Loading...
E-mail Alert Rss
 
Office Online
News
gfff
More>>
Information
Sponsored by:
China Aero Geophysical Survey and Remote Sensing Center for Natural Resources
Edited by:
Editorial Office of Geophysical and Geochemical Exploration
Add:
29 Xueyuan Road, Beijing 100083,China
Tel: 86-010-62060192/62060193
Fax: 86-010-62060193
Email: whtbjb@sina.com
Web: http://www.wutanyuhuatan.com
Editor in Chief: XIONG ShengQing
Published by:
The Geological Publishing House (31 Xueyuan Road,Beijing 100083,China)
Printer:
Beijing Changning Printing Co. Ltd.
Distributor: Beijing Post Office
Abroad Distributor:
China International Book Trading〖DW〗Corporation
Subscription Hander:
Local Post Offices of China
Links
More>>
  • Table of Content
      10 April 2015, Volume 39 Issue 2 Previous Issue    Next Issue
    For Selected: View Abstracts Toggle Thumbnails
    Article
    Characteristics of indicator elements combination and genesis of four types of uranium mineralization in China
    FU Jin, ZHAO Ning-Bo, PEI Cheng-Kai, LI Xin-Chun
    Geophysical and Geochemical Exploration. 2015, 39 (2): 217-221.   DOI: 10.11720/wtyht.2015.2.01
    Abstract   HTML   PDF (1420KB) ( 620 )

    This paper made a systematic exposition of indicator elements for four types of uranium mineralization in China, i.e., element combination characteristics, genesis, mechanism and relationship with uranium mineralization. Based on the anomalies of indicator elements and combination, the authors delineated a uranium-rich geological body, identified favorable metallogenic essential factors, and even directly searched for blind orebodies. The results obtained have important significance for uranium ore prediction and evaluation.

    References | Related Articles | Metrics
    Soil geochemical characteristics and anomaly appraisal of the Huoburenbudun silver mining area in Inner Mongolia
    LIU Shu-Min, WANG Shuai, JI Ren-Zhong, WANG Ru-Jie, SHI Gao-Fei, SU Xin-Yi, HU Hao
    Geophysical and Geochemical Exploration. 2015, 39 (2): 222-227.   DOI: 10.11720/wtyht.2015.2.02
    Abstract   HTML   PDF (3545KB) ( 456 )

    This study is aimed at searching for silver ore-prospecting target areas in Huoburenbudun area based on 1:50 000 soil geochemical survey data. In this paper, the potential Ag resources in the geochemical anomaly area were evaluated and predicted by the geochemical block model. In combination with regional metallogenic geological conditions and soil geochemical characteristics, the authors evaluated the index of geoaccumulation and delineated four prospecting target areas. Through field survey verification, silver orebodies and mineralized bodies were found in Target Ⅱand Target Ⅳ. Further detailed geological survey is necessary for confirming metallogenic province, with special attention paid to mineral survey of AgM13 anomaly.

    References | Related Articles | Metrics
    The application of debris and soil geochemical measurement methods to the Shaquanzi Cu-Ni deposit, Xinjiang
    LIU Han-Liang, WANG Xue-Qiu, ZHANG Bi-Min, LIU Dong-Sheng, CHI Qing-Hua
    Geophysical and Geochemical Exploration. 2015, 39 (2): 228-233.   DOI: 10.11720/wtyht.2015.2.03
    Abstract   HTML   PDF (2740KB) ( 418 )

    Pilot comparative study of detritus and soil geochemical surveys was conducted over the Shaquanzi Cu-Ni deposit of Xinjiang. The results show that there are Cu-Ni-Cr-Co geochemical anomalies delineated by these two methods, and the anomalies are located right over the known orebodies, indicating that the two methods can be used to effectively locate reliable prospecting targets in Gobi desert terrain. A comparison shows that fine-grained soil can yield relatively better results in that it shows higher element concentrations and intensive anomalies over the deposit, which could help identify weak anomalies caused by mineralization in such landscape.

    References | Related Articles | Metrics
    Model and application of radon anomaly in soil of sandstone type uranium deposits in Erlian Basin
    LIU Wu-Sheng, LI Bi-Hong, SHI Qing-Ping, JIA Li-Cheng, ZHAO Xing-Qi
    Geophysical and Geochemical Exploration. 2015, 39 (2): 234-239.   DOI: 10.11720/wtyht.2015.2.04
    Abstract   HTML   PDF (4134KB) ( 396 )

    Erlian Basin is one of the most important sandstone-type uranium fields in northern China. In order to get the weak mineralization data at surface and establish the direct prospecting criteria, the authors carried out measurement of areal-type soil radon and its daughter in the basin. According to the analysis of uranium mineralization data as well as the section and plane data, soil radon anomaly of sandstone-type uranium deposits can be built, i.e., radon anomalies in soil are always located in the upstream direction of uranium, with the anomaly value higher than 15 000 Bq/m3. In general, the upper part of the deposit has the background value of radon, while the larger halos of radon are distributed in the downstream direction of the deposit. On the basis of this model, it can be inferred that Erlian Basin is characterized by fairly favorable potential of uranium mineralization. On such a basis, further prospecting targets can be delineated.

    References | Related Articles | Metrics
    The discovery of the Cuiluan quartz type silver deposit in Heilongjiang Province and its significance
    DENG Chang-Zhou, ZHANG Li-Dong, SUN Zi-Yao, YANG Wen, DING Ji-Shuang, FU An-Zong
    Geophysical and Geochemical Exploration. 2015, 39 (2): 240-244.   DOI: 10.11720/wtyht.2015.2.05
    Abstract   HTML   PDF (1172KB) ( 321 )

    The integrated geophysical and geochemical methods were adopted to detect 1:50000 stream sediment geochemical anomalies in Cuiluan area, which led to the discovery of a high-grade quartz vein type silver ore deposit in the Yichun-Tieli metallogenic belt. The anomaly combination of soil elements is composed of Ag,As,Sb,Pb and Zn, the middle gradient induced polarization is characterized by high values of apparent resistivity and apparent chargeability. Studies reveal that the ore deposit is characterized by weather resistance of quartz vein type silver ore and low value of Ag element in soil, that the quartz vein causes the high value of apparent resistivity, and that pyritization leads to the high value of apparent chargeability.

    References | Related Articles | Metrics
    Comparative research on the combinational test of geophysical methods in the Zhaxikang lead-zinc ore concentration area, Tibet
    JIAO Yan-Jie, LIANG Sheng-Xian, GUO Jing, LI Hua, ZHANG Wei, LI Fu, LIAO Guo-Zhong
    Geophysical and Geochemical Exploration. 2015, 39 (2): 245-252.   DOI: 10.11720/wtyht.2015.2.06
    Abstract   HTML   PDF (2219KB) ( 607 )

    Located geotectonically within the North Himalayan epicontinental warped fault belt in the middle segment of the Tethyan-Himalayan tectonic domain, the Zhaxikang lead-zinc polymetallic deposit in Tibet is one of the rarely-seen large-size lead-zinc-silver association deposits with rich sulfosalt minerals in Tibet. The ore deposit is mainly hosted in Lower Jurassic Ridang Formation, with the ore-hosting rocks being carbon-bearing calcareous slate,calcareous slate,sericite slate,shale and quartz sandstone. The orebodies are strictly controlled by two sets of NE-SW trending faults and exhibit veinlike and lenticular forms. In view of characteristics of the ore-controlling structures, the authors employed the high density resistivity method, induced polarization method, transient electromagnetic method and audio frequency magnetotelluric method to conduct investigation in the typical ore deposit and its periphery, and made inverse comparison of the effects of some methods. In combination with the previous geological and geophysical data as well as engineering verification, the authors hold that the magnetotelluric method and the induced polarization method are fairly credible and economical. In addition, different inversion methods should be jointly arranged to analyze and judge the typical deposits; only in this way can the aim of preliminary prognosis of the orebody be achieved.

    References | Related Articles | Metrics
    An overview of methods for geothermal seismic exploration
    WANG Dan, WEI Shui-Jian, JIA Yue-Wei, LU Zhi
    Geophysical and Geochemical Exploration. 2015, 39 (2): 253-261.   DOI: 10.11720/wtyht.2015.2.07
    Abstract   HTML   PDF (2909KB) ( 736 )

    Geothermal resources are very abundant in the world and thus have great exploration potential.In addition,the geothermal resources will considerably stimulate the global economic development.In the exploration and development of geothermal resources,the seismic technique has been playing the essential role.This technique mainly includes active and passive seismic methods which are to be conducted at different stages of geothermal exploration.In this paper,seismic responses of geothermal reservoir are analyzed first,then new technologies of passive and active seismic methods are summarized,with the purpose of providing some valuable references for the geothermal seismic exploration in China.Studies show that passive seismic method should be conducted first in the initial geothermal survey.Nevettheless,this method has some limitations on the precision in the fracture detection and the description of permeability features;in contrast,active seismic method,which relies on the high S/N ratio and high-resolution itself, can describe reservoir characteristics better,therefore guaranteeing more-refined regional evaluation and extreme site optimization of undeveloped geothermal areas.Besides,multi-wave technique also will be the future orientation of geothermal development.

    References | Related Articles | Metrics
    The effect of applying geophysical and geochemical anomalies to the Shiwuliqiao gold deposit in Heilongjiang Province
    ZHANG Fu-Cheng, YANG Yan-Chen, LI Xiang-Wen, JIANG Bing-Zhong
    Geophysical and Geochemical Exploration. 2015, 39 (2): 262-267.   DOI: 10.11720/wtyht.2015.2.08
    Abstract   HTML   PDF (1212KB) ( 394 )

    Located on the southern margin of upper Heilongjiang foreland basin, the Shiwuliqiao gold deposit was discovered in recent years though checking the small-scale geochemical anomaly by integrated geophysical and geochemical methods . The soil geochemical survey suggests that Au, which is characterized by high content, higher coefficient of variations and obvious local concentration, is the main ore-forming element. Besides, Au element anomaly is a direct indicator for prospecting, whereas element anomalies of As, Sb, Cu, Bi can be used as indirect indicators in prospecting. An analysis of the electromagnetic field and anomalies show that many sets of NNE-striking concealed faults are characterized by high magnetism, low resistivity, and medium-low polarization, caused probably by filling of dikes. The NE—NEE ore-controlling structures exhibit high resistivity and high polarization, and their intersections with NNE trending faults display better gold mineralization. The discovery of the Shiwuliqiao gold deposit suggests that geophysical and geochemical methods are effective means in search for gold and polymetallic deposits in northern areas of marsh landscape in the Da Hinggan Mountains.

    References | Related Articles | Metrics
    The application of CSAMT to the prospecting for Cu-Fe orebodies in the Donggang ore district
    WANG Zhen-Liang, LIN Tian-Liang, CAI Yong-Wen, LU Rui-Jun
    Geophysical and Geochemical Exploration. 2015, 39 (2): 268-272.   DOI: 10.11720/wtyht.2015.2.09
    Abstract   HTML   PDF (1153KB) ( 466 )

    Taking the CSAMT method in the exploration of Cu-Fe ore deposits in Donggang area as an example and combined with geological and physical conditions, the authors delineated the distribution of rock body and provided the reliable basis for further geological work and layout of drill holes. Drilling and gravity validation reveals that Cu-Fe orebodies are mainly produced in breccia, Fe orebodies are generally located in the core of the low resistivity zone with the resistivity below 20 Ω·m, and Cu orebodies are located in the relatively low resistivity zone with the resistivity from 20 Ω·m to 80 Ω·m.

    References | Related Articles | Metrics
    Comprehensive information prospecting model for sandstone uranium deposits in Teguida area, Niger
    SUN Dong-Hua, JIANG Ming-Zhong, LUO Yan, JIANG Xue, GU Da-Zhao
    Geophysical and Geochemical Exploration. 2015, 39 (2): 273-282.   DOI: 10.11720/wtyht.2015.2.10
    Abstract   HTML   PDF (9859KB) ( 268 )

    Through the investigation of integrated anomalies in known deposits in Teguida, a predictive model for sandstone uranium mineralization was established, which helps to discover buried orebodies. Based on the analysis of geological anomaly, it is concluded that the uranium mineralization lies in Lower Cretaceous Assaousas Formation, controlled by regional faults, and occurs along the edge of the upper Paleozoic uplift. It is also pointed out that the different depths of the orebody have different characteristics of geophysical field, but generally show the phenomenon that uranium anomalies are detected by vehicle or ground gamma spectral survey, radon anomalies detected by activated carbon adsorption of radon, and high value anomalies detected by soil-natural themoluminescence. According to audio frequency magnetelluric sounding, the orebodies are located in the transitional part from low to middle resistivity and close to the middle resistivity. On such a basis, five uranium prospecting targets were predicted, in two of which uranium mineralization (clue) was discovered by the later exploration.

    References | Related Articles | Metrics
    An analysis of the effect of the audio magnetotelluric method (AMT) in the exploration of bauxite deposits in Guizhou
    ZHANG Xi-Jun, WANG Yong-Tai, CHEN Po
    Geophysical and Geochemical Exploration. 2015, 39 (2): 283-287.   DOI: 10.11720/wtyht.2015.2.11
    Abstract   HTML   PDF (969KB) ( 472 )

    Guizhou has rich and extensively distributed bauxite resources, but bauxite deposits there are mostly concealed sedimentary ones. The easily-discovered shallow and surface bauxite deposits have almost been totally exploited, and hence the experimental test of geophysical methods in search for concealed bauxite deposits is of great significance for further ore-prospecting work. In this paper, the authors describe in brief the basic working procedure of the AMT method as well as geological and geophysical characteristics of the Changgou work area in Jinsha district, Guizhou Province, and emphatically discuss the application results of AMT in the bauxite exploration of Changgou work area. Based on integrated inference and interpretation of the resistivity section, the authors recognized the stratigraphic boundaries between Permian, Carboniferous and Cambrian, delineated favorable ore-bearing places, and attained fairly good ore-prospecting results, as demonstrated by later drilling verification.

    References | Related Articles | Metrics
    The application of nuclear magnetic resonance (MRS) to the water exploration in permafrost region
    LONG Zuo-Yuan, HE Sheng
    Geophysical and Geochemical Exploration. 2015, 39 (2): 288-291.   DOI: 10.11720/wtyht.2015.2.12
    Abstract   HTML   PDF (1019KB) ( 408 )

    Based on the analysis and interpretation of the application of MRS method to water exploration in permafrost region in combination with an integrated study of drilling data, the authors made detailed explanation and analysis of buried depth and thickness of underground aquifer as well as calculation of outflow rate of groundwater detected by MRS method and obtained satisfactory application result. This paper expounds the unique technical advantages of MRS method in the water exploration of the permafrost region, such as obvious moisture signal reflection, high signal-to-noise ratio and uniqueness of the analytical result, and also points our its weakness in such aspects as determination of lithologic character of the aquifer and the calculation of outflow rate. The results achieved by the authors demonstrate the good prospect of the application of MRS method to water exploration in the permafrost region, and provide some reference experience for further work in this aspect.

    References | Related Articles | Metrics
    The supra-crust element abundance characteristics of the stratigraphic regions in Anhui Province
    ZHAO Hua-Rong, DU Jian-Guo, ZHOU Cun-Ting, CHI Qing-Hua, HU Zhao-Qi
    Geophysical and Geochemical Exploration. 2015, 39 (2): 292-296.   DOI: 10.11720/wtyht.2015.2.13
    Abstract   HTML   PDF (475KB) ( 285 )

    The calculation of the continental crust abundance remains at the exploration stage. In this paper, according to the measurement of the rocks, the exposed crust element abundance value of the 40 elements or oxides were calculated from weighted averages of the stratigraphic thickness and rock exposure area in Anhui Province and the three stratigraphic regions. A comparison with the abundance values of the continental crust and the region calculated shows a very small wave range of the content value as well as the coincidence of the enriched elements with the elements of discovered ore minerals, which well reflects the abundance features of the exposed crust in Anhui Province and the three stratigraphic regions. Therefore the results achieved by the authors have established basic geochemical data for geological prospecting, environmental monitoring and land use in Anhui Province.

    References | Related Articles | Metrics
    Internal structural analysis of geochemical anomaly based on the content arrangement method: A case study of copper stream sediment survey in northwestern Zhejiang Province
    ZHAO Bo, YU Lei, QIU Jun-Ting, SHI Cheng-Long, ZHANG De-Hui
    Geophysical and Geochemical Exploration. 2015, 39 (2): 297-305.   DOI: 10.11720/wtyht.2015.2.14
    Abstract   HTML   PDF (2021KB) ( 357 )

    With 1:200 000 stream sediment survey of copper in northwestern Zhejiang Province as an example, the authors used the content arrangement method to study the internal structural features of Cu geochemical anomalies delineated by the Fractal Summation Method in this area. It is the stability of fractal non-scale section that masks the internal spatial structure of the anomalous field, and the ignored fact therein is that such an internal structure can be manifested by a natural revelation or content arrangement (of copper from small to large content) of the original anomalous sample data itself, rather than an effort to overcome the stability of non-scale sections. Three lines of L1, L2, and L3 are used to fit the hierarchical evolution trends, namely the internal structure, of anomalous data, and therein, L1 specifies the primary anomaly, and L2+L3 specify the advanced anomaly. Studies show that the primary anomaly (L1) may correspond in general to a weak mineralization and essentially barren area, although it does contain some weak mineralization or several hidden ore spots; the secondary one (L2+L3) can be approximately or equally considered as the mineralized anomalous area, between which and the regional tectonomagmatic activity there is a further significant spatial correlation; some new undiscovered copper prospecting target was discovered at last on the basis of the study of the ore-controlling significance of magmatic source, tectonic transformation, and convergence of faults in this area.

    References | Related Articles | Metrics
    Zonation of element association detected by geochemical stream sediment survey in Yulonggou area, Qinghai Province
    HE Qi-Fen, WEI Yin-Tao, CHEN Hong-Jie, LIU Wei, KOU Ya-Wei, LIU Yan-Kui
    Geophysical and Geochemical Exploration. 2015, 39 (2): 306-310.   DOI: 10.11720/wtyht.2015.2.15
    Abstract   HTML   PDF (1671KB) ( 449 )

    In order to understand geology and geochemical mineralization characteristics, the authors used the method of R-type factor analysis to conduct statistical analysis of the data obtained from geochemical survey in Yulonggou area. Five representive types of factor combinations were extracted, geochemical zone division was carried out according to the score value of each factor, and element combination zone diagram was also drawn. On such a basis, the geochemical statistical information, reflected by stream sediment survey in the work area, can be shown in a diagram in the form of zone divisions. An analysis of this diagram can not only reflect the geochemical implications but also demonstrate the background value characteristics of corresponding elements.

    References | Related Articles | Metrics
    The application of geophysical exploration results to the investigation of segmented differences of the role of the Ngola Mountain active faulted zone in Qinghai Province in the control of geothermal and seismic activities
    WANG Bin, LI Bai-Xiang, LI Fu-Cheng
    Geophysical and Geochemical Exploration. 2015, 39 (2): 311-317.   DOI: 10.11720/wtyht.2015.2.16
    Abstract   HTML   PDF (4792KB) ( 384 )

    Through a comparison of the differences between the results obtained by two times of geothermal geophysical exploration conducted in different segments of the Ngola Mountain active faulted zone and on the basis of an analysis of regional gravity field and geological structure, the authors, starting with the study of modern tectonic stress field and tectonic deformation, investigated the segmented differences of the role of the Ngola Mountain active faulted zone in Qinghai Province in the control of geothermal and seismic activities. The southern segment of the faulted zone strikes in NNW direction and intersects the NE-trending stress of the Tibetan Plateau at an acute angle and mainly assumes strike-slip nature under the stress component force; the right-lateral pull-apart area controls the cluster distribution of the warm spring groups and has no intermediate and strong seismic activities. In the northern segment of the faulted zone, The strike turns in NW direction and is nearly perpendicular to the diection of the stress; under the action of compressive stress, the thrust fault is likely to become causative fault, but possesses no conditions for the formation of warm springs and geothermal fields. This paper investigates the formation mechanism of the warm springs and geothermal fields, emphatically describes the good geothermal and geological conditions of the warm springs in Wenquan Town, and also points out that there exists no geological setting for the formation of geothermal fields in the Wulan segment.

    References | Related Articles | Metrics
    A study of nuclear pulse signal digital Gaussian shaping based on dual-factor mode
    ZHOU Wei, ZHOU Jian-Bin
    Geophysical and Geochemical Exploration. 2015, 39 (2): 318-321.   DOI: 10.11720/wtyht.2015.2.17
    Abstract   HTML   PDF (885KB) ( 299 )

    The study of a novel model for digital nuclear pulse signal Gaussian shaping based on amplitude factor and width factor is described in this paper. According to Sallen-Key filter(S-K filter in short), four formulae are established between the input and the output depending on Kirchhoff Current Law. With dual-factor parameter substitution, a general numerical recursive root is obtained by applying numerical differentiation algorithm. The correctness of the model is verified by computer simulation through the standard exponential decay signal and actual nuclear signal. The shaping factors are also confirmed. Finally, the digital Gaussian shaping technique is applied to the Energy Dispersive X-Ray Fluorescence system and, as a result, the spectrum of 55Fe is obtained. Testing results show that digital shaping technique can improve the performance of the EDXRF system in such aspects as energy resolution and count ratio.

    References | Related Articles | Metrics
    The wave field separation method in comparison with other methods in prestack reverse-time migration denoising
    ZHANG Shu-Jie, XUE Ting-Xiao
    Geophysical and Geochemical Exploration. 2015, 39 (2): 322-326.   DOI: 10.11720/wtyht.2015.2.18
    Abstract   HTML   PDF (1876KB) ( 453 )

    Two-way wave equation based on reverse time migration (RTM) has such advantages as simple principle,no angle restrictions,suitability for the model of arbitrary speed changes,and correct imaging for all kinds of waves.Nevertheless,the adoption of the cross-correlation imaging condition can produce low-frequency noise problems.Based on analyzing the mechanism of the low frequency noise,the authors put forward an effective wave field separation denoising method,in which the source and the receiver wave field are separated into different directions of one way wave component,and only cross-correlation imaging is conducted on the effective path of the component,so as to achieve the purpose of removing noise.The results of the model test and comparative study of the denoising effects of Poynting vector filtering,Laplasse filtering and wave field separation show that the wave field separation method is relatively effective in these three methods.

    References | Related Articles | Metrics
    A study of three-component seismic exploration in plateau permafrost region
    LIU Jian-Xun, XU Ming-Cai, WANG Xiao-Jiang, ZHANG Bao-Wei
    Geophysical and Geochemical Exploration. 2015, 39 (2): 327-333.   DOI: 10.11720/wtyht.2015.2.19
    Abstract   HTML   PDF (4117KB) ( 310 )

    Three-component seismic exploration is an effective method for the utilization of P-wave and converted-wave to detect fine structures.With this method,converted-wave imaging profiles have high resolution,and small geological structures such as small faults and small structures can be identified.In this paper,based on the application experiments of three-component seismic exploration technology in Qiangtang basin of Tibet,the authors investigated the three-component seismic data acquisition method,converted-wave data processing technology and comparative interpretation method,and the results achieved prove the effectiveness of this method.This paper has certain reference value for the application and study of multi-component seismic exploration technology in plateau permafrost area in the future.

    References | Related Articles | Metrics
    The application of joint imaging of primaries and multiples to obstacle topography
    GUO Shu-Juan, WANG Li-Xin, XU Zhao-Tao, WANG Jie
    Geophysical and Geochemical Exploration. 2015, 39 (2): 334-340.   DOI: 10.11720/wtyht.2015.2.20
    Abstract   HTML   PDF (5047KB) ( 339 )

    Primaries are usually regarded as the only seismic signals used for seismic imaging. However, when seismic acquisition encounters some obstacle areas where no shooting can be made and only the installation of receivers can be conducted, there are seismic imaging gaps because of missing seismic primaries. Given the developed multiples in obstacle area, the authors proposed a method achieving joint imaging by using primaries and multiples. The method employs sum of impulsive source and recorded primaries and multiples as source wavefield and the wavefield consisting of recorded primaries and multiples as back-extrapolated wavefield under the 2D deconvolution imaging condition. Tests on Sigsbee2B dataset and field data show that the method could provide more valuable imaging information and complement the lack of seismic primary imaging caused by obstacle topography. Tests on Sigsbee2B dataset and field data show that the method is workable and effective.

    References | Related Articles | Metrics
    Feasibility analysis of surface micro-seismic hydraulic fracturing monitoring
    RUI Yong-Jun
    Geophysical and Geochemical Exploration. 2015, 39 (2): 341-345.   DOI: 10.11720/wtyht.2015.2.21
    Abstract   HTML   PDF (2007KB) ( 427 )

    Micro-seismic monitoring,as the most effective means of hydraulic fracturing monitoring,has attracted more and more attention and is becoming a hot research topic due to its advantages such as easy engineering and full observation.Nevertheless,due to the particularity of microseism,the problem whether valid micro-seismic events could be received under the strongly noisy ground is the key point of the whole technique.In this paper,the author conducted an in-depth research in three aspects,i.e.,the energy conducted by the hydraulic fracturing,the interference situation of fracture truck unit noise and the difference of different depth of micro seismic propagation and,from two angles of "signal (effective events) and noise (surface noise)",reached the conclusion that surface microseism is capable of receiving reliable fracture signal.The real micro-seismic data acquisition from Yan227 horizontal hydraulic fracturing well verified the effectiveness of this technology,which provides the basis for the implementation of the surface microseismic technology.

    References | Related Articles | Metrics
    Extended elastic impedance inversion technology and its application to the tight and thin sandstone reservoir
    SHI Lei, LIU Jun-Zhou, DONG Ning, WANG Jian-Bo, XIA Hong-Min, WANG Zhen-Yu
    Geophysical and Geochemical Exploration. 2015, 39 (2): 346-351.   DOI: 10.11720/wtyht.2015.2.22
    Abstract   HTML   PDF (3989KB) ( 335 )

    Compared with the post-stack inversion,the extended elastic impedance is more sensitive to the reservoir and hydrocarbon.In this paper,the authors discussed the theory,key techniques and steps of the extended elastic impedance inversion.Wetake P1x1 and P1s2 in DND gas field of North of Erdos Basin were taken as the study objects.Based on a detailed analysis of logging data,the authors propose fusion method for estimating data of shear wave.This method combines modeling method,formula method and neural network method.It estimates the sandstone section using modeling method,and mudstone with formula method for low frequency model and,in combination with neural network,predicts the mudstone section of shear wave information,thus avoiding the error of mudstone caused by total porosity measurement inaccurate prediction using Xu-White model. Based on cross pictures analysis,the authors deal with sensitive elastic parameters for EEI inversion and effective scale for interpretation of lithology and fluid and,according to deterministic extended elastic impedance inversion,determine the variation and range and complete the pre-stack stochastic extended elastic impedance inversion,thus meeting the requirements of thin reservoir prediction.At last,the inversion results are interpreted crossly and the distribution of gas sand is predicted accurately,with the drilling data matching rate reaching over 90%.

    References | Related Articles | Metrics
    The Definition of Full-domain Apparent Resistivity Based on Air-ground Transient Electromagnetic Data
    ZHAO Yue, WANG Yi-Peng, LI Xiu
    Geophysical and Geochemical Exploration. 2015, 39 (2): 352-357.   DOI: 10.11720/wtyht.2015.2.23
    Abstract   HTML   PDF (1655KB) ( 481 )

    A fast and efficient numerical calculation method of full-domain apparent resistivity for AGTEM has been developed in this paper. We defined the full-domain apparent resistivity using the vertical and horizontal component of time domain magnetic field, in this way we can achieve full space, all time domain apparent resistivity definition. We analyzed thoroughly the Air-ground transient electromagnetic field analytic expression in homogeneous half space, and discovered that the Air-ground time domain response can be expressed in similar polynomial with the central vertical response, use the apparent resistivity translation algorithm, we can achieve full-domain apparent resistivity definition. Model calculation results show that the apparent resistivity definition method does not require iterative, with quicker speed and higher precision. Finally, compared the magnetic field and the voltage based apparent resistivity for resolution of abnormal body.

    References | Related Articles | Metrics
    The analysis and application of the vertical magnetic component in wide field electromagnetic method
    CHEN Wei-Ying, XUE Guo-Qiang
    Geophysical and Geochemical Exploration. 2015, 39 (2): 358-361.   DOI: 10.11720/wtyht.2015.2.24
    Abstract   HTML   PDF (771KB) ( 362 )

    The vertical magnetic component caused by a grounded wire source is sensitive to the earth and decays sharply with the increase of transmitting-receiving distance. It is very difficult to conduct the conventional CSAMT method which measures horizontal electric and magnetic components when the earth is hardly conductive or the topography is very steep. Measuring the vertical magnetism is an effective alternative. Based on the theory of wide field electromagnetic method, the authors analyzed the characteristics of vertical magnetic component and obtained full-zone apparent resistivety by using the method of iteration. This survey mode was applied to mineral deposit detection in a frozen ground area, with good result achieved.

    References | Related Articles | Metrics
    The influence of two typical kinds of magnetic disturbance on the airborne magnetic survey
    XU Dong-Li, FAN Zheng-Guo, SHU Qing, YE Ting-Ming, CHEN Hao
    Geophysical and Geochemical Exploration. 2015, 39 (2): 362-365.   DOI: 10.11720/wtyht.2015.2.25
    Abstract   HTML   PDF (1283KB) ( 425 )

    Magnetic disturbance is disturbance change of Earth magnetic field which occurs discontinuously during the occurrence of magnetic storm. It can happen at different stages of magnetic storm, Its range and shape are related to the scale and type of magnetic storm. The magnetic disturbance that occurs during magnetic storm of rather large-scale shows larger range and higher frequency and lasts longer period than that during magnetic storm of fairly small-scale.Researches show that the range of magnetic disturbance in practical work varies between several nanotesla to more than ten nanotesla, and the shape mainly exhibits linear gradient variation and nonlinear disturbance variation. These two typical kinds of magnetic disturbance both affect the result of magnetic survey, and can be eliminated through magnetic diurnal variation correction. In combination with practical work, this paper deals with the utilization of magnetic diurnal variation correction to eliminate magnetic disturbance.

    References | Related Articles | Metrics
    The application of lead and sulfur isotopes to geochemical exploration
    HU Shu-Qi, LIU Chong-Min, MA Sheng-Ming
    Geophysical and Geochemical Exploration. 2015, 39 (2): 366-370.   DOI: 10.11720/wtyht.2015.2.26
    Abstract   HTML   PDF (370KB) ( 369 )

    The application of lead and sulfur isotopes to geochemical exploration is still at the stage of exploratory work. In order to further confirm its effect on the exploration of polymetallic deposits,the authors selected a hydrothermal lead and zinc deposit to trace deep orebody by means of Pb isotope and a porphyry copper deposit to detect alteration zoning by means of S isotope and, on such a basis, discussed the δ34S vertical regularity. The test results demonstrate that Pb isotopic composition and V value of three-dimensional topology can predict deep orebodies,the V value increases from the top to the bottom,suggesting the existence of orebodies in the depth. The δ34S mean value in the horizontal direction shows increasing tendency from the high-temperature alteration area to the low-temperature alteration area,and these characteristics can be used to distinguish mineralization and alteration zone. General speaking, the δ34S mean value gradually increases with depth in the vertical direction, there are differences in rock properties and the background values of S isotope in different horizons, and the stacking of the rocks and ore-forming solution may lead to the saltatorial change of the δ34S mean value.

    References | Related Articles | Metrics
    Method of suppressing the adjacent source interference in AMT
    WANG Gang, WANG Shu-Min, ZHU Wei, ZHANG Zhen-Yu, YAO Da-Wei, LI Yong-Bo
    Geophysical and Geochemical Exploration. 2015, 39 (2): 371-375.   DOI: 10.11720/wtyht.2015.2.27
    Abstract   HTML   PDF (1733KB) ( 386 )

    The time series data with multiple frequencies which are collected by using audio frequency magnetotelluric method (AMT) often contain interference signals. After a lot of measured time series data viewed, we have found that the data are seriously interfered by adjacent source, but the interference signal appearance is not continuous. According to the features of the interference signal and the analysis result of original data format of V5-2000 magnetotelluric instrument, the author proposed a method for automatic selection of time series data. Real data processing results in Ningwu area show that this method can partly suppress the adjacent source interference.

    References | Related Articles | Metrics
    Research on electromagnetic coupling effects in CSAMT receiving system
    ZHANG Zhen-Yu, WANG Da-Yong, LEI Da, WANG Gang, YAO Da-Wei, ZHU Wei
    Geophysical and Geochemical Exploration. 2015, 39 (2): 376-382.   DOI: 10.11720/wtyht.2015.2.28
    Abstract   HTML   PDF (1329KB) ( 472 )

    In the light of the electromagnetic coupling effect between the receiving cables and between the receiving cable and the earth in data collection in CSAMT and through electromagnetic coupling theory and equivalent circuit calculation,the authors derived the forward modeling formula. Based on a variety of models and forward simulations in comparison with actual field data,the authors studied three factors affecting electromagnetic coupling effects in CSAMT,i.e., cable length, ground resistance of non-polarized electrode, and signal frequency, and summarized three kinds of phenomena corresponding to electromagnetic coupling characteristics: the longer the cable of receiving system, the larger the electromagnetic coupling effects between the cables, the more obvious the distortion of apparent resistivity curve in the high frequencies, and the more evident the distortion of curves; the bigger the ground resistance of non-polarized electrode, the more obvious the distortion of apparent resistivity curve in the high frequencies, and the more evident the distortion of curves; the greater the signal frequency, the larger the inductance and the capacitance, and the more obvious the distortion of curves. When the signal frequency increases to a certain value, the capacitance and the inductance no longer continue to increase, and the curves tend to be stabilized.

    References | Related Articles | Metrics
    Zero drift of CG-5 gravimeter and its service lifetime
    SHEN Bo, YUAN Shang-Wu, MA Xuan-Long, HAO Xiao-Han
    Geophysical and Geochemical Exploration. 2015, 39 (2): 383-386.   DOI: 10.11720/wtyht.2015.2.29
    Abstract   HTML   PDF (464KB) ( 444 )

    The zero drift and its linearity are the most important performance indexes of gravimeter and also considerably dominate the instrumental accuracy and lifetime. Based on an analysis of drift data from 14 CG-5 gravimeters, the authors found that the average drift rates of the majority of instruments are between 0.7 and 1.7×10-5 m/s2/day in two years. On such a basis in combination with the related data provided by manufacturers, the service lifetimes of CG-5 gravimeters have been inferred in this paper. The normal mean operational lifetime seems to be about 10 years in the area of forty degrees north latitude.

    References | Related Articles | Metrics
    Land quality evaluation of the Jitai Basin in Jiangxi Province
    MA Yi-Lin, XIE Chang-Yu, HU Chen-Lin, LIU Tie-Shan
    Geophysical and Geochemical Exploration. 2015, 39 (2): 387-395.   DOI: 10.11720/wtyht.2015.2.30
    Abstract   HTML   PDF (4532KB) ( 297 )

    Based on geochemical indicators affecting the quality of land such as nutrition elements, harmful elements and compounds, organic pollutants, and physical-chemical properties, the authors assigned the weight of each index by using analytic hierarchy and set up the corresponding membership function to get the function value which could be used to classify the land levels. The results indicate that land quality of the Jitai Basin in Jiangxi Province is good. The area of high-level land is 9 640.94 km2, accounting for 85.98% of the study area, the medium-level land accounts for 13.75% and the poor-level land accounts for 0.27%. The results of the study provide geochemical foundation for adjusting agricultural planting structure, developing characteristic agricultural products, and promoting reasonable fertilization in the Jitai Basin. The countermeasures are put forward for soil pollution regulation, such as the application of lime (CaCO3) to reduce the acidity of soil, the increasing application of organic fertilizer and the utilization of phosphate.

    References | Related Articles | Metrics
    Geochemical distribution of Cr in soil of Hebei plain
    SONG Ze-Feng, CUI Xing-Tao, LUAN Wen-Lou, LI Sui-Min
    Geophysical and Geochemical Exploration. 2015, 39 (2): 396-400.   DOI: 10.11720/wtyht.2015.2.31
    Abstract   HTML   PDF (1102KB) ( 342 )

    Based on the data obtained by multi-purpose regional geochemical survey, the authors studied the spatial distribution of Hg in soils of Hebei plain, and drew the geochemical diagram of topsoil and deep soil. The result shows that the mean content of Hg in topsoil is 43.77×10-9, and that in deep soil is 17.58×10-9. The main chemical speciation of Hg in root soil is inert mercury, and the proportion of active mercury is only 3.24%. These data suggest that the degree of soil environmental safety is high. The Hg content in topsoil is higher in the west part of Hebei plain than in the east part. There is a significantly high value area distributed along the Taihang Mountain, which is formed by natural factors. The distribution of Hg low value area is similar to the distribution of rivers. Punctuated high value areas surrounding cities and towns are formed by human activities.

    References | Related Articles | Metrics
    Research on key geophysical technologies for ground fissure survey in Longyao area
    GUO Shu-Jun, REN Zheng-Wei, LONG Hui, HOU Yan-Hua, LEI Ming
    Geophysical and Geochemical Exploration. 2015, 39 (2): 401-407.   DOI: 10.11720/wtyht.2015.2.32
    Abstract   HTML   PDF (1675KB) ( 428 )

    Ground fissures are extensively developed in Longyao area,and cause serious geohazard.Based on previous ground fissure investigation which has lasted for many years in the North China Plain and aimed at analyzing the structure of the existing ground fissures and revealing the factors controlling the development of ground fissures,the authors employed geophysical technologies to conduct ground fissure survey in Dongdianma Village where the ground fissures are exposed. The vibraseis method,α-cup cumulative radon detection method,geological radar method and multi-channel transient Rayleigh wave method were utilized to perform the investigation,and the good exploration results show that the first three geophysical methods have the optimal response characteristics and hence are the key technologies to investigate Longyao ground fissures.The integrated geophysical method based on these key technologies provides not only conclusive geophysical data but also scientific basis for the mechanism of Longyao ground fissures.

    References | Related Articles | Metrics
    The seismic exploration method for buried active faults in thick sediment area:A case study of Qiaobei-Suqian fault
    GU Qin-Ping, XU Han-Gang, ZHAO Qi-Guang
    Geophysical and Geochemical Exploration. 2015, 39 (2): 408-415.   DOI: 10.11720/wtyht.2015.2.33
    Abstract   HTML   PDF (2539KB) ( 387 )

    Seismic reflection exploration is the main technique in present urban active faults detecting.The effect of investigating fault and its up-breakpoint in thick Quaternary sediments depends on the working methods and technical parameters.Qiaobei-Suqian fault is an important buried fault along Tan-Lu fault zone in Jiangsu. In this paper,based on QL14 line laid on the fault in thick sediments during the active fault survey in Suqian City and aimed at investigating the spatial distribution,characteristics and activities of the fault controlled by the line,the authors used different seismic exploration methods and acquisition parameters to perform a high-resolution seismic reflection experiment and obtain the imaging of buried fault in the light of the work thinking of combination and fractional steps and according to different targets,the depth of the target layer and the accuracy requirement.The technique solved the contradiction between the field data acquisition and the geological task.The authors obtained high-resolution images of structures in the depths of 16~450 m after data processing,and the prospecting results provide seismological evidence for the position layout of composite drilling sections,the depth designing of drilling and the evaluation of fault activity.The high-precision composite drilling geological sections show that the main stratigraphic boundaries and tectonic features obtained from the seismic exploration methods are quite consistent with the results from the composite drilling geological section.The experimental result shows that the combined detection methods can receive the attitude and distribution of the fault in different depths and the complete distribution image from the depth to the shallow part of the fault.The feasibility of the seismic exploration methods for locating the buried fault and determining its activity in thick Quaternary sediments and the efficiency of the combination of seismic exploration and composite drilling geological profiles are also demonstrated in this study.

    References | Related Articles | Metrics
    The improvement and applications of the impression method in AMT data processing
    KONG Zhi-Zhao, SHAN Ke-She, WU Yong, AI Hu, WANG Ze-Xia
    Geophysical and Geochemical Exploration. 2015, 39 (2): 416-420.   DOI: 10.11720/wtyht.2015.2.34
    Abstract   HTML   PDF (1342KB) ( 500 )

    In AMT data processing, inversion model construction determines the final inversion, whereas the inversion model of unreasonable deviation leads to erroneous inversion result. Based on thought of previously proposed impression method, the authors made some improvements in this paper: 2D inversion is conducted by using the average resistivity of one-dimensional TM model as uniform half space model resistivity and then, with the inversion result as the element model, the average resistivity as the auxiliary model, and the theoretical probing depth as theimpression depth, a new inversion model is constructed. Comparative studies of examples show that the methods used in this model can better reflect the corresponding geoelectric structure and achieve the balance and unity in the region, thus exhibiting good application effect.

    References | Related Articles | Metrics
    Study of wavelet transform in ground penetration radar weak signal denoising
    WANG Chao, SHEN Fei-Min
    Geophysical and Geochemical Exploration. 2015, 39 (2): 421-424.   DOI: 10.11720/wtyht.2015.2.35
    Abstract   HTML   PDF (1628KB) ( 498 )

    Based on the theory that the wavelet coefficients can signify the wavelet functions and analyze the degree of signal approximation, by superimposing the wavelet coefficients of different scales we compare nine kinds of wavelet functions and find that Mexican hat wavelet can be used to erase high frequency noise in GPR signals and amply effective signals, thereby providing basis for the judgment on suspected abnormal location by adopting the traditional data processing method to process the GPR signals.

    References | Related Articles | Metrics
    The application of CSAMT with small and medium-sized transmit-receive distance to the shallow geological exploration
    SHANG Tong-Xiao, GUAN Yi-Xiao, ZHU Shou-Feng, JIANG Guo-Qing, LI Jian-Ping, LI Xiang-Qian
    Geophysical and Geochemical Exploration. 2015, 39 (2): 425-431.   DOI: 10.11720/wtyht.2015.2.36
    Abstract   HTML   PDF (1579KB) ( 356 )

    Based on analyzing the excitation distribution characteristics of the bipolar source in a homogeneous half-space electromagnetic field and discussing the correlation between the transmit-receive distance and the maximum depth of prospecting, the authors hold that CSAMT characterized by small transmit-receive distance, long bipolar source and short potential electrodes can be applied to geological exploration in the shallow layer of a strong noisy-level environment, and has such merits as high signal-to-noise and uniform distribution of electromagnetic field along the line direction. This paper briefly describes fieldwork and data-processing methods of CSAMT, and illustrates typical experimental curves under man-made interferences, controlled tests on the dipole-dipole resistivity sounding and applied cases in shallow geophysical exploration. The inversion results are similar in controlled tests, but CSAMT has higher resolution and stronger anti-interference capability. Interpretations of applied cases match the drilling verification, indicating that CSAMT with small and medium-sized transmit-receive distance array has practical value and application prospect in the shallow geophysical exploration.

    References | Related Articles | Metrics
    The application of the SNMR groundwater detection technology to the detection of reservoir dam leakage
    WANG Xiao-Ming, CUI Wei, NIE Dong-Gang
    Geophysical and Geochemical Exploration. 2015, 39 (2): 432-436.   DOI: 10.11720/wtyht.2015.2.37
    Abstract   HTML   PDF (1102KB) ( 476 )

    Surface nuclear magnetic resonance(SNMR) technique is a non-invasive detection technology, which, through the recognition of the distribution of hydrogen atom signals in water molecules, infers the distribution of water molecules in the strata, and then determines whether there exists groundwater or not and provides some information concerning the water table, the water-rich degree and the porosity. In this paper, taking a soil dam of a reservoir in Anhui Province as an example, the authors used the SNMR to investigate the dam leakage, and obtained such physical parameters as initial amplitude (E0), longitudinal relaxation time (T1), and transverse relaxation time (T2*). Through analyzing the correspondence between the physical parameters and the geological structure, the authors determined the existence of two leakage points and, through field investigation and engineering geological drilling, verified the geophysical survey results, thus providing the geological basis for the management of dangerous reservoir dam.

    References | Related Articles | Metrics
京ICP备05055290号-3
Copyright © 2021 Geophysical and Geochemical Exploration, All Rights Reserved.
Tel:(8610)62301569   Email:wt@caict.ac.cn