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Enhancing geological Understanding and Identifying Gold Anomalies in the Ailaoshan Orogen

Acta Geologica Sinica(English Edition) 2024年第2期98卷 441-453页

作者： zhao Shiyu YANG Lin SONG Yiwei DONG Yuntao FENG Lihao LI Huajian WU Junyu WANG Qingfei State Key Laboratory of geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China Xi’an Center of Mineral Resources Survey China Geological SurveyXi’an 710010China Yunnan Gold Mining Industry Group Kunming 650299China Jiangxi Provincial Key Laboratory of Genesis and Prospect for Strategic Minerals East China University of TechnologyNanchang 330013China Frontiers Science Center for Deep-time Digital Earth China University of Geosciences(Beijing)Beijing 100083China

The Ailaoshan Orogen in the southeastern Tibet Plateau,situated between the Yangtze and Simao blocks,underwent a complex structural,magmatic,and metamorphic evolution resulting in different tectonic subzones with varying structural lineaments and elemental *** elements can conceal or reduce anomalies due to the mutual effect between different anomaly *** the whole zone into subzones based on tectonic settings,ore cluster areas,or sample catchment basins(Scb),geochemical and structural anomalies associated with gold(Au)mineralization have been identified utilizing mean plus twice standard deviations(Mean+2STD),factor analysis(FA),concentration-area(CA)modeling of stream sediment geochemical data,and lineament density in both the Ailaoshan Orogen and the individual *** FA in the divided 98 Scbs with 6 Scbs containing Au deposits can roughly ascertain unknown rock types,identify specific element associations of known rocks and discern the porphyry or skarn-type Au *** with methods of Mean+2STD and C-A model of data in the whole orogen,which mistake the anomalies as background or act the background as anomalies,the combined methods of FA and C-A in the separate subzones or Scbs works well in regional metallogenic potential *** of lineament densities with a 10-km circle diameter is not suitable to locate Au deposits because of the delineated large areas of medium-high lineament *** contrast,the use of circle diameters of 1.3 km or 1.7 km in the ore cluster scale delineates areas with a higher concentration of lineament density,consistent with the locations of known Au *** analyzing the map of faults and Au anomalies,two potential prospecting targets,Scbs 1 and 63 with a sandstone as a potential host rock for Au,have been identified in the Ailaoshan *** use of combined methods in the divided subzones proved to be more effective in improving geological understanding and identifying

关键词： minerology geochemistry gold stream sediment sample catchment basin concentration-area model lineament density Ailaoshan Orogen

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Stochastic Structural Model of Rock and Soil Aggregate by Continuum-Based Discrete Element Method

Stochastic Structural Model of Rock and Soil Aggregate by Co...

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The Sixth World Congress on Computational Mechanics in Conjunction with the Second Asian-Pacific Congress on Computational MechanicsⅠ

作者： Yuanman Wang~*, Manhong zhao, Shihai Li Division of Engineering Science, chinese academy of sciences, Beisihuan West Road 15#, beijing, 100080, china

Based on Continuum-based Discrete Element Method (CDEM), this paper presents a stochastic structural model to simulate the complex mechanical behaviors of rock and soil aggregates. A new numerical method (CDEM) is advanced which combines finite element method (FEM) and particle-spring model of discrete element method (DEM). The CDEM treats the 8-node solid isoparametric element in FEM as a fundamental system composed of 8 particles and interconnecting springs, by which the complete process from continuous to discontinuous deformations can be described. The breakage of spring stiffness between particles is designed to model the micro -failure process. A stochastic structural model was constructed by means of Monte -Carlo method to describe the geometrical features of rock and soil aggregates which can be obtained through geological investigation and statistics. The used geometrical features include mixture rat io, rock size and rock shape. In order to describe the rock and soil aggregates spatially, two types of structural elements (block element and jointed element) and three types of material elements (rock element;soil element, and weaker jointed element) are introduced. The jointed elements between rock block elements and soil block elements are called weaker jointed elements which have a relatively poor strength, and those jointed elements between rock block elements and between soil block elements are valu ed material parameters as rock element and soil element respectively. In order to study the deformation and failure mechanism of rock and soil aggregate, a series of loading tests aresimulated by the proposed model. It is founded that the stress strained curve of rock and soil aggregate is not linear even the material damage is not considered, and the failure is usually initialized and spread out from the weaker jointed elements. Finally, the factors such as mixture ratio, rock size and rock shape which affect the overall strength of rock and soil aggregate a

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Numerical study on local scour characteristics around submarine pipelines in the Yellow River Delta silty sandy soil under waves and currents

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Deep Underground Science and Engineering 2024年第2期3卷 182-196页

作者： Peng Yu Ruigeng Hu Jike Zhang Qi Yang Jieru zhao Lei Cao Chenghao Zhu Key Laboratory of geological Safety of Coastal Urban Underground Space Ministry of Natural ResourcesQingdaoChina Qingdao Geo-Engineering Surveying Institute(Qingdao geological Exploration Development Bureau) QingdaoChina Sinopec Petroleum Engineering Corporation DongyingChina State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijingChina Department Civil and Environmental Engineering Politecnico di MilanoMilanItaly College of Environmental Science and Engineering Ocean University of ChinaQingdaoChina

Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource *** to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational *** the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference *** volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is *** rationality of the numerical model is verified using a self-built waveflow *** this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is *** results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable *** maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of *** study can provide a valuable reference for the protection of submarine pipelines in this area.

关键词： local scour numerical simulation submarine pipelines Yellow River Delta

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Rock physical characteristics of deep dolomite under complex geological conditions: A case study of 4th Member of Sinian Dengying Formation in the Sichuan Basin, china

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Petroleum Science 2024年第4期21卷 2370-2382页

作者： Chuang Li Shu-Xin Pan Hong-Bin Wang Ji-Xin Deng Jian-Guo zhao Zhi Li Yu Zhang Northwest Branch of Research Institute of Petroleum Exploration & Development Department of Geophysics and Exploration College of Geophysics Chengdu University of Technology State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum (Beijing)

The deep-ultra deep carbonate reservoir in china, commonly subjected to modification of multi-stage diagenesis, has extremely high heterogeneity. Conventional rock physics analysis cannot accurately identify the elastic responses of reservoir. Here, the rock physics properties of the dolomite from the 4th Member of the Sinian Dengying Formation are experimentally measured, and the change law of rock physics characteristics is investigated within the framework of the diagenetic processes by the analysis of the elastic and petrologic characteristics, pore structure, and sedimentary environments. The results show that the differentiated diagenesis results in different pore structure characteristics and microtexture characteristics of the rock. The microbial dolomite of the algal mound-grain beach facies is subjected to the contemporaneous microbial dolomitization and seepage-reflux dolomitization, penecontemporaneous selective dissolution, burial dolomitization, and hydrothermal dolomitization. The resultant crystalline dolomite is found with one main type of the dolomite crystal contact boundaries,and the dissolution pore is extensive development. The siliceous, muddy, and limy dolomite of the interbeach sea environment mainly experiences the weak capillary concentration dolomitization, intensive mechanical compaction-induced densification, and burial dolomitization. Such crystalline dolomite is observed with four types of contact boundaries, namely the dolomite contact, clay contact, quartz contact, and calcite contact boundaries, and porosity mostly attributed to residual primary inter-granular or crystalline pores. The samples with the same crystal boundary condition have consistent correlations between the compressional-and shear-wave velocities, and between the compressional-wave velocity and the velocity ratio. Additionally, the variation of the acoustic velocity with effective pressure and the intensity of pore-scale fluid-related dispersion are controlled by t

关键词： Deep-ultra deep carbonate reservoirs Rock physics properties Dolomite Seismic elastic properties Micro-crack Pore structure types

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Ground subsidence induced by backfill-mining of a nickel mine and development forecasts

Ground subsidence induced by backfill-mining of a nickel min...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： F.S.MA,H.J.zhao,Y.M.ZHANG & J.GUO Key Laboratory of Engineering Geomechanics,Institute of geology and Geophysics,chinese academy of sciences, PO Box 9825,beijing 100029,china

Based on geological investigations and GPS monitoring data,this paper presents ground movement phenomena and characteristics for Jinchuan Nickel Mine,*** results show that ground subsidence occurred with increasing mining *** greatest accumulated subsidence reached 1287.5 mm between 2001 and 2008,and 37 considerable fissures were found at the ground *** establishing a mining-geological model,and by applying a numerical computation method,a short-term forecast of rockmass movement is *** results show that the rate of ground subsidence and deformation will intensify further,and the distribution of subsidence and degree of damage to the mine roadway and shaft induced by ground subsidence and deformation will also extend in the following several years.

关键词： ground subsidence rockmass movement backfill mining metal mine forecast

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PALEOGEOGRAPHIC EVOLUTION OF THE beijing PLAIN DURING THE PAST 30,000 YEARS

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Science in china,Ser.B 1984年第11期27卷 1183-1196页

作者：赵希涛孙秀萍张英礼黄兴根 Institute of geology Academia Sinica beijing Department of Geography beijing Normal University Seismo-geological Brigade National Bureau of Seismology

Based on the landforms, sedimentary sequence, fossil fauna and flora, and paleoclimatereflected by them as well as 14~C datings, the Late Quaternary strata in beijing Plain canbe divided into six members. In this paper, the history of paleogeographic evolution and theinteraction between geographic elements of this area during the past 30,000 years are de-scribed in detail.

关键词： PALEOGEOGRAPHIC EVOLUTION OF THE beijing PLAIN DURING THE PAST 30,000 YEARS

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Seismic Lg-wave Q tomography in and around Northeast china

Seismic Lg-wave Q tomography in and around Northeast China

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Lian-Feng zhao,Xiao-Bi Xie,Wei-Min Wang,Jin-Hai Zhang,and Zhen-Xing Yao 1 Institute of geology and Geophysics,chinese academy of sciences, beijing,china. 2 Institute of Geophysics and Planetary Physics,University of California, Santa Cruz,Santa Cruz,California,USA. 3 Institute of Tibetan Plateau Research,chinese academy of sciences, beijing,china.

[1]We investigate regional variations in the Lg-wave quality factor(Q)in Northeast china and its vicinity with a tomographic *** seismic data recorded at 20 broadband stations from 125 regional events are used to extract Lg-wave spectra. Tomographic inversions are independently conducted at 58 discrete frequencies distributed log evenly between 0.05 and 10.0 *** simultaneously invert for the Lg-wave Q distribution and source spectra at individual frequencies without using any a priori assumption about the frequency dependence of the Q model and source *** best spatial resolution is approximately 1°×1°in well-covered areas for frequencies between 0.4 and 2.0 *** Lg Q shows significant regional variations and an apparent relationship with regional *** use a statistical method to investigate the regional variations of Lg Q and their frequency *** average Q(1 Hz Lg Q)in the entire investigated region is *** basins are usually characterized by lower average Q values (from 155 to 391),while volcanic mountain areas have relatively high average Q values (from 630 to 675).Lg Q generally increases with increasing ***,the frequency dependence has complex nonlinear features on a double-logarithmic scale, indicating that the commonly adopted power-law relationship may be oversimplified in a broad frequency *** frequency dependence varies in different geological areas,with larger variations seen at lower frequencies.

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Discussion on Nontraditional Mineral Resources

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Journal of Earth Science 2000年第3期19卷 21-25页

作者： zhao Pengda Chen Jianping china University of Geosciences, beijing 100083, china

In this paper, the authors introduce the concept of nontraditional mineral resources, and propose the major system of nontraditional mineral resources, including nontraditional resources, research methods, mining and mineral economics. Then the authors conclude that the research on nontraditional mineral resources is not only significant to satisfication the human needs in the 21st century, but also important to the development of the present geological theory.

关键词： nontraditional mineral resources nontraditional research method mining and mineral economics.

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Potential risks of spectrum whitening deconvolution——compared with well-driven deconvolution

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Petroleum Science 2009年第2期6卷 146-152页

作者： Li Guofa Zhou Hui zhao Chao State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China Key Laboratory of CNPC Geophysical Exploration China University of Petroleum Beijing 102249 China

Deconvolution is widely used to increase the resolution of seismic data. To compare the resolution ability of conventional spectrum whitening deconvolution to thin layers with that of welldriven deconvolution, a complex sedimentary geological model was designed, and then the simulated seismic data were processed respectively by each of the two methods. The amplitude spectrum of seismic data was almost white after spectrum whitening, but the wavelet resolution was low. The amplitude spectrum after well-driven deconvolution deviated from white spectrum, but the wavelet resolution was high. Further analysis showed that if an actual reflectivity series could not well satisfy the hypothesis of white spectrum, spectrum whitening deconvolution had a potential risk of wavelet distortion, which might lead to a pitfall in high resolution seismic data interpretation. On the other hand, the wavelet after well- driven deconvolution had higher resolution both in the time and frequency domains. It is favorable for high resolution seismic interpretation and reservoir prediction.

关键词： Well-driven high resolution spectrum whitening deconvolution seismic wavelet

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Sensitivity analysis of CO_2 sequestration in saline aquifers

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Petroleum Science 2010年第3期7卷 372-378页

作者： zhao Hongjun Liao Xinwei Chen Yanfang zhao Xiaoliang Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum Beijing 102249 China

Carbon capture and storage （CCS） technology has been considered as an important method for reducing greenhouse gas emissions and for mitigating global climate change. Three primary options are being considered for large-scale storage of CO2 in subsurface formations： oil and gas reservoirs, deep saline aquifers, and coal beds. There are very many large saline aquifers around the world, which could make a big contribution to mitigating global warming. However, we have much less understanding of saline aquifers than oil and gas reservoirs. Several mechanisms are involved in the storage of CO2 in deep saline aquifers, but the ultimate goal of injection of CO2 into the aquifers containing salt water is to dissolve the CO2 in the water. So it is important to study the solubility trapping and sensitivity factors of CO2 in saline aquifers. This paper presents results of modeling CO2 storage in a saline aquifer using the commercial reservoir simulator ECLIPSE. The objective of this study was to better understand the CO2/brine phase behavior （PVT properties） and quantitatively estimate the most important CO2 storage mechanism in brine-solubility trapping. This would provide a tool by performing theoretical and numerical studies that help to understand the feasibility of CO2 geological storage. A 3-dimensional, 2-phase （water/gas） conceptional reservoir model used finite, homogenous and isothermal formations into which CO2 is injected at a constant rate. The effects of main parameters were studied, including the vertical to horizontal permeability ratio kv/kh, salinity, and residual phase saturations. The results show that the vertical to horizontal permeability ratio has a significant effect on CO2 storage. Moreover, more CO2 dissolves in the brine at lower kv/kh values.

关键词： CO2 geologic sequestration saline aquifer solubility trapping numerical simulation

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