of the surrounding environment of the water system in which the grass carp lived. [ABSTRACT FROM AUTHOR]

The evolution of the Changjiang Delta is obviously affected by current rapidly rising sea level and drastically declining river discharge, and it is also vital for the sustainable development of Shanghai and the Changjiang River Economic Belt, which represent China's economic development leader and major national strategic area, respectively. In this paper, the growth pattern of Jiuduansha Island, the largest uninhabited alluvial island in the Changjiang Estuary, is studied in terms of the change in elevation, position and area over the past 50 years through using satellite-derived instantaneous shoreline positions and high/low tide exposure areas based on 497 satellite images from 1974 to 2020; and the influencing factors and future development patterns are further discussed by comparison with other alluvial islands or sandbars in the estuary The results show that Jiuduansha Island has maintained a rapid or even accelerated area growth rate, although the sediment discharge of the Changjiang River has sharply decreased in recent decades This sustained growth is mainly attributed to the existence of the estuarine turbidity maximum zone, coarsening fluvial sediment, onshore sediment replenishment by tide, cone-like geomorphology of Jiuduansha Island, and siltation promotion effect of vegetation The growth rate of the low tide exposure area of Jiuduansha Island increased from 1.9 km2 a−1 in 1974–1990 to 3.0 km2 a−1 in 1990–2020, and the growth rate of the high tide exposure area reached as high as 3.7 km2 a−1 in 1994–2020. The implementation of the Deep-Water Channel Project has significantly affected the evolution of Jiuduansha Island, including shifting the heads of Shangsha and Zhongxiasha from severe retreat to rapid accretion, and promoting tidal flat progradation seaward of the Jiangyanansha and Zhongxiasha, but restricting the growth of the low tide exposure area of Jiuduansha Island. [ABSTRACT FROM AUTHOR]

The North China Craton is the oldest continental block, and has suffered from large-scale lithospheric thinning and destruction, which in turn led to gold deposits in northern China. The decratonic gold deposits in the North China Craton became the most important gold deposits in China, and geophysical methods are key means to detect and discover gold deposits there. In this paper, based on the geological and petrophysical characteristics of the North China Craton, the geological model of the decratonic gold deposits is transformed into a geophysical model. At present, two methods of geophysical exploration of decratonic gold deposits are in use: rapid and efficient exploration on the scale of the ore concentration area, and large depth exploration on the scale of the deposit area. In detail, the airborne electromagnetic, magnetic and gravity methods are used to detect the shallow (1,500 m) anomaly area on the scale of the ore concentration area. Through the ground-controlled source electromagnetic and ground magnetotelluric methods, explorations for targets at significant depth (5,000 m) are carried out in the mining area. Then, taking the Liaodong ore concentration area as an example, geophysical methods are used to discover two prospecting areas around the Jianshanzi Fault in the Qingchengzi ore concentration area, Baiyun-Xiaotongjiapuzi deep prospecting area, and Qingchengzi deep prospecting area. Next, three prospecting areas are delineated around the Jixingou Fault in the Wulong mining area, Wulong deep prospecting area, Weishagou deep prospecting area, and Chang'an deep prospecting area. The anomalies in the ore concentration area and mining area are revealed by means of three-dimensional exploration methods, thereby providing technical support for the exploration of metal minerals such as decratonic gold deposits. [ABSTRACT FROM AUTHOR]

The North China district has been subjected to significant research with regard to the ore-forming dynamics, processes, and quantitative forecasting of gold deposits; it accounts for the highest number of gold reserves and annual products in China. Based on the top-level design of geoscience theory and the method adopted by the National Key R & D Project (deep process and metallogenic mechanism of North China Craton (NCC) metallogenic system), this paper systematically collects and constructs the geoscience data (district, camp, and deposit scales) in four key gold districts of North China (Jiaojia-Sanshandao, Southern Zhaoping, Wulong, and Qingchengzi). The settings associated with the geological dynamics of gold deposits were quantitatively and synthetically analyzed, namely: NCC destruction, metallogenic events, genetic models, and exploration models. Three-dimensional (3D) and four-dimensional (4D) geological modeling was performed using the big data on the districts, while the district-scale 3D exploration criteria were integrated to construct a quantitative exploration model. Among them, FLAC3D modelling and the GeoCube software (version 3.0) were used to implement the numerical simulation of the 3D geological models and the constraints of the fluid saturation parameters of the Jiaojia fault to reconstruct the 4D fault structure models of the Jiaojia fault (with a depth of 5000 m). Using GeoCube3.0, multiple integration modules (general weights of evidence (WofE), Boost WofE, Fuzzy WofE, Logistic Regression, Information Entropy, and Random Forest) and exploration criteria were integrated, while the C-V fractal classification of A, B and C targets in four districts was carried out. The research results are summarized in the following four areas: (1) Four gold districts in the study area have more than three targets (the depth is 3000 m), and the class A, B and C targets exhibit a good spatial correlation with gold bodies that are controlled by mining engineering at depths greater than 1000 m. (2) The Boost WofE method was used to identify the target optimization in 3D spaces (at depths of 3000–5000 m) of the Jiaojia-Sanshandao, Southern Zhaoping, and Wulong districts. (3) The general WofE method is based on the Bayesian theory in 3D space and provides robust integration and target optimization that are suitable for the Jiaojia-Sanshandao and Southern Zhaoping districts in the Jiaodong area; it can also be applied to the Wulong district in the Liaodong area using a quantitative genetic model and an exploration model. Random forest is a multi-objective integration and target optimization method for 3D spaces, and it is suitable for the complex exploration model in the Qingchengzi district of the Liaodong area. The genetic model and exploration criteria associated with the exploration model of the Qingchengzi district were constrained by the common characteristics of the gold fault structure, magmatic rock emplacement in North China, and the strata fold and interlayer detachment structure. (4) Based on the gold reserves and the 3D block unit model of the Sanshandao gold deposit in the Jiaojia-Sanshandao district, the gold contents of the 3D block units in class A and B targets of the ore concentration were estimated to be 65.5% and 25.1%, respectively. The total Au resources of the optimized targets below a depth of 3000 m were 3908 t (including 1700 t reserves), and the total Au resources of the targets at depths from 3000 to 5000 m were 936 t. The study shows that the deep gold deposits in the four gold districts of North China exhibit a strong "transport-deposition" spatial correlation with potential targets. These "transport-deposition" spatial models represent the tectonic-magmatic-hydrothermal activities of the metallogenic system associated with the NCC destruction events and indicate the Au enrichment zones. [ABSTRACT FROM AUTHOR]