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文章介绍最新的第12代国际地磁参考场(IGRF-12)模型,选取5个具有代表性的日期,应用该模型提取和计算1997—2017年全球地磁正常场值并绘制平面分布图,研究结果表明:全球地磁正常场的总体结构较稳定,IGRF模型具有可靠性。以南海及其周边区域为例,应用IGFR-12模型,采用数据统计、图形展示和时间域对比的综合分析方式,分析其在不同时间段内地磁正常场的分布特征和变化规律,研究结果表明:研究区地磁正常场值总体较低,变化较缓慢,呈增长趋势;地磁正常场总体北高南低且变化较大,同一纬度西高东低且变化较小;地磁正常场变化量由大到小的时间段依次为2012—2017年、2007—2012年、1997—2002年、2002—2007年,与IGRF-12中不同模型的差异相对应;IGRF模型中确定场模型数据的稳定性较优,预测场模型的可靠性较高但需进一步校正。 相似文献
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以IGRF全球地磁位模型为基础,设计地磁测量参考场计算软件,实现地磁场参数长波分量的时间域与空间域离散点计算,为野外磁力测量相关数据采集与仪器配置提供先验信息,使数据采集的作业效率及可靠性大大提高。 相似文献
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从太平洋底发现外星撞击地球的痕迹 总被引:2,自引:1,他引:2
通过对偶然发现于太平洋M14岩心中的微玻璃陨石的显微特征和物质成分的全面研究,首次发现了撞击坑反弹结构、亲铁元素铱、锇等异常、不定形碳、未饱和无环碳氢化合物、有机质及多种挥发分子,根据这些痕迹和证据肯定了发生于大约2.14~2.30MaBP的一次外星撞击地球事件,并推测撞击地球的外星可能为一彗星碎片;另根据岩心中微玻璃陨石层同该岩心中地磁事件和地磁倒转的联系,进一步论证了这次外星撞击地球事件的发生.最后,笔者提出了发生撞击事件的时代──2.14~2.30MaBP可作为深入研究和划分地质历史中第三纪-第四纪界线的重要参考时代,有待科学家通过更多的发现和长期研究加以验证. 相似文献
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海水层对地磁日变的影响 总被引:1,自引:0,他引:1
在海洋地磁测量中地磁日变的影响不可忽视,由于海底地磁日变观测站可建在测区内或附近,通常情况下能较好地反映测区范围内的地磁日变状况.但从实际观测资料对比发现,海底地磁观测站站位水深对地磁有效信息的保留存在一定的相关性.随着水深增大,其保留的信息量逐渐减少,即水层对地磁信息有着明显的衰减作用. 相似文献
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本文对1987及1988两年中在东海南部海域进行的海洋重力,海上磁测及陆地地磁日变观测工作做了系统介绍。共有5个航次,295条测线,站间距25m,剖面总长度达12172km。资料整理结果表明,测量是高精度的,重力测网各交点闭合差的场方差不超过2mgal,地磁则不超过4nT。 相似文献
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Yu. V. Brusilovsky A. G. Gorshkov A. M. Gorodnitskii A. N. Ivanenko S. V. Lukyanov A. M. Filin Yu. V. Khan 《Oceanology》2007,47(3):406-414
The objective of our research is the interpretation of the results of the geomagnetic survey of the geologic structure in the Gorlo Strait of the White Sea. We used the maps of the anomalous magnetic field (AMF) available and processed them with original interpretation software. As a result of this processing, we compiled a structural-tectonic chart of this region. We distinguished the boundaries of the major first-order tectonic structures such as the underwater extension of the Leshukon graben and a number of minor structures related to the Proterozoic and Paleozoic stages of the magmatic activity in the region. Modeling was performed for the most important objects, which allowed us to refine the geological structure of these objects and their genesis. 相似文献
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The importance of geomagnetic studies in the World Ocean for deep structure research and fore-casting of mineral resources is noted. A combined method for development of a marine nuclear magnetometer is adduced. The physical background of operation of nuclear magnetometers is analyzed in order to optimize the measurements of the magnetic field. The results of the experiments on detecting nuclear precession signals against the background of ship noises are considered and the elaboration of an MM-1 nuclear magnetometer at the Shirshov Institute of Oceanology is described. A technique for magnetic survey and comprehensive geological interpretation of the anomalies and Z and H field components are presented. Examples of geomagnetic studies performed in the World Ocean with the MM-Inuclear magnetometer are assessed: for the first time in Russia, linear magnetic anomalies were identified and sea-floor spreading rates were calculated (the northern part of the Indian Ocean); a regional geomagnetic survey was carried out in the region of Iceland, which proved the spreading origin of the seafloor in this vast region. A systematic analysis of geomagnetic data obtained with the MM-1 magnetometer in the World Ocean provided the creation and development of the methodology for their tectonic and geodynamical interpretation. On the basis of the geomagnetic data obtained, new fundamental conclusions about the deep structure, kinematics and paleogeodynanics of the World Ocean floor were made. 相似文献
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Reservoir characterization based on geostatistics method requires well constraints (e.g. seismic data with high quality) to predict inter-well reservoir quality that is conformed to geological laws. Nevertheless, the resolution of seismic data in multiple basins or reservoirs is not high enough to recognize the distribution of different types of sand bodies. In this paper, we propose a new method to improve the precision of reservoir characterization: reservoir modeling with the constrains of sedimentary process model and sedimentary microfacies. We employed stratigraphic forward modeling, a process-based method, to constrain the reservoir modeling in one oil-bearing interval of the third member of Eocene Shahejie Formation in J-Oilfield of Liaoxi Sag, Bohai Bay Basin.We divide reservoir modeling into two orders using different types of constrains. In the first order, we use the simulated shale model from stratigraphic forward model that is corrected by wells data as a 3D trend volume to constrain the reservoir sand-shale modeling. In the second order, different types of sedimentary microfacies in the sandy part of the model are further recognized and simulated within the constrains of sedimentary microfacies maps. Consequently, the porosity, permeability and oil saturation are modeled under the control of precise sedimentary microfacies model. The high-resolution reservoir model shows that the porosity, permeability and oil saturation of distributary channel is generally above 20%, 10md and 50%, respectively, which are much higher than that of other types of sedimentary microfacies. It can be concluded that comparing to other types of sedimentary facies, distributary channel has better physical properties and more oil accumulation in the fan-delta front and therefore is the most favorable zones for petroleum development in the research area. 相似文献
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海底浅层地质灾害的高分辨率地震识别技术 总被引:1,自引:0,他引:1
将渤海某油田最新采集的二维高分辨率资料处理解释后,结合区域地球物理及地质概况,利用地震相分析、波阻抗反演、井(孔)震标定等深层油气勘探的成熟技术,系统研究了各类海底浅层地质灾害因素的成因、特征、危害及展布规律,总结了一套完整的利用高分辨率地震识别海底浅层地质灾害的技术方法。结果表明,浅层断裂、浅层气和埋藏古河道是研究区海底浅层发育的主要地质灾害因素,通过刻画不同期次地质灾害因素的类型及其分布范围,为今后该油田海上施工提供了可靠的工程地质调查成果。因此,高分辨率地震技术能够很好地应用于海底浅层地质灾害的识别。 相似文献
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局部海洋地磁场模型可以为水下地磁匹配导航与磁性目标探测等工作提供高精度的海域地磁背景场数据。针对目前区域地磁场模型构建方法中未考虑到高度或深度变化的影响,截断阶数难以确定及存在边界效应等问题。根据海洋磁力测量的特点,顾及磁测点高度数据,引入粒子群优化的最小二乘支持向量机法(PSO-LSSVM)构建局部海洋三维地磁场模型。在仿真与实测数据建模试验中,与Taylor多项式法、BP神经网络法及曲面样条函数法比较,结果表明,无论是在地磁变化平缓区还是复杂区,PSO-LSSVM法的建模精度均是最高的,建议在局部海洋地磁场模型构建中采用。 相似文献
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与海洋地磁日变改正有关的长期变化和磁扰的处理 总被引:3,自引:0,他引:3
提出地磁日变改正中需要顾及地磁长期变化和磁扰的可靠分离,保证磁力数据改正处理具有明确的基准,提高拼接整合的精度.如果日变站能够控制测区,两者可采用时间同步固定的地磁正常场作为磁异常基准,测区的地磁长期变化由日变站实测的地磁长期变化来改正,反之,对日变站和测区应分别采用时间同步变化的地磁正常场作为磁异常基准,测区的地磁长期变化由地磁正常场的地磁长期变化来改正.为此,应该明确定义与时间相关的日变改正基值为地磁正常场与地磁异常之和.通过磁静日总场观测值偏离正常场的某种形式的长期平均值,可以逼近日变站的地磁异常.磁扰的分离应保证磁扰初动和消失相对于磁静日无磁扰的连续过渡.采用综合模型一并进行日变改正、正常场及其长期变化改正,可以更好地解决目前日变改正中遇到的问题. 相似文献
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Chatillon J. Adams A.E. Lawlor M.A. Zakharia M.E. 《Oceanic Engineering, IEEE Journal of》1999,24(1):4-15
The objective of the Synthetic Aperture Mapping and Imaging (SAMI) project was to develop and to test at sea a wide-band synthetic aperture sonar prototype, capable of providing high-resolution seafloor images together with bathymetry maps. This system used the motion of a physically small array in order to synthesize a longer array, providing images with an across-track resolution independent of both range and transmit frequency. Such systems are clearly very relevant to the high-precision long-range (low-frequency) imaging of the sea bottom. The project has led to the construction of a prototype tested at sea on several well-known areas for comparison with existing images and maps. These areas included several types of sea bottom, depths, and geological structures. The results obtained in real time, on-board ship, have shown the relevance of the proposed wide-band techniques. The many profiles produced have provided high-resolution images and maps of various seafloors. Interpretation by geologists showed that the system was capable of providing the same or finer detail than a deep-sea short-range, high-frequency system and maintained a higher resolution over a wider swath. The sea data processed have shown that the system provided maps with a cubic meter voxel. The resolution cell is constant over the whole range (50 to 2500 m) thanks to the dynamic focusing of the synthetic aperture. Postprocessing of a part of the data stored during the experiments has been carried out in the laboratory. This work has shown that techniques such as autofocusing can give an increase in resolution (i.e., gain in contrast and resolution of about 3 dB). The results displayed in the paper show the relevance of the techniques developed to the provision of a complete high-performance imaging tool for the oceanographic community 相似文献