Abstract:This paper is the result of moon geological survey engineering. Objective Mare basins constitute pivotal geological units on the lunar surface. Their geological evolution characteristics are comprehensively affected by both endogenic and exogenic dynamic geological processes. The ancient Ingenii Basin is located on the northwest rim of South Pole–Aitken Basin on the lunar farside. This special geographical location endows it with great significance for understanding lunar structure, composition, and the evolution of these dynamic geological processes. Methods This study conducts a comprehensive and multi–faceted analysis of Ingenii Basin, encompassing surface attributes like albedo variations, soil maturity indices, topography, slope gradients, and roughness, alongside deep–seated features such as Bouguer gravity anomalies, crustal thickness, and compositional characteristics in elemental and mineral abundances. Results The region of Ingenii Basin exhibits pronounced asymmetry, with a topographic profile characterized by elevated northwest regions and lower–lying southeast areas. Distinctive swirl patterns adorn the basin. The majority of the terrain, excluding swirls, steep basin walls, and impact crater walls, generally displays high maturity. The Ingenii Basin–forming impact event uplifted high–density mantle materials beneath the Moho surface, resulting in a positive gravity anomaly at the basin’s center, where the crustal thickness attains its minimum. A linear inverse correlation emerges between crust thickness and Bouguer gravity anomalies, particularly pronounced for gravity anomalies exceeding 200 mGal. Within the basin’s mare basalt regions, FeO and TiO₂ abundances are elevated, while compositional traits outside the Ingenii region generally mirror those of the impacted target. Through a multi–dimensional examination of surface, subsurface, and compositional features, we delineated the regional geological evolution mode of Ingenii Basin. Conclusions The landform and composition of the Ingenii Basin are comprehensively affected by endogenic and exogenic dynamic geological processes, exhibiting the dual characteristics of the South Pole – Aitken Terrane and the Feldspathic Highlands Terrane, which is a window to understand the early evolutionary history of the Moon.

Abstract:This paper is the result of ecological geological survey engineering. Objective Vegetation cover is a critical indicator of ecosystem stability. Researches about the factors influencing vegetation cover changes in the ecologically sensitive Kunlun Mountains region are limited. This study aims to analyze the spatiotemporal variations of vegetation cover and their driving factors in the Kunlun Mountains and to perform a regional ecological assessment. Methods The Normalized Difference Vegetation Index (NDVI) was used to examine the spatiotemporal patterns of vegetation cover from 2000 to 2020, and the Geodetector (GD) and Random Forest (RF) models were applied to identify the primary drivers of NDVI changes. Meanwhile, RF and Long Short–Term Memory Network (LSTM) models were used for predict the NDVI variations, and the Remote Sensing Ecological Index (RSEI) was used to evaluate environmental quality. Results NDVI showed a generally temporal increasing–decreasing–increasing trend, characterized by a spatial distribution that higher values in the west and north and lower values in the east and south. The RF model identified the digital elevation model (DEM), precipitation (Pre), distance to towns (Town), and gross domestic product (GDP) as the most influential factors, whereas the GD model showed evapotranspiration (ET), DEM, GDP, and temperature (Temp) had the greatest explanatory power. The RF model was more effective for NDVI regression analysis than the LSTM model in the study area. The RSEI value showed an increase in 80.52% of the area, but the overall variation was considerable, with 78.86% of the area showing significant variation. Conclusions DEM, GDP, Pre, and ET are the primary factors affecting vegetation cover in the region and the significant improvement in the regional ecosystem over the past two decades. It also reveals a significant enhancement in regional ecological quality, indicating that ecological conservation measures have been effective.

Abstract:This paper is the result of environmental geological survey engineering. Objective Guilin is a typical and representative karst landform and an important ecological fragile area in China. In recent years, the degradation of karst landscape resources caused by human activities has become severe. Research on the evaluation and management Guilin’s karst landscape resources is of great significance for achieving regional ecological protection, restoration, and high–quality socio–economic development. Methods Taking the national innovation demonstration zone for sustainable development goals of Guilin as the research area, ecosystem sensitivity was evaluated based on factors such as soil erosion, rocky desertification, land use, and lithology, while ecosystem service functions were assessed suing indicators like water conservation, soil conservation, biodiversity, and landform landscape. Results In the study area, the sensitivity of soil erosion and rocky desertification was mainly mild or general, accounting for 67.04%–76.24% of the total karst area.Land use and lithology were predominantly categorized as highly or extremely sensitive, accounting for 52.12%–62.21%. The functional importance of water conservation and soil conservation were generally moderate, representing 36.23%–51.87%, while the conservation of biodiversity and landform landscape were rated as highly important, accounting for 37.99%–44.26%. Based on the comprehensive calculation of ecosystem sensitivity and service function, the importance of landscape protection determined to be at least moderate across 83.57% of karst area. Conclusions Based on the evaluation results, the study areas are divided into zones for enhancing agricultural and forestry landscape function, restoring wetland and water landscapes, rehabilitating mine and geological landscapes, and addressing rocky desertification. The proposed management models include landscape restoration and water resource regulation, as well as karst geological landscape protection and ecological recycling industry collaborative development. This study provides a scientific basis for sustainable utilization of karst landscape resources, ecological environment protection, and comprehensive planning in Guilin City.

Abstract:This paper is the result of hydrogeological survey engineering. Objective A new evaluation method for catchment scale dependent groundwater ecosystem in semi-arid region was established. The method will include both surface and sub–surface information and provides a technical support to groundwater resources development and ecosystem protection in semi–arid areas. Methods Taking the Hailiutu catchment in the Ordos Plateau as the study area. Four indicators including depth to water table, soil types, vegetation coverage and evapotranspiration were selected and the spatial distributions of these indicators were determined based on field survey and remote sensing interpretation. Finally, a systematic assessment was performed in a GIS platform to identify the distribution of GDE and the degree of dependency. Results The results indicate that the areas very high and high dependent on groundwater accounts for 10.2%. Although the areas are small, biodiversity and bio-mass in such place are much higher with high ecological value than the that of others due to the contribution of groundwater to vegetation growth. Conclusions Based on the comparison between this study and site studies, the results have a good agreement and are reliable, indicating that the proposed method is applicable to other similar regions. The sensitivity analysis shows that the most sensitive parameters are soil types and depth to water table that should be paid more attention during data collection in field works.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Meteoric water in the mountain areas infiltrates deep underground and circulates to the surface. It involves deep structural and hydrogeochemical processes, and it is one of the fluid source of forming rich geothermal and mineral resources. Predecessors focused on the groundwater source, circulation depth and flow system using methods of hydrochemistry isotope and numerical simulation, and further evaluated the distribution of regional geothermal and mineral resources. Methods Based on the data of DEM, fault structure, and lithology of the Yangbajing–Ningzhong basin,we establish 3D geometry finite element model. The standard saturated groundwater flow equation is solved using groundwater simulation software, and we analyse the circulation system of the typical hot springsand regional groundwater migration. Results The simulation results show that the maximum circulation depths of groundwater are respectively 5–7 km, 3.5–4 km, and 3–3.6 km at Yangbajing, Laduogang, and Qucai springs, and the corresponding groundwater circulation times are 23–80, 5–6 and 4–8 years. The groundwater of Nyainqentanglha Mountain seeps down to 10 km depth, where the time spans million years. Conclusions In general, the circulation depth and the recharge time of hot springs are different due to their different supply sources and circulation paths. Notably, there is no hydraulic connection between the hot springs at Yangbajing, Laduogang, and Qucai, although they are located in the same rift valley. It results in differences in material composition among these springs.

Abstract:This paper is the result of geothermal exploration engineering. Objective With the gradual adjustment of China's energy structure and the implementation of coal capacity reduction policy, the number of closed/abandoned coal mines has increased in recent years. Under normal circumstances, conventional geothermal mining faces problems such as large investment costs and easy to induce geological and environmental disasters, while closed/abandoned coal mines contain abundant hot water and space resources, which effectively reduces the risk and investment cost of geothermal resource development. Mine geothermal is different from conventional shallow geothermal and medium and deep hydrothermal heat, and also different from oil field geothermal heat, and has its own characteristics, so it is necessary to adopt different geothermal development and utilization technologies. Methods This paper summarizes the distribution characteristics of geothermal resources in coal mines in China by literature review method. On the basis of analyzing the development and utilization methods of mine geothermal resources, this paper proposes a way to transform mine geothermal energy and the heat damage caused by it into effective utilization of geothermal resources, discusses the application of mine geothermal development theory in practical cases, and explores and analyzes the feasibility of various ways of mine geothermal resource development and utilization. Results (1) The utilization methods of mine water geothermal resources are roughly divided into two categories: geothermal recovery closed system and geothermal recovery open system; (2) China's 26 major coal–producing provinces, high–altitude temperature mines are distributed in 13 provinces such as Henan, Jiangsu and Shandong. The thermal reserves of geothermal resources in the main coal–endowed areas are 1.12×10¹⁹ kJ, equivalent to 379.539 billion tons of standard coal, of which 74.66% of the geothermal resources of coal mines are located in North China; (3) Taking Shandong Tangkou Coal Mine as an example, a geothermal resource utilization model was established, and the feasibility of geothermal resource utilization in coal mines in China was discussed. (4) We put forward a variety of mine water geothermal development directions, establish "coal–water–heat" linkage research and intelligent monitoring system, explore the extraction of lithium and other high–value elements from mine water, and use geothermal energy to transform abandoned coal mines into underground farms. Conclusions Carbon reduction is one of the key challenges in addressing climate change. The use of geothermal resources in abandoned coal mines can reduce dependence on traditional fossil fuels, reduce carbon dioxide and other greenhouse gas emissions, and make a positive contribution to carbon emission reduction goals, but China's mine hydrogeological conditions are complex, and the development and utilization experience of typical mines in foreign countries cannot be copied, and a new mode of geothermal application suitable for abandoned mines in China should be actively explored.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Microplastics (MPs) have emerged as a global pollutant, causing increasingly severe environmental problems. While most research has focused on surface water bodies such as oceans and rivers, studies on MPs in groundwater systems have been relatively limited. Methods Based on extensive literature research and analysis, this paper examines the progress made in the study of MPs in groundwater. It explores the sources, detection methods, distribution characteristics, environmental risks and future trends of MPs in groundwater. The objective is to provide references for future research and facilitate risk prevention and control of MPs–contaminated groundwater. Results MPs primarily enter groundwater through three pathways: surface water–groundwater interaction, soil infiltration, and direct injection. Currently, research on MPs in groundwater is primarily concentrated in coastal areas, particularly in China, Europe and North America. However, additional data and research are needed in regions such as South America, Africa and Oceania. The most common types of MPs found in groundwater are polyethylene terephthalate (PET) and polyethylene (PE), with fibers and debris being the predominant shapes. Groundwater contaminated with MPs poses environmental risks to soil and crop health, pollutant migration, human health, underground ecosystem, and the effectiveness of groundwater pollution remediation. Future research on MPs in groundwater should prioritize the establishment of standardized sampling and detection procedures, determination of spatial distribution characteristics, and exploration of key scientific issues influencing the migration and transformation mechanism. Conclusions Numerous studies have been conducted on the sources, distribution characteristics, environmental risks and development trends of MPs in groundwater. However, current research is still in its early stage and is expected to continue growing due to the vital role groundwater plays in sustaining human activities and natural ecosystems. Management strategies for MPs pollution in groundwater should primarily focus on three aspects. Firstly, controlling the source by minimizing plastic waste production is crucial. Secondly, it is important to cut off migratory routes of MPs by implementing preventive measures in high–risk areas. Lastly, developing appropriate remediation technologies is essential for the end–removal of MPs from groundwater.

Abstract:This paper is the result of ecological environment geological survey engineering. Objective The Qinhe River Basin serves as an important water–receiving area and soil–water conservation functional area in the middle reaches of the Yellow River. The main water catchment area in the upper reaches of the basin mainly covers two counties, Qinyuan and Anze. Scientific analysis of the temporal and spatial variation characteristics and influencing factors of its water conservation capacity can provide technical basis for the ecological environment restoration in the middle and lower reaches of the Qinhe River and even the entire basin, as well as for the ecological protection and high–quality development planning of the Yellow River Basin. Methods This paper uses the water balance method to analyze and discuss the spatiotemporal dynamic change characteristics of the water conservation function of the ecosystem in the region during the 30 years from 1990 to 2020 and the influence of different factors on the water conservation capacity.According to the regional water conservation capacity and combined with the distribution of natural protected areas within it, the importance level of regional water conservation is divided. Results (1) In terms of space, the water conservation capacity in the study area shows a pattern of being high in the south and low in the north, high in the middle and low around, with significant regional differences. The average value of multi–year water conservation volume is 366.74×10⁶ m³.The change trend of water conservation function in nearly 30 years shows a characteristic of first decreasing and then increasing. (2) Climate factors have a strong correlation with water conservation volume, and vegetation types also affect the spatial characteristics of water conservation.Among vegetation types, forests are the main body of water conservation in the ecosystem within the region. However, in terms of water conservation capacity, shrublands are higher than forests and grasslands. (3) The total area of important and important–highly water conservation areas in the study area is 733.38 km², accounting for 35% of the total area of the study area.The total amount of water conservation of the two accounts for 53.63% of the whole area. They are mainly distributed in the small and medium–sized undulating mountains in the transition between the two sides of the river and the large undulating mountains and the southern area of Anze County. It is the concentrated area of water conservation in the entire study area. Conclusions For the construction of water conservation capacity in the upper reaches of the Qinhe River Basin, some ecological governance measures are proposed, including identifying the Lingkong Mountain and Huapo areas as extremely important areas for water conservation function. According to local conditions, tree species with strong water conservation capacity can be increased, and the governance and restoration of subalpine meadows and temperate grasslands can be strengthened.

Abstract:This paper is the result of mineral exploration engineering. Objective Zirconium is a rare metal and one of the key metal minerals. Because of its high temperature resistance, corrosion resistance, easy processing, good mechanical properties and stable chemical properties, zirconium metal and zirconium compounds have key applications in military industry, refractories, ceramics and other industries, and zircon is widely used in geological dating and tracing magma source areas. Methods By collecting and summarizing the previous research data, this paper studies the distribution of zirconium ore resources, the characteristics of zirconium deposit types and the key applications of zirconium metal and its alloys in China. Results Zirconium deposits in China are mainly distributed in Inner Mongolia, Hainan, Guangdong, Yunnan and Guangxi provinces, and the sum of the zirconium deposits in these five provinces accounts for 97.6% of the national reserves. Zirconium mine in China has a poor resource endowment, with a reserve of about 500000 tons (calculated by ZrO₂), accounting for only 1% of the global reserves. China's annual demand for zirconium ore is about 1.2 million tons, but China's annual imports of zirconium ore are about 1.1 million tons, and the degree of external dependence of zirconium ore is as high as 90%. Zirconium deposits in China can be divided into endogenetic deposits and exogenetic deposits, among which endogenetic deposits can be divided into four types: alkaline granite, pegmatite, alkaline rock and granulite, while exogenetic deposits can be divided into three types: coastal deposit, river impact, weathering crust and eluvial deposit. Conclusions Based on previous research data, endogenetic deposits are closely related to alkaline rocks, alkaline granites and pegmatites, and the northern margin fault zone of Tarim–North China Craton and the southern section of Daxing'anling Mountains have great prospecting potential. Exogenous deposits are mainly sand deposits, which are mainly distributed in the coastal zone of Hainan Island, the southeast coastal zone and the Bohai Sea–Yellow Sea zone. The eastern sea area of Hainan Island, the mouth of Changhua River in the west and the southeast coastal zone of Jiaodong Peninsula have great prospecting potential.

Abstract:This paper is the result of mineral exploration engineering. Objective In the national dynamic evaluation project of potential mineral resources, the features, type and spatiotemporal distribution of caesium resource in China are studied, and the metallogenic regularities of caesium deposits in China are summarized. Methods This paper introduces the resource characteristics of caesium deposits in China. Caesium deposit types are divided, and the mineralization age and spatial distribution of cesium ore are counted. Results Caesium deposits in China are divided into seven types, namely the granite type, granite pegmatite type, magmatic hydrothermal type, salt lake type, brine type, geyserite type, granite weathering crust type. The spatiotemporal distribution feature of each type of caesium deposits is preliminarily summarized. Based on the statistics, the metallogenic period of caesium deposits in China is divided into Paleozoic, Mesozoic and Cenozoic. 10 caesium metallogenic belts are divided. 31 caesium–related metallogenic series are determined and the metallogenic pedigree of caesium deposits in China is established. Conclusions China's caesium deposits are mainly Mesozoic and Cenozoic granite pegmatite type, granite type and salt lake type cesium deposits in north Altay and North China continental block, salt lake type in Qinghai–Tibet Plateau, granite pegmatite, granite caesium deposit and magmatic hydrothermal caesium deposit in the middle and lower reaches of the Yangtze River. The exploration in Xinjiang, the middle and lower reaches of the Yangtze River, Qinghai–Tibet Plateau and Qianjiang basin should be strengthened.

Abstract:This paper is the result of geological survey engineering. Objective The newly discovered Longwangdong ophiolitic mélange as a typical ophiolite suit in the Tianshui area of West Qinling Orogenic Belt witnessed the westward extension of Shangdan suture zone in Qinling Orogenic Belt. Studying its petrology, geochronology, and geochemistry will help improve our understanding of the tectonic evolution of this region. Methods This study demonstrates through petrological and whole–rock geochemical analyses that this ophiolite suite is mainly composed of amphibolite, metamorphosed basalt, and pyroxenite. Results LA–ICP–MS zircon U–Pb dating shows the meta–gabbro was formed at (474.6±6.7) Ma, constraining the formation time of the mélange. The whole–rock geochemical analysis reveals that the meta–basalts are subalkalic tholeiite in composition and rich in Ti, Mg and Fe. The total REE of the meta–basalts are low and characterized by flat type distribution pattern without obvious Eu anomalies. Their trace element distribution yields flat patterns with negative anomalies of Cs, Th, Nb, and lowed Zr/Nb ratios, consistent with that of the E–MORB. Conclusions The geochemical features of the meta–basalts suggest the Longwangdong ophiolitic mélange was potentially generated in the extended volcanic arc environment, which was considered to be the back–arc basin based on the regional geological data. It further implies that Shangdan Ocean experienced a period of subduction process in the Early Ordovician in the West Qinling region.

Abstract:This paper is the result of geological survey engineering. Objective Dunhuang block is located at the junction of Tarim Plate, Central Asian Orogenic Belt and Qilianshan Orogenic Belt. Its formation age and tectonic attributes have always been controversial. This paper takes the intermediate–acid volcanic rocks exposed in the northeastern margin of Dunhuang block as the research object, and attempts to provide evidence for solving the above problems. Methods In this paper, LA–ICP–MS zircon U–Pb dating of three dacite samples and geochemical analysis of intermediate–acid volcanic rocks were carried out to explore the formation age, petrogenesis and tectonic attributes of the volcanic rocks. Results LA–ICP–MS zircon U–Pb geochronology indicates that three dacite samples form at (533.2±6.1) Ma, (527.7±6.1) Ma and (514.9±3.4) Ma, belonging to Early Cambrian. The andesite exposed in the area has typical characteristics of high–Mg andesite, e.g., SiO₂ contents (51.4%–55.98%), high MgO contents (5.81%–12.31%) and Mg^# values (59–72), high Cr (166×10^–6–1020×10^–6) and Ni (41.4×10^–6–169×10^–6) contents, and low FeO^T/MgO (0.79–1.56) ratios. Otherwise, the andesites have high Ti/Zr, Ti/Y ratios and low Rb/Sr ratios, high La/Nb and Ba/Nb and Ba/La ratios. The intermediate–acid volcanic rocks are enriched in large ionic lithophile elements (Rb, Ba, U, K) and light rare earth elements, depleted in high field strength elements (Nb, Ta, Zr, Ti) and heavy rare earth elements, with characteristics of near–flat right–leaning rare earth distribution pattern, low Nb/La (0.36–0.46) and Hf/Th (1.02–1.34) ratios, high Hf/Ta (5.71–8.60) and La/Ta (21.72–29.50) ratios, indicative of the geochemical properties of island arc volcanic rocks. Conclusions It is considered that the volcanic rocks should be the Early Cambrian volcanic caprock above Dunhuang Group. The volcanic rocks in the area should be formed in the island arc environment, which may be formed by partial melting of metasomatic mantle wedge in the subduction of the Early Cambrian Paleo–Asian Ocean crust melt (fluid), and contaminated by crustal materials during the ascending process. According to the formation age of volcanic rocks and the characteristics of petrogeochemistry, the subduction of the Paleo–Asian Ocean can be traced back to the Early Cambrian.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The formation temperature history is a pivotal determinant in the maturity evolution of organic matter and the hydrocarbon generation and expulsion process within hydrocarbon source rocks. This history is shaped not only by the evolution of basin heat flow and the sedimentary and burial processes but also significantly influenced by anomalous heat events, such as magmatic activity, which must be considered. Investigating these factors is crucial for a comprehensive understanding of the organic matter maturation process. Methods This study leverages the exploration and development insights from the Tarim Oilfield to examine the impact of magmatic intrusions on formation temperature and the thermal evolution of hydrocarbon source rocks. We employ numerical simulation and drilling data to discuss these influences and calculate the spatial and temporal extent and intensity of the intrusions. Results Based on measured vitrinite reflectance data (Ro) from several wells in the Carboniferous–Permian strata of the central and western Tarim Basin, reveal abnormally high values associated with igneous rocks. These high values are indicative of magmatic activity during the late Carboniferous–Permian period. Thermal history modeling of the wells indicates that magmatic activity heated the Paleozoic hydrocarbon source rocks, accelerating the thermal evolution and maturity of the organic matter, leading to a swift transition into the high–over–maturation stage. Conclusions Anomalous magmatic thermal events play a beneficial role in enhancing the hydrocarbon generation intensity of hydrocarbon source rocks, achieving the highest relative hydrocarbon production rates, and facilitating the rapid maturation of organic matter.

Abstract:This paper is the result of oil and gas exploration engineering. Objective Dark shales in Lower Carboniferous upper are widely distributed in the Yadu–Ziyun–Luodian aulacogen, the upper Yangtze Platform, and its thickness varies greatly. In particular, the development characteristics and hydrocarbon generation center distribution of the dark shale of Jiusi Formation in the northwest section of the rift aulacogen are not clear. Methods The strata, sedimentary facies, dark shale distribution and organic geochemical characteristics of Jiusi dark shale in well GWD–2 are studied in detail by the logging, core observation, rock thin–section identification, kerogen type microscopic identification, TOC, vitrinite reflectance measurement and other experimental test data. And the following research results were obtained. Results (1) The drilling thickness of Jiusi Formation in the well GWD–2 is 1148.67 m, according to the characteristics of rock combinations, the Lower Carboniferous Jiusi Formation can be divided into two members and five sub–members. (2) The dark shales are mainly distributed in the first member of Jiusi Formation, which are mainly composed of tidal flat by delta and shallow shelf facies deposits, the cumulative thickness of shale is 525 m, the cumulative thickness of shale with TOC value greater than 1% is 425 m. (3) The TOC value of Jiusi shale of the well is concentrated in the range of 1%–2%, the type of organic matter is mainly type II₂ kerogen and III kerogen, the organic matters are in the early stage of over maturity. (4) It is predicted that the subsidence center of Jiusi Formation is distributed in a long strip with NW–SE direction, and the distribution of hydrocarbon generation center is consistent with the subsidence center. The thickness of argillaceous source rock with TOC value greater than 1% can reach more than 300 m. The hydrocarbon generation center has the hydrocarbon generation conditions of argillaceous source rock with huge thickness, good organic matter type and high degree of thermal evolution. Conclusions It is concluded that the shale of Lower Carboniferous Jiusi Formation in the hydrocarbon generation center of the northwest section of Yadu–Ziyun–Luodian aulacogen has considerable hydrocarbon generation intensity and total hydrocarbon generation, and has good natural gas exploration potential.

Abstract:This paper is the result of oil and gas exploration engineering. Objective As the carrier during the oil and gas migration, stratum water plays an important role in oil and gas accumulation. The oil–water distribution of the Jurassic Ahe Formation (J₁a) oil and gas reservoirs in the eastern Kuqa Depression of the Tarim Basin is complicated, and the characteristics of stratum water and its relationship with oil and gas reservoirs are lack of systematic study. Methods In order to clarify the chemical characteristics of stratum water and its relationship with reservoirs, based on the selection among stratum water samples, the test data of Ahe Formation in eastern Kuqa Depression are obtained to study the distribution of water type, TDS and ion–proportionality coefficients of stratum water and its significance to reservoirs. Result The stratum water of J₁a is mainly NaHCO₃ type, followed by CaCl₂ and MgCl₂ type, and has relatively low salinity. The TDS and ion–proportionality coefficients of stratum water are controlled by tectonics. In the structure opening area and the pinch–out area of the strata, the stratum water is characterized by NaHCO₃ type with low TDS, the sodium–chloride coefficient and desulfurization coefficient are high and the metamorphic coefficient is negative. Nevertheless, the stratum water in the closed strata has the opposite hydrochemical feature. Conclusions There is a good coupling relation between the hydrochemical characteristics of stratum water and the plane distribution of oil and water, with Dibei oilfield as an example, although the strata north of the Yiqikelike fault had been charged, the generated oil and gas had escaped along the fault. The low TDS, high sodium–chloride coefficient, high desulfurization coefficient, low metamorphic coefficient, and high kaolinite content indicate that the strata were affected by the meteoric water that entered along the fault. On the contrary, the hydrochemical characteristics and kaolinite content in the strata south of the fault reflect that the formation was well sealed and less affected by meteoric water, which corresponds to the distribution of gas layers. The connection between the hydrochemical characteristics and the distribution of reservoirs provides a basis for subsequent exploration, development and evaluation of tight oil and gas reservoirs.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The research of deep–water debris flow deposition of the Mid–Late Jurassic Lagongtang Formation on the northern margin of the Lhasa Block is important for the reconstruction on the Mesozoic tectonics–palaeogeography in the southern Qinghai–Tibetan Plateau. Methods This study conducted field investigations and microstructural analyses on the debris flow deposition of the Lagongtang Formation in the Nagqu area, and discussed its controlling factors and transport processes with previous regional geological data, and further established its depositional model. Results The lower part of the debris flow deposition consists mainly of gravelly debris flow deposits, while its upper part is characterized by sandy debris flow deposits alternating with muddy debris flow deposits, containing abundant slip collapse and sliding bodies and have a typical double structure of soft deposition. The soft depositional deformation folds and pudding structure indicate the southward flow of the debris flow. Conclusions This study indicates that the formation of the Lagongtang Formation is controlled by the Bangonghu–Nujiang suture zone, and the "source–drain–sink" of different kinds of debris flow deposition shows coupling relationships to a certain extent. The study also provides new information on the reconstruction on the structure–paleogeography of the southern Qinghai–Tibetan Plateau in Mesozoic.

Abstract:This paper is the result of coastal geological survey engineering. Objective More and more high resolution paleoclimatic records confirm that a number of subcentennial climate abrupt change events were exit in the Holocene. Such abrupt climate change events had a very close relationship with the social and economic development of human. 4.2 ka BP event are recorded in Asia, North America, the Mediterranean, Southern Europe and other places which indicated that this event were global in extent. However, the record of this evnent has not been adequently substantiated in the coastal zone, especially in northern China muddy coastal zones. Methods This paper focuses on three buried oyster reefs and their overlying mud layers located 1–6 km apart on the northwest coast of Bohai Bay, namely Lingtou, Zengkouhe and the sourthern part of Biaokou. Through diatom analysis (83 samples), AMS ¹⁴C dating (32 data) and sedimentological research, the environmental information recorded by the reefs and overlying mud layers was reconstructed, and the possible imprints of the ‘4.2 ka BP event’ in the coastal zone were discussed. Results The study area experienced a transgression–regression environment evolution from upper tidal salt marsh to intertidal zone in the Early Holocene→subtidal zone to lower and middle part of intertidal zone to middle and upper part of intertidal zone in the Mid–Holocene→salt marsh lowlands in the Late Holocene. At about 7 ka cal BP ago, three reefs appeared one after another, and as the reefs build up, the influence of the seawater become weakened. At about 5–4.3 ka cal BP, the three reefs entered the lower and middle part of the intertidal zone, the climate became colder and lead the three reefs be buried at the same time of 4.2–4 ka cal BP and covered by the overlying mud immediately. Conclusions A climate fluctuation process occurred during 5–4 ka cal BP in the study area. The climate became colder during 5–4.3 ka cal BP, and gradually warmed after 4.3 ka cal BP. The turning point of the climate change occurred at about 4.3 ka cal BP. We speculate that this climate fluctuation was probably a response to the ‘4.2 ka BP event’ in the north muddy coast of China.

Abstract:This paper is the result of coastal geological survey engineering. Objective The second marine layer in the coastal lowland of Bohai Bay remains controversial, which restricts the progress of sea level change research in this area. This study performs optically stimulated luminescence dating on this layer, expecting to calibrate the precise stratigraphic age and the corresponding marine transgression episodes. Methods By taking the CZ80, CZ85, and CZ66 boreholes on the west coast of the Bohai Bay as the research targets, based on the examination of sedimentary structures, textures and foraminifera abundance in the cores and sedimentary microfacies, the second marine layer was identified, and a comparative profile of the second marine layer was constructed. The formation age of this layer was precisely determined through the optically stimulated luminescence dating method, and the relationship between the development duration of the second marine layer and global sea level changes was further explored. Results The CZ80, CZ85, and CZ66 boreholes all intersected the second marine layer beneath the Holocene stratum (including the first marine layer). The base of the marine layer was embedded at a depth ranging between 35 and 33 meters, corresponding to the elevation ranging from –31.13 to –28.39 meters in the Yellow Sea. The top of the marine layer was buried within a depth range of 32 to 20 meters, with an elevation varying from –25.58 to –15.39 meters. The optically stimulated luminescence dating outcomes reveal that the occurrence time of the marine transgression event corresponding to the second marine layer was approximately 94 to 71 ka. Conclusions The optically stimulated luminescence (OSL) dating outcomes reveal that the second marine layer in this region commenced at 94 ka or earlier, and the influence of seawater terminated approximately 71 ka ago. Through comparison with the global sea–level curve, the spatio–temporal attributes of the second marine layer are consistent with the MIS5a stage, chronicling the marine transgression event during the MIS5a stage.

Abstract:This paper is the result of environmental geological survey engineering. Objective Nitrate pollution in surface water is a global environmental issue, therefore identifying the source and transformation of nitrate is fundamental to improving water quality. Methods To accurately identify the sources and transformation processes of nitrate in surface water in north of Yantai city, hydrochemistry and dual isotopes of nitrate nitrogen–oxygen technologies were used to sample and analyze surface water from different river basins, including Dagujia River, Xin'an River, Qinshui River, and Han River. And the Bayesian isotopes mixing model MixSIAR was also used to calculate the contribution rates of various nitrate sources. Results (1) The surface water in the study area is weakly alkaline, with NO₃^––N concentration significantly higher than NH₄⁺–N and NO₂^––N concentrations, making NO₃^––N is the primary nitrogen pollutant in the surface water of the study area. Only the NO₃^––N concentration in Xin'an River (NO₃^––N<10 mg/L) fell within the national health standard for drinking water. (2) Nitrification dominates the nitrate transformation process in the surface waters in the study area, while denitrification playing a negligible role. (3) The output results of the MixSIAR model show that the contribution rates of nitrate sources in surface water in the study area are as follows: sewage and manure (51.1%)>soil organic nitrogen (23.9%)>chemical fertilizer (22.9%)>atmospheric deposition (2.1%). Conclusions Overall, sewage and manure have the highest contribution rate to nitrate sources in surface water in the study area, followed by soil organic nitrogen and chemical fertilizer. Sewage and manure from anthropogenic inputs are the main sources of nitrate pollution in the study area. Therefore, reducing discharge of sewage and manure into rivers is key to controlling pollution.

Abstract:This paper is the result of environmental geological survey engineering. Objective It is of great significance to understand the distribution pattern of saline mineral deposits in lake basin for the reconstruction of palaeoenvironment and palaeohydrology. However, the studies on mineral distribution for groundwater recharged lake sediments are few, which hinders the climate–environmental reconstruction in arid area. Methods The Badain Jaran Desert, located in western Inner Mongolia in a hyper–arid area of China, is characterized by the coexistence of more than 110 perennial lakes and thousands of mega–dunes. More than 90% of the recharge of lakes between mega–dunes is groundwater. In this study, we analyzed the mineral assemblage and distribution characteristics of the surface sediments of eight lakes with different salinity in the Badain Jaran Desert. Results (1) For individual lakes, the distribution pattern of saline mineral deposits is similar to those of lakes with runoff recharge, that is, there are more detrital mineral deposits at the edge of the lake, and the saline mineral deposits gradually increase towards the lake interior, and the mineral types gradually change from carbonate to sulfate and chloride. (2) The mineral composition of the sediments near the lake edge is more easily affected by the variation of lake water level and area, while the sediments near the lake center may be affected by the water depth and the groundwater recharge. (3) The shallow lakes are well mixed and are not easily affected by the stratification of lake salinity and water temperature, and the replenishment of fresh water at the bottom. Moreover, the total content of salt minerals has a good linear relationship with the salinity of lake water. Conclusions The changes of saline mineral assemblage and its content in the lakes recharged by groundwater can well reflect the changes of lake salinity and can be used as a proxy of climate–environmental reconstruction in desert areas. The lakes in desert are highly sensitive to climate change. The changes of salt mineral assemblage and content in desert lakes can be used as an important basis for discussing environmental problems such as global warming and desertification.

Abstract:This paper is the result of environmental geological survey engineering. Objective This paper is aim to prove the health risk from the Cd pollution in typical cultivated soils in Jiangsu province, and understand the main geochemical factors to control rice seeds uptake of Cd in soil, and provide scientific evidences to cure Cd pollution. Methods 1330 sets of rice–soil samples were systematically collected in the studied areas, and Cd, Pb, Hg, As, Cr, Cu, Zn, Se, Sb, TOC (Total Organic Carbon), pH, and CEC (Cation Exchange Capacity) in soil and Cd in rice seeds were determined by advanced testing methods such as ICP–MS, etc, the available Cd in soil was determined by calcium chloride extraction, and mastering the actual distribution data related to rice seeds Cd contents and elemental concentrations in soil. By the means of calculating their geochemical parameters and comparing its difference, developing correlation analysis and R–type cluster analysis, etc., and exploring main geochemical controlling factors to impact rice seeds uptake of Cd in soil, evaluating healthy risk in the local Cd polluted farmland. Results The available Cd concentrations are 0.0018–1.44 mg/kg, their mean value is 0.265 mg/kg, and the Cd concentrations are 0.13–30.0 mg/kg with an average amount of 2.11 mg/kg in soil, and the rice seeds Cd contents are 0.0053–2.58 mg/kg with the mean amount of 0.478 mg/kg in the studied areas. The available Cd in soil is the most important factor to control the rice seeds uptake of Cd, and the local Cd pollutants have spread to the food chain and human hairs in the farmland. Conclusions (1) There are significant positive correlations between rice seeds Cd contents and the available Cd in soil, and its correlated coefficient (r) is 0.54 without deleting anyone in the 1330 sets samples, if pH values being from 6.5 to 7.5 in soil, the positive correlated relationship between rice seeds Cd contents and the available Cd in soil is best with correlated coefficient maximum value of r=0.86. In addition to the available Cd, the following geochemical factors as to Cd, TOC, CEC, and pH of soil are also important to control rice seeds uptake of Cd, and there exist some significant or more significant positive correlation between rice seeds Cd contents and Cd concentrations too, and similar significant or more significant negative correlation between rice seeds Cd contents and pH, TOC and CEC in soil. In general, the factors order to impact rice seeds Cd absorption is the available Cd>Cd>pH>TOC≈CEC in soil; (2) As to pollution–free Cd farmland, the Cd carcinogenic health risk index (simplified CR value) increased by more than 85 times, the average amount of Cd concentration in the human hair samples increased by 1.09 times because of eating rice seeds with Cd over standard, and the Cd concentration of the soil solution was significantly increased higher in the farmland distributive area contaminated by Cd. Meanwhile, the rice seeds Cd contents and its relative health risk evaluation are more dependent on the soil effective Cd in those areas contaminated by Cd, it means that there are higher health risks or ecological security risks in those local farmland Cd pollution areas; (3) There are too significant correlation or obvious antagonism in soil between the available Cd and other geochemical factors such as Cd, pH, TOC, CEC and Se, and so on, which comprehensively regulate the Cd absorption of rice seeds , but the available Cd in soil is the most main one; (4) The Cd pollution is generally slight, and its healthy risk level is mainly mild from the cultivated land in Jiangsu province, if we can take appropriate restoration and treatment measures (for example deep tillage, etc.) in order to reduce the Cd, especially effective Cd content in soil, reasonably increase soil organic matter, improve soil pH, etc., block the migration of soil Cd to food chain and human bodies, the Cd polluted risk will completely be controlled, and produce qualified rice seeds to meet the social needs at last.

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