Abstract:Northeast Guangxi has a unique tectonic unit, and is located between the Jiangnan orogenic belt and the South China fold belt. The paper presents the accurate ages of a series of deposits and their related granites with zircon SHRIMP U-Pb, zircon LA-ICP-MS, and the muscovite and biotite Ar-Ar, as well as the molybdenite Re-Os methods. On the basis of deposit types, mineralized elements assembleges in the region, The deposits could be divided into six ore-forming system, namely, (1) W-Mo deposits related to Silurian granite; (2) Sn-Nb-Ta deposits related to late Triassic granite; (3) W-Mo deposits associated with Triassic granite; (4) W-Sn deposits related to Middle-Late Jurassic granite; (5) W-Sn deposits associated with Cretaceous granite; (6) Uranium deposit related to Indosinian granite. The formation of these deposits is closely related to the different periods of tectonic-magmatic evolution, and associated with the syn-collision compressional setting and/or post-collision extensional setting.

Abstract:The Dexing porphyry copper deposit, Jiangxi Province, is the largest porphyry copper deposit in SE China. Considerable studies have been done for the ore–bearing granodiorite porphyries, ore–forming source and ore–forming fluids and etc. However, there are few researches for the quartz diorite porphyrites occurred as veins in this copper deposit. In this study, we have carried out the SHRIMP zircon U–Pb geochronologic analyses for the diorite porphyrite veins from the Tongchang mine of the deposit. Our new SHRIMP U–Pb dating yields a good concordant 206Pb/238U weighted mean age of 153.5 ± 2.4 Ma (2σ, MSWD = 2.5), suggesting that the magmatism occurred in the late Jurassic, emplaced in a back–arc or intra–arc extension environment triggered by the subduction of palaeo–Pacific plate. The high εNd(t) (～0.5) and εHf(t) values (～4.73) possibly indicating that these intrusions have a crust–mantle mixing source. Thus, the Dexing area had not only gone though a continental arc setting in the early period (170～171 Ma), but also gone though an back arc extension setting in the late period (～153.5 Ma), forming the ore–bearing granitic intrusions and ore–barren dioritic intrusions, respectively.

Abstract:Garnet as one of the most typical and important skarn minerals in the Jiama super-large copper polymetallic deposit, Tibet, is a key point for study of skarn due to its wide distribution, various colours and strong mineralization. Through the numerous geological logging of rock/ore core and photo on its colour, crystal shape, mineral assemblage, mineralization, the feature of spatial distribution, mineralization, mineralogy and chemical composition of garnet have been concluded combined with the identification under microscope and electron probe analysis. Garnet in Jiama concentrates in the skarn and few in the hornfels, marble and porphyry close to the skarn. Garnet at Jiama is the andradite-grossularite series and andradite is the major garnet. There are colour and compostion zonations in garnet and it’s partially isotropic due to optical anomaly. The content of SiO2 and Al2O3 of the darker zones are higher than those of the lighter zones, whereas the TFeO content is opposite. Garnet formed at the earlier stage of skarnization, which is favorable for precipitation of sulfides of Cu, Mo, Pb, Zn, Au and Ag mineralization later. The features of mineralogy, component, REE, fluid inclusion and H-O isotope of garnet indicate its contact metasomatism genesis. Therefore, the Jiama ore deposit is a typical magma-derived hydrothermal contact metasomatism skarn type copper polymetallic deposit.

Abstract:This study presents detailed microscopic observations of the Tongguanshan pluton along the Yangtze River region in south Anhui Province, obtained element concentrations of different minerals by electron probe line micro-analysis and LA-ICP-MS. Microscopic features shows there are lots of unbalanced structures in the Tongguanshan pluton, such as embedded crystal structure of plagioclases, hornblendes and acicular apatites, which reveals that the Tongguanshan pluton had undergone through one or several times of magma mixing during its formation process. EPMA results show that the plagioclase zoning is a shock zone, the large-scale zone may be due to a large-scale magmatic activity. Compositions of amphiboles indicate amphibole crystals were most probably originated from mantle or crust-mantle mixing sources. REE and trace elements results illustrate that amphiboles were also from mantle or crust-mantle mixing sources and plagioclase may form from the mixing of magma of different magmatic differentiation. Our results of element concentrations of main rock-forming minerals from the Tongguanshan pluton as well as micro-structural features do reveal the fact of mixture of crust-mantle metasomatism and crystallization kinetics process, well corresponding to former conjecture obtained through geochemical methods.

Abstract:Gongchangling iron deposit is a typical deposit of Anshan-type sedimentary-metamorphic iron deposits. how the high-grade iron body formed is focus on,According to research, the high-grade iron bodies is in the anti-s fold. the high-grade iron bodies are in the rocks composed of plagioclase-hornblende,magnetite-quartzite.The wall-rock of high-grade iron bodies are chlorite schist, garnet-chlorite schist, chlorite-garnet and a little biotite-chlorite schist.By analyzing the iron content of chlorite,garnet and biotite and analyzing the main elements,trace elements,REE of chlorite schist,granet-chlorite schist and chlorite-garnet, the results show that the aluminum-containing pelite - aleurolite between the magnetite-quartzite is an important factor for formating high-grade iron bodies,it can absorb quartz in the magnetite-quartzite and form chlorite,garnet and biotite. the regional metamorphism is the critical condition for forming high-grade iron bodies. On the one hand ,the regional metamorphism can form space for ore and hydrothermal fluid and the power of the hydrothermal fluid migration which could bring out the FeO from the magnetite-quartzite. On the other hand, the regional metamorphism can provided the necessary temperature and pressure conditions for the minerals transforming.

Abstract:By studying the trace elements of the Permian dark mudstones in Ejinaqi and its surrounding Areas，it indicates that it was semi-salt water sedimentary environment during the Permian in this area. Vertically, the water salinity is gradually reduced, which is synchronous with the extinctive process of the rift basin. Horizontally, the eastern（Western Yagan areas）salinity is obviously higher than the western (Beishan areas), which is related with sedimentary paleogeography-with a deeper sea water in the eastern and is consistent with the distribution characteristics of the paleontology. Combing the analysis of V/V+Ni with Ceanom about mudstones indicates that it is reductive environment during the Permian period, which is helpful to the saving of the organic matters. The environment reductibility in the north-eastern area is higher than the south-western area, which controls the distribution of the organic matters. Studying the environmental characteristic has some guiding significance to look for potential favorable hydrocarbon source rocks for us. Combing the distributive pattern of the rare earth elements from dark mudstones with field geological survey indicates its province is from the upper crust and its parent rocks are the mixing of claystones and granite rocks in the studied area.

Abstract:The succeed exploration of porphyry copper deposit in the western Tianshan, Xinjiang, faces much hope but a difficulty. The Tulasu basin is a concentration area of the epithermal gold deposits in western Tianshan, was a south-west-Pacific-type of island-arc setting during late Paleozoic period as the southward subduction of northern Tianshan ocean to Yili plate. The porphyry Cu-Au deposit could be found at the depth or the adjacent of those epithermal gold deposits. Some sulfide mineralized rock enclaves of monzonite porphyry and fine-crystalline diorite are discovered in the andesite, Tawurbieke gold district, Tulasu basin. The enclaves occur in random distribution, generally round or subangular ship, commonly clear boundaries with the hosted andesite, and result chilled margins of the andesite around the enclaves. The monzonite porphyry enclave exhibits porphyaceous texture, and th phenocryst consisits of plagioclase and K-feldspar. The fine-crystalline diorite enclave is mainly composed of plagioclase and hornblende with aplitic texture and massive structure. The hosted andesite show porphyry texture, and the phenocryst consisits of plagioclase, miner hornblende and clinopyroxene, and the groundplasm are composed of short column plagioclase and miner clinopyroxene with hyalopilitic texture. The monzonite porphyry enclave, the fine-crystalline diorite enclave and the hosted andesite shows a similarity of the rare- and the rare-earth-element composition, such as a pronounced enrichment of Large Ion Lithophile Elements, deficit of High Field Strength Elements. The petrology and geochemistry suggests that the rock enclaves were captured from the underlying body by the eruption process of island-arc magma, and the cognate porphyry body may exist under the andesite strata and the porphyry had been sulfide mineralized. The porphyry-epithermal Cu-Au mettallogenic system might occur in the Tulasu basin, western Tianshan, and the Tawuerbieke may be an important target for porphyry Cu-Au exploration based on the fact of the copper mineralizations, acid hydrothermal alterations, the high-sulfidation and the low-sulfidation epithermal gold deposits in the basin.

Abstract:A high-quality database that includes multi-beam bathymetry, piston core, AMS 14C dating, micropaleontologic data, was used to investigate the interactions between down- and along-slope processes within the Taiwan Canyon, South China Sea Slope off southwestern Taiwan. Interactions between down- and along-slope processes are strong and active within the submarine canyons. One thick sand layer with a length of 127 cm and eight thin sand layers ranging from 8-15 cm have been recognized within the core (699cm long) HD133 at a water depth of 3284 m. These sand layers contain significant amount of shallow water benthic foraminifera, revealing that the transportation of sediments form the shelf and/or upper slope basinward into the core site. The following characteristics, however, indicate that along-slope bottom currents were also involved in the construction of core HD133: the sand layers are predominately composed of silt and fine sands with an averaging grain size of 1-4Φ; these sandy sediments are well sorted with sorting coefficient of 2.5-1.0; the feldspar quartz ratio is relatively low, suggesting high textual and compositional maturities; the cumulative frequency diagram indications that grain size of the core sediments commonly shows a tripartite segregation; the sands intervals consist of the matrix-poor clean sands, and show sharp contacts with the silts above. Bulimina aculeate, Planulina wuellerstorfi and Eggerella bradyi, which have been widely accepted as the Northern Pacific Deep Water indicator, are abundant within core sediments. The wide occurrence of the bio-skeletons and shell fragments suggest the erosion of the bottom currents. The Taiwan Canyon is funnel-shaped, with the width increasing from the west to the east. HD133 core is located at the very place where the canyon becomes narrow. Taken together, it is can be concluded that both down-slope turbidity currents and along-slope processes bottom currents were active and vigorous during the deposition of core HD133. The sand deposits with core HD133, thus, are can be interpreted as the products of interactions between down- and along-slope processes.

Abstract:Two periods of fluid movement are recognized in the Big Daqing Anticline (BDA), Songliao Basin. The first period is controlled by the diagenetic process characterized by isolated fluid inclusions inside the authigenic minerals; the second period is controlled by the tectonic movement characterized by linearly distributed inclusions along the fissures or cracks of the autogenetic minerals and a homogeneous temperature higher than the maximum burial temperature. Small-scale hydrocarbon migration during the first episode is indicated by a low content of hydrocarbon fluid inclusions (GOI<5%), while large-scale hydrocarbon migration in the second episode is indicated by a high content of hydrocarbon inclusions (GOI>15%) and a strong fluorescence of yellow-white or brown-yellow. A systematic authigenic illite dating deciphers a rapid hydrocarbon charging process during the tectonic folding. The hydrocarbon accumulation process in the BDA is a typical anticlinal hydrocarbon charging indicated by the negative age-depth distribution model which applies in the flank of BDA with an elevation <－900m, and the positive age-depth distribution model which is suitable in the centre with a height>－900m. The age distribution model indicates that all the strata under the main seal level have undergone hydrocarbon charging in a relatively long short period of 59-69 Ma with reserves >7×109 t (daily charging>2t), which is an efficient but instant hydrocarbon charging process rather than a steady one.

Abstract:The Palaeogene fractured saline muddy limestones are the important reservoir in the western Qaidam Basin. There are shear fracture, tensional fracture, sliding fracture and diagenesis fracture in the Palaeogene reservoirs. Fractures are generally filled with calcite, gypsum and glauberite. The validity of fracture is very important to reservoir evaluation. Effective fractures not only provide storage spaces and channels for fluid flow, but also determine enrichment rule and potential throughput of oil and gas. The validity of fracture is controlled by forming time, solution, uplift and denudation, abnormal fluid high pressure and distribution of gypsum and salt beds. Late fractures are more effective than early fractures. Solution can obviously increase the validity of filled fractures. Uplift and denudation from Quaternary and abnormal fluid high pressure can make filled fractures reopen and have good validity. Fractures distributed far away gypsum and salt beds have better validity. The effective fractures influenced by fault activity are not necessarily aligned with the maximum horizontal stress. Fractures parallel to main faults have the best validity.

Abstract:With continuous expansion of exploration activity, reservoir evaluation system, based on current reservoir characteristics, has not increasingly suited to dynamic evaluation for hydrocarbon accumulation of reservoir with low porosity and permeability. Because reservoir properties often change after hydrocarbon accumulation, lower property limit of reservoir has not objectively reflected the lower limit of the reservoir quality in the hydrocarbon accumulation period. And the application of significance for lower property limit of reservoir becomes very limited. Therefore the author proposes the new ideas that the concept of \"critical properties of reservoir\" is used for reservoir evaluation. By the combination of hydrocarbon accumulation mechanism and reservoir evaluation，hydrocarbon accumulation capacity for low porosity and permeability of the reservoir can be re-understanding. This paper proposes three determination methods of critical properties of the reservoir that are ①log data analysis, ②well testing analysis and ③experimental analysis of critical charge properties in the oil-bearing sandstone. Obviously due to the weak diagenesis after hydrocarbon accumulation, critical properties of normal reservoir, that has little changed, can be determined by the lower property limit of reservoir obtained from log data analysis and well testing analysis. But due to the greatly reducing of porosity and permeability, of reservoir, critical properties of reservoir for low porosity and permeability need be restored. The application of critical properties of reservoir is the supplement for traditional reservoir evaluation. Only being combined with hydrocarbon accumulation and dynamically evaluating reservoir quality, different hydrocarbon reservoir can be objectively distinguished. In the reservoir evaluation for low porosity and permeability, parameters analysis for critical properties of reservoir more effectively evaluate and predict reservoirs’ conditions.

Abstract:Based on the existing high-resolution 2D seismic data and provenance supply mode, the depositional sequence, provenance features and oil-gas exploration prospects were analyzed. Multi-provenances, differences existed between each phase were the characteristics of the provenance supply. In the initial expanding period, the northern marginal area was the primary depocenter, and the North Shelf-Slope provenance system plays an important role. In the initial thermal subsidence period, the depocenter starting to migrate to the basin center, the North Shelf-Slope and Zhong-Xisha uplift zone provenance systems possess mass sediment supply. The two slope-apron fan with downlap characteristics and mass transport depositions with chaotic reflections were symmetrically growing in the north-sourth sides. In the stable thermal subsidence period, the depocenter has moved to the center, the contribution of North Shelf-Slope and Xisha trough provenance systems was reinforced in the short term and produced a large-scale deepwater fan and deepwater channel system, meanwhile, the Zhong-Xisha uplift provenance system was weakened. According to the geological comparison with the middle-high exploration level blocks, preliminarily predicts the basin can be a promising exploration targets in the deepwater area.

Abstract:Organic-inorganic interaction is ubiquitous in the process of formation, evolution, concentration and accumulation of multi-energy resources of oil, gas, coal and uranium. Uranium also alter the process of hydrocarbon generation and evolution of hydrocarbon source rocks while that organic matter accelerate concentration and mineralization of uranium by the strong adsorption and reduction environment from the organic matter. Hydrocarbon- generating simulation experiment is proceeded using hydrocarbon source rock containing kerogen type Ⅱ with uranium (UO2CO3 solution) added to study the effects of uranium on the hydrocarbon generation of hydrocarbon source rocks by comparative study of relevant parameters of experiment products. Experiment results show that uranium can facilitate unsaturated hydrocarbons changing to saturated hydrocarbons, promoting the breaking of long-chain hydrocarbons, the low molecular weight hydrocarbons generating, as a result the content of CH4 increased, the degree of dry gas increased. Uranium can promote the maturity of organic matters, reduce the hydrocarbon generation threshold values and advance the generation of the hydrocarbons of immature hydrocarbon source rocks at low temperature, while delay the over mature of organic matter that benefit to the preservation of hydrocarbons at high temperature. It means that uranium in hydrocarbon source rocks is maybe one of the inorganic accelerating factors of the hydrocarbon generation.

Abstract:Based on the outcrop and core fractures observation and description,fluid inclusion homogenization temperature of in-filled components in fractures,ESR,acoustic emission technology and the rock mechanics property survey，and combined with development characteristics of microscopic fractures,the development period of fractures and its controlling factors is researched of the Second Member of the Upper Triassic Xujiahe Formation in the Jiulongshan Structure in north of western Sichuan Basin.About 4 stages of fracture development have been identified as late Yinzhi Period, fractures are filled by calcite,in which the fracture fillings homogeneous temperature of inclusions was about 84.4~118.5℃;late Yanshan Period,fractures are filled by quartz,,the homogeneous temperature being 72.1~137.9℃;and the 3rd,4th fracture were developed in early-middle and late Himalayan Period,fractures are filled by quartz and calcite,respectively,and the homogeneous temperature were about 153.3~179.1℃ and 165~174.3℃.The first and the fourth stage is the more stronger tectonic movement，fracture more development.The fracture development has been controlled by tectonic stress intensity and the mechanical property of rock.

Abstract:Based on analysis of tight sands reservoir characteristics and cotrolling factors, two types of porosity decrease mathematical model and one type of porosity increase mathematical model in the study area were established by phases. With geological time and burial depth as variables, current porosity as boundary constraint conditions, burial stages and key diagenesis window analysis as basis, the whole porosity evolution process from initial burial until nowadays was divided into seven separate functions which repeated porosity evolution history of the study area dynamically. The quantitative simulation result indicates that: the porosity evolution of each stage follows porosity decrease model or superimposion model of two different types of porosity-evolution model; the variable of porosity decrease model of mechanical compaction stage is burial depth, while variables of compaction-cementation comprehensive stages are geological time and burial depth; porosity increase model is applicable within dissolution window which is identified by Ro from 0.6 to 1.0; the main reason reducing the porosity greatly is mechanical compaction, followed by compaction-cementation, dissolution improves pore space to some extent, and later compaction-cementation causes porosity decrease further until tight reservoir nowadays.