Volcano stratigraphy has three distinguishing features:temporal attributes of ephemeral construction and long erosion, spatial attributes controlled by eruption style and paleo-topography, and occurrence changed with volcanic vents. In this paper,the classification and identification marks of bed, deposit unit and volcanic edifices are introduced in detail. Volcano stratigraphic units were determined by using stratigraphic boundary to reflect temporal attributes, and by using lithology succession and geometrical shape to reflect spatial attributes and occurrence characteristics. The stratigraphic units include bed, deposit unit, volcanic edifice, member, formation, and group. The bed was determined by the differences between rock colors, chemical components,and fabrics. According to an eruptive style and emplacement environment, the deposit units were divided into 3 types,namely lava, volcanic clastics,and reworked volcanic clastics. The occurrence changes continuously within a deposit unit, and the units are separated by an eruptive unconformity/eruptive conformity. A volcanic edifice is a product of ordered stacked deposit units. Volcanic strata lean along volcano vents,and their dip angles decrease gradually from central belt to distal belt. Volcanic edifices were divided by eruptive interval unconformity boundary. More attentions should be paid to the spatial attributes so as to establish a volcano stratigraphic framework. The buried history of volcano stratigraphy should base on the analysis of central belt and distal belt of volcanic edifices. On the basis of the new framework of volcano stratigraphic units,the reservoir distribution are more reasonable

Since the great potential of Precambrian-Cambrian strata for oil and gas exploration in the central and western of China has been discovered, it had attracted widespread attention recent years. In this paper, the petroleum geological characteristics and main control factors for the hydrocarbon accumulation of the typical Precambrian-Cambrian basins are described, taking the Oman basin and East Siberian basin for example. We expect to provide a meaningful reference for the oil and gas exploration breakthrough in Precambrian-Cambrian basins of China. The source rocks of Oman basin and East Siberian basin both developed in the initial rifting area, which have generated lots of hydrocarbons before Silurian or Devonian under the control of depth. Sandstone distributed widely as the main reservoir lithology, which can be transformed into high-quality regional reservoirs by post-reformation impacts, such as weathering, leaching, cement dissolution and tectonic fractures.The cumulative thickness of gypsum-salt strata is more than 1 000 m, which is the key factor of the regional seal to preserve the ancient reservoirs generated from the Precambrian-Cambrian stratum, after compared with the petroleum geological characteristics of the other Precambrian-Cambrian basins, we can find that Tarim basin Cambrian petroleum system also has the characteristics of an ancient giant fields, which mainly includes the development of several sets of high abundance of high-quality hydrocarbon source rocks, a thick layer of rock salt paste regional cap and accumulation hydrocarbon in multiple depths after long-distance migration. These indicate that the Tarim basin Cambrian has huge oil and gas exploration potential.

For the aim of revealing deep-buried Qingshuihe Formation (K₁q) reservoir characteristics and the factors governing reservoir quality, formation test and related researches of regional burial history, paleo-temperature and depositional system were analyzed by casting thin section, SEM, physical properties, X-ray diffraction of clay minerals, together with well drilling-logging data. And on the basis of these data, diagenetic model was proposed. The results demonstrate that K₁q reservoir has a typical characteristic of low composition maturity, high plastic lithic content, and high textural maturity. Although buried mostly deeper than 3 500 m, the reservoir still has a mean porosity of 15.47% and mean permeability of 226.6 mD, and the main pore types are intergranular pores. So the Qingshuihe Formation is a typically favorable reservoir with deep buried depth. Moreover, the overall reservoir diagenesis is characterized by medium compaction, strong dissolution and weak cementation. Despite the deep buried depth, the diagenetic stage still belongs to the stage A₁ of middle diagenesis phase. For the controlling factors on physical properties, the thick mid-fine sandstones and mid-coarse sandstones originated from underwater distributary channels or mouth bars of regionally distributed braided river delta are the basis for the formation of favorable reservoirs. While during the processes of diagenesis, physical properties are mainly controlled by compaction resistance from earlier carbonate cements, chlorite coats on detrital grains and dissolution attributed to acidic diagenetic fluid in later period. In addition to the sedimentary and diagenesis factors above, formation overpressure is the key factor in preservation of reservoir physical properties, significantly reducing the strength of compaction under the condition of deep burial depth. In the meantime, geothermal gradient continuously decreased during the processes of diagenesis and even at present, which resulting in the delying of diagenesis processes and preservation of physical properties.

The Mishrif Formation in the Halfaya oilfield of Iraq develops shoal facies reservoir, and it is one of the main producing horizons in the study area. The Mishrif Formation sedimentary facies has been studied using the data of core, thin section and well logging. The result shows that four types of sedimentary facies are developed in the Mishrif Formation, which are restricted platform, open platform, intra-platform and margin platform. The shoal facies reservoirs are developed mainly in the facies of open platform and margin platform. Casting thin sections observation, physical experiment, and mercury injection are conducted to study the characteristics and genesis of shoal facies reservoirs. A shoal facies reservoir has multiple types of rocks, including bioclast limestone, bioclastic packstone/wackestone and calcarenite etc., and the rock particles are thicker. The pore types are various, mainly in the form of moldic pore, intergranular pore, dissolved pore and visceral foramen, of which intergranular pore and moldic pore development are the most widespread. To all kinds of shoal facies reservoirs, the porosities are higher, the permeabilities differ distinctly with the average permeability at (2.35~139.17) ×10^-3 μm². The overall pore structure is relatively good, displacement pressure is low, but large throats are developed. The development of shoal facies reservoirs is controlled by the depositional environment and diagenetic transformation degree influence. A favorable sedimentary condition is the foundation of the shoal facies reservoirs development, and syngenetic period dissolution modification improves the reservoir properties, so that it become a high quality reservoir.

Ⅱ-Ⅴ oil groups are the main oil layers in the lower part of Minghuazhen Formation(N₁m^L) in Oilfiled A, Bohai. By observation and analysis of the characteristics of sedimentological structure, rock and ore, particle size in core, well logging types, geophysical attributes characteristics,the sedimentary environments mainly include meandering river and shallow water delta. The meandering river mainly develops 4 kinds of sedimentary microfacies, which are channel, splay, natural levee and flood plain. But the shallow water delta mainly develops 4 kinds of sedimentary microfacies, which are underwater distributary channel, the underwater natural levee, the mouth bar and interdistributary in oil field range. Through the analysis of the characteristics of sedimentary facies, combined with high resolution sequence stratigraphy, and discussed the vertical evolution characteristics of Ⅱ-Ⅴ oil groups in the lower part of N₁m^L in Oilfiled A, Bohai, we find that meandering river of Ⅴoil group in a long period of ascending half cycle has the characteristic of strip distribution, and shallow water delta distributes a lump taye in the plane, and the internal sandbody has a poor connection, which is developed in Ⅳ oil group in the early stage of a long period of descending half cycle. The shallow water delta distributes a lobate taye in the plane, sand lateral stack, which is developed in Ⅲ oil group in the middle stage of a long period of descending half cycle. The shallow water delta distributes a bird-foot taye in the plane, sand vertical stack, which is developed inⅡoil group in the last stage of a long period of descending half cycle. Finally, it puts forward the model of sedimentary evolution of the oil field.

Based on the cores and data of residual TOC, chloroform asphalt "A", R_o and hydrocarbon generating potential and other geochemical data of 38 source rock samples from the CSDP-2 overall coring well, this paper distinguished accurately the sedimentary facies and then analysed systematically the characteristics of abundance, maturity and types of organic matter in various formation of the Mesozoic-Paleozoic in the central uplift of the South Yellow Sea basin. Furthermore, combining with the research results of predecessors, we not only compared the differences of source rocks between the sea area with Jiangsu-Anhui area, which are both in the Lower Yangtze region, but also inquired into the oil & gas exploration prospect in the Mesozoic-Paleozoic of the South Yellow Sea basin. The results indicate that the South Yellow Sea had experienced 6 large-scale transgression and regression. Controlled by this mechanism, it developed shallow shelf, barrier coast, and delta depositional system and filled shallow inner shelf, rimmed carbonate platform, tidal flat lagoon and delta front and other continuous sedimentary evolution sequence in the region. The source rocks qualities of 4 sets in the sea basin, Qixia Formation, Longtan Formation, Dalong Formation and Qinglong Formation, are same as the source rocks in Jiangsu-Anhui area, which are all belong to medium-best source rock level. In vertical direction, the qualities of source rocks in Longtan and Dalong Formation are the best, where developed a large number of high-quality hydrocarbon source rocks. Besides, the source rocks in Qinglong Formation are lesser quality but also effective. Based on the above, the marine strata exists rich foundation of hydrocarbons, 7 high amplitude rise sections of gas and fluorescence logging and more than 40 oil & gas shows directly, which all show a great potential for oil & gas exploration in the Mesozoic-Paleozoic of the South Yellow Sea basin.

The central structural belt of Chagan Sag is cut into several fault steps by the Barun fault system, and the oil bearing range in western fault steps is larger than that in the eastern fault steps. The oil CPI in the western fault steps is higher than 1.20, OEP higher than 1.30, Pr/Ph lower than 0.60, and Ph/nC₁₈ higher than 1.00; while the oil CPI and OEP in the eastern fault steps are lower than 1.20, Pr/Ph higher than 0.60, and Ph/nC₁₈ lower than 1.00, indicating the oil maturity is high in the western fault steps. The regular sterane distribution and maturity demonstrate that the oil in the western fault steps was derived from source rocks in the central structure belt; while the oil in the eastern fault steps was derived from source rocks in Hule sub-sag. Internal structures of the fault zones were analyzed using drilling and logging data, and the results reveal that the fault zones are composed of central sliding breaking zones and their induced fractures zones. The sealing capacity of the central sliding breaking zones is better than that of the induced as a result of low permeability. The tight sliding breaking zone is steadily distributed based on a seismic velocity data analysis on the fault that separates the western and eastern fault steps. The faults were active during the deposition of the second member of Suhongtu Formation according to the fault activity analysis. SGR values of the faults are greater than 25%, indicating their excellent sealing capacity. Hydrocarbons accumulated in k₁s²-k₁y according to the result of source rock generation history modeling and fluid inclusion analysis. Since the activity of Barun 3 fault was weak during the hydrocarbon accumulation period and the tight sliding breaking zone is steadily distributed, hydrocarbons expulsed from the Hule sub-sag cannot migrate to the western fault steps. Different source rocks led to the maturity difference of crude oil in different fault steps.

The fine-grained reservoir in Sebei-2 gas field is interbedded by the thin sand-shale beach and bar facies with the characteristics of high porosity and moderate-lower permeability. Aim to evaluate the productivity of gas reservoir, the authors analyzed the connotation of gas productivity. Five geological parameters were selected, including porosity, permeability, gas saturation, effective thickness,and clay content;and their influences on gas productivity were clarified. A single sand body was taken as the basic unit, and the "apparent open flow potential", which eliminates the effect of production pressure drop, was applied as a comparative parameter in combination with the correlation analysis and the analytic hierarchy process (AHP). The weight of each parameter was determined. The threshold values of gas reservoir classification criteria were defined with regards to the actual productive requirement; on which the gas reservoirs were divided into 3 categories. The predicted distributions of gas reservoir productivity are coincident with the trend of the actual gas reservoir productivity. The distributions of the gas reservoir productivity are controlled not only by the gas abundance, the reservoir condition, and the original formation pressure, but also the interlayer quality and structure position. Vertically, the quantity of gas reservoirs increases upwardly and gradually, while the proportion of high level productive gas reservoirs reduces gradually; more gas reservoirs occur in the top gas layers than at the bottom within one group of reservoirs, and the productivity level of gas reservoirs at the top is lower than the ones at the bottom. Horizontally, the high level productive gas reservoirs are distributed in the central and high structural section, and the productivity level reduces gradually and transits to the edge of the plane. The research results can provide some references for a fine adjusting development plan so as to improve the enhanced field gas recovery. By this evaluation, the distribution of gas reservoir productivity can be predicted;and this, in turn, can provide support for optimization of a development plan.

No previous researches have been conducted regarding sealing ability of seal in southeast Ordos basin. In order to evaluate the sealing ability in the study area, four indexes including porosity, permeability, mudstone thickness, and displacement pressure were chosen based on grey system theory. The results indicate that the mudstone thickness is thicker in north and east part of the area, which shows a decreasing thickness from north to south. In the south of the study area, the porosity and permeability increase and the displacement pressures of the seal are higher. The area where displacement value is more than 8 MPa accounts for 70% of the study area. The quality of sealing capacity of Shanxi Formation is good and with a wide distribution of type I and type II. Type I and type II distributed commonly in north and east part as well as areas surrounding City Yanchang, Yan'an and Zhidan. Type III and type IV developed mainly in the south of the study area. The study has been proved that the well evaluated areas have ten thousands m³ output in a single well per day. The research conducted will guide next step of gas exploration and exploitation in southeast Ordos basin.

Copper resources in the Southern and Central Africa are mainly distributed in 12 countries such as Zambia, DR Congo, and South Africa. Based on the study of the formation of African continent, subsequent Neoproterozoic pan-African movement, and Paleozoic-Cenozoic sedimentation, the authors suggest that apart from the northwestern margin of the continent, namely the region from the Morocco to Atlas mountains in Tunisia, the African continent is a grade Ⅰ tectonic unit, and which can be broken down into 5 grade Ⅱ and 28 grade Ⅲ tectonic units by taking the Neoproterozoic pan-African movement as a marker. The 5 gradeⅡtectonic units include the Western African craton, the Eastern African craton, the Central African craton, the Southern African craton, and the pan-African structural belt; on the basis of the above tectonic breakdown, the whole African continent is suggested to be the grade Ⅰ metallogenic domain, and which is divided into 3 grade Ⅱ metallogenic provinces and 32 grade Ⅲ metallogenic regions(belts). 12 of them are related to copper deposits. The 3 metallogenic provinces include Au-Fe-Mn-Cr-Ni-U and diamond metallogenic province in the Southern African craton, Au-Cu-Fe-W-Sn-Nb-Ta and diamond metallogenic province in the Central African craton, and the metallogenic province in pan-African tectonic belt. A preliminary analysis was conducted. Based on the results of geological characteristics and mineralization setting, a summary of the typical ore deposits in the major metallogenic regions (belts) is given in this paper to cover a variety of deposits such as sedimentary metamorphic-reformed Cu-Co deposits, mafic and ultramafic intrusive related Cu-Ni deposits, greenstone belt related copper deposits, carbonate rock related copper deposits, and copper polymetallic deposits associated with limestone. According to the distribution of copper resources, the breakdown of tectonic units, the metallogenic regions (belts), and the characteristics of representative deposits, the authors divide the central and Southern Africa into five potential copper polymetallic ore prospecting areas.

Located in Suichang, Zhejiang Province, Zhilingtou deposit is a large gold deposit on the southeastern coast of China. Its wall rock alterations are widespread in Zhilingtou gold deposit, such as silicification, sericitization, chloritization, pyritization, calcitization and siderite manganese mineralization. From ore body to wall rock, the alteration zone can be divided into quartz-rich, beresitization with quartz, sericite, and chlorite zones. In general, the alteration degree fluctuates with the distance to ore bodies, and forms a shape of lens just as the shape of an ore body surrounded. Gold mineralization is associated with quartz, pyrite, and rhodochrosite alterations. Quartz alteration, pyrite alteration, and rhodochrosite alteration degrees have a similar changing trend; while the sercite and chlorite alteration trend is different. In addition, the deposit develops a low degree of calcite alteration. Both gold mineralization and wall rock alteration occurred in the Paleoproterozoic metamorphic rocks of Badu Group, and did not enter overlying Mesozoic volcanic rocks, which indicates that the formation of the deposit has no relation with the Mesozoic volcanic activities. The elemental quantitative analysis showed that Al₂O₃, TiO₂ and P₂O₅ were inactive components, SiO₂, CaO, MnO, Au, Ag, Cu, Pb, Zn, etc. were gathered,and Fe₂O₃, FeO, MgO, K₂O, Na₂O, Ba, Sr, etc. were lost from the wall rocks in alteration process. According to the alteration features and stable isotope analysis, we conclude that the primitive hydrothermal ore-forming fluids of the deposit were mainly of magmatic water with enrichment in Si, Ca, Mn, Au, Ag, Cu, Pb, Zn, etc., and some meteoric water were added to the fluids in ore forming process.

This paper reports the Mesozoic TTGs outcropped in the Northwestern Lesser Xing'an Range, which was caused by the subduction of the Mongol-Okhotsk Ocean. The TTGs are composed mainly of tonalite, granodiorite, quartz-diorite,and diorite. The zircon U-Pb LA-ICP-MS dating provided the age of (171.1±1.3) Ma, (173.9±3.9) Ma, (178.3±1.5) Ma and (169.1±6.2) Ma corresponding to the four samples, indicating that the magma formed during the Early-Middle Jurassic. They are the High-Al₂O₃ T₁T₂G₁ based on the O'Connor's An-Ab-Or normative classification, and petrochemically belong to metaluminous or weakly peraluminous calc-alkaline series with enrichment in Si and Al, while poor in Fe, Mg, Ti, and Na. The LILE (e.g. Rb, Ba, Th, U, Sr) and LREE are enriched, while HFSE (e.g. Nb, Ta, Zr, Hf) and HREE are relatively depleted with slightly negative Eu anomalies. Such characteristics show that the TTGs have a similarity with type I granite in the Andes type orogenic belt. The low ratios of Sr/Y and (La/Yb)_N and the weakly negative δEu indicate that the residual minerals in the source are hornblende, pyroxene and a little of plagioclase, and little garnet. The co-existence of diorite and tonalite in outcrops reflect that an incomplete and mechanical mixing of two or more magmas might occur, and the intrusion of the TTGs to the Proterozoic strata (such as Xinghuadukou Group and Luomahu Group) and the fact that the TTGs contains lots of captured zircons show that the TTGs magma experienced the assimilation and contamination of the wall rocks during their ascending up through the lithosphere. The authors conclude that the Jurassic TTGs were closely related to the closure of the Mongol-Okhotsk Ocean, and the subduction towards the southern massifs in that period.

The Great Xing'an Range is one of the regions with a development of continental volcanic rocks in the Northeastern China. The volcanic rocks distribute widely, their lithofacies assemblages change greatly, and their formation is complex. We conducted a research on the geology, petrography, geochronology, and Hf isotope geochemistry for the Mesozoic volcanics erupted and emplaced in the granite zone in Xiaomoerke area. The results indicate that: the volcanic rocks in this area can be roughly divided into three assemblages: the first assemblage is mainly of dacitic pyroclastic rocks with dacite interlayer, presenting the characteristics of volcano outbreak; the second one is of basaltic trachyte andesite-trachyte andesite, showing the characteristics of overflow of volcanic magma; the third one is of trachy andesitic fused node clastic rock and breccia trachyandesite lithic crystal tuff combination. The studies on the geochemistry of volcanic lava and tuff reveal that they are all rich in alkali (w(Na₂O+K₂O)=4.88%-7.12%)and belong to the high potassium calcium alkaline series. They possess the similar trace element geochemical characteristics: significant enrichment in large ion lithophile elements (Ba, K etc.) and apparent loss of the HFSE elements (Nb, Ta, Ti, HREE). The fractionation degree of rare earth elements is moderate(LREE/HREE=8.4-8.5) and the negative Eu anomaly is small(δEu is 0.91-1.02). The Above characteristics indicate that these volcanic rocks are the products of homologous magma chamber crystallization, differentiation, and evolution, and the attribute of the magma source is of a mixed transition type of mantle and crust mantle, or of E-MORB or metasomatism of oceanic crust. The two zircon U-Pb ages obtained from the chips of dacitic crystal tuff and trachyandesitic tuff are (124.8±1.0) Ma and (123.3±1.3) Ma respectively, with Hf isotope(ε_Hf(t)=1.7-9.7,T_DM=705-407 Ma, T_DM^C=1 464-748 Ma). In combination with the research progress of regional geodynamics, we further derive that the volcanic activity occurred in the continental margin magmatic arc environment under the subduction of the Mesozoic Paleo Pacific plate to the eastern continent of China;and this coincided with the peak period (120 Ma±) of northeastern area large-scale magma underplating and lithosphere delamination, the initial magma should be adakitic magmas formed through the Paleo Pacific plate deep subduction p. The transitional rocks of adakitic magma and island arc magma might have been formed from crustal the material occurred with a certain degree of contamination during magma invasion and lithosphere delamination; in respect to the compatibility of ore-forming elements, it is confirmed that this period of magmatism provided Mo, Cu and Ag for ore-forming fluids.

Located in the southern end of Yichun-Yanshou metallogenic belt, Wudaoling molybdenum deposit is a typical skarn type deposit. Through researching on the granite porphyry on the edge of the host rocks, we found that the granite porphyry and ore-bearing syenogranite have not only the same formation age, but also the similar geochemical characteristics: the zircon U-Pb ages of the granite porphyry are 194.1±2.0 Ma, and the ore-bearing syenogranite ages are 193.9+1.3 Ma; the type of granite porphyry is transitional from I-type to A-type granites, and is more closer to A-type granites. The syenogranite typically belongs to A-type granites. Besides, both of the granites are high potassium calc-alkaline-weak-alkaline and metaluminous-peraluminous granites with enrichment in Si, K-Na and Al. The granites are enriched in LILE (Rb, K) and light rare earth elements, depleted of HFSE (Nb, Ta, P, Ti). The microelements follow the same trends as that of the rare earth elements, showing that they might be comagmatic products. The initial Sr isotope ratio ⁸⁷Sr/⁸⁶Sr of granite porphyry is 0.723 123. Combining with the regional geological evolution characteristics, the authors suggest that the formation of Wudaoling granitic complex was related to the extended environment after the subduction of the Ancient Pacific plate;and the mineralization of skarn type molybdenum deposit may closely relate to the granite porphyry intrusion. Regionally, it implies a mineralization possibility of the granite porphyry in this phase.

There are ultramafic rocks in Tuquan Mangniuhai, Inner Mongolia. The main rock types are serpentine peridotite,pyroxene peridotite,diallage peridotite,and serpentinite. Under a microscope,the"spinifex"structure is visible,and the columnar hollow skeleton crystal structure in the fake image of serpentine, fishbone, or pinnate structure as well. The petrochemistry is characterized by high Mg (w(MgO)33.63%-39.44%),Cr(2 200×10^-6-17 200×10^-6),and Ni(1 900×10^-6- 3 000×10^-6); high CaO/Al₂O₃(0.56-39.01, an average of 7.05);low Ti (w(TiO₂) 0.01%-0.02%),Al (w(Al₂O₃)0.03%-0.36%),and alkali (w(K₂O+Na₂O) 0.03%-0.65%), similar to that of komatite. The average forsteritic index (87) closes to that of dunite (86); w(∑REE)(0.32×10^-6-2.79×10^-6)is significantly lower than that of ocean ridge, and the LREE/HREE (2.80-16.68) show LREE enrichment with a positive Eu anomaly; the rock is enriched in large ion lithophile elements (LILE) Rb, Ba、Sr, while it is depleted of high field-strength element (HFSE) Nb, P. The results indicate that the mafic magma originated from the depleted asthenosphere mantle, and was altered by subduction in an island arc tectonic environment. The Mangniuhai ultramafic rocks with those in Tuquanweichang, Haolaoluchang, Chaorihaiwula, Meilaotewula Erdaojing of Sonid Left Banner constitute a nearly East-West ultramafic rocks (ophiolite) belt. Based on the analysis of the geological formation, the authors conclude that the structural belt may be the final suture zone of the North China plate and the Siberia plate.

The Paleozoic sedimentary rocks in the Hainan Island are outcropped mainly in the southern Sanya and sporadically in Qiongzhong terranes. Unlike the Sanya terrane, the depositional period of the Paleozoic sedimentary rocks in the Qiongzhong terrane remains as a controversy due to the absence of fossils and geochronological data. This paper presents laser zircon U-Pb dating results for the representative sandstone samples from the Paleozoic sequences in the northern Hainan Island. The three samples collected from the previously-mapped Ordovician (11HN-23) and Silurian (11HN-07, -19) give the youngest ²⁰⁶Pb/²³⁸U apparent age-peaks at 373 Ma, 352 Ma and 369 Ma, respectively. Their detrital zircon age spectrum are similar to those of the sandstone samples taken from the Permian E'cha Formation (11HN-45). These samples yield a predominant age-peak at ~370 Ma and two subordinary age-peaks at ~980 Ma, ~447 Ma, along with two age spans of 1 969-1 520 Ma and 2 681-2 328 Ma. Our results suggest that part of the metasedimentary rocks, which were previously-mapped as Ordovician and Silurian in the northern Hainan Island, were most likely deposited in between Carboniferous and Early Permian. This study enriches the geochronological data for the Paleozoic strata and provides new constraints on the tectonic evolution of the Hainan Island.

Experimental studies were conducted on fast shear conditions of saturated and dry loess at south Jingyang Plateau Landslide, Shaanxi by employing ring shear apparatus. Test results indicate that: 1)Compared with the dry state loess, the saturated loess significantly reduce the shear strength index under the same test conditions. 2)The saturated with the dry loess retrieved from south of Jingyang have shown strain softening characteristics in quick succession shear conditions, but saturated loess is more significant softening characteristics than the dried loess.3)Under the same conditions of normal stress, shear rate has significant influence to peak intensity for drying and saturated loess, but the peak strength of the soil in pace with the shear velocity variation is different under the two states. The peak intensity of swaturated loess increases with shear rate, and peak intensity of dry loess decreases with increasing shear rate.4)In different aqueous state, shear mechanical characteristics of loess retrieved from south of Jingyang have different variation of the mechanism. Among them, in a continuous shearing process the shear strength of dry loess is mainly dominated by clay particles friction (resistance) force, particle alignment and the shear surface morphology. Compared with the dry loess, the peak shear strength of saturated loess soil is mainly affected by changes in the cohesion of control. Effect of soil water in the body can exacerbate their degree of strain softening and form shear smooth surface morphology, thereby affecting its peak after the shear stress.

In order to investigate the effect of pools on solute transport in the conduit, a pool-pipe system was built in the laboratory and the breakthrough curves (BTCs) were generated through quantitative tracer tests under different conditions. The Qtracer2 program was used to obtain solute transport parameters. We use retardation coefficient R to characterize the difference between the 1-D analytical solution of classical advection-dispersion equation and the experimental results. The experimental results reveal that the peak concentration decreases with more pools in series whereas the dispersion and the dispersivity increase gradually. Adding transient storage increases retardation as tailing of the BTC grows with more pools. This demonstrates that transient storage within pools is transformed to retardation. The symmetrical pool has longer tails compared to the asymmetrical pool. The peak concentration lags behind significantly due to the asymmetrical pools. As the flow rate increases, the amount of tailing and the dispersivity decrease in any case. The 1-D analytical solution of classical advection-dispersion equation can fit BTC of the single pipe in maximum discharge well but cannot fit other BTCs with appreciable tails. Therefore, it requires an appropriate model to explain the tailing of BTC.

GMS and TOUGH2 are the famous softwares in the field of groundwater numerical simulation. Although TOUGH2 has the strong ability of numerical calculation, it lacks the friendly interface for pre- and post-process. With the powerful function of pre- and post-process in GMS and the conceptual modeling approach to construct the three dimension model, this paper converts the numerical model of GMS/MODFLOW (including gridding data, rocks property, initial and boundary data) into that of TOUGH2 for numerical calculation. Two examples (flat aquifers and variation elevation of aquifers) are used to analyze the difference of results between GMS/MODFLOW and TOUGH2. The results indicate that this method is elegant to construct complex model fast for TOUGH2 and the difference is small which proves the high credibility for those two softwares. At the same time, this method can take individual advantage of the softwares and provide the feasibility to conduct more complex multiphase flow simulations.

Xianrenqiao hot spring is a great sparesort of China. We conducted a systematic study to explore the genesis mechanism through the methods of geology, hydrogeology and geophysics, for the purpose of further exploration and sustainable development of geothermal resources. Results show that this area belongs to a low-medium temperature geothermal system of convective type, with a composite geothermal genesis model of faults and karsts. The thermal reservoir was originally Paleozoic Cambrian and Ordovician limestone with poor porosity and permeability, but the reservoir property was greatly improved by the structural and dissolved fractures that formed in later period. The cap rocks are mainly Mesozoic Jurassic andesite and andesitic volcaniclastic rocks with strong sealing capability. The hot spring area origins mainly from the rainfall recharged in the area of Changbai Mountain, seeps into the underground thermal reservoir along the lateral faults and karst fractures; Then the groundwater is gradually heated by the normal heat flow during circulating, forming the geothermal water. The thermal reservoir temperature has been estimated to be 89-118 ℃, with a water circulation depth of 2 853-3 820 m; Finally the geothermal water flows upward in the intersection zones of the NE-and NW-striking faults, forming the Xianrenqiao hot spring. In a word, the area that has intersecting faults and abundant karsts is a favorable and prospective area for the exploration of geothermal water. This conclusion provides a theoretical reference for the exploration of similar geothermal resources.

Electromethanogenesis of degrading organics has great potential in bioenergy (CH₄) production, wastewater treatment, groundwater bioremediation, soil and sediment bioremediation. Enriching biocathode with high activity is currently one of the prominent problems to deal with for its development. The cathodic biofilms in glucose-fed SCMMEC exhibited electroactivity. This suggested that wastewater containing glucose could directly be used to enrich biocathode through SCMMEC. Two microbial biocathodes had current density (compared to the geometric surface area of the electrode) of 0.59 A/m² and 0.62 A/m² under 0.8 V applied cell voltage, respectively. However, relative to the bioanode activity, their electroactivity was still lower. They were the current-limiting electrodes in the system. The current with fed-batch mode operation suggested that possible redox mediators or suspended cells did not affect the biocathode electroactivity upon the medium complete replacement. With the medium containing 6 mM phosphate, the biocathode electroactivity showed no difference at day 62 and 153 under 0.8 V. However, the biocathode electroactivity decreased at day 275. Ions concentrating and salt precipitation due to long-term one direction polarization with DC power lead to the activity loss.

During the underground exploratio with frequency domain electromagnetic instruments based on magnetic dipole model, systematic errors are caused by the position and attitude changes of transmitting and receiving coils due to installation errors, the sway of instruments, as well as the geometric distortion of materials and other factors. The quantitative analysis of geometric errors for frequency-domain electromagnetic instruments has a great guiding significance in instrument production, field operation and system correction. According to the sources of the errors, the geometric errors were divided into two categories, one is the primary field error, the other is the secondary field error. By introducing the tensor matrixes of the primary field and the secondary field, we forwarded the primary field and the secondary fields from nine configurations based on homogeneous earth model, and quantitatively analyzed the features and changes of the geometric errors of the nine configurations in a differential way. Numerical results show that, in the primary field errors introduced by the geometric distortion, only PERyz and PERzy coil configurations do not contain linear term of the position change; only VCA, VCP and HCP configurations do not contain linear term of attitude change. In the secondary field errors introduced by the geometric distortion, PERzx and PERxz coil configurations have the maximum relative error; VCA, VCP and HCP coil configurations are greatly influenced by the change of height and coil separation, which needs real-time measurement for correction; and the VCP coil configuration is least influenced by the change of coil separation and attitude.

The accuracy and the application scope of quasi-linear approximation methods, including scalar quasi-linear approximation, diagonal quasi-linear approximation, quasi-analytic approximation and localized quasi-linear approximation, are still a relatively misty concept in large-scale three-dimensional data inversion. In the paper, we implemented three-dimensional numerical simulation based on these approximation methods. By forward modeling,we systematically compared the accuracy of simulation results, and constrained the range of applications of these methods. Theoretical results show that: The diagonal quasi-linear approximation method has the highest accuracy and the widest range of applications among these methods and can give accurate results when electrical resistivity changes within 3-4 orders of magnitude; The accuracy of the quasi-analytical approximation method is a bit lower than that of the diagonal quasi-linear approximation method, and is suitable for calculating the geoelectrical model whose conductivity contrast between abnormal and background is roughly a few times to a hundred times; The accuracy of scalar quasi-linear approximation method and localized quasi-linear approximation method is the lowest, and they are only able to be used to calculate the geoelectric model of anomalous conductivity and background conductivity ratio of roughly tens of times.

The transient electromagnetic response sometimes becomes negative at late times, which may be caused by the induced polarization(IP) effect. Because of the fact that there is no consideration of the IP effect in the traditional real resistivity inversion, the interpretation of the negative part of the observed data has always been a problem which affects the accuracy and reliability of the inversion. In this paper, we first introduced the Cole-Cole complex resistivity model into the forward modeling code and tested its accuracy. Then, one-dimensional TEM Occam inversion algorithm was implemented based on the damped least-squares method. We constructed the inversion equations involving Occam smoothness constraint matrix and inversed simultaneously the four complex resistivity parameters, i.e. DC resistivity, chargeability, time constant and frequency dependence. In order to test the inversion algorithm, we established two different typical theoretical polarized layered models and analyzed their inversion effects. The results show that the complex resistivity parameters can be better recovered in the layer with low resistivity and high chargeability. Comparing with the traditional real resistivity inversion, the complex resistivity inversion can not only perform like the real resistivity inversion, but also solve the fitting problem in the case of the negative response.

Automatic identification of discontinuous geological bodies such as faults and angle unconformity is of significance in seismic structural interpretation, which in the seismic profile appears as the discontinuity of reflection events. The application scope of the conventional seismic data discontinuity identification method is limited due to the fact that its parameter setting relies on human experiences, which could easily results in an improper identification. Therefore, in this paper, coherence is introduced into seismic data processing as a new discontinuity identification parameter. Firstly, the coherence was calculated by the Facet model gradient operator, which is high positioning accurate and easy to be expanded. Secondly, we applied a threshold on the coherence data. Finally, the corrosion, expansion and thinning algorithm in mathematical morphology were used for further processing to realize the automatic identification of the seismic data discontinuity information. Through the synthetic and field seismic data tests, and the comparison with C₃ coherent algorithms, as well as variance algorithm, we can demonstrate that the proposed method can be used as a powerful tool for the discontinuity identification in formations, with a higher stability and identification ability in seismic data discontinuity lineation.

From the electrical image logging data, which has complete coverage and high resolution, by adoption of the multi-scale morphology method, the total porosity volume has been separated into matrix porosity, fracture porosity and karst cave porosity, and the porosity spectrum of the fracture and karst cave has been derived as well. Firstly, the response modes of the FMI (formation microscanner image) corresponding to various fractures and karst caves were analyzed. Secondly, operators of mathematical morphology were introduced, and the method of structuring element selection and filtering operator construction were proposed to improve signal-noise ratio and identify conductivity anomaly from the FMI measurements. After that, based on the edge detection of the conductivity anomaly that were formed by fracture and karst caves, the detection results of karst caves were fitted with elliptic or polygonal functions, and the fracture results were fitted by polynomial. Thus, fracture and karst cave parameters, as well as the spectrum of porosity were deduced from the fitted edge detection results. Finelly, examples of numerical simulation data and field data were provided for the verification of the effectiveness and stability of the multi-scale morphology method in application of FMI processing.

Taking the target imaging of array type ground penetrating radar system as the topic, the authors analyzed the effect and accuracy of the estimation for target echo arrival upon direction of arrival (DOA) in theoretical modeling with three beam forming algorithms, i.e., least square (LS), Capon algorithm and amplitude phase estimation (APES), and put forward a method of array type GPR target imaging based on DOA estimation. This method images the target by integrating the target echo arrival signal estimated from multiple-input-multiple-output(MIMO)array signals with the spatial information obtained from multiple array observations, and localizes target and estimates reflection intensity by the imaging points weighted integral based on the DOA amplitude value estimated from each point by way of imaging points spatial scanning. This method is simple and efficient, and can be used widely in the rapid imaging of simple underground targets.

In order to identify and extract geochemical anomalies, a novel method, which combines projection pursuit classification (PPC), a dimension-reducing technology on high-dimensional data, with the real coded genetic algorithm (RCGA), has been proposed in this paper. We analyzed and discussed the key technological issues in geochemical anomaly identification and extraction using RCGA-PPC model based on the features of geochemical data. At the same time, an application software package was developed for the RCGA-PPC model on MATLAB. As a case study, stream sediment geochemical data in Gejiu, Yunnan, China, were tested with the RCGA-PPC model and Sn, Cu, Pb, Zn, As, Cd, etc. ore forming or/and mineralization associate elements were selected as the variables to recognize anomalies. The results show that most of the local higher optimal projection values are well coincident with the deposits location. Therefore, it can be concluded that RCGA-PPC model could be a useful method for geochemical anomaly identification and extraction.