In Press Articles
Groundwater with high arsenic (As) content seriously threatens human life and health. If drinking high-As groundwater for a long time, excessive intake of arsenic will lead to various pathological changes such as skin cancer, liver cancer and kidney cancer. High-As groundwater has become one of the most serious environmental geological problems in China and even the international community. This paper aims to systematically summarize the sources, migration, distribution, hazard assessment and treatment techniques of arsenic in natural groundwater in China based on a large number of literature surveys. High-As groundwater in China is mainly distributed in the inland basins in arid and semi-arid environments and the alluvial and lacustrine aquifers in river deltas in humid environments, which are in neutral to weakly alkaline and strongly reducing environments. Content of As in groundwater varies widely, and As(III) is the main form. The main mechanism of the formation of high-As groundwater in China is the reduced dissolution of Fe and Mn oxides under the action of organic matter and primary microorganisms, alkaline environment, intense evaporation and concentration, long-term water-rock interaction and slow groundwater velocity, which promote the continuous migration and enrichment of As in groundwater.
Groundwater is an important source of drinking water. Groundwater pollution severely endangers drinking water safety and sustainable social development. In the case of groundwater pollution, the top priority is to identify pollution sources, and accurate information on pollution sources is the premise of efficient remediation. Then, an appropriate pollution remediation scheme should be developed according to information on pollution sources, site conditions, and economic costs. The methods for identifying pollution sources mainly include geophysical exploration, geochemistry, isotopic tracing, and numerical modeling. Among these identification methods, only the numerical modeling can recognize various information on pollution sources, while other methods can only identify a certain aspect of pollution sources. The remediation technologies of groundwater can be divided into in-situ and ex-situ remediation technologies according to the remediation location. The in-situ remediation technologies enjoy low costs and a wide remediation range, but their remediation performance is prone to be affected by environmental conditions and cause secondary pollution. The ex-situ remediation technologies boast high remediation efficiency, high processing capacity, and high treatment concentration but suffer high costs. Different methods for pollution source identification and remediation technologies are applicable to different conditions. To achieve the expected identification and remediation results, it is feasible to combine several methods and technologies according to the actual hydrogeological conditions of contaminated sites and the nature of pollutants. Additionally, detailed knowledge about the hydrogeological conditions and stratigraphic structure of the contaminated site is the basis of all work regardless of the adopted identification methods or remediation technologies.
The Yadu-Ziyun-Luodian aulacogen (YZLA) developed into being NW-trending in the Late Paleozoic, and was considered as an important passive continental margin aulacogen in Guizhou, South China. This tectonic zone is a large intracontinental thrust-slip tectonic unit, which has undergone a long period of development. It was finally determined in the Yanshanian, where the typical Upper Paleozoic marine shales in China were deposited. In 2021, well QSD-1 was deployed in the Liupanshui area at the northwest margin of the trough, and obtained a daily shale gas flow of 11,011 cubic meters in the Carboniferous Dawuba Formation, which achieved a breakthrough in the investigation of shale gas in the Lower Carboniferous in South China, and revealed the good gas-bearing properties and broad exploration prospects of the aulacogen. Being different from the Lower Paleozoic strata in the Sichuan Basin and the Yichang area of the Middle Yangtze, the development of the Carboniferous Dawuba Formation in the aulacogen exhibits the 3 main characteristics. Comparative analysis suggests that the area covered by the current Triassic strata has a low degree of destruction and good conditions for shale gas preservation, which can be regarded as the favorable area for the next exploration.
Our paper reports the first discovery of ~2.87Ga granitic gneisses from the Susong Complex, a possible Precambrian microcontinent exposed in the southeastern part of the Dabie orogen. The granitic gneisses are the oldest known rocks in the Phanerozoic Qinling–Dabie orogenic belt, which form a rare Mesoarchean rock archive that can be used as important “geologic barcodes” for terrane correlations. Our results from high-precision zircon U-Pb dating indicate that Archean crust of the Yangtze Block, as old as the Mesoarchean, was extended into the Qinling–Dabie orogenic belt, and Archean crust of the Yangtze Block was more widespread than previously recognized.
The Luanhe River is the most important water system in north-eastern Hebei Province, China and is located in the transitional zone of the Eastern Yan Mountains, North China Plain and Songliao Plain. The well-developed river terraces of its tributary, the Yixun River, provide excellent information for studying neotectonics and climate change. There are seven terraces in the lower reaches of the Yixun River, numbered T7–T1. The optically stimulated luminescence dating results of 23 samples show that terraces T7–T2 formed at 111.36±5.83 ka, 78.20±4.45 ka, 65.29±4.15 ka, 56.44±3.07 ka, 40.08±2.66 ka, and 13.14±0.76 ka, respectively. A comparison with the oxygen isotope curves of deep-sea sediments reveals that the sediment formation of each terrace corresponded to cold periods of marine isotope stages (MIS) 4 and MIS 2 and the relatively cold periods of MIS 5e, MIS 3, and MIS 1. Since the Late Pleistocene, the incision rate of the Yixun River has ranged from 0.371–1.740 mm/a. During the formation of T7–T6, T5–T4, T4–T3, and T3–T2, the incision rate was low. However, in the two stages during which T6–T5 and T2–T1 formed, these rates reached 1.554 mm/a and 1.592–1.740 mm/a. The river gathered in the north of Langying to form the ancient Erdaowan Lake, which resulted in the drying of the river in the lower reaches of the Yixun River during the last glacial maximum without forming river deposits.
The Cenozoic Himalayan leucogranite–pegmatite belt has been a hotspot for rare metal exploration in recent years. To determine the genesis of the pegmatite in the Himalayan region and its relationship with the partial melting of the Greater Himalayan crystalline complex (GHC), the Gyirong pegmatite in southern Tibet were chosen for geochronological and geochemical studies. The dating analyses indicate that the U‒Th‒Pb ages of zircon, monazite, and xenotime exhibit large variations (38.6-16.1 Ma), and the weighted average value of the four youngest points is 16.5 ± 0.3 Ma, which indicates that the final crystallization of the melt occurred in the Miocene. The age of the muscovite Ar–Ar inverse isochron is 15.2 ± 0.4 Ma, that is slightly later than the intrusion age, showing that a cooling process associated with rapid denudation occurred at 16-15 Ma. The εHf(t) values of the Cenozoic anatectic zircons are concentrated between -12 and -9 with an average of -11.4.
Palaeoclimatic and palaeoenvironmental reconstructions of the Cryogenian Period have attracted attention in relation to the debated “Snowball Earth” hypothesis and the early evolution of metazoan life. The carbon cycle and redox conditions of the Sturtian-Marinoan non-glacial interval have been subjected to much controversy in the past decades because of the difficulty of the lack of a high-resolution stratigraphic correlation scheme. As one of the typical Sturtian-Marinoan interglacial deposits, the Datangpo Formation was widely distributed in South China with shales continuously deposited. The previous zircon dating data of the Datangpo Formation provide important ages for global constrain of the Sturtian-Marinoan non-glacial interval. Here we present a high-resolution straitigraphic study of the organic carbon isotopes, of the Datangpo Formation from a drill core section in northern Guizhou Province. Based on measured episodic δ13Corg perturbations, three positive shifts and three negative excursions are identified. A δ13Corg-based chemostratigraphic correlation scheme is proposed herein that works well for the Datangpo Formation regionally. Meanwhile, the δ13Corg vertical gradients changed dynamically throughout the formation. This discovery implies that a significant ocean circulation overturn might have occurred in the upper Datangpo Formation, coinciding with the potential oxygenation.
(Objective)To reveal the microbial community composition of regional shallow porous brackish groundwater and its response characteristics to groundwater environment, (Method)the first and second aquifers in Taocheng District, Hengshui City were selected, and 10 groundwater source samples were collected for hydrochemical analysis and microbial 16S RNA gene V4-V5 regional sequencing. (Results)The results showed that the shallow brackish groundwater in the study area is weakly alkaline and has high ion content. The spatial zonation of the abundance and diversity of groundwater microorganisms is obvious. The number of endemic bacteria in groundwater from upstream, midstream to downstream is 11, 135 and 22 respectively, with a total of 22 bacteria. Proteobacteria is the most dominant in groundwater level, and there are obvious differences in different sections. At the genus level, the main dominant species in each group and sample are Pseudomonas and Hydrogenophaga. In terms of composition difference, Pseudohongiella, Pseudorhodobacter and Limnohabitans are the representatives of UR, MR and LR. (Conclusion)On the whole, the composition of flora in groundwater is sensitive and closely related to hydrochemical processes. Species abundance is affected by alkaline and high salinity environmental indicators, while species diversity is related to depth and DO in weak reduction environment.
The sea of Japan is located in the northeast margin of Eurasia, in the triangle area of the western Pacific Ocean. Due to the interaction of the Pacific plate, Eurasian plate and Philippine plate, its tectonic environment is complex, forming a typical trench-arc-basin system. At present, 148 oil and gas fields have been discovered in Japan, with an oil and gas resource of 255.78×106 t, showing a good prospect for oil and gas exploration.Based on the previous research and the recently collected geological and geophysical data, the characteristics of tectonic-sedimentary evolution and geothermal field in the basins around the Sea of Japan are analyzed.
This study aims to explore the impact of heavy metal pollution on soil and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soil and crops, this study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, explored the sources of heavy metals, and assessed the health risks caused by heavy metals intake through crops. The results of this study are as follows. The root soil of crops in the study area suffers heavy metal pollution to varying degrees. The maize fields suffer a higher degree of heavy metal pollution than the wheat fields, and both types of fields are polluted by Cd the most seriously. Moreover, the root soil of different crops suffers compound pollution, and the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area.
Elemental analysis, 13C nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), combined with Grand Canonical ensemble Monte Carlo (GCMC) simulations and energy minimizations were used to establish the molecular structure model of middle-high coal rank accurately. The three-dimensional molecular structure models of middle-high coal rank (from the No. 6 Mine of Pingdingshan (PDS) Mining Area and the No. 4 Mine of Hebi (HB) Mining Area in Henan Province, Xiegou (XG) Mine, Changping (CP) Mine, and Sihe (SH) Mine in Shanxi Province, China) were optimized and constructed. The results showed that the structural arrangement is more orderly and compact with the increase of coal rank. The established molecular formulae for PDS, HB, XG, CP, and SH are respectively C69H43NO3, C166H93N3O8, C191H125N3O7, C169H105N3O7, and C221H123N3O7.
We report paleomagnetic data from late Cretaceous diorite dykes that sub-vertically intrude granodiorites in the eastern Gangdese belt near the city of Lhasa. Our research goals are to provide further constraints on pre-collisional structure of the southern margin of Asia and the onset of the India-Asia collision. Magnetite is identified as the main magnetic carrier in our study. The magnetite shows no evidence of metamorphism or alteration as determined from optical and scanning electron microscope observations. A strong mineral orientation is revealed by anisotropy of magnetic susceptibility analysis both for the intruded dykes and the country rocks. We interpret this AMS fabric to have formed during intrusion rather than deformation. Fifteen of 23 sites yield acceptable site mean characteristic remanences with dual polarities. A scatter analysis of the virtual geomagnetic poles suggests that the mean result adequately averaged paleosecular variation. The paleomagnetic pole from the Gangdese dykes yields a paleolatitude of 14.3°N ± 5.8°N for the southern margin of Asia near Lhasa. The paleolatitude corresponds to an in-between position of the Lhasa terrane during ~130-60 Ma. Furthermore, the mean declination of the characteristic remanent magnetization reveals a significant counterclockwise rotation of 18° ± 9° for the sampling location since ~83 Ma. In the light of tectonic setting of the dykes, the strike of the southern margin of Asia near Lhasa is restored to trend approximately ~310°, which is compatible with the hypothesis that the southern margin of Eurasia had a quasi-linear structure prior to its collision with India.
Upper Ordovician-Lower Silurian Wufeng-Longmaxi Foration is the most developed strata of shale gas in southern China. As several shale gas wells were drilled in the mountain-basin transition zone in the Southwest Sichuan basin, the attraction was drawn by this area. While, due to the complex sedimentary environment adjacent to the Kangdian Uplift, the area favorable for organic-rich shale development is still in fog. Further study is necessary to obtain a more complete understanding of organic matter enrichment in the marginal region around Sichuan Basin. We therefore focus on the mechanism of accumulation of organic matter and the characterization of the sedimentary environment of the Wufeng-Longmaxi Shales. In this study, a combination of methods was applied, including thin section identification, scanning electron microscopy (SEM) observations and X-ray diffraction (XRD), and elemental analysis on outcrop samples. According to the mineralogical and petrological analyses, five lithofacies have been defined, including mudstone, bioclastic limestone, silty shale, dolomitic shale and carbonaceous siliceous shale. And for the geochemical characterization, the detrital influx, redox conditions and paleo-productivity have been studied. The results showed that Wufeng period is generally a suboxic environment and the early Longmaxi period is a reducing environment.
Passive-warming, open-top chambers (OTCs) are widely applied for studying the effects of future climate warming on coastal wetlands. In this study, a set of six OTCs were established at a Phragmites wetland located in the Yellow River Delta of Dongying City, China. With data collected through on-line transmission and in-situ sensors, the attributes and patterns of realized OTC warming are demonstrated. OTCs produced an elevated average air temperature of 0.8°C during the growing season of 2018, and soil temperatures actually increased by 0.54°C at a depth of 5 cm and 0.46°C at a depth of 30 cm in the OTCs. Variation in diel patterns of warming depend greatly on the heat sources of incoming radiation in the daytime versus soil heat flux at night. Instant warming effects were of a wider range from -2.5 to 8.3°C. Within the OTCs, plant shoot density, basal diameter, and biomass of Phragmites decreased by 23.2%, 6.3%, and 34.0%, respectively, under experimental warming versus controls, and plant height increased by 4.3%, reflecting less carbon allocation to stem structures as plants in the OTCs experienced simultaneous wind buffering. Pest damages on the plant leaves and lodging within the OTCs were extensive and serious.
Soil pH plays an important role in crop growth and soil fertility. The status, variations and controlling factors of soil pH are of great significance to understand soil acidification and alkalization processes and to make decisions on maintaining soil productivity and ecological functions. In this paper, we analyzed the distribution and spatio-temporal variation characteristics of soil pH in the Nenjiang River Basin and the geochemical driving mechanism of soil pH distribution pattern, based on the National Multi-objective Regional Geochemical Survey data of topsoil, the Second National Soil Survey data and Normalized Difference Vegetation Index (NDVI). The results demonstrated that the topsoil pH had changed from neutral and alkaline levels to acidic and strongly alkaline levels in the past 30 years. NDVI decreased with the increase of soil pH when soil pH > 8.0, and decreased with the decrease of soil pH when soil pH < 5.0. There were significant differences in soil pH with various surface cover types. The weathering products of rocks and minerals rich in K2O, Na2O, CaO and MgO from the Daxing'an Mountains and Xiaoxing'an Mountains entered into the southern low plain and were enriched in different parts by water transportation, river and lake deposition.
It is still controversial in the existence, scale and affinity of the basement of the Bainaimiao Arc Belt (BAB). We report a new discovery of Neoarchaean zircon ages from the diabase in the Ar Horqin Banner area of the north edge of the BAB. All of the zircons analyzed are subhedral, show fine-scale oscillatory growth zoning in CL images and have high Th/U ratios of 0.3—1.0, implying their magmatic origin. As a result of the LA-ICP-MS U-Pb zircon dating from the diabase, high proportional captured zircons (16 data of the total 22 zircons) have a weighted mean 207Pb/206Pb ages of 2526±19 Ma (MSWD=1.5) and an upper intercept age of 2559±20 Ma (MSWD=0.42), which clearly suggests the presence of Neoarchaean geological body on the northern edge of the BAB, reflecting the existence of the Neoarchaean crystalline basement.
The continuous enrichment of heavy metals in soils poses a potential hazard to groundwater. Previous research lacked a method to quantitatively evaluate the hazard degree of soil heavy metals to groundwater. This paper combined the groundwater cycle and solid-liquid equilibrium theory to construct a simple and easy-to-use flux model of soil heavy metals into groundwater, and proposed an innovative method for evaluating the hazard of soil heavy metals to groundwater on the basis of evaluating the environmental capacity of groundwater.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn, Cu, As, Pb, Cd, Ni and Hg in descending order, and that the heavy metals in groundwater (As, Hg, Cu, Pb, Zn, Ni and Cd) in most areas do not reach the environmental capacity threshold within 10 years, and the hazard level of soil heavy metals to groundwater in the majority of townships is at the moderate level or below. This evaluation method can quantify the flux of soil heavy metals into groundwater in a simple and quick way, determine the remaining capacity of groundwater for heavy metals, evaluate the hazardous status of soil heavy metals to groundwater, provide support for relevant departments to carry out environmental protection of soil and groundwater, and provide reference for related scholars to carry out similar studies.
The development of oil and gas resources has always been highly concerned by scholars at home and abroad. The chemical property of the reservoir water is very important to the evaluation of reservoir, and is an important indicator of the sealability of reservoir oil and gas resources. Therefore, the caprock of Chang 6 oil reservoir in Yanchang Formation was evaluated. This paper selects water samples from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the basin to test and analyze water chemical characteristics. The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium chloride water type, and its sodium chloride coefficient is generally less than 0.5; the chloride magnesium coefficient is between 33.7 and 925.5, most of which are greater than 200.The desulfurization coefficient ranges from 0.21 to 13.4, with an average of 2.227; the carbonate balance coefficient is mainly concentrated below 0.01, with an average of 0.008; the calcium and magnesium coefficient ranges from 0.08 to 0.003, with an average of 0.01.The above results combined with the characteristics of the four corners territory of the reservoir water show that the graphics are basically consistent.
The supergiant Shuangjianzishan (SJZ) Ag-Pb-Zn deposit is in the southern segment of the Great Hinggan Range, Northeast China. Previous studies suggest the ore-forming material and fluid were originated from magmatic system, and the mineralization age were consistent with the diagenetic age. However, the relationship between the granitic magmatism and the mineralization are still unclear in the SJZ. In this study, C-H-O-He-Ar and in-situ S-Pb isotope analyses were conducted to determine the sources of ore-forming fluids and materials, which combing with geochemistry data of SJZ granitoids from previous studies to constrain the relationship between the magmatism and the mineralization. The C-H-O-He-Ar-S-Pb isotopic compositions suggested the SJZ ore-forming material and fluids were derived from a magmatic source, which have mixed a small amount of mantle-derived materials. In addition, the disseminated sulfide form the syenogranite have comparable S-Pb isotopic composition with the sulfide minerals from ore veins, suggesting the generation of the SJZ ore-forming fluids have a closely relationship with the syenogranite magmatism. Combing with the geochemical characters of the syenogranite, we proposed that the mantle-derived fingerprint of the SJZ ore-forming fluid might be caused by the syenogranite magma derived form partial melting of juvenile lower crust, and the syenogranite melt extraction further concentrated the fertilized fluids, which is crucial to mineralization of the SJZ deposit.