首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
庐枞矿集区内的沙溪斑岩铜矿床是长江中下游成矿带中一个典型的岩浆热液型矿床。为了查明沙溪斑岩铜矿床深部岩体范围及控矿构造空间特征,作者在矿区进行了AMT探测,经过数据去噪处理和反演得到了18条电阻率拟二维断面图。反演结果表明受背斜控制的石英闪长斑岩体与志留系地层电性差异明显,呈现高阻特征;通过对电阻率值进行3D克里金(Kriging)插值及可视化显示,建立了石英闪长斑岩3D电阻率模型,揭示了深部岩体的形态和空间分布,为矿区及外围找矿提供了参考依据。  相似文献   

2.
金属矿电法勘探由于受限于探测深度和复杂矿体形态的解释,在深部矿产资源勘探中难受重视.安徽庐江泥河铁矿床是长江中下游成矿带中最主要的矿床类型之一,矿区复杂的地质结构和矿体形态以及矿体的大深度赋存状态给地球物理勘探特别是电法勘探带来了很大的挑战.为了研究电阻率/极化率法在大深度复杂金属矿体探测中的应用效果,本文以泥河铁矿某勘探剖面为例,在实际矿区的地质模型基础上通过简化建立了相应的地球物理模型,采用偶极-偶极装置及二极装置,对矿区进行直流电阻率/极化率数值模拟.提出采用有限元-无限元耦合法以解决传统有限元法截断边界所引起的问题.理论和计算结果表明:有限元-无限元耦合法相比传统有限元法,能显著提高计算的效率和精度.偶极-偶极装置的视电阻率断面图较二极装置能更好的区分不同地层及磁铁矿异常,而根据铁矿高极化特性,探测深度相对较大的二极装置的视极化率断面图能够更好的反映出异常体位置及范围.  相似文献   

3.
类中梯装置三维激电成像技术兼顾了激电测深与激电剖面二者的特点,能快捷高效的获得测区三维电阻率及极化率信息,空间分辨率高,探测深度大。本文从类中梯装置的数据采集方式入手,阐述了采用类中梯装置进行三维激电成像的工作方式.建立了一个三维地电模型,采用类中梯装置进行三维正演模拟,并进行反演及成像。数值模拟结果表明,采用类中梯装置进行三维激电成像能较好地刻画实际地电模型的特点。以甘肃省某多金属矿为例,利用阵列式电磁法综合测量系统,进行了三维大功率激电成像技术的应用研究。实际应用结果表明,采用三维激电成像技术,可以多角度、多细节显示测区地下介质电阻率、极化率的分布情况,明确电性突变界面的延展状态,快速圈定成矿有利区。该研究对多金属矿产勘探等领域具有一定的指导性意义。  相似文献   

4.
荣那铜矿床位于西藏班怒西段多龙斑岩铜矿集区,以往1∶50000磁法和水系沉积物测量已经显示出荣那异常带具有寻找隐伏斑岩铜矿的潜力.为进一步查明该异常区的异常源属性和铜矿地质特征,对以往地质、物探等资料进行了综合研究,并投入了大比例尺磁法和电法测量等物探工作;在优选区内成矿有利部位的基础上,利用钻探施工进行异常查证.区内物探工作将荣那异常带进一步分解为两个次级异常区:在荣那异常区中心呈现低磁、低阻、高极化异常有利成矿区块,在荣那外围异常区呈现环状高磁、高阻、低极化异常环带.进一步在荣那异常区布设两条激电测深剖面,约150 m以深呈现钟状陡峭的低阻高极化异常.通过对该异常进行综合分析,在荣那异常区选定成矿有利部位施工ZK3204钻孔,86.83~1067.6 m进尺处揭露厚大铜矿体,连续穿矿厚度980.77 m,铜平均品位0.69%.矿体呈巨厚橄榄球状,矿石类型为黄铜矿、辉铜矿化、斑铜矿、黄铁矿化浸染状铜矿石.截止2015年末,探获332+333+334级别铜金属量1097.92万吨,平均品位0.53%.荣那铜矿勘查工作表明,该物探异常是由隐伏铜矿体引起,铜矿类型属斑岩型.阿里地区的铜矿勘查工作表明,青藏高原等高海拔地区高精度磁法和激电测量是经济有效快速圈定靶区的铜矿勘查手段.  相似文献   

5.
江西省冷水坑矿集区具有浅部斑岩型矿体与深部层控叠生型矿体的复杂组合.利用现代地球物理方法对矿集区地下深部结构进行了探测,对圈定地下容矿、示矿地质信息和认识地下深部成矿过程具有重要意义.本文以位于江西省贵溪市境内的冷水坑银铅锌矿田为试验研究区,开展了混场源音频大地电磁测深法(EH4)、音频大地电磁测深法(AMT)以及可控源音频大地电磁测深法(CSAMT)三种不同频率域的探测试验,研究和总结了频率域方法以及不同仪器电磁法数据采集特点和应用效果,为频率域电磁法勘探提供借鉴和参考.通过对冷水坑矿集区典型勘探线上三种电磁方法的数据处理,绘制了视电阻率和相位单点测深曲线、原始拟断面及二维反演断面图.发现单点曲线形态基本一样.由于AMT在低频段受矿区工业干扰,视电阻率曲线呈45°上升;视电阻率、相位拟断面对地下电性分层结构基本一样,总体可分为三层,且分层结构较清晰;二维反演断面能够较好反映地下高低阻异常响应,但响应效果有所差异且CSAMT法效果较好.因此在干扰严重地区,建议选用人工源发射的可控源音频大地电磁测深法(CSAMT).  相似文献   

6.
水下激发极化测深异常特征研究   总被引:5,自引:0,他引:5       下载免费PDF全文
利用有限单元法对水下激发极化测深进行数值模拟以研究其异常特征和适用条件.水下的电阻率测深和激电测深均可对水底地质体进行近距离探测,提高探测分辨率.而水底地形对视电阻率测深的影响很大.水底极化体有限元正演模拟的结果表明,水底地形对激发极化测深结果没有影响.采用水下激发极化法进行地质体探测是可行、有效的.通过计算不同水体和水底岩石电阻率对视极化率幅值的影响发现,水体电阻率是影响水下极化率测深的主要因素.由于海水的电阻率过低,观测视极化率异常微弱而不适合开展水下激电工作.  相似文献   

7.
应用大功率激电法对深部隐伏矿体的探测是一种行之有效的方法。通过激电中梯对承德槽子沟金矿区进行激电面积性测量,圈定出与金矿伴生的金属硫化物及氧化物引起的激电异常分布区带,利用激电测深查明地下极化异常体的展布,而后结合已知地质、物性资料布置验证钻孔,并取得了较好的勘查效果。本文总结出利用大功率激电方法勘查隐伏金矿的行之有效工作模式,该找矿模式可广泛应用于同类隐伏金矿的勘探之中,必将有力提高物探方法寻找隐伏金矿的勘探水平。  相似文献   

8.
自然界中几乎所有的地质结构都是三维的,尤其是对于矿体形态变化很大的金属矿,常规的二维电法探测很难准确刻画其三维形态,另一方面,极化率参数对硫化物金属矿的反映更为直接有效,因此开展三维电法工作获取电阻率和极化率三维形态,是深部矿产资源探测的迫切需求,也是当前电法的发展方向.本文从原理、装置、硬件系统、反演方法及软件等方面,介绍了分布式三维直流电法勘探研究进展.通过对TITAN-24、NEWDAS和IRIS分布式系统的特点及其应用实例分析,发现由于同时观测不同方向的电性参数,大大提高了横向分辨率;大功率、大极距的采集方法,有效加大了勘探深度;分布式的测站布设,提高了工作效率;采用全波形记录前提下,在干扰严重的老矿山周边,仍能采集到有效的电法数据,为危机矿山的深、边部找矿开辟了新的途径.  相似文献   

9.
综合地球物理方法在某金多金属矿区找矿中的应用   总被引:5,自引:3,他引:2  
某金多金属矿区地表矿化痕迹较多,矿化体和围岩物性差异明显,为了准确查明区内矿体的空间分布以及控矿构造,在该区实施了对称四极装置的激电扫面和EH4连续电导率测深工作.激电测量获得了总体呈NE走向、与地表矿带对应的中高视电阻率(?s)及中高视极化率(?s)矿化异常带.异常带西窄东宽,矿化集中在测区327°向测线800~1350 m处;在与已知矿体对应的?s-2高极化率激电异常开展的EH4测深工作结果进一步确定了深部成矿潜力:含矿构造延深可达500 m,具有低阻异常特征,倾角近直立.激电扫面和EH4测深相结合的综合物探方法在该区达到了查明矿体分布规律、控矿构造的目的,是有效的多金属矿找矿方法之一.  相似文献   

10.
三维大地电磁激电效应特征研究   总被引:2,自引:1,他引:1       下载免费PDF全文
在积分方程法的大地电磁三维正演模拟中引入Cole-Cole模型研究激电效应特征,对均匀半空间中存在极化体时的三维大地电磁测深响应进行了理论计算,分析了极化参数的影响规律.结果表明:激电效应使观测视电阻率值变低;地下高阻极化体比低阻极化体的激电效应强,特别是极化率大的高阻极化体对大地电磁响应影响大,使观测结果出现假异常.  相似文献   

11.
In this paper, the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport, such as precipitation depth, discharge, and human activities are studied. To investigate the changes in sediment yield in this watershed, a trend analysis on sediment concentration, precipitation depth, and discharge is conducted. Precipitation depths at 2 Climate Stations (CSs), as well as discharge and sediment transport at 3 Gauging Stations (GSs) are used to assess the features of sediment transport in the Kuye River. The rtmoff modulus (defined as the annual average discharge per unit area, L/(s·km^2)) and the sediment transport modulus (defined as the annual suspended sediment transport per unit area, t/(yr km^2)) are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m^3/s in August with an average monthly sediment concentration of 88.9 kg/m^3. However, the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m^3 and occurs in July, which has an average discharge of 42.6 m^3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August, the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In July, the average monthly median grain size of suspended load approaches another peak and decreases until September. Then, the median grain size of suspended load starts to increase until February of the following year. However, the average monthly median grain size of suspended load in the Yellow River at Toudaoguai and Longmen GSs is the smallest between early summer and late fall The median grain size in the Yellow River starts to increase in November and approaches the largest size in January.  相似文献   

12.
Observations of trace gases (SO2, NH3, NO2 and O3) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH3 was found in the range of background values. Also, the average concentrations of NO2 and O3 at the different environments were in the order of background values. However, the concentrations of SO2 were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO2, NH3 and NO2 showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world.  相似文献   

13.
ABSTRACT

This study analyses trends in low flows in Spain in the period 1949–2009, based on daily flow data collected at 60 gauging stations located in near-natural catchments. Two low-flow indicators were considered: (i) the seven-day annual minimum streamflow and (ii) the 10th percentile of the yearly flow duration curve. Catchments were clustered into three regions in terms of monthly mean flows. The Mann-Kendall test was used considering four periods between 1949 and 2009. A multi-temporal trend analysis was also applied to the longest series to identify wet and dry periods that could influence the results. Lastly, a field significance test provided a regional assessment of the at-site detected trends at each region. The results for each indicator reveal a clearly decreasing trend in low flows throughout the northern half of Spain that was found to be field-significant over the (Atlantic and Mediterranean) regions.
Editor Z.W. Kundzewicz; Associate editor not assigned  相似文献   

14.
2008年云南地震灾害概况   总被引:1,自引:1,他引:0  
列出了2008年云南省破坏性地震目录.在此基础上,结合云南省地震局的地震灾害评估资料,总结了2008年云南地震灾害的主要数据和特性.最后列出1990~2008年云南地震灾害的相应数据,并进行了简要对比.  相似文献   

15.
2007年中国大陆地震灾害损失述评   总被引:4,自引:0,他引:4  
在列出2007年中国5级以上地震目录的基础上,结合有关省(自治区、直辖市)地震局的地震灾害评估资料,总结出2007年中国大陆地震灾害的主要数据和特性。最后列出1990—2007年中国大陆地震灾害的相应数据,并进行了简要的比较。  相似文献   

16.
3He/4He ratios up to 3.5 times the ratio of atmospheric He were found in groundwater samples. The3He enrichment can be attributed to radiogenic3He produced by in-situ beta-decay of3H. This shows that tritiogenic3He is accumulating in confined waters. From tritiogenic3He and3H concentrations, ages of groundwaters can be calculated. Detection of tritiogenic3He gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the3H counting method.  相似文献   

17.
18.
In an active spreading area like Iceland, where the regional geothermal gradient is in the range 50–150°C/km, it is normally not a problem to find high enough temperature with deep drilling, but the difficulties arise with finding permeable layers at depth within the strata. Various volcanological methods can be applied in the search for aquifers and geothermal reservoir rocks. The flow pattern (as deduced from deuterium studies) indicates that the thermal water flows preferentially along high porosity stratiform horizons and dyke swarms from the recharge areas in the highlands to the hot spring areas in the lowlands. The primary porosity of the volcanic strata is dependent on the chemical composition and the mode of eruption of the volcanic units. Both the reservoir rocks and the flow channels forming the geothermal plumbing system are thought to vary from the Tertiary to the Quaternary provinces due to environmental conditions at the eruptive sites.  相似文献   

19.
The aim of this study is to estimate likely changes in flood indices under a future climate and to assess the uncertainty in these estimates for selected catchments in Poland. Precipitation and temperature time series from climate simulations from the EURO-CORDEX initiative for the periods 1971–2000, 2021–2050 and 2071–2100 following the RCP4.5 and RCP8.5 emission scenarios have been used to produce hydrological simulations based on the HBV hydrological model. As the climate model outputs for Poland are highly biased, post processing in the form of bias correction was first performed so that the climate time series could be applied in hydrological simulations at a catchment-scale. The results indicate that bias correction significantly improves flow simulations and estimated flood indices based on comparisons with simulations from observed climate data for the control period. The estimated changes in the mean annual flood and in flood quantiles under a future climate indicate a large spread in the estimates both within and between the catchments. An ANOVA analysis was used to assess the relative contributions of the 2 emission scenarios, the 7 climate models and the 4 bias correction methods to the total spread in the projected changes in extreme river flow indices for each catchment. The analysis indicates that the differences between climate models generally make the largest contribution to the spread in the ensemble of the three factors considered. The results for bias corrected data show small differences between the four bias correction methods considered, and, in contrast with the results for uncorrected simulations, project increases in flood indices for most catchments under a future climate.  相似文献   

20.
冬季亚洲中强震与夏季我国东部主雨带的准同纬性   总被引:1,自引:1,他引:1       下载免费PDF全文
根据1954~2003年50年亚洲中强震与我国地温资料,分析了冬季震中纬度—震涡中心纬度—冬季我国东部强地热涡中心纬度—夏季我国东部主雨带纬度4者之间的相互关系,发现冬季中强震与夏季主雨带之间具有较好的准同纬性. 这是每年汛期降水预报的一个指标. 文中也讨论了应用此预报指标时的一些特例.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号