Supported by the Continental Shelf Drilling Program (CSDP), borehole CSDP-2 is not only the first drilling in the central uplift of the South Yellow Sea basin, but also a full-drilling record with a depth of 2 843.18 m. The multi-types and multi-levels oil and gas have been detected in the cores of the Triassic Qinglong Formation, Permian Dalong, Longtan, Gufeng and Qixia Formations,and Silurian Fentou Formation. Three Permian oil sand samples obtained from borehole CSDP-2 indicate a large-scale migration and accumulation of oil and gas in this study area. The geochemical analysis and oil-source rock correlation reveal the near-source hydrocarbon accumulation in the oil sands of 1^# and 2^#. Among them, the crude oil in the 1^# oil sand of the Dalong Formation has obvious genetic relationship with the source rocks of the Dalong Formation and Upper Longtan Formation, the crude oil in the 2^# oil sand of the Longtan Formation is closely related to the source rocks of the Lower Longtan, Gufeng, and Qixia Formations; While the crude oil in the 3^# oil sand is in obviously low maturity, which may be derived from the Cretaceous and Paleogene source rocks in the depressions on both sides of the central uplift. The mutual corroboration of basin modelling and temperature measurement of hydrocarbon-bearing inclusions shows the multi-stage hydrocarbon accumulation characteristics with relay hydrocarbon generation and wavy hydrocarbon charging between the four sets of source rocks and three sets of reservoirs in borehole CSDP-2, which is benefited from the good sealing of the three sets of caprocks. It proves a relatively broad exploration prospect for marine oil and gas in the South Yellow Sea basin.

At the end of December 2018, a high-yield gas-flow of 22.5×10⁴m³/d was discovered by the risk exploration well of Permian volcanic rock-Well YT1 deployed by PetroChina southwest oil & gas field company, which made a breakthrough in the exploration of volcanic rocks in Sichuan basin and broadened a great exploration potential of pyroclastic gas reservoir. According to the latest drilling results,the latest analysis,and test data, the gas-gas correlation method in different areas was adopted. The analysis of the geochemical characteristics of natural gas, the anatomy of the source reservoir contact relationship and the comprehensive comparison of gas sources in this area were carried out,and the origin of natural gas in the Permian volcanic gas reservoir and the gas source were determined. The results show that the natural gas of Well YT1 in the volcanic gas reservoir is typically dry gas, with a drying coefficient of 0.997, the content of CH₄ is high with an average of 99.03%, the content of C₂H₆ is low with an average of 0.35%, C₃H₈ is almost absent and the content of H₂S is zero; the carbon isotope values of methane and ethane are relatively light with the average carbon isotopic values of-32.17‰ and -34.27‰ respectively,and a large amount of reservoir bitumen can be seen in the core and under the microscope. The genetic identification analysis shows that the natural gas of Well YT1 in the volcanic gas reservoir is the secondary cracked gas of crude oil. Based on the source reservoir contact relationship and the comparison of methane and ethane carbon isotopes of natural gas, the natural gas of Well YT1 in the volcanic gas reservoir is mainly from the thick, high-quality,and effective source rocks of the Lower Cambrian Qiongzhusi Formation, which developed in the internal rift valley of the Deyang-Anyue platform and partially from the Middle Permian.

In terrestrial rift basins, faults and sand bodies are the main elements of hydrocarbon migration network. In order to explore the mechanism of hydrocarbon migration and accumulation in the Chengbei fault terrace zone of Qikou sag under the control of fault-sand configuration transportation conditions, the types of fault-sand configuration and their controlling effect on hydrocarbon migration and accumulation were analyzed through quantitative evaluation of fault and sand body conductivity. The results show that the fault-sand configuration can be divided into four types according to the main functions of faults in the process of hydrocarbon accumulation, including configuration of oil source faults and multiple sets of sand bodies superposed vertically, configurations of transport faults and sand bodies terraceped forward and backward, and configuration of adjusting faults and sand bodies in "Y" shape with a "relay-style" accumulation model formed in the space. The controlling effect of fault-sand configuration on hydrocarbon enrichment is mainly reflected in three aspects:1) Control the types of oil and gas reservoirs:The configuration of oil source faults and multiple sets of sand bodies mainly controls the formation of structural-lithologic and fault block oil-gas reservoirs, the configurations of transport faults and sand bodies in the forward or reverse direction control the formation of fault block, fault nose, and composite oil-gas reservoirs, and the configuration of regulating faults and sand bodies in "Y" shape controls the formation of fault block oil-gas reservoirs; 2) Control the hydrocarbon migration process:The configuration of oil source faults and large zone sand bodies at the fault root connects the deep hydrocarbon source, during the activity period of oil source faults, oil and gas migrate along the fault to the shallow layers, and then accumulate in the high part of fault terrace zone after a long distance migration. The terrace-by-terrace vertical or reverse configuration of transport fault and sand body provides the terrace-by-terrace vertical and lateral migration channel for hydrocarbon, and the configuration of adjusting faults and sand bodies plays a role of readjustment and distribution in the process of hydrocarbon accumulation; 3) Control the position of hydrocarbon migration and accumulation:When the probability of fault migration f is more than 50% and the ratio of sandstone thickness to total formation thickness is more than 0.50, the fault-sand configuration is considerred to be completely fluidly connected. In the middle-shallow layers, oil and gas migrate along the transport fault, and the sealing property of the transport fault controls the hydrocarbon accumulation, while in the middle-deep layers, the degree of oil and gas accumulation is positively related to the ratio of sandstone thickness to total formation thickness.

Fault trap is an important type of structures in a slope area. To identify the location and formation period of fault traps, the authors analyzed the formation and evolution process of the consequent and antithetic fault traps in the slope area on the basis of considering the formation and evolution of faults. The result suggested that the consequent fault traps were formed in the "hard-linkage" stage and developed at the segmented growth sites of the hanging wall of the fault; while the antithetic fault traps were formed at the beginning of the fault activity and developed at the site with the largest displacement of the footwall of the fault. On this basis, a method was established to identify the fault trap location and formation period combined fully with the technology of throw-distance curve, coherent slice, the quantitative representation of the fault segment growth stage, and the throw back-stripping using detailed 3D seismic data. This method was applied to identify the fault trap location and formation period in the Wen'an slope of Jizhong depression, and the result is in accord with the actual hydrocarbon distribution.

Sanjiang basin is an important Mesozoic-Cenozoic basin in northeastern Heilongjiang Province. Based on the study of the uranium source conditions, Mesozoic-Cenozoic tectonic evolution, tectonic framework, Mesozoic-Cenozoic paleoclimate evolution, the sedimentary formation characteristics of the main caprock and the epigenetic alteration characteristics, the metallogenic conditions of the sandstone-type uranium deposits in Sanjiang basin is comprehensively analyzed under the guidance of the metallogenic theory of sandstone-type uranium deposits,and the prospecting direction of the basin is discussed. It is concluded that the uranium source conditions in the western part are better than those of other parts of the basin;Since the Mesozoic, two stages of tectonic inversion occurred from the end of the Early Cretaceous to the end of the Late Cretaceous and from the end of Paleogene to the Early Neogene. Under the control of the tectonic reversal, the coal-bearing clastic rocks of the Lower Cretaceous Houshigou Formation and Paleogene Baoquanling Formation are the main target strata for prospecting in the basin;The Lower Cretaceous Houshigou Formation and Paleogene Baoquanling Formation have good stratigraphic structure, lithologic and lithofacies with oxidized zones developed in the local area, which are important clues for finding sandstone-type uranium deposits;The metallogenic conditions of the sandstone-type uranium in the basin are generally better. The western depression should be the key area of exploration, while the Lower Cretaceous Houshigou Formation, Paleogene Baoquanling Formation and Neogene Fujin Formation should be the key horizons for prospecting.

The polymetallic mineralization system of the Baotan Sn deposit frequent magmatic activities in northern Guangxi, the Pingying plutons are composed of early intrusions and late intrusions which is related to the polymetallic mineralization system of Sn deposit. The latter often contains more tourmalite-quartz enclaves. A study on petrology, zircon U-Pb geochronology and geochemistry, shows that the latest intrusive rocks in the Pingying granite pluton is composed of (medium) fine-grained porphyritic biotite (monzonite-) alkali feldspar granite. The U-Pb zircon dating results show that the formation age of the late intrusions was in (769.2±2.5) Ma, and that of the tourmaline-quartz spherulitic bodies was in (795.1±3.1) Ma. The Pingying plutons are generally characterized by rich large ion lithophile elements (LILE, including Rb, Th, U, etc.) and depleted high field strength elements (HFSE, including Nb, Ti, etc.). However, the early and late intrusions are quite different from each other in terms of geochemical characteristics:The early intrusions is belonging to high-K calc-alkaline strongly peraluminous S-type granite, with obvious "U"-shaped peaks for Th-U and "V"-shaped troughs for Ti on the trace elements spider diagram; While the late intrusions is belonging to the shoshonite series, which show "V"-shaped peaks for uranium (U) and "U"-shaped troughs for La-Nd and Eu-Ti on the trace elements spider diagram. According to the results of the study on the properties of the magma source region, the early intrusions belongs to the post-orogenic granite, and may be derived from magma generated by the partial melting of argillaceous rocks and then fractional crystallization of high degree; The late intrusions falls into the non-orogenic granite, and may be the product of the mixing of various degrees of magma and mantle-derived magma generated by the partial melting of argillaceous rocks and psammitolite. There was a genetic relationship between the tourmalite-quartz veins formed in magmatic water at the metallogenic stage of tourmalite-quartz enclaves combined with Zhaigun tin-polymetallic deposit. Moreover, the formation age was basically the same as that of Tianpeng rock mass. Therefore, it is speculated that the tourmalite-quartz enclaves were formed by late intrusive rock capturing the magmatic hydrothermal tourmalite-quartz vein formed during the emplacement of early intrusive rock (Tianpeng rock mass), and the formation age may represent the metallogenic age of tourmalite-quartz mineralization in this area.

The Tongshan rock mass is located at the south of stretching branch of Funiu Mountain in the southern margin of the North China craton, which is composed of medium-grained biotite syenogranite and monzonitic granite. The study on the zircon U-Pb dating and petro-genesis of the Tongshan rock mass is significant for understanding the Yanshanian deep tectonic evolution of the southern margin of the North China craton. The LA-ICP-MS zircon U-Pb dating results of the Tongshan rock mass fall into two groups of (147.0±4.3)-(144.1±4.4) Ma (n=5) and (133.0±3.9)-(127.4±3.6) Ma (n=21), characterized by a bimodal zircon age spectrum with weighted averages of (145.5±4.5) Ma and (130.6±1.8) Ma, respectively. The age of (145.5±4.5) Ma suggests the magmatism concealed around the Tongshan rock mass, and the age of (130.6±1.8) Ma represents its formation of the Tongshan rock mass in the Early Cretaceous. The Tongshan rock mass is characterized by higher SiO₂ and alkali, lower MgO and CaO, and its compositional spots fall into the high-K calc-alkaline series in the w(K₂O)-w(SiO₂) diagram. The peaks of Rb, Th, Zr and Hf and troughs of Sr, P and Ti are shown in the spider diagram. The total rare earth elements are from 43.07×10^-6 to 173.14×10^-6 with the (La/Yb)_N ratios of 1.97-19.58. In the chondrite-normalized REE patterns, the Tongshan rock mass has the characteristics of LREE-enrichment and HREE depletion with Eu negative anomalies ranging from 0.33 to 0.73. It is suggested that the compositional change of the Tongshan rock mass was resulted mainly from the partial melting of source rocks as the compositional trend shown in the (La/Yb)_N-w(La_N) diagram. The partial melting source of the Tongshan rock mass is located in the amphibolite-facies with a crust thickness of 40 km, and its residual phases of the partial melting source includes mainly hornblende and plagioclase. Due to the lithosphere delamination of the Sanhedian-Jigongshan area in the Tongbai Mountain at about 131 Ma in the Early Cretaceous, the deep fluids/magmas discharged rapidly, intruded into the incompletely consolidated magma/fluid reservoir, crystallized the 145 Ma zircon grains, and finally formed the Tongshan granite with the mixed materials in the activation reservoir as shown on the bimodal zircon age spectrum. The Tongshan rock mass was almost the simultaneous magmatic response to the Sanhedian-Jigongshan lithosphere delamination, and the related magma activities occurred not only on the Tongbai-Dabie orogenic belt, but also on the northern Qinling orogenic belt and the southern margin of the North China craton.

Located in the eastern part of the Yanshan orogenic belt on the northern margin of the North China plate in eastern Hebei Province,Yu'erya is one of the main gold producing areas especially with hydrothermal gold deposits. The Yu'erya deposit is representative in eastern Hebei Province, which occurs mainly in the granite of the Jurassic Yu'erya pluton with a few orebodies in the Jurassic diorite that intruded into the granite. The geochemical data show that the w(SiO₂) of diorites is 51.99%-61.88% and w(Na₂O+K₂O) is 5.07%-8.89%, with Mg^# values between 0.37 to 0.64. They are high-potassium calc-alkaline and quasi-aluminum with A/CNK and A/NK values ranging from 0.73 to 0.96 and 1.37 to 2.26, respectively. All samples are rich in LREE and LILE including Rb, Ba, K,and Sr, and are depleted of HREE and HFSE such as Nb, Ta and Ti. The zircon Hf isotope studies show that the ε_Hf(t) values of the diorites range from -16.5 to -6.5. These data indicate that the Jurassic diorite magma originated from the enriched lithospheric mantle replaced by subduction fluids, and was contaminated limitedly by the ancient lower crust material of the North China plate during magma upwelling. In the ore-forming period,the diorite magma provided part of the material for the gold mineralization. Combined with other regional results, this study suggests that the magmatism is likely associated with the subduction of the paleo-Pacific plate beneath Eurasia.

The Shimiaogou area in Liaodong is tectonically located in the Liao-Ji orogenic/active belt in the eastern part of the North China block,which has experienced a very complex tectonic evolution with multiple magma-tectono-metamorphic events. The Shimiaogou rock mass is of granite porphyry,rich in SiO₂,Na₂O, and K₂O,poor in CaO, MgO, and Al₂O₃; It lacks high field strength elements (Nb, Ti,Ta and P) but is rich in large ion lithophile elements(K, Rb, Ba, U) with A/CNK values greater than 1; The REE distribution curve shows"seagull"type, characterized by significant negative Eu anomaly,and Ga/Al value is consistent with the typical characteristics of type A granite. The granite-porphyry magmatic zircon LA-MC-ICP-MS U-Pb dating results show that its rock age was (123.0±1.6) Ma in the Early Cretaceous. Through Hf isotope analysis,the ε_Hf(t) values are between -15.72 and -12.85 with the average of -14.14 and the two stage model age(T_DM2) is between 2 164 and 1 989 Ma with an average of 2 067 Ma,reflecting the main continental crust composition of the source rock. Furthermore, combined with the characteristics of high SiO₂,low Mg,Co,Cr,Ni, enrichment of LREE and LILE and loss of HFSE,it is suggested that the Early Cretaceous granite porphyry magma should be the melting product of continental crust material formed under the subduction of the Pacific plate beneath the Eurasian plate in the active continental margin. The Early Cretaceous environment of Liaodong region is affected by the subduction post-tectonic extension and lower crust delamination. The formation of the Early Cretaceous granite porphyry is controlled by Pacific tectonic domain,the dynamic environment formed in the lithosphere stretching is a direct evidence of lithospheric thinning in Liaodong area.

The Zhuguang-Guidong area is the most important granite-related hydrothermal uranium ore deposit cluster in South China. The Mesozoic mafic dykes are widely distributed in this area, and they are closely associated with the uranium mineralization. In order to confirm the geochronological data of the mafic dykes and the uranium metallogenic time,a whole-rock ⁴⁰Ar-³⁹Ar analysis was carried out. The ⁴⁰Ar-³⁹Ar isotopic ages of the whole diabase are (171.7±1.6) Ma and (169.1±3.8) Ma, indicating that the Lujing area underwent a lithosphere extension in the Middle Jurassic (170 Ma). The results show that at least five major episodes of mafic dykes occurred at 200, 170, 140, 105, and 90 Ma, and at least six major events of uranium mineralization occurred at 195, 165, 125, 90, 75, and 55 Ma, which is consistent with the previously published geochronological data. The ore-forming hydrothermal fluid followed right after each regional basalt event (5-20 Ma),so the uranium mineralization was closely related to the regional basalt events represented by the diabase wall in time, space, and genesis. The correlation between the diabase veins and metallogenic structures and the genesis characteristics of the shallow forms of the mantle hypomagma indicate that it may provide a certain amount of volatile matter (mineralizer) for uranium mineralization and the enrichment place for ore deposits;The ore-forming hydrothermal fluid may improve the carrying capacity of uranium and promote uranium mineralization.

In this paper, the geological,petrological, and geochemical characteristics of volcanic rocks of the Batamayineishan formation are studied in the Aoyituolangge area at the northwestern margin of Santanghu basin of the eastern Junggar orogenic belt, and the genesis, formation environment, and tectonic evolution of the eastern Junggar orogenic belt are discussed in combination with the relevant chronological results. It is concluded that the Carboniferous volcanic rocks in this area have obvious characteristics of continental volcanic rocks and bimodal volcanic rocks. The basic end member of the rock combination is mainly basalt, and the acid end members are perlite and dacite. The characteristics of the major elements show that the basic endmembers have calc-alkaline-alkaline properties; While the acidic endmembers of perlite and dacite have alkaline and freckling properties respectively. The characteristics of trace elements show that the fundamental end elements are relatively rich in LILE, such as Ba, K, Sr, etc., while Th, Nb, Nd, and other high-field strength elements (HFSE) are poor. Among the acidic end elements, Ba, Nb, Sr, Sm, Ti and other elements are strongly depleted, while K is more enriched. The analysis of rare earth elements show that LREE at both ends are relatively enriched, while HREE are relatively depleted. The main and trace elements characteristics of perlite are obviously different from the whole. The geochemical characteristics indicate that the basic end members of the bimodal volcanic rocks came from the partial melting of mantle rocks, the acidic end member of dacite came from the separation and crystallization of the basic end members, and the perlite came from the partial melting of the lower crust. The geodynamic background was the subduction of oceanic crust, which caused the upwelling of asthenosphere heat source, the partial melting of mantle rocks, the extensional thinning of lithosphere, and the decompression and melting of the mafic rocks in the lower crust. The tectonic environment was late in the post-collision extension stage, showing the characteristics of plate chain suture.

In order to analyze the random distribution characteristics and probability distribution model, taking the thermal conductivity of canal foundation clay in cold regions as a sample, the probability distribution laws of the thermal parameters of frozen soils were inferred by using the classical distribution fitting method, polynomial method, maximum entropy method, and normal information diffusion method. Through analyzing the dispersion of thermal parameters and comparing the probability distribution curve, fitting test values, and cumulative probability distribution values, the advantages and disadvantages of different methods to describe the randomness of thermal parameters were evaluated. The results show that the thermal parameters of canal foundation clay are variable in cold regions. The random fluctuation of thermal parameters can be described by the normal information diffusion method. Among the four methods, the fitting precision of the normal information diffusion method is the highest. Based on the sensitivity of the thermal parameters of canal foundation clay to temperature, a standard with an ideal fitting precision is put forward for determining the probabilistic inference interval of the thermal parameters of frozen soils.

The shear experiments were conducted to investigate the effect of different persistency and freezing-thawing cycles on the shear failure mechanism of the joint specimens. The attenuation trend of shear strength of the joint specimens was compared and analyzed, and the change law of cohesion and friction angle with the fractal dimension of shear failure surface was obtained. The results showed that the peak shear stress decreased significantly with the increase of freezing-thawing cycles; the cohesion and friction angle also deteriorated significantly with the increase of freezing-thawing cycles, and the degree of deterioration gradually increased with the increase of persistency; When the joint persistency was constant, the fractal dimension of the shear failure surface showed an exponentially increasing trend with the increase of freezing-thawing cycles; With the fractal dimension increase, the cohesion and friction angle damage factors of joint specimens also showed an exponential trend; When the freezing-thawing cycles were constant, the friction angle damage factor decreased first and then increased with the increase of joint persistency, while the cohesive damage factor increased and decreased first and then increased before and after around 30 times of freezing-thawing cycles.

Four moisture samples were obtained from the unsaturated zone profiles distributed in a typical plain area of Chad Lake basin to estimate the rainfed recharge based on the chloride (Cl) mass-balance method. The rainfed recharge results of the four sampling points (Y₁, Y₂, Y₃, Y₄) are 4.9, 1.5, 7.9, and 26.2 mm/a respectively; That is, the rainfed recharge rate are only 0.72%, 0.22%, 1.17%, and 3.87% correspondingly. Based on the survey work, combined with field investigation and drilling, the reason for the small amount of rainfed recharge is that the infiltration water from the surface is mostly consumed in evapotranspiration in the surface soil or the interface between the clay layer and the aeolian sand layer, and eventually lost to the atmosphere. Undoubtedly, the research area is facing a serious problem of water resources depletion under its single recharge source of Hadejia River, which has been interrupt by local people so greatly that the amount of infiltration to groundwater has been decreasing.

Non-point source (NPS) pollution is one of the key source pollution that leads to the deterioration of water quality in watersheds. In order to estimate the non-point source pollution load, COD_Mn and NH₃-N were taken as the representative indexes, the 1-dimensional water quality model was applied to separate the point source pollution load and the NPS pollution load from water quality monitoring sections,and combined with the improved export coefficient method to estimate the NPS pollution load in the basin. The application results from the downstream of the Chao River basin were compared with that of the traditional hydrological segmentation method combined with the improved export coefficient method. It is shown that the Nash coefficients of the 1-dimensional water quality model combined with the improved export coefficient method are both over 0.8 to estimate the simulated values of NPS pollution load of COD_Mn and NH₃-N, which shows a high simulation accuracy; At the same time, it avoids the shortcomings that the hydrological segmentation method cannot be used to simulate the NPS pollution load in dry season. The result shows that 1-dimensional water quality model combined with improved export coefficient method is a reasonable method to estimate different non-point source pollution loads, this method can be used to predict the NPS pollution load in the basin based on the hydrological data by the SWAT (soil and water assessment tool) model, and as a supplement to the COD simulation of the SWAT model.

Aiming at the impact of coalbed methane (CBM) exploitation on groundwater environment in Qinshui basin, a total of 129 water samples were collected and analyzed by statistical methods, and the relationship between groundwater and CBM co-produced water was systematically evaluated. The hydrochemistry characteristics were analyzed by Piper diagram. The main ions of groundwater are HCO₃^-, SO₄^2-, Ca²⁺, and Mg²⁺, and those of the CBM co-produced water are HCO₃^-, Cl^-, and Na⁺. The types of hydrochemical characteristics of groundwater and CBM co-produced water are quite different. The average concentration of F^-in CBM co-produced water is higher than that in groundwater, so F^-could be treated as a tracer of CBM co-produced water. The concentration of F^-in groundwater did not increase in regional, however, the water samples from Shizhuang block South (1027-4, 1027-5) and Zhengzhuang block Southeast (1030-3) showed high F^-. The relationship of F^- from CBM co-produced water and groundwater was analyzed by cluster analysis. The cluster analysis results show that F^- from CBM co-produced water in Shizhuang block South has a good correlation with Na⁺, HCO₃^-, and Fe³⁺, and the concentration of Na⁺, HCO₃^-, and Fe³⁺ from 1027-4 is higher than that in the surrounding area. F^- from CBM co-produced water in Zhengzhuang block Southeast has a good correlation with NO₃^-, however, the concentration of NO₃^- from 1030-3 is not higher than the surrounding value. It is shown that CBM exploitation does pollute the groundwater in regional, while in the Shizhuang block, the shallow groundwater is polluted by CBM co-produced water.

Aiming at the shortcomings of the system dynamics method in the analysis of the interaction of underground resources, the multi-field coupling theory of porous media was introduced. Taking the hypothetical model of shallow geothermal energy resource development in the form of GSHP as an example, a coupled numerical model of temperature field, seepage field and stress field was established by using the COMSOL platform, and the changes of regional multiple physical fields before and after the GSHP operation and the adjustment of pumping and recharging wells were compared. The results show that the seepage field around the pumping well and recharging well changed significantly after the operation of groundwater source heat pump. After 10 a, the water temperature of the pumping well dropped from the initial 21℃ to about 17℃, and the regional land subsidence was about 2 m. After the pumping and recharging wells were reversed, the temperature of the pumping well decreased from 4.0℃ to less than 0.5℃. All these indicate that the COMSOL platform has good application potential in the interactive analysis and optimal utilization of various underground resources.

In order to assess the ecological safety of mining cities, by using domestic high-resolution satellite image data such as BJ2, GF1, ZY3 and remote sensing technology, the landscape safety evaluation system was constructed based on a GIS platform. The distribution status data of various natural resources and terrain factors in the study area in 2017 were obtained to calculate various landscape indexes(fragmentation index,splitting index,landscape dominance index,disturbance degree,vulnerable degree, and ecological risk). After grid analysis, the general Kriging interpolation method (semi-variogram implicit function) was used to quantitatively analyze and evaluate the landscape safety index of the whole research area. The results show that the landscape ecological security is at the middle and high level in most parts of this area, which is 538 951.58 hm², accounting for 86.75% of the total landscape. From the mining concentrated area to its exterior plains, low mountains,and hilly areas, the ecological environment is gradually improving, as shown by the upward trend of the security level. The total area of the low, middle and low security areas in the study area is 82 342.18 hm², accounting for 13.25% of the land area; Its landscape ecological security is still a big issue and needs the attention of local governments.

Aiming at the low resolution problem of smooth inversion in gravity exploration, the authors proposed a local smooth constrained three-dimensional inversion algorithm based on certain prior information such as the depth of geological bodies and stratum inclination, and a storage method of roughness matrix in smooth inversion. By this method the computer's calculation memory can be reduced through storing the M×N dimension roughness matrix as M×2 dimension, and when the roughness matrix is multiplied by other matrices in this storage mode, the position information stored in the roughness matrix can be read,and the calculating results can be obtained. The theoretical model and measured data were used to perform inversion trial calculations using the algorithm proposed in this study. It is shown that the result of the local smooth inversion algorithm is more accurate than the result of the global smooth inversion, and the algorithm is still stable,effective,and feasible under a given noise level in production.

Unmanned aerial vehicle (UAV) aeromagnetic survey is gradually applied to the field of small and medium-sized large-scale resource exploration due to its advantages of high efficiency, safety, and low cost. This study aims at the structure description and prospect prediction of the 22 km² area in Sanshan district, Wuhu City, Anhui Province. For this purpose,the 1:20 000 high-precision UAV aeromagnetic survey was carrued out. The authors deduced the process of Euler inversion, analyzed and compared the selections of the tectonic index, used Euler deconvolution with the tectonic index 0 to solve the aeromagnetic data inversion, and finally obtained the structural boundary solution set information of the underground magnetic anomaly body. This was applied to the inversion of aeromagnetic data in the study area. According to the boundary position and depth information obtained from the inversion, 18 faults are recognized and combined. A magma distribution area of 8.7 km² is delineated based on the anomalous characteristics. According to the metallogenic characteristics of an iron ore in Ningwu area, the magmatic distribution area and its boundary are determined as a detailed metallogenic survey area.

Impedance inversion is an important technique for estimating the parameters of underground media using the relationship between wave impedance and dielectric constant, which is widely used in GPR and post-stack seismic data interpretation. Conventional impedance inversion requires drilling or logging parameters as constraints, which directly affect the estimation accuracy of the final impedance inversion. In the practical application with lack of borehole data, how to carry out GPR impedance inversion is one of the important contents of the method. To solve the above problems, the authors proposed a GPR impedance inversion method based on velocity analysis. The basic idea is to carry out velocity spectrum analysis and Dix inversion based on multiple offset radar data to obtain velocity information of different depths as the constraint term of impedance inversion. At the same time, the K-means method can automatically pick up the velocity spectrum information, so as to greatly reduce the conventional manual picking error and improve the calculation efficiency. Through a typical random soil medium model, it is verified that the method can also obtain better dielectric constant estimation results without drilling data, and can test noise adaptability effectively. Based on the GPR data acquired from Wurtsmith AFB, in Oscoda area, Michigan, the method proposed in this paper has a good application effect in the parameter estimation of GPR measured data.

Before the M4.8 earthquake on January 24, 2010 in Hejin,Shanxi, the broadband inclinometer at the Linfen seismic station recorded the images that are similar to the sub-instability process of rock fracture, and a number of quasi-synchronous short-term and imminent anomalies were also captured in the laboratory in the epicenter and nearby areas. In this paper, the change characteristics of different geophysical fields observation data before the Hejin M4.8 earthquake and the changes in different stages before stick-slip instability of the seismogenic fault are discussed as follows:1) The sub-instability phenomenon recorded before the earthquake is not a single point or single measurement event but multi-points and multi-physical fields characteristics; 2) The occurrence time of these anomalies is basically synchronous with the time of the sub-instability events recorded by the Linfen broadband inclinometer, and their morphology is mainly characterized by large sudden changes, mostly concentrated in the period of about 45 days before the earthquake within 100 km from the epicenter, and with time passed, they become frequent from the periphery to the epicenter area; 3) Before the Hejin M4.8 earthquake, not only were similar sub-instability phenomena recorded in various geophysical field observation data, but also some small events related to pre-slip were captured by some precursory observation instruments before the instability of the seismogenic fault 1-6 d before the earthquake; 4) The sub-instability phenomenon recorded by the Linfen broadband tilt-meter before the Hejin M4.8 earthquake, and the amount of quasi-synchronous short-term and imminent anomalies in the epicenter and nearby areas occurred when the regional stress in the source and nearby areas increased and the medium characteristics changed; 5) The various geophysical field anomalies before the Hejin M4.8 earthquake showed the coordination of migration and concentration from the periphery to the epicenter along the direction of the seismogenic fault over time, which should be related to the Hejin earthquake.

To reveal the superficial structure of the Central Asian orogenic belt, provide precise constraints on the evolution and deep processes of the crust, a fine model of near-surface velocity structure with a thickness about 3 000 m was obtained through the first-arrive wave tomography based on a total of 2 186 shots across a 400 km long deep seismic reflection profile in the eastern section of the Central Asian orogenic belt (Naiman Banner-East Wuzhumuqin Banner). This model calculated the variation of sedimentary thickness and the bedrock undulation, and the scale and thickness of the forearc basin with low-velocity characteristics were obtained near the Hegen Mountain suture zone and Xar Moron suture zone. Based on the near-surface velocity structure and the strong amplitude reflection information of the deep seismic reflection profile, a structure model was inferred that coincides with the bidirectional subduction of the paleo-Asian Ocean on the north and south sides of the profile and merges with the residual microcontinent block in the middle. The results showed the deposition thickness varies from 0.3 to 3.0 km, there were multi-periodic magmatic and tectonic activities in the study area, and the buried and continuous high velocity structures in Linxi area are mostly caused by orogenic granites. Through our work, the subduction process of the paleo-Asian Ocean can still be traced in the near-surface velocity structure of the continental margin after hundreds of millions of years of evolution.

Surface-related multiple elimination (SRME) is a key step in marine seismic data processing. However, under rough seabed conditions, diffractions are well developed,and the conventional SRME can hardly eliminate complex diffracted multiples. To analyze the causes of multiples with poor suppression effect, firstly we proposed wavefield separation based on f-x EMD to separate the whole data into a reflection part and a diffraction part, so that the multiple prediction can be carried out with these different subsets of the input data, and then the new subsets of predicted multiples can be obtained as reflected-diffracted predicted multiples, diffracted-reflected predicted multiples, and diffracted-diffracted predicted multiples. Further, we modified the interactive process of the conventional SRME by using the better matched diffracted multiple subsets to eliminate multiples. Compared with the conventional SRME, our improved SRME achieved better multiple attenuation results in both synthetic data and field data.

Strong heterogeneity is a problem in the exploration in fracture and vug zones of carbonate formations in the Xinjiang oil work region. In this study, we developed a method based on information fusion of seismic multi-attributes optimized and electric image well logging, then applied it to identify and evaluate the fracture and vug zones existed in carbonate formations,and further to optimize the borehole tracks in carbonate reservoirs. First, we predicted and sculptured the spatial distribution of fractures and vugs by using the information derived from the multiple seismic attributes of coherence, ant tracking, and others in combination with the result of pulse inversion constrained by dip vectors to determine the scope of the potential hydrocarbon trap; Second, the orientation and dip of the fractures and the scattering of the vugs were statistically estimated through the information automatically picked up from the borehole electric images by means of mathematical morphology filtering; Third, the orientations of maximum and minimum stresses in the formations were estimated through the information of borehole collapse deduced from the multi-arm dipmeter logs and the drill bit induced fractures extracted from the electric image well logs; Furthermore, the results of fracture distribution and vug scattering were obtained through information fusion of multiple seismic attributes and electric images, which can be used as an indicator of the orientation of the maximum stress in regional slipping faults. The orientation of the maximum stress in this region is directed to NE-SW, locally directed to NW-SE, and the fractures with medium-high dip are along the maximum stress direction. Based on the predicted maximum stress, the optimization borehole track of deviated borehole and horizontal well was designed along the direction of NW-SE. In application, the drilled boreholes penetrated large scale high quality reservoirs, and obtained stable amount of oil production. Also, by using this method, the risk of deep formation exploration can be significantly decreased.

Since the impoundment of the Three Gorges Reservoir, a large number of reservoir earthquakes have occurred around the Yangtze River, mainly in the area of Badong-Xietan-Xiannüshan. So far, they have reached tens of thousands of times, with the maximum magnitude of 5.1. Through the field geological survey of the Xiannüshan and Jiuwanxi fault zones and the existing seismic data of the reservoir, a tectonic geological method is adopted to analyze the law of migration, the periodicity of time, and the genetic mechanism of the micro-seismic groups. It is concluded that from the time point of view, the reservoir earthquake has periodicity of long period (related to reservoir water level) and short period (related to rapid fluctuation of reservoir water level). From the space point of view, the reservoir earthquakes have a certain migration law:The reservoir earthquakes triggered by the Jiuwanxi fault have the characteristics of gradual migration to the south; The reservoir earthquakes triggered by the Xiannüshan fault are limited to the northward extension of the Xiannüshan fault; the banded earthquakes induced by reservoirs on the west side of the Xiannüshan fault (near Zhouping Township) have the trend of gradual migration to the south.

Landslide is important hidden geological disasters that effect on the safety of roads and bridges. As a nondestructive and efficient investigation method, geophysical methods can effectively find out the features of geological structures and sliding surfaces inside the landslide body. By taking the landslide at the exit of Chongli tunnel of Zhangyu line as an example, the geophysical characteristics were analyzed by means of high-density resistivity method and shear wave velocity test combined with borehole data. The apparent resistivity and shear wave velocity of the landslide have obvious vertical differences, which reflect the differences in the vertical rock properties, density, and moisture of the landslide. The result shows that the top surface of the highly weathered rhyolite with high apparent resistivity and shear wave velocity is the potential sliding surface. On this basis, it can basically be inferred that the landslide body is composed of alluvial and alluvial deposits, attached to the rhyolite rock body, with a transverse length of 300 m, a longitudinal length of 260 m, and a sliding body thickness of 20-30 m. Simultaneously, according to the analysis of the high-density resistivity of the three-dimensional profile, it is considered that the slide toe at the bottom of the sliding body is the shear outlet position. Based on the above characteristics, the geological model of the landslide is established.