The principle and methods of base flow index (BFI) and line separation have been employed to calculate the baseflow in 13 hydrologic sections on the main stream and 31 hydrologic sections on 20 major tributaries of the Yellow River basin. Based on the baseflow separation results, a comprehensive analysis was made on the forming mechanism of baseflow,the contribution of groundwater to the Yellow River,baseflow changes,the composition and the total amount of groundwater resources in the basin,which has provided a sound and reliable foundation to evaluate the groundwater renewal capability and  set up a rational water resources management strategy in the Yellow River basin.The research result shows that the baseflow of the Huayuankou section accounts for 44% runoff for many years average. The extremely close relationship existed between groundwater and the Yellow River and the groundwater had great contribution to the river. The runoff and baseflow of the Yellow River are mainly from the source area above Lanzhou.The annual runoff and baseflow of the Lanzhou section account for 59% and 60% of the Huayuankou runoff section. However, the groundwater contribution to the Yellow River water was very small in the vast area of upper and middle reaches of the Yellow River between Lanzhou and Huayuankou. Around 1990s, the baseflow in the main stream and tributaries of the Yellow River had been changed greatly. The main stream above Lanzhou had a sharp baseflow reduction (decrease rate of 0.08-0.20) except the source above Maduo (decrease rate of 0.38).However,in the major hydrological sections downstream the Yellow River in Lanzhou, baseflow had large reduction rate(0.22-0.31). The dramatic reduction of baseflow mainly results from the reduction of groundwater resources quantity affected by the nature and human activities such as groundwater exploitation. From the viewpoint of hydrologic cycle on the basin scale,the regional groundwater resource of the Yellow River basin was constituted of three following parts: groundwater resource that participates in the Yellow River water cycle, groundwater not involved in the Yellow River water cycle and the groundwater exploitation in the basin. The natural groundwater quantity from June 1990 to June 2000 is estimated to be 35.39 billion m³/a, which is 15% less than that of groundwater resource of many years average.

The carbonate reservoir evaluation based on well logging data of Russian logging series is done in Yurubcheno oil field in Siberian platform. On the basis of the conversional log characteristic analysis, evaluation parameters from the logging data are given for identification of the reservoir types, fractures, shale intervals of the formation and tight reservoirs in the carbonate reservoir with dual porosity. The reservoirs are classified into matrix type, micro fracture type and macro fracture type. The preferential directions of fractured reservoir distribution are NE-SW and NW-SE which are consistent with the distribution of carbonate and the structural high of the buried hill. It generally locates 0-100 m under unconformity which corresponds to the distribution direction of the dolomite corrosion zone, which controls the distribution of the high production wells. But the distribution of the fractured reservoir is heterogeneous and anisotropic in this field. Factors controlling the distribution of oil and gas in this field are the lithology of the reservoir and its structural location in the buried hill. The reservoir in Yurubcheno Formation, which is pure dolomite and has good location in the structure, has high oil and gas yield. There is poor oil and gas production in the reservoirs in Dolgoktinskaya Formation, where the lithology is not pure dolomite, and the Kuyumbinskaya Formation which located at a lower structural location.

In order to study the formation conditions of the different reserve abundance of gas reservoirs quantitatively, main controlling factors for formation of gas reservoirs, formation conditions of gas reservoirs and reserves abundance are studied by dissection of gas reservoirs and matching relations among accumulation conditions of gas reservoirs, and concluded supply gas capacity of source rock, transporting gas capacity of fault and seal and preservation ability of gas reservoirs are 3 main controlling factors for formation of gas reservoirs. K₁sh rock supply capacity of source is mainly better and bad grade, transporting gas capacity of faults is mainly good grade and seal and preservation capacity of gas reservoirs is also mainly good. The comprehensive evaluation of gas reservoirs formation conditions was mainly in middle grade, secondly in good grade, the least in bad grade. Gas reserves abundance is mainly middle grade, and high and low abundance is less. Relationship between comprehensive evaluation value for the formation conditions and gas reserves abundance was considered to have a direct. To form gas reservoirs with high reserves abundance, comprehensive evaluation of gas reservoir formation conditions should be good, and to form gas reservoirs with middle reserves abundance, comprehensive evaluation of gas reservoir formation conditions should be middle.

The matrix lithology of tight sandstone/gravel reservoirs at the Member 4 of Yingcheng Formation of Xujiaweizi depression in Songliao basin is main target of deep gas prospecting, which includes the upper and the lower of the Member 4 of Yingcheng sequence. During the upper depositional stage, the fault depression is deep and narrow, divided and mutual independent volcanic lake, dominated by the depositional system of alluvial fan facies, fan delta facies (braided delta facies) and flood plain facies; while during the late depositional stage, the fault depression is united and dominated by strongly zonational facies. With the high resolution sequence stratigraphy, the isochronous stratigraphic framework and the depositional evolutional model was built up. The study indicated that structural framework controlled the distribution of various sequence facies in the lake basin.A series of trenches developed in the rim of the fault depression and braided plain, braided delta, fan delta and river delta depositional system developed in the eastern flank to the axial tectonic high.

In order to understand main controlling factors and quantitative characterization of oil-bearing of complex structural trap in west sag of Liaohe depression，the 103 complex structural traps were researched on the base of statistical analysis of geology and R-factor analysis. The results showed that the oil fullness degree of complex structural trap was controlled by the distances between the center of expulsion hydrocarbon and trap, the fluid potential energy, the thickness of caprock and sand body and the numbers of faults cutting the reservoir. The geological analysis showed that the oil fullness degree of the complex structural traps will benefit from the close distance from the center of expulsion hydrocarbon, the relatively low fluid potential energy and the thickness of sandrock in reservoir is less than fault throw and the fault throw is less than the thickness of mudstone in caprock. The comprehensive quantitative connection models between the oil fullness degree and the controlling factors of complex structural traps are established by using the methods of correlation analysis and multiple regression analysis. The 21 complex structural traps are predicted and the validation results of the forecast model indicate that the value of 80% forecast oil fullness degree of the trap is consistent to the real value.

Fuyu reservoir of Sanzhao depression in Songliao basin is a typical down-migration accumulation in syncline of large depressions.Applying the high-resolution sequence stratigraphy theory，analyzing different scales of base-level cycles and stacking patterns with sediment dynamics，based on 11 well cores and loggings of 825 wells，Fuyu reservoir were classified into 1 long-term level cycle，4 mid-term level cycles and 35 short-term level cycles，proposed sequence framework that is regression followed by transgression.The sediment characteristic of short-cycle reservoir suggests that Fuyu reservoir is mainly affected by two sources，the northern Baiquan-Qinggang and the southwest Baokang，which meet around Xujiaweizi then flow to the east，Fuyu reservoir develops typical sedimental system of shallow water delta that controlled by rivers，and distributary channels are main microfacies type. Faults analysis shows that T₂ has the features of intensive belts in plane and flower-like in section，and the oil-sources faults that petroleum accumulation period successively active are main boundary faults of concentrated ribbons. At the end of Mingshui Formation, hydrocarbon generated by Qingshankou source rocks migrates down along open boundary faults of concentrated ribbons at the force of overpressure，then short lateral-migration  along channel sand, finally accumulated on horsts and fault terraces of the uplifted side of both sides，but in the intensive fault zone，most of the units are grabens，so it is not good for accumulation. Based on of the accumulation model，47 hydrocarbon rich target area were depicted，50 million tons of geological reserves are submitted，which gave a clear direction in the exploration and development for the Fuyu Formation in Songliao basin.

The authors made a detailed analysis of the diagenesis types，physical property evolution and its influencing factors  of Chang 6 reservoir of the Chuankou oilfield. According to petrography, thin section analysis and scanning electrical microscopy analysis, the diagenesis mainly includes compaction-pressolution, cementation, metasomatic alteration and denudation, and its diagenetic stage is on phase A of the late diagenetic stage. Among these, compaction and chemical bond are the main factors to cause the sandstone porosity reduction and the accumulation capability degradation. The compaction is mainly demonstrated as the plastic deformation of soft debris, and the evolution from the point contact of granular particles to concave-convex contact of granular particles. The cementation is mainly displayed as aedelforsite cementation, chlorite cementation, hydrosyalite cementation, carbonate cementation, quartz secondary enlargement and feldspar secondary enlargement. The denudation, especially the aedelforsite corrosion, enhances the sandstone accumulation capability. The main factors that influence the reservoir physical property are sedimentation and diagenesis.

The volcanic rocks of Early Cretaceous Yingcheng Formation contain abundant perlitic rocks and they are important petroliferous layers in Songliao basin. Fresh perlitic rocks are found in the Jiutai area of the southeastern uplift of Songliao basin. In the perlitic rocks, phenocrysts are well preserved and they are mainly composed of plagioclase, biotite, amphibole, and mafic clinopyroxene and orthopyroxene. We conducted geochemical analyses on the perlitic rocks as well as vitreous rocks after removing phenoscrysts, and probe analyses on the phenocrysts. The results indicate that the perlitic rocks are felsic high-K calc-alkali series rocks and their trace-and-REE characteristics are similar to upper crust. The clinopyroxene phenocryst is rhombic-hypersthene and/or salite, and hypersthene for orthopyroxene phenocryst. Both clinopyroxene and orthopyroxene phenocrysts are xenocrysts of metamorphic origin. Whereas in the neighbor basaltic layers of perlitic rocks, the plagioclase phenocryst is labradorite, and Fe-salite for clinopyroxene phenocryst, and both are of magmatic origin. All these characteristics suggest that the perlitic rocks might have originated from upper crust, and their pyroxene xenocrysts may be the results of assimilation and contamination of wall rocks during the migration and ascent of magma.

Abundant microsparite(MT)  carbonates was found in the Mesoproterozoic Gaoyuzhuang Formation in Jixian area, Tianjin City. A new type of MT was also found in turbidites. Meter-scale cycle and sedimentary environment were analyzed by using  technologies of profile detailed measured, fischer plot, scanning electron microscope, electron probe and isotopes of Sr and C. Primary MT structures of Gaoyuzhuang Formation were mainly developed in the subtidal of carbonate mesa, midupper meter-scale cycle of deep-water asymmetric type(micrite and calcareous mudstone ) and core of the turbidites. The MT carbonates were developed during HST stage of meter-scale cycle in paleoocean sedimentary environment with the low ⁸⁷Sr/⁸⁶Sr value( <0.709 67) and δ¹³C value((0±1)‰).

The Qingshankou Formation in the Honggang oilfield in the southern Songliao basin contains abundant dawsonite-bearing sandstones. The results show that these sandstones are arkoses and lithic arkoses. The dominant cements are secondary quartz overgrowths, calcite, dawsonite, ankerite and clay minerals. Dawsonite, either as cements, filling inter-grain pores as radial,comb and platy collectives, or as replacement of feldspar and lithic grains with intricately trichoid and platy shapes，and alkaline feldspar replaced by dawsonite are much more than plagioclase. Besides，dawsonite filling in inter-grain pores is microlite collectives when beginning to grow，with the augment of the depth, the average granularity of radial dawsonite and comb dawsonite is bigger and bigger, and the content of platy dawsonite is increased. However, the total content of dawsonite is increased firstly, then decreased. According to the crystal characteristic, combined with the experiment about hydrothermal synthesis and stability of dawsonite, we have discussed the genesis of dawsonite. The crystal characteristic and content of dawsonite correlate with temperature, pH value and CO₂ pressure of fluid closely.

Grade-tonnage model is one of the three essential parts for mineral resource assessment. The authors establish the gradetonnage models for all the types of bauxite deposits in China through a series of statistical tests, including histogram analysis and normal and lognormal distribution tests on the data of 255 bauxite deposits from the Reserve Database of Mineral Resources in China (1999). The research manifests that all the bauxite deposit types are lognormal distributive. The Monte Carol simulation results show that under the 90 percent probability of bauxite resources in China, accumulative bauxite deposit of AlO(OH)₃ and sedimentary bauxite deposit of

AlO(OH)₃ resources are accounted for 198.78 percent and 155.29 percent of the discovered bauxite resources respectively. The bauxite resources have great potential in China, and both accumulative and sedimentary bauxite deposits of AlO(OH)₃ are major future prospecting types and exploration efforts.

Analysis on the mineral composition and chemical data of the topsoil in the northwest sector of the Luanjiahe fault shows that the topsoil in the study area have undergone low-temperature (<150 ℃), neutral to weak alkalic hydrothermal alteration and consist of potash feldspar, plagioclase, mica, quartz, kaolinite of weathered origin and montmorillonite of hydrothermal origin. Comparison of the altered characteristic of the topsoil in the studied area with those of the topsoil covering the known mineralized zones and the hydrothermal origin of the montmorillonite indicates the possible gold mineralization in the sector of the fault under study.

The geochemical characteristics and depositional environment of Pengcuolin chert are studied based on the field investigations and analysis on major elements, trace elements and rare earth elements. The massive chert is green and brown, being high in SiO₂ content, locally enriched in  Fe and Mn, Al/(Al+Fe+Mn) ratio being low. In Fe-Mn-Al triangle diagrams, most chert samples fall into the hydrothermal region. Trace elements such as Sr,Zr,Cu,Zn and Ba are higher and ΣREE is lower, with Ce negative anomaly and Eu anomaly. Their NASC-normalized REE distribution patterns are slightly left-leaning, indicating their hydrothermal origin. In sedimentary environment discrimination diagrams such as 100×Fe₂O₃/SiO₂-100×Al₂O₃/SiO₂, Fe₂O₃/(100-SiO₂)-Al₂O₃/(100-SiO₂) and Fe₂O₃/TiO₂-Al₂O₃/(Al₂O₃+Fe₂O₃), chert samples fall into the areas of the mid-ocean ridges or deep-sea. In parameter variation diagrams, samples of PCL-1,PCL-5 and PCL-7 are closer to the hydrothermal center. It is shown that the Pengcuolin chert, southern Tibet was formed by the hydrothermal systems at convergence and subduction sites of plates.

There is a set of structural melange of oceanic features in Mudanjiang area, Heilongjiang Province. Based on its mineral assemblage and petrographical characters, the melange is divided into three metamorphic and deformed belts, namely, the blueschist, stilpnomelane and biotite belts in turn. The existence of the two intense ductile belts separating the three belts shows they are not successive metamorphic belts but structural belts. Hence, the Heilongjiang melange of the Mudanjiang area does not belong to the normal metamorphic strata of the strictly stratigraphic meaning. The three belts are related to the thrusting from the north to the south. Based on present research and known chronological data, the structural evolution in the area can be divided into three stages: (1)before 305-296 Ma, a stage of subduction of intercontinental oceanic crust and closure of intercontinental ocean between the Jiamusi terrain and the Xingkai terrain;(2)170.26-154 Ma, a stage of collision between the Jiamusi terrain and Xingkai terrain and of an integrated continent affected by western pacific plate;(3)after 154 Ma, a stage of sinistral strikeslip and of its reworking of the Dunmi fault on Heilongjiang melange.

The age and tectonic setting of the Shadegai pluton are discussed based on field investigation and the detailed petrological, mineralogical, geochemical and isotopic geochronological studies. Zircon U-Pb dating gives a weighted mean of  ²⁰⁶Pb/²³⁸U apparent age of 198.5 Ma, which is interpreted to represent the emplacement age of the Shadegai pluton. The pluton was sited at the frontal compressive area of an Indosinian thrust nappe. The pluton is also concluded to be high-k calc-alkaline, postorogenic A-type granite based on petrological, mineralogical and geochemical studies and on tectonic setting analysis. The thrusting-related thicken crust resulted in the melting and emplacement of the magmas responsible for the formation of the Shadegai pluton. Magmatic activity made up an important part of the Indosinian movement in the area.

Aimed at the land-subsidence cased by groundwater exploitation in Quaternary loose sediments, based on Biot’s consolidation theory, took the shallow groundwater exploitation in Wujiang as the case study, a three dimensional full coupling numerical model between the hydraulic action of the seepage field and the stress field was established, in which Duncan-Chang non-linear model and the dynamic models of permeability were introduced with considering the non-linear characteristics and the dynamic variation of hydraulic conductivity of soils with stress. Based on identification and verification of the model, with the constraint condition that the groundwater level would not be lower than half of the roof depth of the first confined aquifer and the land-subsidence wound not exceed 50 mm, the allowable exploitable quantity of groundwater in every town was predicted, the exploitable quantity of groundwater is 1 203.59×10⁴m³/a in the whole area.

It is the key work to determine the hydraulic relationship between surface water and groundwater for setting up the local water hydrologic cycle, opening out water resources forming-mechanism, evaluating water resources quantity and sustainably developing water resources. In Malianhe River catchment located in arid and semi-arid climatic zones, water resources are unevenly distributed in temporal and spatial with fragile ecological environment, therefore water resources problem become serious. Affected by local climate, geological structure and geographical environment,the interaction between river water and groundwater can not be understood yet due to the frequent and complex interaction. Therefore, the interaction of surface water and groundwater has been studied by hydrogeochemical and isotopic methods based on analyzing the characteristics of groundwater hydrodynamic field. Through the analysis, it can be known that Malianhe River water is dominantly recharged by the groundwater of Lower Cretaceous Huanhe aquifer except for minority section in the midstream where hydraulic connection between the river and the groundwater is weak.

Studying the compensation characteristics of the Luan River diversion reservoirs’ inflow, has great significance to optimal operation of the reservoir’s group in the middle and lower reaches of Luan River, and can provide scientific basis for the water resources rational allocation of this region. By using Copula functions, trivariate joint distribution was constructed among the natural inflow series of Panjiakou reservoir, Douhe reservoir and Yuqiao reservoir, and the probability of wetness-dryness that the natural inflow series of these reservoirs can encounter was analyzed. The result shows that the synchronous wetness-dryness encounter probability of the three inflow series is up to 46.96%, and the probability that Panjiakou reservoir fail to compensate Douhe reservoir and Yuqiao reservoir is about 30.2%.

In order to discuss the application of changeable weight combination forecasting model in groundwater levels forecasting, based on the date of groundwater levels from 1997 to 2008 in eastern suburbs of Tongliao City, Inner Mongolia Autonomous Region, the changeable weight combination forecasting method which is based on index model, grey model and linear regression model was used to simulate and forecast groundwater levels of the research area. It was calculated that the sum squares of errors of various forecasting were 5.116 1,5.080 1,4.914 8,4.672 3 respectively. The results indicated that the changeable weight combination forecasting method was more precise than one single forecasting method. From the predictive value, the depth of groundwater level in this research area will decrease to 15.39 m by the end of 2015, and compared with the depth of groundwater level in 2008, the decreasing range will come up to 20%.

The large area nitrate pollution in unconfined water is very serious in Guanzhong basin,and “three nitrogen”  is main contaminant, the concept of groundwater special vulnerability and its influence factors such as groundwater intrinsic factor, artificial factor, and specific factor about contaminant were analyzed. From these factors, 13 parameters were chosen to assess groundwater special vulnerability. The simulating results of “three nitrogen” transport and transformation were coupled to the special vulnerability evaluation model so that the process models were cupled with evaluation model, together with GIS technology, the special vulnerability of groundwater was evaluated. It is shown that the areas in which groundwater is polluted by “three nitrogen” easily are the alluvial plain which located at middle and lower Weihe River, low loess tableland, and the loess tableland that the thickness is less than 20 m near Xi’an at the south bank of Weihe River. The assessment results are accorded with the actual groundwater nitrogen pollution distribution in the year 2001, the concentration of nitrate in groundwater in these areas have exceed criterion in a large region.

According to the theory of dissipative structure，the greater is the information entropy of system, the lower is its order degree. The groundwater environment is a dynamic ordered system, and it meets the characteristics of dissipative structure. The characteristics of information entropy reduction during the course of groundwater system evolution can be used to distinguish its evolution direction. The groundwater resource quantity was regarded as the sequential parameters, which determined order degree of groundwater system. The order degree of groundwater system can be indicated by concordance degree between groundwater actual withdrawals and allowable withdrawals of the groundwater system. The evaluation model of groundwater environment evolution pattern based on grey correlation entropy was founded, through which the evolution direction can be distinguished by using the change characteristics of information entropy in various timeinterval. The model was applied in the study of groundwater environment evolution in Hengshui, and the results indicated that information entropy of deep groundwater system had been tending to decrease since 1970’s, and the function of the groundwater system had been degenerating. Therefore, the groundwater environment was in the evolution state of rebuilding a new stable state, which was significantly different from the primitive stable state. This assessment result is consistent with the evolution trend reflected from the geological environmental monitoring of groundwater environment.

Three strains of gramnegative bacteria, named Mn1, Mn2 and Mn3, which were capable of effective Mn²⁺ oxidization were identified in the water of watersupply plant in Zhangshi economic development zone, Shenyang, PRC. Phylogenetic analysis showed that strain Mn1 and strain Mn2 may belong to the family of Delftia, while strain Mn3 was in the family of Klebsiella. The capability of Mn²⁺ oxidation and fermentation characteristics of these three bacteria were measured using groundwater containing 2 mg/L Mn²⁺. The results showed that the biomass of those bacteria accumulated through 12 h incubation to a level satisfying the requirement of a 1 m³ biofilter and the relative oxidation of Mn²⁺ were about 96%, 94% and 85%, respectively, for Mn1, Mn2 and Mn3. The strains obtained may be of significance for a rapid initiation of biofilter in underground water treatment.

Experiments were conducted to investigate influences of N, S, P and humidity on microbial activity in landfill leachate polluted site. The results indicated that maximum microbial activity in soil and fine sand was up to 0.685 and 0.588 in the 7th day and the 14th day while N and P added, respectively; organic substrate decreased 10.97% and 22.1%, and its average degradation rate was 0.405 and 0.190 mg/(kg·d), respectively. Organic substrate decreased 10.3% and 28.9% for NO^-₃ addition and 8.87% and 28.4% for SO^2-₄ addition in soil and fine sand, respectively. In addition, the maximum microbial activity was 0.259 and 0.266 in soil which humidity was 50% and 60%, respectively, and the average degradation rate of organic substrate was 0.195 and 0.305 mg/(kg·d), respectively. Therefore, N, S, P and humidity had significant effects on subsurface microbial activity.

The authors study on the wetland’s change of Sanjiang Plain in the past 20 years, with the TM, ETM and CBERS data, analyzing and quantifying the present distribution and spatial-temporal dynamic variety by RS and GIS technology. The results show that the wetland is now mainly distributed in the counties of Tongjiang, Fuyuan, Fujin, Hulin and etc., the varieties of lake and river are almost stable. During the study period, the mire area reduced 5 356.69 km² greatly and the constructed wetland increased 11 597.68 km². The results also indicate that the natural wetland landscape’s fragmentation is enhanced and the constructed wetland is connecting together gradually affected by human activity.

The CSAMT is playing an important role in exploring deep buried deposits at present. The application of CSAMT has been studied to explore buried deposits in Longhu Mountain in Tongling, Anhui Province. Pre-processing and inversion of CSAMT data were obtained based on metallogenic regularity and ore-controlling factors in this region. The reliability of CSAMT inversion was verified by TEM inversion and the unity of electrical characteristics.  The irruptive rock body and the channels of magmatic-hydrothermal were successfully discriminated in combination of CSMAT and TEM inversion results.

Magnetic fabric has extensive applications in geosciences research. The shape of anisotropy of magnetic susceptibility (AMS) ellipsoid in a sample can reflect abundant geological information. AMS ellipsoid can not be intuitively reflected by graphs through software used by AMS measuring instrument at present. Its data were stored in binary and text format and were displayed by plain text. It is difficult to estimate the shape of AMS ellipsoid without help of other data processing and graph drawing software. We use Visual Basic.net programming language to calculate the principal susceptibility and principal directions, to display a 3D graph of AMS ellipsoid by calling kernel of mathematical system software-Mathematica and to display principal directions by calling kernel of graphdrawing software-Grapher. AMS data measured can be directly stored into an Excel file. This is the first time that 3D graph display of AMS ellipsoid is realized and 2D graph of principal direction is displayed at the same time. It is also  convenient to transfer data from sample coordinates to geographical coordinates. Furthermore, the principal susceptibility and  direction can be calculated with 15 directional susceptibilities manually input.

A method to modulate seismic vibrator signals was proposed based on aperiodic pseudorandom sequences given a definition of ternary aperiodic pseudorandom sequence. Compared with binary m-sequence modulation, this method doesn’t waste seismic data resources.Generally,a ternary aperiodic pseudorandom sequence has smaller ratio of side lobe to main lobe than a binary one. The simulation results show that the correlation noises in response section to the seismic vibrator signal modulated by ternary aperiodic pseudorandom sequence with smaller ratio of side lobe to main lobe are obviously weaker than that by binary aperiodic pseudorandom sequence with the same length.

The SVD inversion algorithm was improved based on  analysis of the relationship between the optimum  number of singular value retained and SNR. A new iterative scheme was proposed to achieve the nonnegative constraint .The results of numerical simulations and application indicated that the improved SVD algorithm could adapt to low SNR (5<SNR<100) signal inversion and reduce the amount of computation greatly and keep the continuity of T₂  spectrum. This algorithm can well meet the needs of NMR logging.

Urban wetland is an important ecological basis of Shanghai and it is characterized with complex properties. In this study, a decision tree based classification method is used to extract and classify the urban wetland information in Shanghai area. The method uses multispectral bands of Landsat-5 TM image as the main variables, and a series of derivative data as the auxiliary inputs, derived from the Landsat-5 TM images by using respectively K-T transformation, IHS transformation, principal component analysis and textural analysis. With these variables in association with the spatial characteristics of the urban wetland in Shanghai, the method builds a decision tree model for urban wetland extraction and classification. The application of the model shows that the total area of the urban wetland in Shanghai is about 1 277.40 km². The rice cultivated area occupies the highest portion up to 65.30% of the total wetland, and the next the area of rivers, ponds, lakes and reed fields. The decision tree model based method has a relative high precision in the urban wetland extraction and classification. The classification result indicates that the overall accuracy reaches 89.05%, more than 10% increase when compared with the maximum likelihood algorithm.

The availability of spectral information in the shortwave infrared (SWIR) and thermal infrared (TIR) channels of the advanced spaceborne thermal emission and reflection radiometer (ASTER) is much better than that from Landsat ETM. It allows a detailed spectral characterization of land covers, particularly of those rocks and minerals with diagnostic spectra falling into the wavelength range of SWIR and TIR. The authors present a technical approach based on spectral angle mapper (SAM) for hydrothermal alternation information extraction from ASTER images. The method is applied to northern Dong Ujimqin in Inner Mongolia as a case study. The results shows that the ASTER images, through appropriate band combination and image enhancement, are preferable for retrieval of the following three kinds of hydrothermal alteration which contains Fe-OH (jarosite,iron dolomite),Al-OH (clay mineral, alunite, chlorite, sericite) and Fe³⁺(limonite, hematite). Comparatively, ASTER images indicate a greater ability of depictin.

It is because different types of soft rocks have different erosion and weathering levels that the categorization of soft rock samples becomes important in the study of the erosion resistance of soft rocks.The paper implements the algorithms of fuzzy cluster analysis via Matlab and applied to the classification of the soft rocks in Inner Mongolia. The results show that the soft rocks in the study area can be categorized into nine types, namely purple sandstone with celadon mudstone interbeds，purple sandstone，purple sandstone interbedded with offwhite sandstone，purple sandstone with purple mudstone interbeds，offwhite sandstone with purple sandstone，offwhite sandstone，purple mudstone，offwhite sandstone with celadon sandstone and pink sandstone interbeds.