Seismic data show that the crust of the buried Bachu uplift in the central Tarim consists of the crystalline basement and Paleozoic strata, without Mesozoic and Cenozoic strata, and is unconformly covered by Quaternary terrestrial clastic rock. Both north and south margins of the Bachu uplift present intense deformation with basement-involved structures and thrust fault under the Paleozoic cover. A large-scale northward arcuate structure of the Tumuxiuke basement-involved fault is developed in the north margin of the Bachu uplift. By use of the fault-related theories, we interpreted 2D seismic data with the strata determined by the well logging data, and concluded that the Tumuxiuke basement-involved fault was formed by reactivation of the pre-existing basement-involved wedge-shaped structures. The Late Cenozoic India-Asia collision caused intense intracontinental deformations in the Central Asia and the reactivation of the Bachu uplift. It is unlikely that the pre-existing structures are perfectly perpendicular to the applied contraction direction of the new tectonic event,and most of these structures should consequently experience a strike-slip motion during the reactivation and the arcuate Tumuxiuke basement-involved fault was deformed by the progressive bending of once-straight structural trends (the pre-existing Tumuxiuke basement-involved wedged-shaped structure) during this time. The seismic data show that a wedge-shaped basement-involved structure is clear in the east part, but unclear in the west and central parts of the arcuate Tumuxiuke thrust belt, where many normal faults were formed in anticline core or fore-limbs of monoclines in the seismic reflection sequences. On the top and west parts of the orocline, the late basement-involved faults were developed on the pre-existing Tumuxiuke basement-involved wedge-shaped structures. On the east part of the orocline, the late Tumuxiuke basement-involved wedge-shaped structure reactivated the pre-existing wedge-shaped one. Our interpretations state clearly that there were three general strain zones and corresponding structures in the caprock monoclines that formed the above oblique-slip Tumuxiuke basement-involved fault in the western part of the arc-shaped structure, which is very similar to the physical modeling by Keating et al. (2012), but only in the two strain zones (extension and contraction) on the top of the arc-shaped structure. The extension faults are dominant in the upper-hinge region, while the contraction faults are dominant in the lower-hinge region, and the strike-slip faults are dominant in the middle of the fold limb. The boundaries of these three zones and the magnitude of strain in each zone vary with the oblique slip determined by its position in the arcuate structure.

The thin interbedded sand body is a difficult point in the study of lacustrine sedimentology. Based on the Fourth Member of the upper Shahejie Formation (Es⁴) in the Western sag of Liaohe basin, the theory of sequence stratigraphy, sedimentology and logging geology, the thin interbedded sand bodies are described and analyzed integrated with core, logging and seismic data. It is considered that the braided delta and lacustrine sedimentary facies are mainly developed in the study area, among which the beach bar is the main sand body. The beach bar can be divided into five different parts based on their different sedimentary genetic characteristics:the lateral reformed beach bar, the front reformed beach bar, the bedrock reformed beach bar, the flooded reformed beach bar,and the tempestite reformed beach bar. Through analysis of the control factors of the thin beach bar sand bodies,they are controlled by "wind field-source-basin".

Kaolinite is a common aluminum-rich silicate clay mineral in sandstone reservoirs. It usually fills in the pore-throat of reservoirs. Its appearance generally indicates the dissolution of feldspars and the formation of secondary pores. The authors studied the characteristics, types, origin of the kaolinite through analyzing the data of polarizing microscope, scanning electron microscope, and the physical properties of the reservoir in the third member of Dongying Formation (Ed³) of CFD18-2 oil field in the southeastern part of Shaleitian uplift in Bozhong Sag. The results reveal that:1) The kaolinite of the study area is authigenic kaolinite formed by feldspar dissolution by organic acid. The authigenic kaolinite shows typical "accordion" and "worm" shapes, and is often filled in intergranular pores, feldspar secondary dissolution pores, and carbonate cement dissolution pores, forming good inter-crystalline pores. 2) Two phases of kaolinite are developed in the study area. The first phase of kaolinite is mainly filled in the dissolution pores of early carbonate cement, showing a tiny "worm" shape; the second phase of kaolinite is filled in the dissolution pores of ferrocalcite and ankerite cements, some kaolinite have the characteristics of alkaline dissolution, and the second phase of kaolinite is symbiotic with late illite. 3) The reservoir in the third member of Dongying Formation has a certain ability to seep, so that the "byproducts" formed by feldspar dissolution can be taken away by the fluid. However, under the action of destructive diagenesis, the seepage ability of the reservoir will gradually deteriorate, eventually causing "byproducts" to accumulate in the pores and reduce the physical properties of the reservoir. 4) The effect of kaolinite and siliceous cement on reservoir properties are "double-edged sword". When the content of kaolinite and siliceous material is low, dissolution of feldspar is beneficial to improving the physical properties of reservoirs; while the high content of kaolinite and siliceous is not conducive to the improvement of reservoir quality.

Three reservoir groups are existed in the lower combination of the Yanchang Group in Wuqi-Zhidan area:Chang 8, Chang 9 and Chang 10. In the mid-western part of the study area, the oil and gas mainly originate from the source rocks of Chang 7₃;while in the eastern part of the study area, the oil is from the Chang 9₁ source rocks. The X-ray diffraction and microscope observations of 624 reservoir samples show that laumontite cement is commonly developed in the reservoir in the lower combination. The content of laumontite has obvious vertical regularity:it is the lowest in Chang 8 in the mid-western part of the study area, gradually increases downward,and commonly develops in Chang 10; in the eastern part of the study area, the content of laumontite is the lowest in Chang 9₁, gradually increases in the upper reservoir of Chang 8 and lower Chang 10, and reaches the maximum in Chang 10. This change of laumontite is closely related to the maturity of the organic matter and fluid released from the source rocks. Laumontite belongs to the aluminosilicate mineral formed in the early diagenetic stage under alkaline and low temperature. Under the action of the organic acids and CO₂ released from the mature source rocks, different degrees of laumontite dissolutions occur from near to far. The closer to the source rocks in the vertical direction the formation is, the less the laumontite remains. This distribution regularity indicates the distance and range of hydrocarbon generation and expulsion from source rocks.

Like the homogenization temperature, the salinity of saline inclusions is also an important basis for fluid activity analysis. Based on the test data of fluid inclusions such as salinity and homogenization temperature, the characteristics of episode combinations and episodic activities of reservoir fluid were analyzed in Fushan sag. The results show that the fluorescence color is abundant, the homogenization temperature is of single peak, and the salinity of saline inclusion is characterized by the trend of first falling, then rising and falling again. The fluid inclusions can be divided into seven combinations, corresponding to the seven fluid activities of the Paleogene reservoir forming period:the first two fluid episodic activities were for early hydrocarbon expulsion, the middle three fluid episodic activities were for hydrocarbon accumulation, and the latter two thermal fluid activities were with higher thermal abnormality. According to the comprehensive analyses, characteristics of hydrocarbon reservoir accumulation analyzed about that it include the single stages of petroleum accumulation, and multiple in filling from various source rocks. The analysis result shows that the reservoir in Fushan sag was formed from 13 to 6 Ma in Neogene. The main period of hydrocarbon filling is consistent with the hydrocarbon expulsion peak, and another centralized filling period is consistent with the period of regional tectonic movement. The active period of abnormal thermal fluid is later than the time of hydrocarbon accumulation. It is considered that the abnormal thermal fluid activity is the main reason for the sudden rise of formation water salinity.

The authors studied the organic geochemical characteristics of the oil shale of the Middle Jurassic Shimengou Formation in the Tuanyushan area of the Northern Qaidam basin. The hydrocarbon generation potential, origin of organic matters, depositional environment and metallogenic differences were discussed based on Leco, rock pyrolysis, GC and GC-MS analysis. The results show that three layers of oil shales are developed in the shale member of the Shimengou Formation, and the content of organic carbon is high with an average of 8.16%; the organic matter contains type Ⅰ and type Ⅱ₁ kerogens, with better hydrocarbon generation potential in the first and second layers. Abundant biomarkers, including n-alkanes, isoprenoid, sterane and terpenoid were detected in the samples. The n-alkanes have the features of unimodal distributions with nC₂₃ or nC₂₇ as mean peaks, Pr/Ph from 0.20 to 1.08, C₂₇/C₂₉ sterane ratios, aryl isoprenoids, hopanes and hopenes of the oil shale in the first and second layers are significantly higher than those in the third layer, revealing that the oil shale in the first and second layers were formed under strong reduction conditions, and the organic matters are mainly lower aquatic organisms, whereas the oil shale in the third layer was formed in a weak reduction to reduction environment, and the organic matters are characterized by dual origins of lower aquatic organisms and higher plants. Combined with the differences in the characteristics of oil shale and paleo-lake conditions, it is suggested that deeper lake water is not necessary for the formation of high class oil shale; while the biological input of high class organic matter such as algae and bacteria and strong reduction conditions of bottom water are more conducive to the formation of high class oil shales.

The Muguayuan W deposit in Taojiang County of Hunan Province is a newly discovered large W deposit in the west part of the Jiangnan massif, which is hosted in the Sanxianba granite porphyry. The main ore-forming types include disseminated, veinlet, and reticular types.The major alteration types of wall rocks are comprise of potassium alteration, silicification, sericitization, pyritization, and carbonation etc., typical alteration characteristics of porphyry W deposits. The different mineralizing types of molybdenum-bearing samples were selected for precise Re-Os dating, and the model ages are from 228 to 223 Ma, indicating that the deposit was formed in the Late Triassic. The Re content of molybdenite is (70-181)×10^-6, indicating that they were derived from mixed crust and mantle sources. The metallogenic environment was the post collision in the period of Late Indosinian.

Dongping tungsten deposit is the first super large quartz vein type wolframite deposit found in the north of Jiangxi Province in recent years. It is located in the east of the prospecting area of Dongping-Xianglushan in the Mufu Mountain metallogenic belt in the middle and lower reaches of the Yangtze River. The ore bearing strata of the deposit are shallow metamorphic rocks in the Neoproterozoic Anlin group of Shuangqiao Formation. The north-east trending fault and its secondary fissures are the main ore controlling and ore bearing structures in the area. The concealed Late Yanshanian black mica granites are the ore-forming rock mass, and the quartz vein silicification is closely related to the tungsten polymetallic mineralization in the area. The tungsten ore bodies of the two ore belts occur in the contact zone of the ore forming rocks, showing the typical "five storey" zoning characteristics of the quartz vein type wolframite deposit, and wolframite ore is the main ore type. It is concluded that the mica-pyritization alteration zone, sulfide-bearing quartz vein zone, quartz vein, heavy sand and geochemical anomalies are the main prospecting indicators in this area.

The Gaoyaohai BIF-type iron deposit in Inner Mongolia is located in the northern margin of Western Block of North China Craton,and occurs in the Guyang greenstone belt. The iron deposit is hosted in amphibolites of the Neoarchean-Paleoproterozoic Maohudong Formation Se'ertengshan Group. The iron ores develop needle-columnar granular structure with banded structure. The mineral compositions are mainly magnetite, quartz,and hornblende. The zircon LA-ICP-MS U-Pb dating from the host rock,amphibolite,shows that the weighted average age of (1 933±12) Ma represents the Gaoyaohai BIF ore-rich thermal event. Through protolith restoration,the amphibolites are metamorphic rock, which originated from sub-alkaline basalt series based on the Zr/Ti-Nb/Y diagrams. The geochemical characteristics of the amphibolites indicate that the original rock may be T-MORB. Combined with the tectonic background of T-MORB formation and the regional BIF metallogenic regularity, it is considered that the Gaoyaohai iron deposit formed in the tectonic environment of island arc superimposed mantle plume.

The cherts of Dengying Formation are widely distributed in Huize County in northeastern Yunnan in the 1:50 000 regional survey. This paper mainly focuses on the petrogenesis and their petrological and geochemical characteristics. The cherts in the lower segment of the Sinian-Cambrian Dengying Formation are relatively rich in Al, Ti and ΣREE, with negative Ce anomaly and positive Eu anomaly; the cherts in the middle segment are characterized by high contents of Ca and Mg, relatively low contents of ΣREE (total LREE> total HREE), with negative Ce anomaly and various Eu anomalies; the cherts in the upper segment display relatively low contents of ΣREE (total LREE> total HREE), with negative Ce anomaly and various Eu anomalies. Combined with the regional tectonic evolution in the Sinian-Cambrian region, the petrological and geochemical characteristics indicate that the lower segment chert is deposited in a normal seawater environment, the middle segment chert is a product of a hydrothermal sedimentary environment, and the upper segment chert belongs to a product of normal seawater influenced obviously by hydrothermal fluids. The Dengying Formation chert in the Huize area is formed in a shallow sea shelf environment on the edge of heterogeneous continent.

In this research, the whole-rock geochemistry and zircon U-Pb isotope chronology of moyite from Suotuhan area in the northern Great Xing'an Range are studied and their petrogenesis and tectonic significance are discussed. The LA-ICP-MS zircon U-Pb dating shows that the moyite formed in the Early Cretaceous with the ages of (139.50±0.56) Ma. The geochemical characteristics suggest that the Suotuhan moyite belongs to high K calcalkaline A type granite, and it is featured by high content of SiO₂ and alkaline, and low content of CaO and MgO. The moyite has high rare earth elements (REE), and is relatively rich in LREEs with distinct negative Eu anomalies in chondrite-normalized REE diagram, which is characterized by right oblique and ‘V’-shape. The Suotuhan alkali feldspar granite is a weakly peraluminous A-type granite derived from partial melting of crustal material. The regional geological characteristics indicate that the formation of the moyite was related to lithospheric extension caused by closure of the Mongol-Okhotsk Ocean.

A total of 21 species of the 18 genera sporopollen fossils are discovered for the first time from the section of the Laolongtou Formation (stratotype section of Xingfuzhilu Formation) in Chaganbulage Village, Xingfuzhilu Town, Bairin Right Banner, Southern Da Hinggan Mountains, including Cyclogranisporites sp., Alisporites parvus De Jersey, Alisporites circulicorpus Clarke, Sulcatisporites rhombicus Qu, Lueckisporites virkkiae R. Potonie et Klaus, Piceites sp., et al. Comparing the typical members with the contemporaneous sporopollen assemblages, and combining with the research results,such as the fauna, flora, sporopollen assemblages and LA-ICP-MS zircon geochronology, the Laolongtou Formation should be formed in the Latest Permian to Early Triassic. The botanical affinities of the sporopollen fossils mainly consist of conifers, belonging to a dry-semi arid and hot-worm climate environment prevailing from the Latest Permian to Early Triassic in Xingfuzhilu area.

The seismicity of the Danjiangkou area is well studied for the need of reservoir building. Using different ways such as geological-geomorphological survey, geological age testing, drilling and shallow seismic exploration, we carried out a 1:10 000 scale geological mapping on active faults. It is found that:1) The accumulated sinistral strike slip is 250-500 m of the eastern segment of the Danjiang fault since the Quaternary, and the vertical fault throw is 10-20 m in the Upper Pleistocene stratum. 2) The last active period of the fault is in late Pleistocene and the mechanism is characterized by thrusting of the slip from NE to SW. 3) The fault activity migrates from hill to basin, meaning that the new active site moves to the basin side. 4) The fault in Late Pleistocene shows that the western edge is more active than the other edges. This study provides an important reference for further evaluation of the seismic-tectonic environment of the Danjiangkou area and the west margin of the Nanyang-Xiangfan basin.

In order to systematically study the engineering characteristics of loose rock masses, a detailed geological cataloging and physical prospect testing of the slope rock mass in the area of Lenggu hydropower station were carried out, and the spatial development law of joints and fissures, the development depth and spatial distribution of mosaic and cataclastic rock masses, and the weak structural planes were mainly studied. The systematic statistics and analysis were conducted on the development and distribution of rock masses and the deformation and failure characteristics of the slope. The results show that the rock mass engineering effect is poor,and the deformation modulus is low. The wave velocity of most loose rock masses is less than 3 000 m/s, the maximum principal stress is less than 20 MPa, and the permeability coefficient is greater than 10 L/(min·m·m). The evolution process and characteristics of rock mass fractures and loosening are analyzed combined with the experimental results of stress test, acoustic velocity measurement, and high density electromagnetic exploration. It is concluded that loose rock masses are the result of regional fracture activity and shallow transformation, and rock mass fractures are mainly affected by faults and joints.

In order to study the anisotropic permeability of undisturbed loess, Yan'an Q₃ loess with obvious anisotropy was chosen as the research object. The vertical and horizontal permeability coefficients of different deep-buried undisturbed loess were measured by variable water head permeability tests in laboratory. The results showed that the vertical permeability coefficient of undisturbed loess was larger than the horizontal permeability coefficient of the same horizon. In addition, both vertical and horizontal permeability coefficients of undisturbed loess decreased with the increase of burial depth of loess, and the anisotropy of undisturbed loess was weakened as the burial depth increased, which indicates that anisotropic undisturbed loess gradually become isotropic with the increase of buried depth. Furthermore, in order to investigate the anisotropy of undisturbed loess from microstructure, the longitudinal and transversal sections of undisturbed loess in different buried depths were characterized by SEM (scanning electron microscopy). It was found that the contact and arrangement of soil particles are the fundamental factors resulting in the anisotropic loess.

Siphon drainage combined with surcharge loading is a new technology for soft ground improvement,in which the clogging issue of soil column in siphon flow is critical. The results show that the clay column is prone to form a blockage in the curved section of the siphon tube. Siphon tubes with inner diameter of 4 mm are widely used in field engineering. When the radius of the curved section is greater than 40 cm and the height of the clay column is greater than 4 cm, the clay column will clog in the siphon tube. Aiming at the clogging problem,the critical height solution of clay column under siphon flow is derived by using the particle subsidence model and corresponding hydrodynamic theory. According to the above solution, the anti-clogging measures are proposed to guarantee the siphon drainage operate smoothly. In practice, the siphon drainage process can be maintained by reducing the radius of curved sections, the length of siphon tubes, and the height of siphon outlets.

In order to explore the damage mechanism of frost heave and freeze damage to waterfront light platform structure in seasonally frozen soil regions, and to test the effectiveness of the methods for controlling frost heave and freeze damage of the sleeve, a light platform group in Changchun was taken as the research object. Both vertical displacements of the natural frozen-swelling light platform structure and the light-platform structure equipped with anti-freeze and freeze-frozen sleeve device were observed in cold season by precise leveling instrument, and the foundations of the two were compared. It turned out that there was freeze damage to the foundation of the natural frost heave in the structure, and the frost heave curve demonstrated a "half hump shape" because of the temperature of the observation year. The displacement curve of frost heave showed the characteristics of decreasing-rising-decreasing-stable corresponding to continuous cooling, continuous low temperature, continuous heating in the positive temperature period of the observation year. The uplift of light platform pile was pulled by frost heave force, which caused damage. The vertical displacement of the structure with anti-freezing sleeve device was stable for a long time within a small displacement interval of±5mm, and the average displacement of the structure reduced by 98% compared with that of the natural frost heave in observation. The results showed that the device effectively isolated the effect of frost heave force on the structure; thus the displacement and damage were effectively controlled. During the inspection of the structure with anti-freezing-damage sleeve device, no typical freezing damage of frost heave displacement occurred, such as "misplacement" or "platen cracking", which confirms that the structure equipped with anti-freeze sleeve device is effective for controlling displacement freeze damage.

In order to improve the accuracy of the simulated daily streamflow by the snowmelt runoff model (SRM) and focus on the snowmelt runoff process in the typical watershed of cold and arid mountainous areas, the authors selected the Tizinafu River basin in Xinjiang as the study area, and conducted uncertainty analysis on the basis of streamflow calculated by SRM through adding base flow-data. Based on the Bayesian method, combined with the four commonly used base flow separation methods (digital filter,Kalinlin,BFI, and HYSEP(hydrograph separation program)methods), the parameter uncertainty analysis was carried out by using Markov chain Monte Carlo (MCMC) simulation, and the model performance was evaluated comprehensively. According to the results of the model evaluation, the model using Kalinlin base-flow data (SRM_K) has higher accuracy in both calibration and validation periods (the values of NSE (Nash-Sutcliffe efficiency coefficient)during model calibration and prediction periods are 0.866 and 0.721, respectively). MCMC method can identify model parameters very well, and can accurately obtain the posterior probability distribution of parameters, while TRMM data can describe the characteristics of precipitation in the study area when the related data is lacking or poorly representative.

Hydraulic fracturing is one of the most important technical challenges in the development of hot dry rock geothermal reservoirs in Gonghe basin, Qinghai. Based on the advanced large-scale true triaxial hydraulic fracturing simulation experimental system, the authors studied the hydraulic fracture initiation and propagation in hot dry rock geothermal formations with high temperature and high pressure. The samples were from the outcrop core of Gonghe basin. According to the experimental result, the hydraulic fracture initiation and pressure could be predicted by the crack initiation model proposed in this paper. The propagation in the hot dry rock matrix has a simple extension along only with the direction of the maximum horizontal stress. The hydraulic fractures, however, are affected by natural fractures to achieve larger stimulation reservoir volume. Therefore, it is suggested that in the field, the hydraulic fracturing treatment should be in the formations rich in natural fractures so as to get a complex fracture network for geothermal energy extracting.

Steam injection is a newly developed and promising soil remediation technology for non-aqueous phase liquids (NAPLs) in a vadose zone. In order to investigate the migration characteristics of hot steam in unsaturated porous media and evaluate the effectiveness of steam injection for remediation of chlorobenzene contaminated soil, the authors carried out a steam migration experiment in porous media and steam injection remediation experiment of chlorobenzene through one-dimensional simulated column. The results indicated that the temperature of the given point in the simulated column can be divided into three stages, namely, the environment temperature stage, the heating stage, and the saturated steam temperature stage. The migration velocity of temperature front decreased with distance. The pressure was distributed in the steam-occupied region, and the spatial distribution was linear, and the pressure showed an increase first and then tended to balance over time in a given location. At the end of the experiment, the water saturation measured gradually increased with the migration distance of the steam. The steam injection flow rate was 0.3 kg/h and initial mass fraction of chlorobenzene was 56.8 mg/kg. The removal rate of chlorobenzene in fine sand by hot steam was 98% after 3.5 h. Outflow was produced at the bottom of the simulated column due to the saturation of steam condensate water. The mass concentration of chlorobenzene in the effluent reached the maximum of 152.98 mg/L after 10 min of outflow; while the concentration of chlorobenzene in the effluent was less than 7 mg/L after 70 min. The concentration of chlorobenzene in the medium increased with the distance, maximum residual amount is 0.36 mg/kg. This result shows that steam injection can effectively improve the smearing in contrast to soil vapor extraction.

Yishu fracture zone is the Shandong section of Tanlu fracture zone. The fracture is not only large in scale, but also strongly active, which has the tectonic framework of "two grabens with one base". Based on the 1:200 000 seabed high-precision gravity survey data, the characteristics of gravity field in Laizhou Bay of Yishu fault zone were studied. The data were processed and interpreted by Euler deconvolution and texture analysis for equal boundary recognition in order to refine the tectonic framework of the study area. According to the characteristics of gravity field, 22 faults are inferred, and the main faults are NE-NNE and near EW faults. The four main faults of Yishu fault zone are distributed in Laizhou Bay, in NNE-trending, paralleling, soothing and undulated. The tectonic units are initially divided into three third level, five forth level,and twelve fifth level of tectonic units. It is inferred that on the west side of the Changyi-Dadian fault the high gravity reflects the basal uplift, and the low gravity mainly reflects the Mesozoic-Cenozoic depression; while on the east side of the fault the high gravity mainly reflects the distribution of the Early Precambrian metamorphic rocks, and the low gravity mainly reflects the distribution of the Mesozoic sequence rocks.

The exploration depth of a time-domain airborne electromagnetic (EM) system is closely related to many factors such as sampling time, transmitting dipole moment, earth conductivity, instrument background noise,and sensitivity. This study is about the exploration depth of time-domain airborne EM systems based on time-domain one-dimensional forward modeling. The forward algorithm starts from the Maxwell equation and combines the quasi-static approximation conditions to obtain the vertical component of the EM field response in the frequency domain of the central loop over a one-dimensional layered medium. Hankel integral is used to calculate the EM responses in frequency-domain and then obtain the time-domain responses via time-frequency transform. We set the minimum identifiable signal threshold to be three times of the system background noise level to obtain the maximum detectable departure time, from which we obtained the maximum depth of exploration with the average conductivity. Finally, taking the VTEM system as an example, we analyzed and discussed the maximum exploration depth of airborne EM system in the time domain under different layered media models and different transmission magnetic moments, background noise, transmission pulse width and flight altitude.

The clay adsorption cations in pore fluid can form a double electric layer, which affects the soil conductivity, and together with pore fluid and soil structure make the conductive structure complicated. To address this issue, the resistivity values and other physical properties of soil from the Yellow River Delta and the northern South China Sea slope were tested. The results show that the effects of clay content on the resistivity of marine soil with different consolidation degrees are different. The resistivity characteristics of marine soil can be divided into 3 stages. The variation of resistivity of normally consolidated marine soil can be expressed by simplified binary model formula. When the porosity was less than 50%, the resistivity was power function reduction, when the porosity was between 50% and 60%, the resistivity decreased slowly with the decrease of porosity, when the porosity of unconsolidated marine soil was higher than 60%, the resistivity decreased linearly with the porosity,which can be described by the linear model formula. The resistivity testing technology has a good ability to reflect the changes of the normally consolidated soil structures (porosity) with high clay content, and the detection sensitivity is up to 25 Ω·m; however, it is difficult to reflect the changes of the unconsolidated marine soil.

Underground rocks with vertical aligned fractures can be equivalent to horizontal transversely isotropic (HTI) media. For HTI medium model, the authors studied the inversion method to estimate anisotropic parameter using the seismic amplitude varying with azimuth (AVAZ) of fractured reservoirs. Firstly, in the seismic AVAZ inversion process, the simulated annealing particle swarm optimization algorithm was proposed to invert the anisotropic parameters of fractured reservoirs; then, the validity of seismic AVAZ inversion based on simulated annealing particle swarm optimization algorithm was verified by theoretical model test; finally, the inversion method was applied to the field azimuth seismic data of Longmaxi shale gas reservoir in Sichuan basin. Before inversion, the Fourier series method was used to estimate the fracture orientation and correct the field data to provide more accurate input data. The anisotropic parameters of P and S waves obtained by calculation can be used to evaluate the degree of fracture development. The inversion results show that the fractures on the top of the study area are well developed, which is consistent with the basic geological theory. It verifies the rationality of the inversion method and proves that the inversion results can provide a basis for reservoir fracture identification.

With the continuous expansion of land development and construction scale, land use conditions are also changing year by year. Accurate forecasting of future land use development trends can provide a basis for regional land use planning and improve the efficiency of regional land use. Traditionally,the methods of CA_Markov, ANN, and CA_ANN models are usually used for prediction; however,there are problems such as long training time, poor prediction accuracy, and lack of persuasiveness. Aiming at the above problems, the authors established an adaptive variable filter network model in combination with the cellular automaton and neural network models, and created multiple data sets based on the number of land use categories within a certain area for training of multiple neural networks with different parameters. This model can predict the future land change situation, thus avoid the cancellation of network weights when training a single network. Compared with the best model CA_ANN out of the traditional ones, the overall accuracy of this model is improved by 1%-3%, the accuracy of land conversion is improved by 12.82%-33.33%, and the model predicting time is reduced by 49.47%.

The Yangtze Estuary is located in the intersection of sea and land, and its sea surface salinity (SSS) is affected by the Yangtze River, East China Sea, and social and economic activities of the delta. Salinity can directly reflect the distribution of freshwater plumes;therefore, the research on the spatial and temporal distribution and variation of the Yangtze River salinity is significant for understanding the importance of freshwater plumes, material transport,and estuarine environment. Terra MODIS (moderate-resolution imaging spectroradiometer) remote sensing reflectance, reflectance ratio and field data in dry and flood seasons were used to establish the experienced retrieval models of the Yangtze Estuary, and their RMSE are 0.45‰ and 0.88‰ respectively. The applicability of the model in time scale was also analyzed. The models were used to retrieve SSS in the Yangtze estuarine waters from 2007 to 2016, combined with the runoff observational data from the Datong gauging station, the temporal and spatial variations of SSS were analyzed. The results showed that the SSS distribution in the Yangtze Estuary appeared increasing from the west to the east, which was deeply influenced by the Yangtze River runoff with obvious seasonal differentiation. The off-shore SSS appeared high in the dry season, with high SSS waters reaching westward 123°E, around the bifurcation of the southern and the northern branches of the Yangtze Estuary. Diluted water influenced a larger area in the flood season, which caused the high SSS waters gathering east of 123°E and south of 31°N, along with a low SSS area in the north of the Yangtze Estuary. The Datong gauging station runoff increased during 2007 to 2016 in the flood season, along with the decrease of the average SSS of the study area, and the average SSS was 29.27‰. The runoff decreased in the dry season, along with the increase of the average SSS, and the average SSS was 27.10‰. The SSS variations during 2007 to 2016 had a negative correlation with runoff.

Reconstructing 3D spatial distribution of geological phenomena with 3D geological simulation techniques is essential for natural resource management and risk assessment. Based on the spatial structural relationship of multiple points,and combined with stochastic simulation techniques to create different results, multiple-point statistics (MPS) can be used to reconstruct complicated geological phenomena. However, how to build an appropriate and effective training image is the key problem in MPS-based 3D geological simulations. The authors present a modified MPS algorithm, which combines sequential simulation and iterative methods to extend 2D training images into 3D training images, and applies the EM-like algorithm to optimize the simulation of 3D geological structures. The modeling examples show that the simulation grids are conditional to the training images; on which the stratigraphic sequence of the study area is simulated accurately, and the relationship of stratigraphic structures in 2D cross-sections is effectively reconstructed.