Abstract:This paper is the result of mineral exploration engineering. Objective The middle part of Nanling metallogeny belt, an important resource base of non–ferrous metal, energy minerals, non–metallic minerals, groundwater and gas minerals, has superb metallogenic geological conditions, abundant mineral types and complex mineralization types. In depth understanding of the metallogenic law is the key to carry out regional metallogenic theory research and to achieve prospecting breakthrough. Methods In this paper, the metallogenic regularity and prospecting direction of the middle part of Nanling metallogenic belt are summarized and studied on the basis of the abundant previous data. Results The main ore–controlling geological conditions are identified and the two ore–controlling structure frameworks are determined in the middle part of Nanling metallogeny belt. Depending on the characteristics of mineral resources, the metallogenic characteristics, rules and evolution are summarized, and regional magmatic evolution and metallogenic potential are further discussed. Moreover, 50 minerals, 872 ore deposits and 15 deposit types developed in the middle part of Nanling metallogeny belt are sorted out, and the predominant magmatism characteristics, evolution and metallogenic potential are discussed. Conclusions The prospecting of the middle part of Nanling metallogeny belt should be focused on: comprehensive prediction of U ore near the contact zone, sliding overburden structure of coal mine, metamorphic and weathering type Fe ore in pyrite mining areas, comprehensive prediction and exploration of missing types of non–ferrous metals, exploration new types of rare and scattered metals and independent Au ore, protection and exploitation the associated gem mine. Two important prospecting potential areas, which include Qitianling and its surrounding, and Lechang–Shaoguan–Wengyuan, are proposed for the key region for prospecting breakthrough of tungsten, tin, molybdenum, bismuth, copper, zinc, uranium, rare earth, etc.

Abstract:This paper is the result of mineral exploration engineering. Objective Hornfels, as an important part of the Jima porphyry copper polymetallic system, is host rocks and a lithologic trap for ore–forming fluid. However, the origin of tourmaline in hornfels is unknown, which restricts the further understanding of the mineralization. Methods We carried out detailed drilling logging, petrographic observations and major element analyses of tourmaline with distinctive occurrences in hornfels from the Jiama deposit to elucidate the genesis of tourmaline and evolution of magmatic hydrothermal fluids. Results Four types of tourmalines in hornfels from the Jiama deposit have been identified in this study: 1) Tur–I, tourmaline occurring as cement in hydrothermal breccias; 2) Tur–II, quartz + tourmaline ± pyrite vein; 3) Tur–III, tourmaline ± pyrite ± chalcopyrite vein; 4) porphyritic tourmaline ± pyrite. Tourmaline with distinctive occurrences in hornfels, which belongs to alkali group and dravite–schorl solid solution series, has a wide range of Al₂O₃, Fe/(Fe+Mg) and Na/(Na+Ca). ^X□Al(NaMg)_–1, Fe²⁺Mg_–1 and Fe³⁺Al_–1 exchange dominates the substitutions of Tur–I–IV. Conclusions Tourmaline in hornfels with complicated zoning texture has a very variable compositions, indicating that the tourmaline is caused by different degrees of mixing of magmatic hydrothermal fluid and formation fluid, and the water–rock interaction between magmatic hydrothermal fluid and reduced hornfels may play an important role on the mineralization. The various textures and compositions of tourmaline with distinctive occurrences in hornfels from Jiama record some detailed information related to evolution of magmatic hydrothermal fluid, and can provides evidence for understanding the mineralization.

Abstract:This paper is the result of mineral exploration engineering. Objective The Chiwawu copper–molybdenum deposit is located in the northern Taihang Mountains metallogenic belt, which is one of the key exploration zones as part of the ‘Prospecting Breakthrough Strategy’ implementation. However, the mineral exploration in this deposit has entered a bottleneck stage currently. This study aims to provide new target areas for the deposit. Methods Identify exploration indicators based on a comprehensive interpretation of the geological, geophysical, geochemical, and remote sensing data of the deposit. Results The deposit was formed in the Early Cretaceous and exhibits similar mineralization characteristics to typical porphyry deposits, indicating a close association with deep–seated granite porphyry. Circular structures are widely distributed in the study area, with large circular structures associated with the Chiwawu coplex and other concealed intrusions, while small to macro–sized circular structures are associated with cryptoexplosive breccias or concealed small stocks. There is a strong spatial correlation between the geochemical anomalies and alteration zones discriminated using the remote sensing data, which can serve as an effective indicator for mineralization. Four exploration target areas are delineated. Conclusions Within the Chiwawu complex, locating the cryptoexplosive breccias and concealed granite porphyry is crucial for Cu and Mo prospecting, while in the surrounding area prospecting, the focus is recommended to be on Cu, Au, and Ag.

Abstract:This paper is the result of mineral exploration engineering. Objective Fluorite is an important mineral resource in modern industries, and it is listed as the top priority of nonmetallic mineral prospecting in Henan Province. In recent years, several geological prospecting units in Henan Province have been engaged in prospecting fluorite in the Heyu area of Luanchuan County, and the Madiu fluorite deposit is the first proven large deposit, with an estimated amount of 8.84 million tons of fluorite ore and 4.76 million tons of CaF₂ mineral. The average grade of CaF₂ is 53.83%. The east–west ends of the ore body are not closed along the strike. Therefore, summarizing the geological characteristics is of great significance for guiding the prospecting activities in this area. Methods Based on the general and detailed investigation of the Madiu fluorite deposit in the last five years, the metallogenic geological conditions, geological characteristics, quality characteristics, and prospecting indicators are systematically summarized. Results The Madiu fluorite deposit is the largest single fluorite ore body in Henan and its surrounding provinces. There are many ore veins of different sizes, which are equal spaced along the trend and are nearly parallel along the strike. There are also many fluorite ore bodies scattered around. Conclusions The Madiu fluorite mineralization is related to granites and NW–trending structures, and the deposit type is medium–low temperature vein deposit with fissure filling in silicate rock.

Abstract:This paper is the result of mineral exploration engineering. Objective Sidaogou deposit is located in the Au–Cu–W ore concentrated area of the eastern Yanbian, and is a typical quartz vein type scheelite deposit. This paper studied the property and source of the ore–forming fluids and genesis of the deposit, to promote the understanding of the quartz vein type scheelite deposit in NE China and further prospecting. Methods This paper presents the petrographic observation, microtemperature measurement and Laser Roman spectral analysis of the fluid inclusion, C–H–O isotope analysis and rare earth element compositions for the Sidaogou scheelite–quartz veins. Results Petrographic observation indicates that the liquid–rich, daughter minerals–bearing, gas–rich, and CO₂–bearing inclusions coexisted in the quartz, and all the types of fluid inclusions have similar homogenization temperatures, which indicate that they belong to boiling fluid inclusions. The lowest homogenization temperature of the gas–rich fluid inclusion (283℃) represents the ore–forming temperature. Laser Raman spectral analysis indicates that the gas phases in the fluid inclusions include H₂O and CO₂, as well as minor CH₄ and N₂. Scheelite grains yield “hump” type REE patterns with weak negative δEu anomalies. Conclusions The results indicate that the ore–forming fluids of the Sidaogou scheelite deposit are oxidizing NaCl–H₂O–CO₂±CH₄±N₂ fluids with high–medium temperature. C–H–O isotopic data indicate that the ore–forming fluids were mainly derived from magmatic water, mixed with a little bit of meteoric water, and the carbonaceous material resulted from oxidation of organic material in the sedimentary rocks from the Wudaogou Group. Therefore, Sidaogou scheelite deposit belongs to mesothermal vein type scheelite deposit, and the fluid boiling induced the precipitation of scheelite.

Abstract:This paper is the result of mineral exploration engineering. Objective Chromium, as one of the critical minerals in China, supports the development of China's emerging industries. China is short of chromium ore resources, poor resource endowment and low production. For a long time, the chrome ore has been highly dependent on foreign countries. It is important for the healthy and sustainable development of chromium ore resource industry to study the future supply and demand of chrome ore. Methods This paper summarizes the geology, spatial distribution, resource reserves and other characteristics of chromium deposits in China, and analyzes the historical data of the development and utilization of chromium resources in China. On this basis, the chromium supply in China is analyzed and predicted. And the stainless steel production and chromium demand in 2021–2035 in China are predicted under three scenarios, namely high, medium and low, by using chromium sector consumption method, S–curve of per capita stainless steel production, ARIMA model method (stainless steel) and other prediction methods. Results (1) The production of chromium in China will be 150,000–200,000 tons, and the secondary chromium will be 1.82–2.84 million tons from 2021 to 2035; (2) Under the medium scenario, the demand for chromium in China from 2021 to 2035 is projected to follow an increasing and then decreasing trend, with the peak occurring in 2030. And, the per capita stainless steel production will keep an upward trend from 2021 to 2030, and will reach its peak in 2030. At that time, the per capita stainless steel production will be 35 kg, the stainless steel production will be 50.05 million tons, and the chromium demand will be 9.45 million production; After that, it will gradually decline. By 2035, the per capita stainless steel production will drop to 30 kg, the stainless steel production will be 42.8 million tons, and the chromium demand will be 8.07 million tons; (3) The supply and demand situation is severe in China from 2021 to 2035, and the external dependence rate of chromium will exceed 99%. If secondary chromium production is used, the external dependence rate of chromium will drop to more than 69%. Conclusions The supply and demand situation of chromium in China will still be severe, and the gap still needs to be supplemented by a large number of imported ores from 2021–2035. On this basis, it is proposed to strengthen the geological exploration of chromium ore, strive to achieve a breakthrough in chromium ore prospecting, attach importance to the secondary chromium recovery, develop the secondary chromium recovery industry, strengthen the reserves of chromium ore products, ensure the safety of chromium ore product supply, optimize the structure of chromium ore products, and make use of overseas chromium ore resources and products. The conclusions and suggestions formed in this paper are of practical significance to the compilation of mineral resources planning and the formulation of chromium mineral resources management policies in China.

Abstract:This paper is the result of environmental geological survey engineering. Objective As a pivotal component of the global carbon cycle, the role of soil inorganic carbon in arid regions as a carbon sink cannot be ignored. Methods This paper reviewed a large amount of literature related to soil inorganic carbon in arid regions at home and abroad, and focused on the confirmation of soil inorganic carbon carbon sink, carbon pool composition, source identification, and carbon sink influencing factors in a systematic summary. Results The role of inorganic carbon carbon sinks in arid regions was confirmed along with the study of negative fluxes in arid regions, but the composition of its carbon pool is very complex, including liquid–phase carbon pools and solid–phase carbon pools. The liquid–phase reservoir is mainly in the form of Dissolved Inorganic Carbon in the groundwater of the arid regions; the solid–phase reservoir is the solid–phase Soil Inorganic Carbon in the soil profile, which is divided into Lithogenic Carbonate and Pedogenic Carbonate according to different genetic sources, and the latter is subdivided into carbonaceous soil–forming carbonate and silicic soil–forming carbonate . The SPC in PC has a real long–term stable carbon sink. The factors influencing inorganic carbon sinks are complex, including natural factors: climate, soil properties and depth, biological effects, soil–forming parent material, soil organic matter, etc.; anthropogenic factors: land use and land cover, agricultural management measures (irrigation and fertilization), etc. Conclusions Soil inorganic carbon in drylands is extremely important for global carbon sequestration, and current research focuses on the identification of soil inorganic carbon sources, confirmation of carbon sink strength and quantification of carbon sequestration potential, as well as the clarification of influencing factors and assessment of the possibility of human intervention. Driven by the goal of achieving carbon peaking and carbon neutrality goals, the identification of soil inorganic carbon sources and influencing factors will be a research hotspot in the future within the global region, especially in arid and semi–arid regions. It will be a breakthrough point to solve the scientific problem of "Missing carbon sink", which will greatly promote the research of Global Carbon Cycle.

Abstract:This paper is the result of environmental geological survey engineering. Objective The continuous accumulation of heavy metals in soil has potential harm to groundwater, but there is no quantitative method to evaluate the harm of heavy metals in soil to groundwater in previous studies. Methods Based on the theory of groundwater circulation and solid–liquid equilibrium, a simple and easy–to––use flux model of soil heavy metals into groundwater is constructed in this paper. On the basis of evaluating groundwater environmental capacity, an innovative method for evaluating the harm of soil heavy metals to groundwater is proposed. Results The application was carried out in Hunchun Basin as an example, and the results showed that the fluxes of soil heavy metals into groundwater in the study area were Zn, Cu, As, Pb, Cd, Ni, and Hg in descending order, and that the heavy metals of the groundwater in most of the areas could not reach the limit of the environmental capacity within 10 years, and the damage level in most towns and villages to groundwater was moderate or below. Conclusions Through this evaluation method, the flux of heavy metals in soil into groundwater can be calculated simply and quickly, the residual capacity of heavy metals in groundwater can be determined, and the harm of heavy metals in soil to groundwater can be evaluated, which provides support for relevant departments to carry out environmental protection of soil and groundwater, and provides reference for relevant scholars to carry out similar research.

Abstract:This paper is the result of environmental geological survey engineering. Objective The objective of this research endeavor is to evaluate the ecological asset value, thereby facilitating an enhanced comprehension of the foundational aspects of regional ecological resources. By furnishing a scientific foundation for the establishment of comprehensive natural resource management systems and the effective implementation of ecological compensation policies, this study assumes a pivotal role in promoting the realization of the value of ecological products. Methods This study presented a comprehensive approach for assessing the value of ecological assets. The methodology encompasses the integration of diverse data sources such as land use, remote sensing imagery, meteorology, geochemistry, and socio–economic indicators. Through this integrated framework, evaluations were performed to determine the stock, quality, and value of ecological assets. Furthermore, geographical detector tool was employed to investigate the spatially varying factors that influence the values of ecosystem services. Results The ecological asset quality in the Xin'an River Basin is primarily in the good and moderate levels, accounting for 80.96% and 10.25%, respectively. The comprehensive index of ecological asset stock in the Xin'an River Basin in 2020 is 0.77. Wetland, forest land, and cultivated land occupy prominent positions. The value of ecosystem service is estimated at 133.448 billion yuan, with forests and water resources having the highest proportion Slope, elevation, and annual precipitation are the main driving factors of spatial differentiation in the value of ecosystem services. Conclusions Xin'an River Basin has a high ecological asset value. Forests and water resources are the main carriers of ecosystem services in the basin. The impact of natural endowments on the spatial differentiation of ecosystem service values is greater than that of socio–economic factors.

Abstract:This paper presents the results of hydrogeological survey engineering. Objective As an important water supply source in Beijing, karst groundwater plays an irreplaceable role in the security of the urban water supply and the improvement of the ecological environment. Methods Based on the analysis of 278 karst groundwater samples systematically collected in Beijing in June 2021, both single-factor quality evaluation and comprehensive quality evaluation of karst water were carried out in different karst water systems. Additionally, the organic indicators were statistically counted and analyzed for the first time. Results (1) The average values of pH, TDS, and TH of karst water in Beijing are 7.69, 334.77 mg/L, and 262.01 mg/L, respectively. These results indicate that the groundwater is weakly alkaline, with low salinity and low hardness, suggesting generally good water quality. (2) The detection rates for unconventional indicators, in descending order, were benzo[a]pyrene (4.32%), tribromomethane (3.60%), and total xylene (2.52%). These contaminants warrant significant attention. (3) The results of groundwater quality evaluation show that the overall proportion of karst water quality falling within Classes I–III is 82.01%, while Classes IV and V constitute 17.99%. The exceedance points are primarily located at the interface between mountainous and plain areas, with the primary exceedance indicators being Fe, TH, NH₃-N, Mn, SO₄^2–, F^–, and NO₃-N. Conclusions As the important water source supply area and ecological protection zone in Beijing's ecological conservation area, karst groundwater in the study area plays a very important role for ensuring the safety of the capital's water supply and protecting the ecological environment. In the future, to practically protect karst groundwater, measures such as increasing vegetation cover to enhance water conservation and recharge capacity, strictly controlling point source and non-point source pollution to reduce pollutant inputs, continuously optimizing the monitoring network for early warning, and broadly promoting public awareness and education on ecological protection should be implemented systematically.

Abstract:This paper is the result of environmental geological survey engineering. Objective This study aims to elucidate the migration patterns of characteristic pollutants, i.e., chromium (Cr(III)) and ammonium nitrogen (NH₄⁺–N), from tannery wastewater in the vadose zone of the North China Plain and to assess the potential risks of soil and groundwater contamination. Methods The adsorption and transport characteristics of Cr(III) and NH₄⁺–N in typical silts were examined using soil column leaching experiments. Additionally, the vadose zone water flow and solute transport model established by Hydrus–1D was utilized to simulate and predict the time required for NH₄⁺–N to reach the groundwater table at a depth of 0.5 m under continuous infiltration conditions, along with changes in concentrations at various depths. Results Under a constant head of 3 cm and a pollutant solution concentration (Cr(III) 20 mg/L and NH₄⁺–N 250 mg/L) maintained for 120 d, the vertical migration distance of Cr(III) in the soil column was less than 10 cm, predominantly in the residual form (73%), with no detection of Cr(VI). By contrast, NH₄⁺–N exhibited a stronger migration capability, penetrating a 50 cm thick silt column within 40 d. Under high salinity conditions (EC: 10.08 ms/cm), the migration of NH₄⁺–N was controlled by adsorption, with a K_d of 25.87 L/kg, and no nitrification occurred. After 150 d of continuous leaching, NH₄⁺–N migrated to the groundwater table (18 m depth) with concentrations exceeding the Class III Groundwater Quality Standard (0.5 mg/L, GB/T 14848–2017). By 223 d, it completely penetrated the vadose zone, severely contaminating the groundwater. Conclusions In high–salinity tannery wastewater, Cr (III) exhibits limited migration capacity in silt and is difficult to oxidize to Cr (VI), posing a lesser threat to groundwater. Conversely, NH₄⁺–N rapidly migrates to the groundwater surface with water flow, posing a serious threat to groundwater safety.

Abstract:This paper is the result of agricultural geological survey engineering. Objective The study aims to delineate the distribution characteristics and geological origins of selenium in the soil of the Chengde area, providing a scientific foundation for the exploration and effective utilization of selenium in the region's soils. Methods Geological surveys were conducted to identify the types of soil parent materials in the area. The content of selenium and multiple elements in 553 soil samples and 66 rock/ore samples were determined using X–ray fluorescence spectrometry, inductively coupled plasma emission spectrometry, and the Kjeldahl nitrogen method. Data analysis was performed using SPSS software, with geological genesis being interpreted in conjunction with geological processes. Results The soil parent materials in the Chengde area are categorized into nine distinct groups. The selenium content in surface soils ranges from a minimum of 0.016 mg/kg to a maximum of 0.743 mg/kg, with an average value of 0.17 mg/kg. This average selenium content is half of the national average, indicating a state of deficiency. The average selenium content in iron ore, gold ore, and lead–zinc ore are 0.860 mg/kg, 1.233 mg/kg, and 3.365 mg/kg, respectively, significantly higher than those in the tailings and wall rocks associated with various ores. Conclusions The overall selenium content in the soils of Chengde is very low, primarily determined by the soil parent materials, with distribution patterns influenced by geological formations. Selenium–rich soil areas are notably concentrated in the south of Longhua County (Area A), the southern parts of Chengde City (Area B) including Shuangluan and Shuangqiao districts, and the eastern part of Kuancheng County (Area C). Area C is characterized as “rock weathering type”, associated with the presence of selenium–enriched primary carbonate rocks and carbonaceous mudstones. Area B is classified as “mineralization associated type”, linked to the symbiotic relationship between selenium and metal sulfides during lead–zinc mineralization, as well as the substitution relationship between selenium and sulfur. Area A is defined as “river sedimentary type”, relating to the dynamics of river and lake sedimentation and the adsorption by organic matter. The selenium–rich region in southern Chengde possesses a natural advantage for developing a forest and fruit economy. Weichang County, situated in a low selenium environment, is identified as a contributing factor in the prevalence of Keshan disease and other endemic conditions.

Abstract:This paper is the result of Agricultural geological survey engineering. Objective Potassium is one of the three essential nutrients for plants and an important factor influencing soil fertility. Distribution characteristics of potassium in topsoil of cultivated land in Tongzi County was carried out to provide environmental geological background reference for county agricultural development and ecological environment evaluation. Methods Taking Tongzi County as the research area, this paper systematically discussed the content, spatial distribution, grade status and influencing factors of potassium and available potassium in surface soil samples obtained from cultivated land quality geochemical survey. Results The content of potassium in topsoil of cultivated land in the study area ranged from 2.50 to 49.60 g/kg, with an average of 20.30 g/kg, and the overall potassium content is mainly in medium, relatively rich and rich grade. The content of available potassium ranging from 22.40 to 684.00 mg/kg, with an average of 112.66 mg/kg, and the content of available potassium was in moderate to relatively deficient grade. Potassium and cation exchange capacity are positively correlated with available potassium, while the pH is negatively correlated with available potassium in topsoil of cultivated land. Conclusions The distribution of potassium and available potassium in topsoil of cultivated land in the study area is uneven. The geological factor plays an essential role in the content of potassium in topsoil of cultivated land, and the distribution of high–value and low–value of potassium is well integrated with the stratigraphic and tectonics of the study area. The content of potassium in topsoil of cultivated land is mainly controlled by the parent rock, which is relatively low in the limestone and forming soil. Large–scale potassium depletion in the southern part of the study area is related to the widely distributed of the Permian Maokou Formation limestone.

Abstract:This paper is the result of agricultural geological survey engineering. Objective Most of the food crops are low in zinc and it is difficult for humans to obtain sufficient zinc through the normal diet. Land quality geochemical survey, as nature–based solutions, is the best scheme to find the suitable region for cultivating zinc–rich crops. Methods This study takes agricultural land in Weining Plain of Ningxia as the research region, geochemical data of surface soils, wheat seeds and rhizosphere soils of agricultural lands were obtained through land quality geochemical survey, the geochemical characteristics of zinc in surface soil and wheat seed were studied, and the influencing factors of zinc enrichment in wheat seed were explored. The interval value of zinc content in zinc–rich wheat was calculated based on the nutritional structure of healthy diet in China and the reference intake of dietary nutrients in residents. Results In the research region, the range of zinc content in surface soils was 25.1 mg/kg to 102.0 mg/kg, and the background value of surface soil was 61.4 mg/kg. The range of zinc content in wheat seeds was 13.34 mg/kg to 37.78 mg/kg, the average content was mg/kg, and the averagebio–enrichment coefficient was 0.41. The range of zinc content in Zn–enriched wheat was 26.5 to 50.0 mg/kg, and the proportion of zinc enriched wheat seeds in the research region was 36.7%.Based on the neural network model, we predicted that the region of agricultural lands, which were suitable for cultivating zinc enriched wheat in Wei Ning Plain, was 242.86 km². Conclusions The spatial distribution of zinc in the surface soil of the research region was relatively uniform and was mainly controlled by soil parent materials. The zinc enrichment ability of wheat seeds was medium. The zinc enrichment ability of wheat seeds is significantly correlated with Zn, Fe₂O₃, K₂O, SiO₂/Al₂O₃ in rhizosphere soils. Neural network model can construct a reliable prediction model, which can be used as a method to explore suitable cultivating regions for beneficial micronutrient enrichment crops through geochemical survey data.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Higharsenic (As) groundwater occurred in the west of Hetao Basin. Investigating the spatial distribution and occurrence characteristics of As in aquifer sediments and studying the enrichment mechanism of As ingroundwater are beneficial to ensure the safety of water for local residents. Methods Twenty five sediment samples from borehole K02 in the piedmont alluvial fan and twenty sixsamples from borehole K01 in the plain were collectedto analyze lithological characteristics and geochemical components. These samples were further to conduct sequential extraction and desorption experiments of As in sediments. Results The aquifers in the piedmont alluvial fan were in a relatively oxidized environment, while the aquifers in the plain area were in a closed reducing environment. Salinity of the latter sediment was generally higher than that of the former, and salinity of both sediments had a decreasing trend with depth. Total solid As content in the sediments of the piedmont alluvial vans and the plain area displayed little difference, but the occurrence pool of solid Aswas quite different. The former sediment solid As was dominated by the As incorporated in very amorphous Fe–(oxyhydr) oxides, while the latter was dominated by strongly adsorbed As. Conclusions The differences of As occurrence characteristics in sediments were the main reason why groundwater As concentration in the plain area was higher than that in piedmont alluvial vans. Desorption experiments showed that weak alkalinity or high Na/Ca^0.5 molar ratio could promote the desorption of As.

Abstract:This paper is the result of geological survey engineering. Objective Clarifying the Late Quaternary stratigraphic framework in Ningde area, Fujian can provide basic information to support the regional division of saline and freshwater, and new comparable information for the study of Late Quaternary marine intrusion in Eastern China. Methods Through lithological, chronological and micro–body paleontological analyses of hole NDGK2 and regional borehole comparisons, we reconstructed its Late Quaternary stratigraphic framework and further explored the regional stratigraphic spreading characteristics and evolutionary processes. Results The Quaternary stratigraphy of hole NDGK2 has been deposited since the Late Pleistocene, and there are three layers of dark gray clay from bottom to top, with ages of about 90 ka, 39–44 ka, and <10 ka, respectively. Conclusions The Quaternary stratigraphy of hole NDGK2 is developed on top of ancient weathering crust, and is mainly deposited since the late Middle Pleistocene–early Late Pleistocene. There are three layers of dark gray clay in the core of the borehole, all of which are likely to be deposited during the transgression period, and the three layers of dark gray clay may correspond to MIS5, MIS3 and MIS1 phases, respectively. The spatial difference of the development of dark gray clay layer shows that the transgression scope of MIS3 is wider than that of MIS5. At that time, the paleotopography was close to the modern topography, and the tectonic subsidence was obvious. After MIS3, the structure was relatively stable, and the most extensive transgression was formed with the influence of the maximum transgression surface in the Holocene.

Abstract:This paper is the result of geological survey engineering. Objective The purpose of this paper is to synthesize the theories and methods of comprehensive geochemistry and high resolution sequence stratigraphy. The high–precision chemical sequence stratigraphic framework of Wufeng Formation and Lower Longmaxi Formation in Xindi 1 Well, Upper Yangtze region was established to provide scientific basis for shale gas exploration in the study area. Methods We use the core, logging and sample analysis data of Well Xindi 1 in Upper Yangtze region to optimize the indicators system which can divide the chemical sequence stratigraphic. The indicators system contains three elements assemblages: the terrigenous input intensity(TII), the autogenetic precipitation intensity(API), and the organic matter adsorption and deoxidation intensity(ODI). Then the fourth–order chemical sequence stratigraphy is divided by these three elements assemblages. Results Based on the above indicators system, Wufeng Formation of Liutang section is divided into LCW sequence, the lower part of Longmaxi Formation is divided into MCL1–1, MCL1–2, MCL1–3, MCL1–4 fourth–order sequences upwardly. The total amount of elements assemblages related to TII is relatively high near the sequence boundary, but relatively low near the maximum oceanic flooding surface. However, the total amount of element assemblages related to API and ODI are generally lower near the sequence boundary and higher near the maximum flooding surface. Conclusions Representing different genetic significance, the cyclic variation of element assemblages is respond to regional sea level change, and has regional consistency. The sedimentary environment with smaller TII, smaller API and larger ODI is conducive to organic matter enrichment in shale. So it can be used as the basis for regional stratigraphic correlation.

Abstract:This paper is the result of mineral exploration engineering. Objective The copper–nickel–cobalt deposit in the Alxa Left Banner is a typical sulfide deposit in western Inner Mongolia, developed in the ultrabasic–medium basic magmatic rock zone. The gabbro is an ore–forming rock, and recognizing the magmatic activity, metallogenic regularity and tectonic background have become an urgent geological problem. Methods Related samples were collected to study petrography, petrogeochemistry, zircon U–Pb chronology and Hf isotope. Results Geochemical characteristics shows that the Yagan gabbro has the characteristics of high Al₂O₃ (15.99%–17.47%), sub–alkaline (K₂O+Na₂O=4.94%–5.86%), low TiO₂ (0.81%–1.12%), low P₂O₅ (0.14%–0.21%), high MgO (3.18%–5.64%), low K₂O (1.14%–2.05%), indicating of the calcium alkaline series. The total amount of rare earth (ΣREE) is 71.43×10^–6–94.22×10^–6, presents right–inclined distribution model, the light rare earth is relatively enriched and the heavy rare earth is depleted. The high field strength elements (Nb, P, Ta) are obviously depleted, incompatible elements (U, Sr) are enriched, suggested that the Yagan gabbro originated from the lithospheric mantle and experienced crystallization differentiation in the late magmatic stage. The zircon U–Pb weighted average age of the Yagan gabbro is (268.8±3.1) Ma, indicating the age of diagenesis belongs to Middle Permian. The ε_Hf(t) values is –7.1–2.9 and two staged Hf model age is 1272–2177 Ma. Conclusions Regional geological data and geochemical characteristics indicate that the Yagan gabbro original magma may be confused by some crustal materials during the migration process. The formation tectonic background may be the post–collision and extension environment in the Late Paleozoic. In addition, the emplacement age of Yagan gabbro limited the collision closing time, which provides new constraints for the study of Cu–Ni–Co deposits in this region.

Abstract:This paper is the result of geological survey engineering. Objective Jiaodong area is the largest gold ore concentration area in China and the most important copper–molybdenum polymetallic ore deposit area in Shandong Province. Strengthening the study of petrography, petrogeochemistry and chronology of Mesozoic granites is conducive to further promoting the prospecting of gold and polymetallic deposits in this area. Methods Taking the medium–fine grained monzogranite and granite porphyry as the main research object, this study primarily carried onlaser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb chronology on the zircon, whole–rock geochemistry,whole–rock Sr–Nd–Pb and zircon Hf isotopic study, aiming to confirm the timing and discuss the petrogenesis and tectonic settings of the Sanheshan pluton in Southwest Jiaodong. Results The results of LA–ICP–MS zircon U–Pb show that the medium–fine grained monzogranite was formed in (115.42 ± 0.27) Ma and the granite porphyry was formed in (115.21±0.25) Ma, both of which are belonging to the Late Early Cretaceous of Mesozoic. Geocahemical research shows that the medium–fine grained monzogranite and granite porphyry are both belong to themetaluminous high–K calc–alkaline series I–type granites; LREE are more obvious than HREE,with weak Ce negative anomaly and obvious Eu moderate negative anomaly; trace elements enriched in Rb, K, Zr and Hf, depleted in Sr, Ba, Nb, P and Ti. The whole rock Sr–Nd–Pb and zircon Hf isotope analysis results show that the Sanheshan pluton was originated from the remelting lower crust, and was contaminated by mantle materials. Conclusions The Sanheshanpluton was formed in the continental extension background caused by the subduction of the Pacific plate relative to the Eurasian plate in the Early Cretaceous, which was the product of crust–mantle interaction during the lithospheric thinning in eastern China.

Abstract:This paper is the result of mineral exploration engineering. Objective The East Qinling molybdenum belt which located in the North China craton is the second largest Mo belt in the world, among which occur the most famous orogenic gold deposits of the Xiaoqinling. In recent years, through the implementation of geological survey engineering, molybdenum mineralization with industrial significance has been found in the deep of Dahu Au (Mo) deposit from Xiaoqinling area, and molybdenum ore mining has begun. Through the constraint on its metallogenetic stages, it is helpful to study the Au–Mo metallogenic regularity. Methods In this paper, based on the Crisis Mine deep–seated deposits prospecting in Xiaoqinling area, we studied the metallogenic model of deep Au (Mo) deposit, and analyzed the role of molybdenite Re–Os and K–feldspar ⁴⁰Ar/³⁹Ar isotope dating in the classification of metallogenic stages. Results Six molybdenite samples from the S35 ore vein yield Re–Os isotopic isochron age of (214.9±5.2) Ma (MSWD=0.77), with model ages ranging from (192.3±2.9) Ma to (223.4±3.2) Ma. K–feldspar samples from F5 ore vein yield Ar–Ar weighted plateau age of (95.22±1.16) Ma and the isochron age of (95.10±4.57) Ma. Conclusions Molybdenite age suggests that the Mo mineralization in S35 vein occurred in Indosinian period, and K–feldspar age indicates a new tectono–magmatic–thermal event during the Middle Yanshanian, and this hydrothermal event may contribute to metallogenic activity of Au (Mo) deposit, which superimposed the molybdenum mineralization events of Indosinian. Combined with the results of hand samples and BSE images analysis, it is concluded that there are at least two episodes of hydrothermal event related to Au (Mo) mineralization in Dahu Au (Mo) ore district.

Abstract:This paper is the result of geological survey engineering. Objective The Galwan Valley, which adjacent to the Huoshaoyun super large lead–zinc deposit, located in the Karakoram Mountains of the Northern Qiangtang terrane. A systematically lithogeochemistry and chronological studies was conducted on the newly discovered magmatic rocks in the Galwan Valley area to helps us deeply understanding the regional metallogenic dynamics and magmatic evolution history, providing a theoretical foundation for the study of regional magmatic–tectonic–mineralization processes. Methods This study reports seven samples of intermediate–basic magmatic rocks in the Galwan Valley area, including basalt, diabase, and diorite. A systematic mineralogical, major and trace element, zircon U–Pb age, and trace element analyses were conducted on these samples. Results The zircon U–Pb dating results indicate that the Bingdong diorite is emplaced at (98.9±1.2) Ma, and its whole–rock composition is characterized by low–potassium calc–alkaline features. In contrast, the zircon U–Pb dating results for the basalt show an eruption age of (232±9) Ma, with its whole–rock geochemical composition displaying calcium alkali or peralkaline characteristics. The zircon dating results show that both the diorite and basalt samples contain a large number of ~800 Ma inherited zircons, and both have age spectra featuring six distinct age peaks. Conclusions The Bingdong diorite is a product of crust–mantle mixing under a crustal thickening background, related to the remote effect of the India–Asia collision orogeny following the closure of the Neo–Tethys Ocean. The existence of numerous ~800 Ma inherited zircons in the diorite and basalt indicates that they originated from the melting of Neoproterozoic basement material. The six distinct zircon age peaks in both the diorite and basalt reflect six periods of tectono–magmatic activity, ranging from the Mesoproterozoic crystalline basement and the breakup of the Rodinia supercontinent to the closure of the Neo–Tethys Ocean and subsequent collisional orogeny.

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