Abstract:This paper is the result of mineral exploration engineering. Objective The Xiarihamu giant magmatic nickel-cobalt sulfide ore deposit in the eastern Kunlun orogenic belt, the largest magmatic nickel-cobalt sulfide deposit discovered in orogenic belt in the world, is the world's largest prospecting breakthrough in the magmatic sulfide deposits area in the past twenty years after the discovery of the Voisey's Bay deposit in Canada. In addition, several large-scale magmatic nickel-cobalt sulfide deposits, such as Shitoukengde, were discovered, indicating enormous prospecting potential in the eastern Kunlun orogenic belt. Methods Accurate zircon U-Pb dating found that the ore-bearing mafic-ultramafic rocks in the eastern Kunlun orogenic belt formed at 425-330 Ma. The ore-bearing mafic-ultramafic rocks are distributed along the north Kunlun fault and the central Kunlun fault. The ore-bearing mafic-ultramafic rocks reflected a large-scale magmatism event. Results The lithofacies of these ore-forming rocks are mainly dunite, pyroxene peridotite, and pyroxenite. The SiO₂, MgO, Al₂O₃, and CaO content ranges from 31.52% to 53.31%, from 7.5% to 39.03%, from 0.1% to 16.01%, and from 0.23% to 13.85%, respectively. On the Harker diagram, the MgO content is negatively correlated with SiO₂, Al₂O₃, Na₂O, and K₂O, respectively. The total amount of rare earth elements is between 6.36×10^-6 and 81.5×10^-6, with an average of 29.92×10^-6. The average LREE/HREE, (La/Sm)_N, (La/Yb)_N, (Sm/Nd)_N, (Gd/Yb)_N value is 5.34, 2.58, 5.99, 0.76, and 1.78, respectively, indicating the degree of differentiation between light and heavy rare earths is high. On the primitive mantle-normalized trace element spider diagram, the ore-bearing mafic and ultramafic rocks have a relatively uniform distribution curve, which are characterized by depletion of high field strength element (Ta, Nb, Ti, and P) and enrichment of large-ion lithophile elements (Rb, Th, and U). The Sr and Nd isotope data indicate that the magma source areas of the Xiarihamu ultramafic intrusion and the Shitongkengde ultramafic intrusions were derived from the asthenosphere mantle. The δ³⁴S value shows a high positive value, revealing that crustal-sulfur contamination played a great role during sulfide saturation. Conclusions Based on the regional tectonic evolution, we believed that the magmatic nickel-cobalt sulfide deposits in the eastern Kunlun orogenic belt are associated with the break-up of the Paleo-Tethys Ocean. This opinion is significant to the ore-forming theory of magmatic nickel-cobalt sulfide deposits in the orogenic belt and could guide the regional exploration of the magmatic nickel-cobalt sulfide deposits.

Abstract:This paper is the result of mineral exploration engineering. Objective The Naruo deposit is one of four super large deposits in Duolong ore district. It is composed of porphyry and breccia type orebodies. Previous researches have focused on porphyry orebody, while the research on cryptoexplosive breccia ore bodies is relatively weak. The temporal relationship between cryptic explosion processes and mineralization remains inadequately studied. The cryptoexplosive breccia is generally produced in a cylindrical shape, with the breccia composed of feldspar quartz sandstone and granodiorite porphyry, and the cement mainly composed of rock powder. Methods This study is to explore the age relationship between the formation and mineralization of cryptoexplosive breccia through chronological evidence. Results Zircon mineralogy shows that the zircon edge of the granite diorite porphyry (NR1) is characterized by dissolution, weak oscillation zone, and incomplete recrystallization. Zircons in cement (NR1) is characterized by fine crystalline form, clear oscillatory zone. The trace element characteristics of these two types of zircons show that the source of two stages of magma is continental crust. The rare earth distribution curves are relatively steep, with enrichment of heavy rare earth elements, loss of light rare earth elements, significant positive Ce and negative Eu anomalies. LA-ICP-MS zircon U-Pb dating results show that the zircon ²⁰⁶Pb/²³⁸U age of granite diorite porphyry is between 117.3 Ma and 125.4 Ma, with weighted average age of (120.8±1.4) Ma, indicating the diagenetic age of 120.8 Ma. The zircon ²⁰⁶Pb / ²³⁸U age of cement is between 113.5 Ma and 119.9 Ma, with weighted average age of (116.4±1.2) Ma, indicating the cryptoexplosive age of 116.4 Ma. Conclusions The results in this study show two stages of diagenesis in Naruo deposit, ~120 Ma and ~117 Ma, respectively. Mineralization occurred between 116 Ma and 117 Ma, rather than ~120 Ma. The chronological data shows that the mineralization and cryptoexplosion are controlled by contemporaneous magmatism, with cryptoexplosion occurring first and mineralization occurring later, and there are differences in the time and space of magma evolution.

Abstract:This paper is the result of mineral exploration engineering. Objective The Qingshan medium-size Pb-Zn deposit is located in the middle of the Weining-Shuicheng metallogenic sub-belt in the southwest margin of the Yangzi Block. The ore-body of the Qingshan deposit is strict controlled by structure and the resource potential is huge. Methods Based on the theory and method of orefield geomechanics, this research has revealed the mechanism of structural ore control by the fine survey of large-scale structural profile, the identification of mechanical properties of typical ore-controlling structures in different directions and the screening of structures in different periods and orders, combined with the characteristics of regional tectonic stress field. Results The results show that the principal compressive stress direction of the mining area since the Indosinian had changed from NE-SW-trending to NW-SE-trending to NE-SW-trending to near EW-trending, sequentially forming tectonic systems of the early NW tectonic belt, the NE tectonic belt, the late NW tectonic belt and the SN tectonic belt in turn. By the analysis of ore-controlling structure and the discussion of its relationship with mineralization, the metallogenic structural system of the north-east tectonic belt has been determined, and the hierarchical ore-controlling regularity of structure is revealed, it is, the northwest-trending Weining-Shuicheng fault and Weining-Shuicheng anticline are the first-grade ore-controlling structures, which control the distribution of the Weining-Shuicheng metallogenic sub-belt or orefield; The NW-trending faults (F₁ and F₂) derived from the Weining-Shuicheng fault, control the distribution of the deposit or orebody group, and are the second-grade ore-controlling structures in the mining area; The interlayer fracture zones between F₁ and F₂ faults directly control the feature and attitude of orebodies, which is the third-grade ore-controlling structure in the mining area; The joint fissures on the sides of orebodies control the ore-veins, which is the fourth-grade ore-controlling structure. Conclusions The regularities of structural classification control are obvious for the Qingshan Pb-Zn deposit, which is mainly controlled by the ore-controlling structures of four grades, and has formed the four types of mineralization styles.

Abstract:This paper is the result of mineral exploration engineering. Objective The Erdaohe silver-lead-zinc deposit is located in the middle section of the Greater Khingan Range. It is a representative large-scale skarn-type deposit discovered in recent years. Studying the origin of this deposit will help guide the exploration of polymetallic deposits in the middle section of the Greater Khingan Range. Methods On the basis of field geological survey, this paper made research on the fluid inclusion in the keatite selected at each stage of mineralization, and discussed the ore-forming fluid and material sources in combination with the S and Pb isotopes of ore and the C and O isotopes of calcite. Results The research result showed the formation of the deposit throughout the process from the skarn stage to the quarte-sulfide stage and to the quartz carbonate stage. According to the temperature measurement result, the inclusion in keatite was mainly characterized by gas-liquid phase, with the homogenization temperature of 310–435℃ at the skarn stage, 195–310℃ at the quarte-sulfide stage and 148–195℃ at the quartz carbonate stage, and the salinity of 11.7%–0.71% NaCleqv at the skarn stage, 12.9%–0.35% NaCleqv at the quartz-sulfide stage and 4.18%–0.35% NaCleqv at the quartz-carbonate stage. The C and O isotopes of calcite indicated a water-rock reaction of the deposit, in which atmospheric precipitation was found. The δ³⁴S value of the S isotope of ore was 5.4‰–10.0‰ from a mixture of sulfurs in magma and strata; as per the characteristic parameter of lead isotope, the source of lead was associated with the orogeny-related magmatism, where the lead was mostly from the upper crust, and slightly from the deep source. Conclusions Accordingly, the ore-forming fluid and material sources were considered the products of the large-scale magmatism caused by the extension after the closure of Mongolia-Okhotsk for orogeny.

Abstract:This paper is the result of mineral exploration engineering. Objective The Manono–Kitotolo spodumene (40%-70%) pegmatite, one of the lithium-cesium-tantalum pegmatite (LCT) in the world, is located at the Mesoproterozoic Kibaran rare metals metallogenic belt in the Democratic Republic of Congo (DRC). The field works revealed that the symbiotic minerals of pegmatite gradually evolved from outside to inside: granite aplite zone(Ⅰ), muscovite-feldspar quartz zone (Ⅱ), quartz albitite zone (Ⅲ), spodumene zone (Ⅳ) and quartz kernel (Ⅴ). Methods In this study, the composition of major elements of mica, spodumene, cassiterite and columbite-tantalite are analyzed by Electron probe X-ray micro-analyzer (EPMA) to bring light on Li-Nb-Ta-Sn mineralization and pegmatitic crystallization differentiation. Results The results show that the content of Rb, Li, and F in muscovite gradually increased from outward (Ⅰ) to inward (Ⅴ), meanwhile the K/Rb gradually decreased. The content of Fe and Rb in lepidolite (V-1) is relatively higher than in muscovite(Ⅱ), which indicating highly fractionated pegmatite inside. Li mineralization mainly occurs in spodumene pegmatite (Ⅳ). Conclusions The grain size of spodumene varies from macro-crystal to coarse grain and medium grain and its principal components keep consistent except Li lost by oxidative leaching, argillation, greisenization and other alterations. Cassiterite with high Nb and Ta is generally formed by greisenization in zone Ⅲ–Ⅳ. Nb-Ta is mineralized in the form of the columbite-tantalite-manganotantalite isomorphism in the zone Ⅱ–Ⅳ, with the development of differentiation, the content of Ta and Mn in minerals increases, while the content of Nb, Fe and Ti decreases and formed Ta-rich and Mn-rich Columbite-tantalite.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Fluorine contaminated groundwater is considered a major public health hazard worldwide. According to statistics, over 200 million people worldwide are at risk of fluorosis, and at least 28 countries have experienced fluorosis incidents caused by drinking high fluoride water. High fluoride groundwater is mainly distributed in underdeveloped areas with drought and water scarcity, and there is a general lack of alternative drinking water sources, making the problem of endemic fluorosis difficult to effectively solve for a long time. Therefore, developing economically feasible fluoride removal technologies has become the key to solving the problem of high fluoride groundwater. Methods Based on the results of literature research and the current global pollution status of fluorinated groundwater, This article summarized and analyzed the research and application cases of fluorinated groundwater both domestically and internationally, taking into account various factors such as research depth, theoretical and application feasibility, removal efficiency, and renewability comprehensively. Results This article systematically introduced the causes and distribution of fluorinated groundwater worldwide, summarized the advantages and disadvantages of existing mainstream fluorinated groundwater treatment technologies, fluoride removal mechanisms and application progress, and analyzed and prospected the existing problems and future development trends. Conclusions Each technology had its own processing advantages and certain limitations, and when selecting and applying specific technologies, it was necessary to comprehensively consider the water quality and target requirements of fluorine contaminated groundwater. At the same time, there were also problems in the current research and development process of groundwater fluoride removal technology, such as lack of targeted service objectives, poor comprehensive treatment efficiency, and significant deviation between the application of adsorption capacity and theoretical values. The coupling application of multiple treatment processes could better leverage the advantages of different treatment technologies and achieved the effect of complementing each other's strengths, which was receiving increasing attention from people. In addition, the joint removal of multiple pollutants and the design and development of new adsorption materials with manually adjustable structures are also important development directions in the future.

Abstract:This paper is the result of geological survey engineering. Objective Inversion tectonics occurred at a specific period in the evolution of worldwide hydrocarbon basins throughout the Mesozoic and Cenozoic eras. It involved the modification and superimposition of early rift basins to induce inversion. With a focus on regional or localized mantle convection inversion, this study attempts to explain the factors that contribute to inversion tectonics in the Earth's crust. Methods Based on geophysical data, with the help of tectonic geology and geophysical research methods, summarize and compare the tectonic inversion events and characteristics of the Mesozoic and Cenozoic basins in the late Cretaceous and Paleogene periods worldwide, study the positive tectonic inversion time of oceanic and continental intraplate rift basins, and establish a mantle convection inversion model for the development of inversion structures. The time of negative tectonic inversion events in adjacent continental plate orogenic belts is synchronous, Study the correlation between basin mountain coupling and local mantle convection units and their variations. Results A large amount of evidence indicates that the time of positive tectonic inversion in continental rift basins is synchronous with the time of negative tectonic inversion events in the adjacent continental plate orogenic belts. For example, the compression and extensional collapse of the Dabie orogenic belt are correspondingly correlated with the extensional rift and contraction inversion of the South Huabei Basin and Hefei Basin, respectively. Although the current evidence may not be exhaustive, the positive and negative inversion tectonics in the rift valleys (mid-ocean ridges) of oceanic plates and the negative inversion tectonics within subduction zones demonstrate a contemporaneous relationship. Irrespective of their origin in rift basins or interplate active zones, inversion tectonics constitute a developmental and evolutionary transition of the tectonic units they represent. Although there is some acceptance regarding the development of these inversion tectonics, the underlying mechanisms that cause their formation in various tectonic units continue to be unclear. Whether it is the reverse structures generated by the reverse tectonic events in the inter plate active zone or the reverse structures generated by the reverse tectonic actions in the intra plate rift basin, all indicate that the tectonic evolution of these structural units has entered a new stage of development and evolution. Conclusions By capitalizing on the correlation between extensively dispersed inversion tectonics across the exterior of the Earth and preceding tectonic features, we propose that inverse flow in mantle convection underlies the dynamic mechanism that triggers the formation of inversion tectonics. In this study, we lay out a model that explains the inverse contraction movements in the lithosphere or crust that occur as a result of mantle convection inversion and the mechanisms that initiate these movements in inversion tectonics. The theory in consideration holds immense importance due to its capability to greatly influence the comprehension and investigation of mantle convection states, dynamics, and their variations. Consequently, this could have a profound effect on the pursuit of mechanisms that cause inverse plate movements.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Hainan Island serves as the largest special economic zone in China and plays a crucial role in the "One Belt and One Road" strategy. Unveiling the groundwater resource endowment of Hainan Island, exploring the distribution characteristics of groundwater resources, and addressing existing environmental geological issues can provide vital support for ecological protection and sustainable development on the island. Methods This study focuses on Hainan Island as its research area. It divides the evaluation units, analyzes the characteristics of groundwater flow fields, evaluates both quantity and quality of groundwater resources, explores their development and utilization prospects while identifying key environmental geological problems. Results The average annual groundwater resource quantity on Hainan Island is approximately 132.05×10⁸ m³/a. Haikou City possesses the highest amount with an average of 11.33×10⁸ m³/a among all administrative areas, whereas Changjiang County has only 0.07×10⁸ m³/a annually which is significantly lower than other regions. Overall, there is poor groundwater quality across Hainan Island with superstandard factors mainly being pH, Al and Mn distributed in coastal plain area and piedmont area. A series of environmental geological problems exist including regional water level decline in Qiongbei Basin, seawater intrusion and soil salinization in Haitang Bay and Yulin Bay (Sanya City) and Banqiao Town (Dongfang City), land desertification in Dongfang City, Changjiang County and Ledong County, geological environmental problems caused by mining. Conclusions Despite rich groundwater resources with large distribution differences on Hainan Island, poor water quality remains a prominent issue along with various environmental geological challenges that need to be addressed for sustainable development purposes. It is imperative to further enhance the investigation and monitoring of hydrogeology and water resources, accelerate the establishment of a new paradigm for conserving and intensively utilizing water resources, as well as promote safeguarding the ecological environment of groundwater.

Abstract:This paper is the result of geological hazard survey engineering. Objective The Yalong River Basin is an important base for forestry, animal husbandry, hydropower, energy, and minority communities in western China. It is of great significance to study the causes and distribution of landslides in the Yalong River Basin to formulate scientific disaster prevention and mitigation strategies and ensure stable economic and societal development. Methods The Zituoxi–Malangcuo river section in a deeply incised valley area of the Yalong River Basin was used as the study area. Basic landslide data were obtained through high-resolution satellite remote sensing interpretation, InSAR analysis, and field investigation. The typical landslide types and their formation mechanisms were summarized and analyzed using an engineering geology analysis method, and the distribution regularity and dominant development range of landslides were revealed by means of GIS spatial analysis and statistical methods. Results (1) A total of 606 landslides were identified in the study area, among which the number of landslides with an area of 10⁴-10⁵ square meters was the most, accounting for approximately 60 percent of the total, and the number of landslides with areas of 10³-10⁴ and 10⁵-10⁶ square meters were essentially equal, accounting for approximately 20 percent of the total respectively; (2) Landslides were divided into five main types, i.e. rainfall-induced type, structure-controlled type, excavation-induced type, river erosion type and water impoundment-induced type, according to the main controlling factors of landslides. The key mechanism responsible for the occurrence of landslides mainly including the weakening effect of rock and soil strength by rainfall and impounded water, the deterioration effect of rock structures and its mechanical properties by fault structures, and the release effect of the anti-sliding and supporting action at the front of slope caused by excavation and river erosion; (3) The dominant terrain ranges for landslide development were of elevation 2500-3500 m, slope angle 15°-35°, and slope aspect NE-E and S-W; (4) The soft metamorphic rock group composed of thin-bedded slate and silty slate was the dominant lithological group for development of landslides, while landslides in the magmatic rock group consisted of hard intrusive rocks such as granite and quartz diorite was the least; (5) the Kangdu fault, Qianbeinima fault, Zhusang fault, Tanggang fault, Huozezhari fault and Nieda fault were found having less impact on the development of landslides, however, landslides developed densely at both sides of the Mazishi fault, Chengzhang fault, Rangong fault and Jida-Milong-Muhui fault and at zones where these faults intersected in the downstream of the study area; (6) A negative correlation between the distribution of landslides and the distance to the river systems can be obviously seen, and a distance to the river systems of 0-0.5 km was found to be the dominant distance range of landslide development. The landslides were macroscopically concentrated along river valleys such as belts. Conclusions The research results provide a significant scientific basis for understanding the causes and regularities of landslides in the deep incised valley of the Yalong River, and preventing and controlling the risk of geohazard chains in the river basin.

Abstract:This paper is the result of mineral exploration engineering. Objective The Yichang phosphate ore in Hubei Province contains associated rare earth elements. Studying their distribution patterns and occurrence states is of significant importance for the recycling and utilization of rare earth elements. Additionally, the comprehensive utilization of associated minerals is expected to become a crucial source for future rare earth ores. Methods This study primarily focuses on rare earth-containing phosphate rocks. Based on systematic sampling, analyses including rock and mineral identification, whole-rock geochemical analysis, XRD diffraction analysis, SEM observation, and LA-ICP-MS testing are carried out. Results The total rare earth element content (ΣREE+Y) in phosphate rock ranges from 63.5×10^-6 to 271.8×10^-6. There are variations in rare earth element contents among different layers or rock types of phosphate rock. Conclusions The content of rare earth elements is notably controlled by rock types, with an increase from dolomite → dolomitic phosphorite → dense massive phosphorite → argillaceous banded phosphorite to mudstone. Trace elements compositions reflect the ancient climate of the Yichang phosphate deposits, characterized mainly by a dry and hot climate, with a slightly warm and humid characteristic in the northwest. Ce anomaly, V/Ni and Y/Ho ratio reflect the oxidation of seawater conditions from the bottom to the top, corresponding to the the Ph₂² to the Ph₁³ phosphogenesis periods. The total rare earth elements content in the Yichang phosphate deposit are relatively low, and mudstone has higher content compared to phosphate rocks, indicating a higher concentration of adsorbed rare earth elements than the isomorphic rare earth elements. The rare earth resources associated with the Yichang phosphate deposit can be comprehensively recovered using appropriate technologies, holding significant importance for the rational utilization of the Yichang phosphate ore resources and economic development.

Abstract:This paper is the result of geological survey engineering. Objective This research aims to analyze the challenges and opportunities facing geological work in the new era, construct a new conceptual framework for geological work, and strive for its healthy, sustainable, and stable development. Methods The research methodology is grounded in the logic of theory and practice, history and future, inheritance and innovation, and development and protection. It puts forth a new conceptual framework for geological science and analyzes its significance. Results The new conceptual framework for geological science mainly includes: (1) Geological Great Foundation Perspective: Strengthening regional foundational geological surveys, enhancing national surveys on resources, environment, ecology, disasters, and spatial national conditions, and deepening the understanding of the Earth. (2) Geological Great Resource Perspective: Conducting comprehensive surveys, development, and protection of all geological elements to maximize the integrated benefits of various geological element resources. Energy and strategic minerals are the core geological resources, and geological work should give top priority to ensuring national energy and strategic mineral resource security. (3) Geological Great Ecology Perspective: Leveraging the role of geological work in promoting ecosystem stability and sustainability, addressing ecosystem issues, or maintaining ecosystem functionality. (4) Geological Great Data Perspective: Making full use of modern information technology to comprehensively realize the digital and intelligent transformation of geological work. (5) Geological Great System Perspective: Considering the Earth and the natural, social and economic systems as a whole in an integrated manner, maintaining the stability of the Earth system and sustainable development of human economy and society, and promoting the transformation of traditional geological science into Earth system science. Conclusions In conclusion, based on the new conceptual framework, geological work in the new era should: Establish the Geological Great Foundation Perspective by enhancing foundational geological survey levels and deepening understanding of the Earth's development and evolution. Embrace the Geological Great Resource Perspective by consolidating traditional geological prospecting work, achieving significant breakthroughs in the new round of prospecting, and expanding into new domains of natural resource investigation and evaluation. Adopt the Geological Great Ecological Perspective by developing ecological geology and providing geological solutions for ecological restoration and protection. Implement the Geological Great Data Perspective by constructing a new paradigm for geological science research and providing intelligent geological solutions to societal needs. Promote the Geological Great System Perspective by developing and improving Earth system science, establishing a new generation of geological science knowledge systems.

Abstract:This paper is the result of geological hazard survey engineering. Objective The loess landslide is a major hidden danger to the safety of human settlements and urban construction in the loess region. Landslide identification is the foundation of other research work on landslide disasters. By utilizing unmanned aerial vehicle oblique photogrammetry three-dimensional (3D) modeling, loess landslides can be intuitively and quickly identified from different dimensions and perspectives, enabling the extraction of feature parameters. This can provide technical support for risk identification and refined risk management research of loess landslides. Methods While researching Heiniugou Village in the southwest of Honghe Town, Pengyang County, Guyuan City, and the Ningxia Hui Autonomous Region, regional loess landslide identification and feature parameter extraction and analysis were carried out using unmanned aerial vehicle oblique photogrammetry data acquisition, 3D modeling, on-site verification, and geostatistical analysis. Results Based on a 3D-real-life model, we located steep walls and their surrounding shapes in the geomorphic depression areas along the valley in the study area. By combining color tone, texture, and micro-geomorphology indicators, we were able to identify all of the loess landslides in the specified region. A total of 23 landslides were delineated, and two non-landslide points were removed through on-site verification. The remaining 21 landslides were densely distributed at the mouth of the main and branch gullies, appearing to slide towards each other from opposite sides of the gullies and exhibiting a mass occurrence. The proportion of large and super-large landslides reached 57.14%. The landslides primarily slid to the southwest (sunny slope) and to the southeast (semi-sunny slope), with relative height differences between 80–120 m. The slopes of these landslides were mostly concave and measured between 20°–30°. The sites of these landslides were mainly sources of vegetation, bare land, or farmland, with a small percentage of the land made up of roads and rivers. Conclusions A 3D-realistic model based on unmanned aerial vehicle oblique photogrammetry can accurately and quickly identify regional loess landslides from multiple dimensions and perspectives and analyze their related feature parameters, which can make up for the shortcomings of current two-dimensional planar remote sensing images. Moreover, this process can also provide data support for research on landslide susceptibility, danger, vulnerability, and risk assessment.

Abstract:This paper is the result of oil and gas exploration engineering. Objective Clarifying the control mechanisms of ancient climate and sea level changes on high-frequency sequences and favorable reservoirs of shallow water carbonate rocks is of great significance for clarifying the genesis and distribution patterns of reservoirs. Methods Microfacies and sequence stratigraphy analysis and geochemical analysis including carbon and oxygen isotopes, major and trace elements with core samples were used. Results The Four types of microfacies including dolomitic lagoon, inter-shoal, grain shoal and tidal flat were identified in the Longwangmiao Formation. The Formation was subdivided into two fourth-order sequences which was regionally correlated. The δ¹³C of the Longwangmiao Formation vertically shows two periodical changes, which indicates two episodes of sea-level changes. This trend of sea-level change is consistent with the change of water depth reflected by the variations of Al₂O₃, TiO₂, B and V values. Using carbon and oxygen isotopes coupled with the well-correlated Mg and Ca values, the estimated Z values and seawater temperaturesduring the deposition of the Formation collectively reflect arid and hot climates and a subtropical marine environment. Systematic variations in MgO/CaO, MnO₂, Fe₂O₃/MnO₂, and Al₂O₃/MgO values indicate a brief transition to warm and humid conditions during the early stages of the two successions, and the Sr/Ba values reflect the marked increase in late-stage seawater salinity during deposition. Conclusions A warm and humid climatecoupled with a rapid rise in sea level, led to the formation of transgressive systems tracts. During the hot and arid climates, rapid deposition of grain shoals and dolomitic tidal flat constitutes the highstand systems tracts. The grain shoal and dolomitic tidal-flat deposits serves as the material basis for high-quality reservoirs. Early dissolution and dolomitization processes occurring during sea-level fall and a hot and arid climate are crucial for reservoir development.

Abstract:This paper is the result of geological survey engineering. Objective The catastrophe and extinctions that occurred in Late Cretaceous is during geological history make the K/Pg boundary become one of the most important geological boundaries in the world. The study of Late Cretaceous–Early Paleocene sedimentary environment evolution of Tarim is helpful to reconstruct the paleogeography in the northern Tethys basins. Methods This study employs the sensitivity index analysis of geochemical elements from core samples of Well PBX1 located in the southwestern Tarim Basin to investigate the environment evolution associated with the K/Pg boundary. Results The climate was hot and dry in Late Cretaceous and transitioned to a short-term warm and humidity environment in Early Paleocene. The paleo-salinity changed from normal marine environment in Late Cretaceous to brackish water or marine to saline lake in Early Paleocene. The salinity reached minimum at the K/Pg boundary. For redox environment, it experienced the oxic to anoxic environment and weak redox environment in Late Cretaceous to a short-term oxic environment near the boundary to a major anoxic and weak redox environment in Early Paleocene. Conclusions The geochemical element sensitivity index of well PBX1 reveals the response characteristics of the catastrophic anomaly event between Cretaceous and Paleocene in the Tarim Basin, which is effective evidence of the of Late Cretaceous–Early Paleocene sedimentary environment evolution in the northern basins of Tethys Ocean.

Abstract:This paper is the result of geological survey engineering. Objective Recently, more studies show that the sediment recycling plays an important role in the inversion of the tectonic events, the identification of sediment source areas and the sources of eolian dust. Methods In order to explore the Cenozoic sediment recycling in the Qaidam Basin, this paper conducts thin section identification, detrital framework grain composition and heavy mineral analysis of sandstones, and major, trace, and rare earth elements, and clay minerals of mudstones of the Dahonggou section in the northern Qaidam Basin. Results The major, trace, and rare earth elements of mudstones are similar to the standard distribution patterns of upper continental crust (UCC) and chondrite, which may indicate that the sediments have been completely mixed or recycled; Sandstone is mainly composed of quartz, and a small amount of feldspar and lithic grains which are mainly composed of sedimentary ones. Sandstone framework detrital mode indicates a provenance type of recycled orogenic belt; The content of stable heavy minerals and ZTR (zircon, tourmaline, and rutile) index suddenly decrease in the upper portion of the section, indicating a closer source area to the section during the late stage; On the contrary, the contents of chlorite, which is easy to decompose, suddenly increase in the upper portion of the section. This observation might also shows that its source area was closer at this time. Conclusions Based on the analysis of sedimentary facies, sandstone thin section and detrital zircon U-Pb age, it was suggested that the Jurassic and Cretaceous sedimentary rocks in the thrust-fold belt of the northern Qaidam Basin experienced large-scale sediment recycling and were one of the important provenances of the Cenozoic strata in the basin; Then, the fission-track analyses of detrital apatite show that the Cenozoic sedimentary rocks in the northern margin of the Qaidam basin have experienced significant recycling at 9-7 Ma; After about 3 Ma, with fold-thrusting propagating into the basin center, the uplifted sedimentary rocks in the northern basin experienced recycling, which form the important provenance of the Quaternary lakes within the center of the Qaidam Basin and of the Quaternary loess deposits in China Loess Plateau.

Abstract:This paper is the result of geological survey engineering. Objective The Ediacaran Dengying Formation in the Central-Hubei Platform of the Yangtze region hosts abundant stromatolites, yet there is a lack of systematic reports on them. This study aims to address this gap by identifying stromatolite types in the Dengying Formation at the Baiguoping section in the southwestern part of the platform. Through this, we analyze the sedimentary environment, aiming to elucidate the influence of the ancient environment on stromatolite distribution. The insights gained serve as a valuable reference for future research on Ediacaran stromatolites in the Central-Hubei Platform. Methods Utilizing section surveys and microscopic observations, this study identifies stratiform and columnar stromatolites in the dolostones of the Ediacaran Dengying Formation at the Baiguoping section. Stratiform stromatolites include flat-laminated, Stratifera, and wavy-laminated forms, columnar stromatolite see the Baicalia form genus. Results In the southwestern Central-Hubei Platform, these stromatolites are associated with various environments: Periodic exposure settings for the flat-laminated and Stratifera forms, lagoon environments for the wavy-laminated form and intertidal to upper subtidal zones for the columnar stromatolites. Published data reveals that during the deposition period of the Ediacaran Dengying Formation, stratiform stromatolites were abundant on the Yangtze Platform, meanwhile columnar and other stromatolite forms were rare, indicating limited morphological diversity. Conclusions The scarcity of stromatolite variations can be attributed to widespread shallow water niches and locally deeper water niches resulting from long-term stable tidal flat environments in the Yangtze Platform.

Abstract:This paper is the result of geological survey engineering. Objictive The exploration of the petrogenesis and tectonic setting of the Kafang diabase is crucial to know about the tectonomagmatic evolution in Gejiu area. Methods Based on LA-ICP-MS zircon U-Pb age, whole-rock geochemistry and Sr-Nd-Pb isotope analysis, the formation age, geochemical characteristics and geological significance of Kafang diabase dike are studied. Results Zircon U-Pb dating shows that the age of Kafang diabase is 77 Ma. Inherited zircon ages (2409 Ma, 2616 Ma, 290 Ma) indicate tectono-thermal related Neoarchean and Paleoproterozoic metamorphic basement and the magmatic activity in Early Permian in Gejiu area. The Kafang diabase belongs to the shoshonite series with the characteristics of low SiO₂ content and high K₂O, TiO₂, MgO contents. In primitive mantle normalized trace elements diagram, these samples show similarities with OIB and enriched in LILEs (such as Rb, K, Sr), depleted in HFSEs (such as Nb, Ta, Zr, Hf). High initial ⁸⁷Sr/⁸⁶Sr ratios (0.70782-0.70791), positive εNd(t) values (2.07-2.29) and initial Pb isotopic compositions (²⁰⁶Pb/²⁰⁴Pb=18.286-18.465, ²⁰⁷Pb/²⁰⁴Pb=15.668-15.717, ²⁰⁸Pb/²⁰⁴Pb=37.763-38.830) indicate the enriched mantle (EM2) source. Conclusions The petrogenesis of Kafang diabase is that the upwelling of asthenosphere in an extensional setting induced 5%-15% partial melting of garnet lherzolite at a depth of 60-120 km in the lithospheric mantle. The new-formed magma with characteristics of EM2 consists of the primary magma of the Kafang diabase. During the ascent of magma, contamination of the lower crust occurred accompanied by weak fractional crystallization, and then formed the Kafang diabase.

Abstract:This paper is the result of environmental geological survey engineering. Objective Lianjiang Dam is located in Huishui County of Guizhou Province. To find out the Se distribution features of soil in Lianjiang Dam, 337 surface soil samples, 4 soil mother rock samples and 16 soil profile samples were collected, and the contents of Se, nutrient elements and heavy metal elements such as As、Cd、Cr、Cu、Hg、Ni、Pb、Zn were analyzed and determined. Methods The contents of Se, nutrient elements and heavy metal elements in the samples from surface soil, soil mother rock and soil profile were compared and the Se distributions features of soil were evaluated based on correlative analysis method. Results It showed that the soil in this area were acidic with the contents of Se in the soil from 0.19 to 3.65 mg/kg. The contents of nutrient elements such as P, B and SOM in the soil were high. The average Se values of surface soil of different mother rocks in this area appeared the transformation law: Upper Carboniferous limestone > Middle Permian Maokou Formation limestone > Middle Permian Qixia Formation limestone > Upper Cretaceous Maotai Formation sandstone > Middle Triassic Luolou Formation limestone > Middle Triassic Bianyang Formation clastic rocks. The Se contents of soil profile in this area decreased with the depth deepening. Conclusion The Selenium-rich soil is abundant in this area, mainly of medium and high. The area of selenium-rich soil is about 42.94 km². There is a significant positive correlation between Se and SOM, while a significant negative correlation between Se and K₂O, and pH in soil.

Abstract:This paper is the result of hydrogeological survey engineering. Objective The Beiluo River Basin is an important secondary tributary of the Yellow River. Research on groundwater quality in typical tributary basin of theYellow River is of significant for ecological protection and high-quality development. To ensure local drinking water safety, we systematically identified status of groundwater quality and delineated inferior groundwater region in the Beiluo River Basin. Methods Besides, based on analysis of D-¹⁸O isotope in groundwater, characteristics and evolution mechanism of groundwater hydrochemistry were studied and effects of hydrogeological condition and anthropogenic activities on groundwater hydrochemistry were revealed. Results Groundwater hydrochemical composition was jointly affected by rock weathering and evaporation concentration, part of which was influenced by anthropogenic activities. D-¹⁸O isotope composition suggested that evaporation concentration is the major influence factor of groundwater hydrogeochemistry. Conclusions Leaching of soluble minerals such as gypsum halite in clasolite and evaporation concentration of pore water in Cenozoic faulted basin in the downstream caused salt accumulation and high TDS in groundwater in the upstream and downstream, respectively. Hydrochemical composition of groundwater in Ordovician karst aquifer and Cenozoic faulted basin aquifer was mainly controlled by evaporites and anthropogenic activities. While hydrochemical composition in Cretaceous aquifer and Carboniferous-Jurassic aquifer was mainly controlled by rock weathering (especially silicate rocks and evaporite) and less affected by anthropogenic activities. Moreover, groundwater in the upstream and downstream was significantly affected by industrial and mining activities. While groundwater in the midstream is of good quality due to less influence of industrial/mining activities, agricultural activities and domestic wastewater.

Abstract:This paper is the result of agricultural geological survey engineering. Objective Selenium (Se) intake in the human body primarily originates from the food chain, mostly derived from soil. The research aims to establish a scientific and rational evaluation system for the development and utilization of selenium-rich land due to the limited and valuable selenium-enriched soil resources in China. Methods This study focuses on the Guanzhong region, particularly Lintong District, integrating geophysical survey findings with assessment criteria reflecting agricultural land's natural conditions and infrastructure levels. The developed evaluation system encompasses five major categories and twelve indicators, including site conditions, soil selenium content, physicochemical properties, soil quality, and land management. Moreover, suitability assessment for selenium-rich land development and utilization was conducted in Lintong District as a case study. Results The land in Lintong District was categorized into five levels: highly suitable, suitable, moderately unsuitable, unsuitable, and highly unsuitable. The highly suitable and suitable development areas covered 248.35 km², mainly distributed in the northern areas of Lintong District, as Xinshi Town, Liyang Town, Xuyang Town, Xiangqiao Town, and the central-eastern parts of Hezhai Town. Analysis of wheat Se content and Se enrichment ratios within different suitability evaluation zones revealed a strong correlation between the suitability of selenium-rich land and the degree of selenium enrichment in wheat. Conclusions The developed evaluation system demonstrates significant scientific guidance and exemplary significance for the utilization of selenium-rich land resources. It underscores the need for a systematic approach to efficiently develop and utilize these resources, emphasizing the critical link between soil suitability and the selenium enrichment of agricultural produce.

Abstract:This paper is the result of coastal geological survey engineering. Objective Microfossils, especially pollen, spores, and dinoflagellate cysts, as direct indicators or proxies, provide significant information on geological environment. Therefore, palynological analysis has an important role in restoration and reconstruction of vegetation history and sea-level fluctuations, which provides information from the sediment cores, especially in alluvial coastal plain regions. Methods In this study, we carry out analyses using detailed palynological records of pollen, spores, freshwater algae, marine dinoflagellate cysts, and foraminiferal organic linings from Borehole HLL01 on the southern coastal plain of Laizhou Bay, Bohai Sea, northern China. Results The results provide valuable information on vegetation history and sea-level fluctuations since the Late Pliocene. Large amounts of terrestrial herb pollen (75.13%; mainly composed of Chenopodiaceae, Artemisia and Poaceae) were identified at Borehole HLL01, suggesting that coastal steppes flourished in the study area and its adjacent areas, and a cold and dry climate than the present during the Late Pliocene to Early Pleistocene, ca. 6.8-1.6 Ma. After that, the steppe areas began to shrink, and the transition of coastal steppes to forest grasslands occurred in the Early-Middle Pleistocene, ca. 1.6-0.6 Ma, indicating a warm and humid climate. A sharp increase in freshwater algae indicates that large rivers’ discharge had been injected into the study area, or large lakes were formed. Afterward, relatively cool and dry climatic conditions appeared, with little precipitation, and a relatively significant transgression event revealed by dinoflagellate cysts and foraminifera organic linings, and forest grassland vegetation was distributed in the study area and its adjacent areas, during the Middle Pleistocene to Holocene, ca. 0.6-0.004 Ma. Conclusions Three ancient plants have occurred and the sea level fluctuations occurred since the Late Pliocene (6.8-0.004 Ma) in the Laizhou Bay.

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