Abstract:This paper is the result of oil and gas exploration engineering. Objective The Sanmenxia Basin located in the composite and joint part of the Zhongtiaoshan fault block, Xiaoqinling fault block and Xiaoshan fault block has undergone many stages tectonic movements and changes. It gradually evolved into a triangular fault basin on the Precambrian crystalline basement. Methods Due to its complex structure and low exploration level, the structural framework and evolution history of Sanmenxia Basin has unknown. This has affected the potential evaluation and exploration process of oil and gas resources in the study area. In this paper, Sanmenxia Basin is selected as the research object. Based on regional geological data, field geological survey, comprehensive interpretation of non–seismic exploration and recent drilling results, the structural framework and burial depth of the top and bottom of Paleogene are preliminarily identified to explore the prospect of oil and gas resources. Results The evolution process of Sanmenxia Basin has mainly experienced four stages: (1) Precambrian metamorphic basement and depression trough formation stage; (2) The Paleozoic transgression and orogenic stage. During this stage, marine facies and marine–terrestrial transition facies were mainly developed, after which the basin was uplifted and the depression trough evolved into a syncline structure; (3) The Mesozoic graben–type faulted basin formation stage; (4) Paleogene faulted basin development and post–sedimentary stages. Conclusions At this stage, due to the influence of the Himalayan movement, Sanmenxia Basin was in an extensional environment, and formed inland lake bounded by three–sided uplifts in the South, North, and East. The graben area was relatively descended to accept deposits. The Paleogene in the Lingbao Sag of the Sanmenxia Basin has the characteristics of large thickness and continuous distribution, and the dark mudstone is particularly developed, which has good prospects for petroleum resources.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The purpose of this paper is to reveal the shale gas accumulation conditions in the complex structural area and to identify the shale gas accumulation potential of Wufeng Formation–Longmaxi Formation in Northern Guizhou by analyzing the shale accumulation elements of Wufeng–Longmaxi Formation in Well SX 1. Methods This paper focuses on the comprehensive study of shale gas accumulation from the three dimensions of "source, reservoir, and protection", based on the comprehensive experimental analysis of the series drilling coring, logging curves, seismic data, and geochemical testing and reservoir characteristics of Well SX–1. Results The thickness of organic–rich shale in Wufeng–Longmaxi Formation of Well SX 1 is about 25 m, the TOC content is between 2.79% and 4.77%, and the equivalent vitrinite reflectance is about 2.01%–2.59%. The organic matter type is the primary type I, which has a good gas foundation. The content of brittle minerals in the organic–rich shale section is relatively high, with an average value of about 61.05%, indicating high brittleness. A large number of micro–nano pores are developed, mainly organic pores and inorganic–organic composite pores. The pore volume and specific surface area parameters are good, which provides a good reservoir space for the occurrence of shale gas. The roof and floor of the organic–rich shale section in the residual syncline have a good sealing ability. The three vertically form a good source–reservoir–cap assemblage. There are two large faults in the east and west of Well SX 1, but they are far from Well SX 1. At the same time, due to the good sealing of the faults and the gentle formation occurrence, Well SX 1 has a good gas–bearing display. Conclusions In summary, the shale of Wufeng–Longmaxi Formation in the residual syncline in northern Guizhou also has oil and gas geological conditions with high efficiency and large–scale production of shale gas, which is the key direction of next exploration and research. The results expand the scope of shale gas exploration, broaden the depth and breadth of shale gas exploration around the Sichuan Basin, and are expected to form a new resource replacement area.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The brittleness evaluation of shale reservoir is of great significance for determining the favorable stratigraphic zone in shale gas exploration and development. Methods Based on the basic data of mineral composition, geophysical logging, rock mechanics experiment and fracture development characteristics of Lower Cambrian Niutitang Formation in Xuefeng region, the brittleness characteristics of Niutitang Formation shale are comprehensively analyzed and evaluated by mineral composition and rock mechanics parameter based on geophysical logging, and the influencing factors of shale brittleness are discussed. Results The results indicate that the brittle mineral composition based on the contents of quartz, feldspar, pyrite and carbonate is the most suitable method to evaluate the brittleness of Niutitang Formation shale in this region. Taking Well XZD–1 in this area as an example, the brittleness index of Niutitang Formation shale is 59.2%–93.8%, with an average value of 74.4%, which is influenced by sedimentary environment, diagenetic evolution, burial depth, tectonism and other factors. Conclusion The stable deep–water shelf basin facies sedimentary environment and late diagenetic evolution stage determine that the overall brittleness of Niutitang Formation shale in Xuefeng region is relatively high. In this sedimentary environment, biogenic brittle minerals such as siliceous and pyrite are more abundant. The content of brittle minerals is affected by the change in water depth during sedimentation, showing a trend of increasing first and then decreasing from bottom to top, gradually decreasing overall. This leads to a similar vertical variation law in shale brittleness and the development of natural fractures, and the three complement each other. Meanwhile, such brittle minerals have a good positive correlation with organic matter content, and their contribution to shale brittleness is much greater than that of organic matter to shale plasticity. In addition, the correlation between rock mechanics parameters and brittleness index indicates that the Young's modulus plays a more important role in the evaluation of Niutitang Formation shale brittleness in this area than the Poisson's ratio.

Abstract:This paper is the result of oil and gas geological exploration engineering. Objective The carbonate reservoirs of the Ordovician Yijianfang Formation are developed in Yueman area, south of Tarim River in Halahatang oilfield, Tarim Basin. The exploration and development results show that the high–producing wells are mainly distributed along four strike–slip faults in the area, and the oil and gas production along the fault zone is different, with strong heterogeneity, and the reservoirs are obviously controlled by faults. Therefore, it is of great significance for oil and gas exploration and development to clarify the characteristics and distribution regularities of fault–controlled reservoirs. Methods In this paper, based on drilling logging data, cores data and 3D seismic data, the petrological characteristics, reservoir types and development regularities are analyzed, and the coupling relationship between high–quality reservoirs and strike–slip faults is discussed to clear the distribution regularities of such fault–controlled reservoirs. Results The reservoir rock types of Yijianfang Formation in the area are mainly bioclastic limestone, arenaceous limestone, granular limestone and micritic limestone, with low porosity and permeability. According to the types of reservoir space, the reservoirs can be divided into four types: cavernous reservoirs, vuggy reservoirs, fractured reservoirs and fractured–vuggy reservoirs. The cavernous reservoirs develop vertically along the main fault, the vuggy reservoirs, fractured reservoirs and fractured–vuggy reservoirs are banded distributed along the fault. Conclusion The structure of strike–slip faults controls the distribution of high–quality reservoirs, and the reservoir stratums in Horsetail, en echelon and overlap sections of faults are the best developed, the oblique intersection sections of branching faults are fair developed, while the linear sections are poorly developed. On this basis, the reservoirs in the superposition area of high–energy facies belts are better developed than those in the non–superposition area.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The heterogeneity is the inherent nature of shale. Study of the microheterogeneity of shale is of great significance for determining the enrichment mechanism of shale gas and the selection of high–quality reservoirs. Methods This study investigated the marine shale of the Wufeng–Longmaxi Formation in the northern Guizhou area. Through XRD mineralogy, low–temperature N₂ adsorption and high–pressure mercury intrusion (HPMI) analyses, we explored the macro and micro heterogeneity characteristics of pore structures of this formation. Results The Wufeng–Longmaxi Formation shales in the northern Guizhou area are mainly of siliceous lithofacies, followed by mixed lithofacies and clayish lithofacies. The shales of different lithofacies exhibit large differences in total organic carbon (TOC) contents, mineral compositions, and pore structure characteristics. The FHH fractal model of N₂ adsorption curves, and the porous fractal theory of HPMI methods, were utilized to calculate the low pressure fractal dimension D₁ (0<P/P₀<0.45) of N₂ adsorption as 2.5351–2.6722, and the high pressure fractal dimension D₂ (0.45<P/P₀<1) as 2.8311–2.9113. Additionally, the fractal dimension D_Hg of HPMI was determined to be 2.0904–2.3736, indicating strong heterogeneity within the Wufeng–Longmaxi Formation shale pore structures. A larger fractal dimension corresponds to a more complex pore structure within the shale reservoir and stronger adsorption capacity for shale gas. Furthermore, there are notable differences between various types of pore fractal dimensions and TOC content, mineral composition, pore structure parameters, and other influencing factors. Specifically, it has been found that the fractal dimension D_Hg exhibits a strong correlation with different mineral contents, suggesting that macropore fractal characteristics are primarily influenced by mineral components. Moreover, there is a clear correlation between fractal dimensions D₁ and D₂ with TOC content and pore specific surface area parameters within the shale, indicating that micropore and mesopore heterogeneity are mainly influenced by organic carbon contents and development of organic pores. Conclusions Generally, siliceous shale exhibits relatively high total organic carbon (TOC) contents, high proportions of brittle minerals, and high fractal dimensions. This confirms the siliceous shales are the primary high–quality lithofacies within the Wufeng–Longmaxi Formation in the northern Guizhou area, followed by the mixed lithofacies. Meanwhile, higher organic matter contents indicate not only more favorable conditions for hydrocarbon generation, but also better conditions for shale gas exploration and extraction. Our study offers theoretical and practical support for guiding the optimal selection of favorable reservoirs in marine shales in the northern Guizhou area.

Abstract:This paper is the result of oil and gas geological exploration engineering. Objective Kuqa Depression is rich in oil and gas resources, but the study of tectonic–thermal evolution related to oil and gas generation and preservation is very weak. Methods In this study, the apatite fission track test analysis and thermal history simulation were carried out on typical drilling samples in the eastern part of Kuqa Depression. The tectonic–thermal evolution history of the eastern part of Kuqa Depression since Mesozoic was accurately reconstructed, and the maturity evolution period of source rocks was evaluated. Results The apatite fission track ages measured by in–situ LA–ICP–MS are between 77.7 Ma and 104.5 Ma, which are much smaller than the stratigraphic age, and the rapid uplift events of Late Cretaceous are effectively recorded. The thermal history simulation reveals that Kuqa Depression has experienced two periods of rapid uplift since Jurassic (Early Cretaceous–Late Eocene (120–40 Ma) and Late Miocene–present (10–0 Ma)), which are caused by the remote effect of the collision between Lhasa plate, Indian plate and the southern margin of Eurasia plate. Conclusions The differential tectonic uplift in Kuqa Depression is caused by the subduction and compression of the southern Tianshan Mountains gradually advancing from north to south. The Jurassic source rocks in Kuqa Depression show a multi–stage mature evolution model under the influence of multi–stage subsidence. Affected by tectonic uplift events, the Jurassic source rocks mature evolution was at a stagnation stage from early Cretaceous to late Eocene and late Miocene. This study determines the tectonic–thermal evolution history of eastern Kuqa Depression since Mesozoic, and clarifies the mature evolution process of main source rocks, which have important guiding significance for regional tectonic evolution and next oil and gas exploration.

Abstract:This paper is the result of mineral exploration engineering. Objective With the development of science and technology, the market demand for green energy mineral resources has been increasing in recent years, and lithium as a core strategic metal resource, related exploration and research has become a hot spot for mineral exploration and geological research. Methods Based on previous research, this paper compares and summarizes the main types, distribution and development and utilization of lithium resources in China according to the principle of statistical analysis. Results Lithium ores in China are mainly classified into hard rock type, brine type and clay type lithium ores. The distribution of lithium resources is relatively concentrated, among which hard rock–type lithium ore is mainly distributed in Sichuan, Jiangxi, Hunan, Xinjiang and other regions, and the salt lake brine–type lithium ore is distributed in Qinghai, Tibet and Hubei and other regions. At present, granite pegmatite lithium ore is an important source of domestic lithium supply because of its high ore grade and easy mining. Brine–type lithium ore has large resources, but the lithium extraction technology is relatively complex; clay–type lithium ore was discovered late and has not been exploited on a large scale, but there is a distribution pattern and realistic demand for lithium resources. Conclusions On the whole, there is an imbalance between supply and demand of lithium resources in China and a high dependence on resource imports. At present, the new energy automobile industry, mobile energy storage technology and the national green energy industry are developing rapidly at home and abroad, and the demand for lithium resources will grow significantly in the long term. In order to gain a say in this global scarce strategic resource, it is necessary to re–evaluate the existing lithium resources in China, map out the resource base, and increase the research and exploration and development of new lithium resources.

Abstract:This paper is the result of environmental geological survey engineering. Objective Cadmium(Cd) and zinc(Zn) are both important mineral resources and harmful heavy metal elements. The recent development of multi–collector inductively coupled plasma mass spectrometry (MC–ICP–MS) has improved the precision of Zn isotope composition analysis in different environments. The establishment and application of non–traditional stable isotope systems such as cadmium and zinc have raised the geochemical research of cadmium and zinc to a new level, which also have become hot topics in isotope geochemistry. Methods This paper reviews recent research progress on the analytical methods, fractionation mechanisms, isotopic compositions in different reservoirs, and application fields of Zn and Cd isotopes investigated in many studies. Results (1) The improvement of Zn and Cd isotope analysis technology has promoted the establishment of their isotope systems. (2) The compositions of Zn isotopes in various reservoirs have been basically identified. The data for Cd isotope compositions in reservoirs and anthropogenic sources is in the period of accumulation. (3) The isotopic fractionation mechanisms of Cd and Zn mainly include mineral adsorption, biological processes, and chemical reactions, which have been applied in the indication of planetary evolution, the exploration of metallogenic mechanisms, paleoenvironmental reconstruction, and pollution source tracer. (4) The combination of multiple isotopes helps to reduce uncertainty in the analysis of heavy metal pollution sources. Conclusions The development of new isotope analysis instruments and technologies has made the research of Zn and Cd isotopes more promising. It is expected that more work should be carried out in the near future to improve the fractionation mechanisms, compositions in partial reservoirs, and application fields.

Abstract:This paper is the result of hydrogeological survey engineering. Objective A systematic review has been conducted on groundwater investigation and research in the Taklimakan Desert over the past 60 years to consolidate significant achievements and insights regarding groundwater recharge, discharge, and circulation. The review highlights key deficiencies in current research efforts, presents ten unresolved questions, and identifies areas for future study. Methods Investigation reports and academic papers were meticulously gathered on groundwater in the Taklimakan Desert for a comprehensive review on groundwater quality, quantity, and circulation. This review was conducted in conjunction with the latest relevant findings on desert groundwater from both domestic and international hydrogeological communities. Results Groundwater in the desert primarily originates from lateral groundwater flow from oases, precipitation, and river water infiltration. It is predominantly consumed by evapotranspiration, with a limited amount withdrawn by humans. The vast groundwater storage in the region is estimated to be around 80 trillion m³. However, there is currently significant uncertainty in estimating groundwater recharge and discharge. The overall groundwater quality is generally poor, as evidenced by the spatial distribution of total dissolved solids (TDS), with most of the desert containing saline groundwater with TDS levels ranging from 5 to 10 g/L, while only a small area has TDS levels below 5 g/L. Vertically, the groundwater quality is characterized by saline groundwater in deeper layers and brackish groundwater in upper layers. Regionally, groundwater flows northward and then shifts eastward at the northern edge of the Tarim River fluvial plain, with an average velocity of 55.94 m/a. Conclusions To address these scientific questions, future studies should focus on quantifying groundwater recharge and discharge using more precise and extended methodologies. Detailed data on groundwater circulation can be obtained through packer tests and monitoring to systematically analyze circulation patterns, establish regional groundwater flow patterns, and quantitatively summarize the characteristics of each flow system. Additionally, efforts should be made to identify sources of fresh water and develop techniques for utilizing high Total Dissolved Solids (TDS) groundwater in the desert in upcoming investigations and research endeavors.

Abstract:This paper is the result of mineral exploration engineering. Objective Uranium resources are China's important strategic resources and energy minerals. The thorough understanding of geological characteristics and metallogenic models of sandstone–type uranium deposits in the northern Sichuan Basin is to the benefit of exploration and development. Methods The petrological characteristics of sandstone–type uranium deposits are studied through field investigation, rock and mineral identification and geochemical analysis, and the mineralization process is analyzed. Results The ore–bearing rocks are mainly the calcareous cementation medium–fine–grained sandstone and conglomerate of the Lower Cretaceous Cangxi Formation. Uranium exists in the form of authigenic uranium minerals. Uranium minerals are mainly coffinite, which are in xenomorphic, euhedral and hypautomorphic granular. Conclusions The metamorphic acidic volcanic rocks and granites of the Tiechuanshan Formation in Micangshan provided the initial uranium source for the formation of sandstone–type uranium deposits in the basin. Uranium migrates in the form of carbonic acid containing uranyl ions in the aqueous solution. The reductive environment of swamps and stagnant water rich in organic matter and pyrite destroys the carbonic acid containing uranyl ions, causing uranium to precipitate and accumulate in the primary diagenesis stage and secondary epigenesis stage.

Abstract:This paper is the result of mineral exploration engineering. Objective Mantle–derived magma generally provied an object to reveal geodynamic evolution in the depth and uranium mineralization. The mafic dikes in the west of Xiangshan uranium deposit are regarded as a key aspect to understand the regional tectono–magmatic evolution and uranium mineralization. Methods In this paper, the comprehensive research of petrology, geochronology and geochemistry were carried on the lamprophyre in the west of Xiangshan uranium deposit. Results There are three stages of lamprophyre in this area, which are 134 Ma, 120–125 Ma and 84.5 Ma. The lamprophyre is sodium–alkaline lamprophyre and characterized with the enrichment of LILE and LREE, depletion of HFSE, and obvious negative anomaly of Ta–Nb–Ti. The lamprophyre is the product of partal melting from the source region and crystallisation differentiation, which experienced the crystallization differentiation of olivine and clinopyroxene as well as strong assimilation and contamination of upper crustal meterials during the magmatic intrusion. The lamprophyre was formed in the extentional entraplate tensioned tectonic environment, and was not affected by the subduction of the ancient Pacific Plate. The source region is a mixture of asthenospheric depleted mantle (main source) and lithospheric enriched mantle, which is mainly characterized by asthenospheric depleted mantle. Conclusions The first period of lamprophyres is much older than the age of uranium mineralization, only providing favorable conditions for uranium accumulation. The later two periods of lamprophyres are closely associated with uranium deposits on space and time, possibly providing mantle hydrothemal fluids (∑CO₂ and He) and a favorable reducing environment for uranium enrichment and deposition.

Abstract:This paper is the result of mineral exploration engineering. Objective A very special and echelon arrangement uranium mineralized lenses group were found in the Datian area of Panzhihua, Sichuan Province, with important research value. Methods Through the comprehensive studies, including petrology, mineralogy petrochemistry, isotope geology and chronology, uranium occurrence state the genetic relationship between uranium mineralization and lenses. Results The lenses mainly consist of plagioclase with strongly sodium zoisitization, and have typical magmatic mosaic texture, with age of 821 Ma (SIMS zircon U–Pb age). They have the chemical composition characterices of high Na₂O (3.95%–5.68%, average 5.09%), CaO (4.40%–7.35%, average 5.46%), low SiO₂ (51.52%–55.09%, average 53.34%). The analysis of trace element show that lenses have very low ΣREE content (9.96×10^–6–33.63×10^–6, average 22.03×10^–6), positive Eu anomalies (δEu=1.59–5.51, average 2.68) and special REE distribution pattems. The results of I_Sr (0.7060–0.7088, average 0.7074) indicate that the raw material of lenses coming from the mantle. The mainly uranium occurrence state in lenses is the unique "U–Ti minerals aggregates". The "U–Ti minerals aggregates" are mainly composed of rutile, uranium–titanium mixture, brannerite and uranium, and the minerals in "U–Ti minerals aggregates" have the evolutionary characteristics of "rutile (Ti)→uranium–titanium mixture (Ti>U)→brannerite (Ti<U) → uranium(U)". Conclusions According to the relationship between uranium minerals and lenses, and the REE tracer method of uranium minerals, it is confirmed that the uranium mineralization genesis is relation to magmatism. It is speculated that the NaU⁴⁺(Ti⁴⁺)[TiO₄]⁴⁺(F,Cl) is mainly complex in the deep environment with high temperature (>700 °C) and high pressure (>15 kbar), and it can move and concentrate in the sodium–rich site in the lenses. The U and raw material of lenses originate from same magma, and the "U–Ti minerals aggregates" are separated from magma body in the process of isobaric cooling. The discovery of uranium mineralized lenses in Datian area of Panzhihua provides the direct geological case that uranium can be enriched in the mantle, and this discovery provides a reference for the discussion of deep-source uranium metallogenesis.

Abstract:This paper is the result of mineral exploration engineering. Objective This study aims to ascertain the petrological, mineralogical, and geochemistrial signatures of the sandstone (mudstone) of the uranium bearing target layer in Erennur Sag, Erlian Basin, and to discuss uranium mineralization. Methods Research methods include field geological cataloging, polarized light microscopy, electron probe spectroscopy analysis, major trace elements, environmental geochemistry, and uranium valence analysis. Results (1) Uranium minerals exist in the form of adsorbed and independent uranium minerals, often co-existing (associated) with carbon chips and pyrite, with occasionally with presence of sphalerite. (2) The ore exhibits the characteristics of high organic carbon, S and CO₂. The average U⁶⁺/U⁴⁺ of mudstone is 1.01, and the average U⁶⁺/U⁴⁺ of sandstone is 0.57. (3) The CIA value of sandstone (mudstone) is 50.83 to 66.34. The characteristics of rare earth elements are consistent with those of granite in the erosion source area, the characteristics of main and trace elements all show that there is obvious water–rock interaction in the late sedimentation–diagenesis stage. Conclusions The following conclusions can be drawn: (1) The Hercynian granite is the dominant source of the sandstone (mudstone) of the Saihan Formation. The sedimentary environment is a semi–arid–semi–humid paleo–climate. (2) Adsorption and oxidation–reduction are the main mechanisms of uranium enrichment in the study area. Mudstone–type uranium enrichment is mainly in the form of adsorption, while sandstone–type uranium enrichment is mainly in the form of oxidation–reduction. (3)The deep fluid may have participated in the mineralization.

Abstract:This paper is the result of mineral exploration engineering. Objective Straz area (Bohemia Basin, Czech Republic) is a well–known uranium metallogenic area. The mineralization of sandstone–type uranium deposits is complex. Determining its metallogenic characteristics and metallogenic model is of great significance to perfect the metallogenic theory of sandstone–type uranium deposits and know the prospecting and exploration of the similar uranium deposits in China. Methods On the basis of summarizing the geological characteristics and metallogenic conditions of sandstone–type uranium deposits in the Straz area, this study focus on the uranium source, metallogenic stage and genesis of the deposits, and comparative studies are conducted by the similar sandstone–type uranium deposits in Songliao Basin. Results The Straz deposit can be divided into six metallogenic stages according to its mineral assemblage characteristics, i.e., carbon-hydromica, hematite–kaolinite, uranium, polymetallic, limonite and hematite–quartz stage. Proterozoic and Paleozoic igneous, metasedimentary, and sedimentary rocks outcropping to the northeast of the Bohemia Basin are considered potential sources for uranium. The Lusatian Massif contains biotite granodiorite and porphyritic biotite granite with. The low Th/U ratios suggest that part of the uranium is probably present in leachable form and these rocks constitute viable uranium sources. Conclusions The metallogenic model of the Straz area belongs to the “three factors and three majors”: Multi uranium source–basin basement primary uranium source, multi stage tectonic ore controlling–early Alps (about 70 Ma) orogenic movement, multi genetic composite mineralization– early Alps magmatic hydrothermal superimposed mineralization.

Abstract:This paper is the result of geological survey engineering. Objective The Neoproterozoic Guaizhangshan Group was disintegrated from the Silurian Balonggonggaer Formation. The study of the petrogenesis and tectonic setting of the basalt in Guaizhangshan Group is crucial to clarify the tectonic evolution of South Qilian. Methods Based on LA–ICP–MS zircon U–Pb datingand whole–rock geochemistry analysis, the formation age, geochemical characteristics and geological significance of the basalt in Guaizhangshan Group are constrained. Results The dating results indicate the eruption age of the basalt is (786.6±5.8) Ma, suggesting that the Guaizhangshan Group formed during Early Neoproterozoic. Geochemical analyses of the basalt show that: SiO₂=48.09%–50.97%, TiO₂=1.34%–2.55%, MgO=5.78%–7.11%, displaying characteristics of subalkaline tholeiite; Significant differentiation between light rare earth element (LREE)and heavy rare earth elements (HREE) ((La/Yb)_N=3.76–4.51), and inconspicuous Eu anomalies (δEu=0.80–1.05); Enrichment of Ba, Th, U, Pb, and depletionin Nb, Ta, Ti. Conclusions These geochemical characteristics indicate that the basalts were derived from mantle and contaminated by crustal materials. The basalt was formed in continental rift setting, which may be relevant to the break–up of the Rodinia supercontinent.

Abstract:This paper is the result of geological survey engineering. Objective The diagenetic age, petrogenetic types, source properties and geodynamic background of the Early Cretaceous granites of Haliheba pluton in the central and southern part of Great Hinggan Range are discussed based on the regional geological survey. Methods The lithography of granite, U–Pb chronology, geochemistry and Hf isotope composition of zircon are studied by means of microscope, XRF and (LA–) ICP–MS. Results The Early Cretaceous granites in Haliheiba are composed of fine to medium–grained biotite granite and fine–grained porphyritic biotite granite, and zircon U–Pb ages are (139.1±0.7) Ma and (138.4±1.0) Ma, respectively. The granites are characterized by high SiO₂ (74.09%–77.19%) and alkali enrichment (7.92%–8.46%), and belong to high–K calc–alkaline series. The A/CNK values range from 0.95 to 1.08, indicating that they are metaluminous to weakly peraluminous rocks. The chrondrite–normalized REE patterns are characterized by enrichment of LREEs with (La/Yb)_N values varying from 3.69 to 13.17 and by prominent negative Eu anomalies with δEu values ranging from 0.11 to 0.47. The granites show the enrichment of Rb, U, Th , Nb, Ta, Zr and Hf, and the depletion of Sr, Ba, Ti and P. Zircon Hf isotopic compositions suggest that these granites have high positive ε_Hf(t) values (+5.0 – +11.2) and fairly young two–stage Hf model ages (408–731 Ma). Conclusions The Haliheiba granites are aluminous A–type granites, which were mainly derived from partial melting of the juvenile crustal materials associated with ancient crustal materials under extensional tectonic setting that was probably controlled by lithospheric delamination and thinning.

Abstract:This paper is the result of mineral exploration engineering. Objective Remote sensing has been widely used in geological survey and mineral exploration in recent years. Alteration mineral mapping using multispectral remote sensing data provides important technical support for geological prospecting. However, only a limited number of surveys were carried out based on the Chinese hyperspectral remote sensing data. The smaller spectral interval of the GaoFen–5 (GF–5) hyperspectral remote sensing data provides a richer spectral information of geological targets than multispectral data, which offers an ideal data source for mineral identification. This paper was mainly focusing on the extraction of alteration minerals based on GF–5 data in the south of Geji, Tibet. Moreover, the alteration minerals extracted from GF–5 were overlaid and compared with the results extracted from Landsat–8 and ASTER data. The results were verified by field survey, which could deepen the application of remote sensing in mineral resources investigation. Methods A spectral index model for different alteration minerals was proposed based on the multispectral data. During the extraction of alteration information from GF–5 data, traditional methods such as spectral angle mapper were abandoned, while the decision tree algorithm was adopted to support mixture tuned matched filter for the extraction of mineralized alteration information. Finally, regional structure, alteration information and other factors were integrated to delineate mineralization anomalous targets. The field investigation was carried out to verify the technical reliability. Results The information of iron–stained, hydroxyl (Mg–OH, Al–OH) and carbonate minerals was enhanced and extracted using Landsat–8 and ASTER. Eight alteration minerals including calcite, paragonite, muscovite, phengite, alunite, kaolinite, dickite and chlorite were identified by GF–5. Conclusions Combined with the extraction and superimposition results from different data sources, the reliability of the mineralization alteration information extraction method proposed in this paper was confirmed. The field investigation results showed that the area is characterized by high–sulfur epithermal alteration mineral assemblage, which has the potential for porphyry–epithermal hydrothermal deposit. It is suggested that the combination of hyperspectral and multispectral could help the subsequent analysis of alteration zonation and provide accurate mineralization prediction for prospecting, so as to serve the sector of mineral exploration engineering.

Abstract:This paper is the result of environmental geological survey engineering. Objective Seawater intrusion has become a major environmental and geological problem as well as research hotspot in coastal areas all over the world. To explore the characteristics of groundwater microbial communities in coastal areas can play a fundamental role in the management and prevention of seawater intrusion. Methods This study took two typical costal zones in Yellow Sea and Bohai Sea such as Longkou west bank and Dagu river coast. The microbial 16S rDNA of groundwater was analyzed by high–throughput sequencing method, to explore the diversity and structure characteristics of groundwater microbial communitiesin different areas. Results The groundwater in Dagu river study area was more seriously affected by seawater intrusion than that in Longkou. In Dagu river study area, the TDS concentration of groundwater was 1.06–3.19 g/L, mainly Na–Cl–HCO₃ and Na–Cl type water. In Longkou study area, the TDS of groundwater was relatively low, mainly Ca–Na–Cl–HCO₃ type water. The Alpha diversity index showed that the microbial uniformity and richness of groundwater decreased with the increasing seawater intrusion in Longkou, while the variation of microbial diversity of groundwater in Dagu river study area was complex. The groundwater microbial community structures of three monitoring wells in Longkou study area were similar, but the groundwater microbial community structures in Dagu river study area were different. The representative microorganisms of groundwater in Longkou were Burkholderiales, Comamonadaceae and Hydrogenophaga. In Dagu river study area, the representative microorganisms of groundwater are a little, only Proteobacteria was identified at the threshold St≥4.0. TOC and DO were positively correlated with bacterial abundance in groundwater in Longkou study area. In the Dagu river study area, Na⁺, Cl^–, SO₄^2– and other indicators were negatively correlated with bacterial abundance in groundwater, which was related to the long period of seawater intrusion. Conclusions This study revealed the response characteristics of groundwater microorganisms and the environment under the influence of seawater intrusion at different degrees, and showed different representative microorganisms, indicating that microbial indicators can be used as a new and effective method to identify seawater intrusion.

Abstract:This paper is the result of ecological geological survey engineering. Objective As one of severe desertification areas in China, the northern piedmont of Yin Mountain is seriously impacted by wind erosion. The relationship of wind erosion, land desertification and the distribution of vegetation types in this area was studied, to clarify the impact of wind erosion on the weathering process from the bedrock to the soil, to reveal the effect of wind erosion on land desertification, to interpret the coupling relationship between eco-geological characteristics and ecosystems, and to provide a scientific basis for the protection and restoration of ecosystem at arid and semi-arid regions. Methods Weathering profiles was selectively collected from rocks to soils, which distributed in the gentle slope hills, low mountain hills and mid-mountain. To compare the influence of different wind erosion intensities, some works were performed to analyze the migration processes of elements during rock weathering, characteristics of soil texture, and change patterns of surface vegetation types and its coverage. Results The gentle slope hilly area was greatly influenced by wind erosion. Many fine particles of weathering products were moved out, which appeared as the content of Al₂O₃ in surface soil decreasing significantly and values of CIA in soil profile changing abnormally. Thus, the soil thickness became thinner with the soil nutrients being lost and the water retention ability be weakened. As the result, the grass is the main vegetation type with sparse distribution. The low hilly area was less affected by wind erosion. A small amount of clay and silt grains were emigrated, and some fine sands were immigrated, which appeared as the content of Al₂O₃ in surface soil decreasing and values of CIA in soil profile changing normally. Thus, the soil thickness was almost unchanged with the soil nutrients being lost slightly. As the result, the vegetation type was dominated by the grass with low shrubs growing, and their distribution was relatively denser. The middle-mountain area was impacted by the wind erosion at the least degree. A certain amount of clay and silt was immigrated almost without emigration of weathering products, which appeared as the content of Al₂O₃ in surface soil increased with a great increase of CIA values. As the result, the vegetation types were mainly short shrubs, and a large number of trees were densely grown on the hillside. Conclusions Intense wind erosion caused the migration of fine-grained materials in the soil from the gentle slope hills north of Yin Mountain to the mid-mountain area, which resulted in worse soil thickness and quality at the gentle slope hills while comparing to those at the mid-mountain area. Consequently, vegetation is sparse and land desertification is more severe in the gentle slope hills, while vegetation shows better growth in the mountain areas.

Abstract:This paper is the result of geological survey engineering. Objective Based on the health status and resilience of the ecosystem, a risk assessment system of lake basin ecosystem degradation was constructed to provide a scientific basis for ecological environment protection and sustainable development at the basin scale. Methods Taking the Chahannur Lake basin on Bashang Plateau as an example, the interactive risk assessment matrix of ecosystem health and resilience was created, the ecological degradation risk assessment system was established, and the risk assessment of ecosystem degradation in the ChahannurLakebasin was carried out. Results 91.10% of the region's ecological health was in a good state, and 6.66% was excellent. In the basin, 22.76% of the regional ecological resilience level is 1–2, and 75.00% is 3–4. The results of the interactive assessment showed that 27.51% of the basin was in a state of low risk of ecological degradation, and 70.25% of the basin was in a state of medium risk. Conclusions The ecosystem of the Chahannur Lake basin is generally good, but the risk of ecological degradation is moderate in local areas due to poor resilience. The assessment method proposed in this study can accurately classify the risk level of ecological degradation at the watershed scale and provide a basis for the scientific decision–making of precise ecological protection and degradation control measures.

Abstract:This paper is the result of hydrogeological survey engineering. Objective There is limited research on the sources of strontium elementand the potential for the development and utilization of karst water in the large–scale strontium rich mineral water field in Xintian County, Hunan Province. Exploring the hydrochemical characteristics of strontium–rich karst water and the sources of strontium element can provide theoretical support for searching for strontium rich groundwater in karst areas. Methods PHREEQC software, water stoichiometry, end element method and hydrogeological parameters were used in this study to reveal the mineral saturation index characteristicsof strontium–rich karst water, as well as the sources of Sr²⁺ and SO₄^2– and its development potential through the hydrogeological investigation and hydrochemical testson groundwater in this strontium–rich mineral water field. Results Calcite is mainly saturated both in the springs and shafts, while dolomite changes from unsaturated in the springs to saturate in the shafts. Strontium is saturated in the shafts, and gypsum is unsaturated both in the springs and the shafts. In the springs, mineral saturation index increases with the total dissolved solids, and they areof a good positive correlation, but of a poor correlation in the shafts. The correlation of SO₄^2- betweenthe springs and shaftsare positive. According to the stoichiometric relation of Ca²⁺, Mg²⁺, Sr²⁺, HCO₃^- and SO₄^2-, SO₄^2- in the shafts may come from gypsum dissolution. The Sr²⁺ in the springsare mainly derived from strontium which replaces calcium with isomorphism in limestone, while Sr²⁺ in the shafts probably come from strontium siderite in the aquifer. 85.2% of the groundwatersamplings in the research area meet the national standard for drinking water quality, and the excess water samplings are mostly single indicator exceeding the standard. Through calculation, the natural recharge resources, exploitable resources and groundwater resource potential of strontium–rich groundwater in dry years are 3.83×10⁷ m³/a、1.05×10⁷ m³/a、7.28×10⁶ m³/a respectively. Conclusions Strontium in the strontium–rich groundwater in Xintian County is mainly derived from the dissolution of strontium–containing minerals in Shetianqiao Formation strata of Devonian. Those minerals, including strontianite, were form by isomorphicly substitute of calcium with strontium. The amount and resource potential of strontium–rich groundwater are considerable, with a great value for development and utilization.

Abstract:This paper is the result of hydrogeological survey engineering. Objective The study on the characteristics of groundwater chemical evolution and its control factors in coastal zones is of great significance for the sustainable utilization of groundwater resources in coastal cities. Methods On the basis of field investigation and comprehensive analysis of historical data, the characteristics of groundwater chemical evolution in Wenzhou Plain were systematically analyzed by using hydrochemical diagram, ion proportional relationship, multivariate statistical analysis and environmental isotope methods, and the main controlling factors affecting groundwater chemical evolution were discussed. Results (1) Phreatic water in Wenzhou Plain was dominated by fresh water, and HCO₃^–, Na⁺ and Ca²⁺ were the predominant ions. However, confined water is brackish and salt water, and Cl^– and Na⁺ were absolutely dominant ions. (2) From the mountain front to the marine deposition plain, the transition from low–salinity HCO₃ type water to high–salinity Cl type water in the study area is mainly controlled by natural processes, and human activities caused abnormalities of local groundwater chemistry. (3) On the ten–year scale, the content of the main components of phreatic water decreased to a certain extent, and the hydrochemical type evolved in the direction of the decrease of Cl^– and the increase of HCO₃^–. (4) Natural factors such as water–rock interaction, seawater interaction, redox environment and human factors such as industrial and agricultural production and domestic sewage are the main controlling factors of groundwater chemical evolution in Wenzhou Plain. Conclusions The results of groundwater health risk assessment show that certain potential non–carcinogenic risks of groundwater exist in the area, the non–carcinogenic risk of phreatic water is less than that of confined water, drinking water intake is the main way to harm human body, and the non–carcinogenic risk of children in the same environment is higher than that of adults. Therefore, it is necessary to conduct long–term monitoring of groundwater with health risks and strengthen groundwater resource management and pollution prevention in such areas.

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