湘西自治州北部铅锌矿找矿标志及找矿远景区     

张安源 《湖南地质》1991,(3)

湘西自治州北部铅锌矿带,处于桑植复向斜西南段,长100km以上,宽50km左右,矿带内铅锌矿点广布,受地层、构造、岩性的控制。上寒武统耗子沱群至下奥陶统大湾组共有7个含矿层位,北东向背斜倾伏端及北东向断裂、层间裂隙以及次级北西向横跨背斜是矿床控矿构造,有矿体赋存的含矿层有明显的硅化作用,且硅化体中Pb,Zn,Cu明显富集,分别为地层的66、32、8倍,Sr/Ba比值为0.60,无矿存在的硅化体则Pb,Zn,Cu含量接近地层或稍高于地层,Sr/Ba比值高达1.15。在砂子坡背斜南翼、红岩溪背斜北东端和南西倾伏端、盐井背斜,下奥陶统红花园组顶部含矿层内为找矿远景区。  相似文献   

气候变化对江河流量变化趋势影响研究进展   总被引：9，自引：0，他引：9  

刘春蓁 《地球科学进展》2007,22(8):777-783

气候变化对基于自然稳定气候假定的流量变化趋势的检测和水资源评价方法提出了挑战。在流量变化趋势的检测中分离出气候变化的影响,不仅对水资源管理和水利工程设计有重要的应用价值,而且有助于了解气候变化以何种方式、在何时、何地、已经或尚未对水文循环产生影响,对改进气候模型的模拟与预测有重要的科学价值。 统计方法是检验流量变化趋势显著性的有效工具。直接用气候模型模拟和预测未来径流变化的可靠性取决于模型对当代降水模拟的可信度。多个气候模型集合分析有可能在一定程度上减少模型对降水、径流模拟的不确定性。近年发展起来的多个气候模型集合分析与统计显著性检验技术结合的方法,有可能模拟并预测出气候强迫导致大尺度径流空间分布的变化。随着气候模型尤其是陆—气耦合的区域气候模型对降水模拟的改进,可以预见径流变化的检测、归因和预测的趋同化模拟已为期不远。将温室气体外强迫导致的水文气候变化作为一个因子引入到水资源评价中,对于水资源管理经济与生态评估,以及未来的发展规划将是一件十分重要的变革。   相似文献   

Investigation of waste disposal areas using electrical methods: a case study from Chania,Crete, Greece   总被引：1，自引：0，他引：1  

Pantelis Soupios  Ilias Papadopoulos  Maria Kouli  Irene Georgaki  Filippos Vallianatos  Eleni Kokkinou 《Environmental Geology》2007,51(7):1249-1261

A geophysical investigation of a landfill area was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical resistivity tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modeling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7 km east of Chania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36 m. The resulted images conduced, to overcome geotechnical problems since the spatial distribution of karstic voids was determined, to plan the future sites for waste disposal as the geological conditions were studied in detail and to reliably estimate the thickness of the already deposited wastes. The resulted images were confirmed using available borehole logs and ambient noise measurements.  相似文献   

A New Approach for Border Detection of the Dumluca (Turkey) Iron Ore Area: Wavelet Cellular Neural Networks     

A. Muhittin Albora  Abdullah Bal  Osman N. Ucan 《Pure and Applied Geophysics》2007,164(1):199-215

Anomaly analysis is used for various geophysics applications such as determination of geophysical structure's location and border detections. Besides the classical geophysical techniques, artificial intelligence based image processing algorithms have been found attractive for geophysical anomaly analysis. Recently, cellular neural networks (CNN) have been applied to geophysical data and satisfactory results are reported. CNN provides fast and parallel computational capability for geophysical image processing applications due to its filtering structure. The behavior of CNN is defined by two template matrices that are adjusted by a properly supervised learning algorithm. After training stage for geophysical data, Bouguer anomaly maps can be processed and analyzed sequentially. In this paper, CNN learning and processing capability have been improved, combining Wavelet functions and backpropagation learning algorithms. The new architecture is denoted as Wavelet-Cellular Neural networks (Wave-CNN) and it is employed to analyze Bouguer anomaly maps which are important to extract useful information in geophysics. At first, Wave-CNN performance is tested on synthetic geophysical data, which are created by a computer environment. Then, Bouguer anomaly maps of the Dumluca iron ore field have been analyzed and results are reported in comparison to real drilling results.  相似文献   

Time–frequency representation of earthquake accelerograms and inelastic structural response records using the adaptive chirplet decomposition and empirical mode decomposition     

P.D. Spanos  A. Giaralis  N.P. Politis 《Soil Dynamics and Earthquake Engineering》2007,27(7):675-689

In this paper, the adaptive chirplet decomposition combined with the Wigner-Ville transform and the empirical mode decomposition combined with the Hilbert transform are employed to process various non-stationary signals (strong ground motions and structural responses). The efficacy of these two adaptive techniques for capturing the temporal evolution of the frequency content of specific seismic signals is assessed. In this respect, two near-field and two far-field seismic accelerograms are analyzed. Further, a similar analysis is performed for records pertaining to the response of a 20-story steel frame benchmark building excited by one of the four accelerograms scaled by appropriate factors to simulate undamaged and severely damaged conditions for the structure. It is shown that the derived joint time–frequency representations of the response time histories capture quite effectively the influence of non-linearity on the variation of the effective natural frequencies of a structural system during the evolution of a seismic event; in this context, tracing the mean instantaneous frequency of records of critical structural responses is adopted.The study suggests, overall, that the aforementioned techniques are quite viable tools for detecting and monitoring damage to constructed facilities exposed to seismic excitations.  相似文献   

再论拟准检定法的原理、实施和应用   总被引：2，自引：0，他引：2  

欧吉坤 《测绘工程》2002,11(4):3-6

综合阐述了拟准检定法的原理和特点、研究思路。拟准检定法的关键是如何正确选择拟准观测，文章介绍了初选的复选拟准观测的实施要点。列举了拟准检定法在图相关情况下的相差检测，形变分析中的异常探测以及GPS相位观测的周跳检测和修复等方面的应用例子。  相似文献   

桩基动力检测技术的现状及存在的问题   总被引：3，自引：0，他引：3  

曹宇春  吴世明  高广远 《上海国土资源》2002,86(1):43-45,60

文章通过对桩基动力检测方法应用现状的简要回顾，分析了桩基高应变和低应变动测的特点和局限性。在此基础上，提出了在桩基检测和测试结果分析中注意的问题。  相似文献   

A FRAMEWORK FOR AUTOMATED CHANGE DETECTION SYSTEM     

SUI Haigang LI Deren 《地球空间信息科学学报》2001,4(3):29-34

1Ｃｕｒｒｅｎｔｃｈａｎｇｅｄｅｔｅｃｔｉｏｎｔｅｃｈ ｎｉｑｕｅｓＡｕｔｏｍａｔｉｃｃｈａｎｇｅｄｅｔｅｃｔｉｏｎｉｎｉｍａｇｅｓｏｆａｇｉｖｅｎｓｃｅｎｅａｃｑｕｉｒｅｄａｔｄｉｆｆｅｒｅｎｔｔｉｍｅｓｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｎｔｅｒｅｓｔｉｎｇｔｏｐｉｃｓｏｆｉｍａｇｅｐｒｏｃｅｓｓｉｎｇ .Ｉｔｆｉｎｄｓｉｍ ｐｏｒｔａｎｔａｐｐｌｉｃａｔｉｏｎｓｗｉｔｈｉｎｄｉｆｆｅｒｅｎｔｃｏｎｔｅｘｔｓ,ｒａｎｇ ｉｎｇｆｒｏｍｖｉｓｕａｌｓｕｒｖｅｉｌｌａｎｃｅａｎｄｖｉｄｅｏｃｏｄｉｎｇｔｏｔ…  相似文献   

多窗谱分析方法及其在全球变暖研究中的应用   总被引：12，自引：0，他引：12  

江志红  屠其璞  施能 《气象学报》2001,59(4):480-490

多窗谱分析方法是一种低方差、高分辨的谱分析方法 ,尤其适合于非线性气候系统中高噪声背景下弱信号、时频演变信号的诊断分析。文中简要地介绍了多窗谱分析方法的基本原理 ,并将其用于近 1 5 0 a来全球及南、北半球温度变化的研究。结果表明 :(1 )在温度呈线性变暖的背景趋势下 ,北半球、全球年平均温度还具有显著的 40～ 70 a的准周期低频振荡 ,它们与变暖过程中的波动性密切相关 ;(2 )年代际振荡信号在北半球温度序列中也相当明显 ,南半球则存在多种低于 5 a尺度的显著振荡周期 ,半球或全球 ENSO振荡分量、QBO周期信号的振幅都具有缓变包络的特性 ;(3 )与传统功率谱估计、最大熵谱估计结果的对比表明 ,多窗谱分析方法方法得到的谱估计分辨力高 ,稳定性强。  相似文献   

反向VSP透射层析成像法在岩墙松动层检测中的应用     

何正勤  吴庆举  冯锐  陈立杰 《物探与化探》2001,25(1):50-53

通过实例介绍了反向VSP透射层析成像方法的基本原理、数据采集和资料处理方法。利用该方法在检测岩墙松动层厚度中取得了很好的勘探效果。  相似文献