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1.
为满足中国海岸带海陆统筹调查的需求,基于最新编制的中国北部海岸带(台州以北)1:50万航磁图件,利用逐点化极、延拓、垂向导数等数据位场转化处理,结合地质背景、物性资料和已有航空物探解释成果,对研究区磁场特征进行分析,分区探讨航磁异常成因,并编制北部海岸带(台州以北)断裂分布图。结果表明,海岸带地区磁性较强的岩石广泛发育,以NE—NNE向为主的线性磁异常带是大量中新生代中酸性岩浆岩的反映,而区域性团块状磁异常或宽缓正负磁异常则为区域变质岩系的反映。研究区断裂发育,断裂展布方向基本以NE向、NNE向为主,NW向次之,其中深大断裂对区域构造、岩浆活动等有明显的控制作用。本研究编制的北部海岸带航磁"一张图"作为质量可靠的基础数据,可为解决海岸带基础环境和地质问题提供丰富的地球物理信息。依据航磁资料划分的断裂,解决了特殊地理环境下海陆断裂不衔接的问题,实现了断裂海陆统筹的目标,可为海陆交互区重大工程规划提供安全性评价依据。 相似文献
2.
中国航磁异常管理信息系统开发与建设 总被引：3，自引：4，他引：3
航磁异常管理信息系统是采用GIS可视化技术及数据库技术在MAPGIS软件系统平台上建立的信息管理系统，它能够完成航磁异常的可视化检索、统计、属性编辑和图形显示，并实现检索结构数据的自动成图。首次建立的航磁异常信息数据库整理录入完成中国国土资源航空物探遥感中心资料室保存的20世纪80年代以前全国大部分少、市、自治区的1万多份航磁查证异常登记表和检查卡片的相关信息：航磁异常属性记录约11350条、地检异常属性记录约12870条、见矿异常属性记录约1120条，扫描及矢量化地检异常图件约7270份。本系统通过建立异常属性数据库与航磁地检异常矢量图文件、全国省级航磁数据库文件、全国航磁测量工作程度图及全国1：50万数字地理底图数据库之间合理的逻辑关系，实现了多种信息基于GIS平台与技术的统一管理和应用。 相似文献
3.
Pauline Le Maire Lionel Bertrand Marc Munschy Marc Diraison Yves Géraud 《Geophysical Prospecting》2020,68(7):2307-2319
Magnetic measurements with an unmanned aerial vehicle are ideal for filling the gap between ground and airborne magnetic surveying. However, to obtain accurate aeromagnetic data, the compensation of magnetic effects of the unmanned aerial vehicle is a challenge. Typically, scalar magnetometers are towed several metres under the unmanned aerial vehicle to minimize its magnetic field. In this study, a fluxgate three-component magnetometer is attached 42 cm in front of the unmanned aerial vehicle at the tip of a composite pipe. Using a scalar calibration, the sensor can be calibrated, and the permanent and induced magnetic fields of the unmanned aerial vehicle can be compensated. The contributions of the magnetic measurements at different altitudes to the unmanned aerial vehicle results were tested over an area of 1 km² in the Northern Vosges Mountains. The area is located in a hamlet surrounded by a forest where few geological outcrops are observed. Three magnetic surveys of the same area are obtained at different altitudes: 100, 30 and 1 m above the ground. The unmanned aerial vehicle magnetic data are compared with a helicopter aeromagnetic survey at 300 m above the ground and a ground magnetic survey using upward continuations of the maps to compare the results. The magnetic maps (300, 100, 30 and 1 m above the ground) show very different magnetic anomaly patterns (e.g. amplitude, shape, wavelength and orientation). The magnetic data at different altitudes improve the understanding of the geology from the local to more general scales. 相似文献
4.
Microlevelling procedures applied to regional aeromagnetic data: an example from the Transantarctic Mountains (Antarctica) 总被引：1，自引：0，他引：1
The extensive application of digital enhancement and filtering as a powerful tool for aeromagnetic interpretation, not only of high resolution but also of regional data, requires an improved levelling. Two microlevelling techniques were thus compared in order to find an effective but relatively simple procedure to remove, or at least to reduce, residual magnetic errors remaining after standard levelling processes. This study was carried out on regional aeromagnetic data recently acquired at high magnetic latitudes along the Transantarctic Mountains in Antarctica, where it is particularly critical to remove time-dependent magnetic variations. Two-dimensional FFT filters applied to the gridded data, namely the Butterworth and a directional cosine filter, proved to be more effective than previously proposed one-dimensional space-domain filters in the reduction of the 'residual corrugation' not removed by statistical levelling. Tectonic interpretation of trends detected in the total field magnetic anomaly map and in the 3D analytic signal improved after application of frequency-domain microlevelling. However, we also show that when interpreting microlevelled data, two factors must be considered: (i) the possible presence of real geological trends aligned along the flight lines; (ii) modifications in the results yielded by depth estimates of magnetic sources due to the FFT filters applied during the microlevelling procedure. Such changes were seen both in the well-established 2D FFT method, based on the slope of the energy spectrum, and in the more recent 3D Euler deconvolution technique. Overall our results indicate that microlevelling could profitably be applied to older gridded aeromagnetic data sets in Antarctica, thus improving the accuracy and geological significance of future regional magnetic compilations, as already seen in other continents. 相似文献
5.
前寒武纪变质基底的起伏变化特征和沉积盖层的厚度变化对研究地质构造、能源和资源勘探具有重要意义.而前寒武纪变质基底与沉积盖层之间通常存在一定的磁性差异,这就为利用航磁资料研究磁性基底深度提供了地球物理条件.本文集合了中国国土资源航空物探遥感中心30多年来编制的中国陆域30多个盆地和地区的磁性基底深度图以及补算的部分地区磁性基底深度,经过统一坐标系、统一比例尺之后编制了1/100万比例尺的中国陆域磁性基底深度图(成图比例尺为1/250万).研究结果表明,以E105°线为界,我国西部地区沉积坳陷区盖层厚度大,集中分布在塔里木盆地、准噶尔盆地、柴达木盆地和西藏地区;东部地区沉积坳陷区盖层厚度整体上相对较薄,主要分布在松辽盆地、二连盆地、鄂尔多斯盆地、华北南部盆地、四川盆地、南黄海—苏北盆地等,但最厚处在四川盆地的西南部和鄂尔多斯盆地西缘.这些研究成果展现了我国前寒武纪变质基底和具有一定规模的岩浆岩侵入岩体的深度变化特征,同时反映了沉积盖层的厚度和赋存现状,可直观了解各种类型的沉积盆地和沉积坳陷区的深度和范围,为寻找基底之上油气藏提供了直接依据. 相似文献
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New techniques for the integration of gravity and aeromagnetic data through rock physical property relationships are tested for the rapid location of potential iron oxide–copper–gold (IOCG) exploration targets across the Great Bear magmatic zone (GBMZ). These techniques are based on the recognition of coincident or near-offset magnetic and gravity anomalies associated with IOCG deposits, resulting from their intense and combined iron-oxide and alkali alteration. In the GBMZ, the NICO (Au–Co–Bi–Cu) deposit is an atypical magnetite-group IOCG hosted within an intensely hydrothermally-altered metasedimentary sequence. Prospectivity maps for the NICO area are derived from the integration of high-resolution aeromagnetic and surface gravity data with physical property measurements of magnetic susceptibility and density. Method 1 combines the pseudo-gravity (derived from the aeromagnetic data) and Bouguer gravity data to determine the locations of superimposed high anomalies. Method 2 estimates the apparent susceptibility and density subsurface distribution based on vertical prism models of the magnetic and gravity data. The apparent susceptibility data are transformed to apparent density using physical property relationships. The two apparent density datasets are then combined to determine the location of coincident magnetic and gravity derived anomalies. The results of these methods are supported by, and compared with, similar prospectivity maps generated through weights of evidence techniques. At NICO, the prospectivity maps accurately locate the deposit and nearby occurrences. Despite the lower resolution of the regional gravity data, application of the techniques across the GBMZ is successful at locating mineralised IOCG systems including the magnetite-group systems at Grouard, Fab, DeVries and Cole Lake, the magnetite to hematite-group systems of the Port Radium-Echo Bay district, and has highlighted possible targets for future exploration. 相似文献
7.
20多年来,中国海陆及邻域的地质地球物理调查在不断进步,尤其是海域取得很多新认识,但中国海陆及邻域的大范围编图,尤其是大地构造图,没有随之更新;中国海陆的编图还一直存在海陆不接、海域编图相比陆域落后的问题;亟需编制一幅中国海陆及邻域的大地构造图.1992年编制的"中国海域及邻区地质地球物理系列图"的大地构造图,运用以活动论为内涵的全球构造理论作为指导思想,对中国海区及邻域的大地构造特征做出了较好的诠释.最近,中国海陆地质地球物理系列图编制项目,把1:500万中国海陆及邻域大地构造格架图作为图种之一.在全球构造理论基础上发展而来的块体构造学说,作为本次编图的指导思想,根据其大地构造体系,板块和板块边界作为一级构造单元,块体和结合带(缝合带等)作为二级构造单元,结合系列图中重力图、磁力图、地质图等图件成果,以及最近的其他调查研究资料,完善了对特提斯在南海周边的界线、东海陆架的基底构造属性等认识,在研究区内共划分出了欧亚板块、菲律宾海板块和印度-澳大利亚三大板块,6个板块边界构造单元,30个块体、14个结合带和10个缝合带. 相似文献
8.
闽西南地区位于福建武夷山成矿带西南部,自远古宙以来经历了多期次的构造演化.该区地处东南沿海构造-岩浆-成矿带上,为环太平洋大陆边缘多金属成矿带与南岭多金属成矿带复合部位,是我国重要的多金属矿产地.永定大排多金属矿区作为近年来武夷山成矿带新发现的大型多金属矿,区内叠加作用和控矿作用相对复杂,现有的地质地球物理工作程度不足以满足对该区域成矿规律的深入认识,一些基础地质问题亟待解决.因此,本文在深入收集永定大排矿区地质地球物理资料基础上,综合分析区域成矿背景与成矿构造,在重点区域布设综合地球物理勘探工作,包括1：1万高精度磁测、可控源音频大地电磁剖面及反射地震剖面.基于上述工作：1）开展了研究区航磁数据三维磁化率反演与分布特征分析与大地电磁二维电阻率反演与分布特征分析,开展了地震资料真地表深度偏移成像,获得了更加准确的地震剖面成像结果.2）结合推覆体控矿特征,地震剖面和电阻率剖面、航磁反演结果相互验证和约束,勾画了地下构造形态.地表地质剖面延伸和标定了构造形态的地质内涵,获得了从地表到3000 m深度的构造解释结果.解释结果清晰地显示了与推覆相关的构造、控矿层位以及岩体信息,为三位一体的找矿思路提供了地球物理依据. 相似文献
9.
The Potiguar Basin is a ∼6,000 m thick aborted NE-trending rift that was formed during the Cretaceous in the continental margin of northeastern Brazil. Its ∼E–W-trending offshore faults form part of the successful continental margin rift that evolved into the South Atlantic Ocean. The region represents one of the most significant pre-Pangea breakup piercing points between eastern South America and West Africa. We used gravity, aeromagnetic, and geological data to assess the role of reactivated Precambrian shear zones and major terrain boundaries in the development of the Potiguar Basin from the Cretaceous to the Cenozoic. We also looked for possible links between these structures in northeastern Brazil and their continuation in West Africa. Our results indicate that the major fault systems of the Potiguar Basin were superimposed on the Precambrian fabric. Both gravity and magnetic maps show lineaments related to the shear zones and major terrain boundaries in the Precambrian crystalline basement, which also characterize the architecture of the rift. For example, the Carnaubais fault, the master fault of the rift system, represents the reactivation of the Portalegre shear zone, the major tectonic boundary between Precambrian terrains in the crystalline basement. In addition, part of the Moho topography is controlled by these shear zones and developed during the period of main rift extension in the Neocomian. The shear zones bounding the Potiguar rift system continue in West Africa around and underneath the Benue Basin, where fault reactivation also took place. 相似文献
10.
Pierre Keating 《Geophysical Prospecting》1997,45(3):521-534
Aeromagnetic maps poorly represent lineaments that are at acute angles to the flight-line direction. Commonly used gridding algorithms cannot cope with local trends, magnetic anomalies at an angle with the main trend of the map, and tend to generate closed contours around the flight lines. By introducing some a priori information, it is possible to add extra data between the flight lines, i.e. trend lines, to reinforce local trends. The proposed automated technique is based on a nearest neighbour search of the maxima and minima in the aeromagnetic map. The resulting map is more realistic and derived maps, such as vertical gradients and analytical signal maps, are greatly improved. Moreover, this automated procedure is user independent and easy to implement. The technique is demonstrated on aeromagnetic data from the Kirkland Lake region, in north-eastern Ontario, Canada. 相似文献
11.
Abdullah Ates Funda Bilim Aydin Buyuksarac Attila Aydemir Ozcan Bektas Yasemin Aslan 《Surveys in Geophysics》2012,33(5):869-885
In this paper, aeromagnetic and gravity anomalies obtained from the General Directorate of Mineral Research and Exploration were subjected to upward continuation to 3?km from the ground surface to suppress shallow effects and to expose only regional, deep sources. Then, a reduction to pole (RTP) map of aeromagnetic anomalies was produced from the 3?km upward continued data. A sinuous boundary to the south of Turkey is observed in the RTP map that may indicate the suture zone between the Anatolides and African/Arabian Plates in the closure time of the Tethys Ocean. The sinuous boundary can be correlated with the recent palaeo-tectonic maps. The southern part of the sinuous boundary is quite different and less magnetic in comparison with the northern block. In addition, maxspots maps of the aeromagnetic and gravity anomalies were produced to find out and enhance the boundaries of tectonic units. Crustal thickness, recently calculated and mapped for the western Turkey, is also extended to the whole of Turkey, and the crustal thicknesses are correlated with the previous seismological findings and deep seismic sections. The average crustal thickness calculations using the gravity data are about 28?km along the coastal regions and increase up to 42?km through the Iranian border in the east of Turkey. Density and susceptibility values used as parameters for construction of two-dimensional (2D) gravity and magnetic models were compiled in a table from different localities of Turkey. 2D models indicate that all of the anomalous masses are located in the upper crust, and this could be well correlated with the earthquakes which occurred at shallow depths. 相似文献
12.
为解决地面人员难以到达的特殊区域大比例尺磁测数据获取问题,本文提出一种基于三轴磁通门传感器,采用旋翼无人机进行航空磁测的方法.项目组研制适合旋翼无人机搭载的航磁数据记录仪,并完成旋翼无人机、三轴磁通门传感器、航磁数据记录仪的集成工作,开展了三轴磁通门传感器安装点位噪声水平试验、地面空中对比试验、磁性体识别试验、动态飞行一致性试验、区域飞行试验.旋翼无人机航磁系统具有操作简单、设备轻便、效率高的特点,能在地面人员难以达到的区域开展低空航磁测量.中国四川省黑竹沟地区是地磁异常区域,项目组在该区域内的沟壑、峡谷、湖泊等实地开展了野外应用测试,完成了这些特殊区域的航磁调查工作. 相似文献
13.
Virtual Pole from Magnetic Anomaly (VPMA) is a new multi-disciplinary methodology that estimates the age of a source rock from its magnetic anomaly, taken directly from available aeromagnetic data. The idea is to use those anomalies in which a strong remanent magnetic component is likely to occur. Once the total magnetization of the anomaly is computed through any of the currently available methods, the line that connects all virtual paleogeographic poles is related with the position, on a paleogeographic projection, of the appropriate age fragment of the APWP curve. We applied this procedure to five (5) well-known magnetic anomalies of the South American plate in SE Brazil, all of them associated to alkaline complexes of Mesozoic age. The apparent ages obtained from VPMA on three of the anomalies where the radiometric age of the source rock is known – Tapira, Araxá and Juquiá – were inside the error interval of the published ages. The VPMA apparent ages of the other two, where the age of the source rock is not known (Registro and Pariqueraçu magnetic anomalies) were geologically coherent. We expect that the application of the VPMA methodology as a reconnaissance geochronological tool may contribute to geological knowledge over continental areas, especially when the source rocks of the magnetic anomalies are unknown or buried below superficial sediments. 相似文献
14.
基于最新编制的1/100万全国航陆域磁异常图数据,采用功率谱法对中国陆域的居里点深度进行了估算,获得了8004个居里点深度,完成了中国陆域居里面深度图的编制,首次完整的展现了中国陆域的居里面起伏特征.研究表明,居里面在稳定地块表现为坳陷,埋深为28~45km,如塔里木盆地,准噶尔盆地,柴达木盆地,可可西里—巴颜喀拉坳陷区,扬子盆地区,华北盆地区,松辽盆地,二连盆地,巴彦浩特—武威—潮水盆地,珠江口—琼东南盆地等.华北盆地区的居里面深度与塔里木陆块和扬子陆块有较大的差异,相对偏浅,这可能与华北陆块遭受了复杂的后期改造,导致软流圈上隆和岩石圈减薄有关.可可西里—巴颜喀拉地块是青藏高原北部发育的呈NWW向展布的巨型居里面坳陷带,其原因是该地区发育大面积的三叠系沉积地层和较少的岩浆活动,这些稳定的地块都具有莫霍面隆起和居里面坳陷的特征.在活动频繁的造山带居里面以隆起为特征,埋深为18~26km,如东北部山岭区、西北部山岭区、秦岭—大别山地区、西昆仑—西藏—三江—康滇地区、东南沿海地区等.这反映了构造运动及岩浆活动所引起的地壳地温梯度的差异.根据我国816个大地热流数据,对比研究居里面深度与地温梯度和大地热流的关系,结果显示居里面深度与热流值并非线性关系,居里面深度大于30km时,热流值较低,均小于100mW·m~(-2);在居里面深度小于30km的地区,热流值变化范围较大.并且,随着热流值的升高,热流值有向中国东部沿海、藏南—三江地区、秦岭—大别地区、辽东等集中的趋势,这些地区都呈现出居里面隆起的特征,是地热资源勘探开发的重要远景区. 相似文献
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We report the results of a joint analysis of aeromagnetic, topographic and tectonic data in central-eastern mainland Greece. The emphasis of the analysis is placed on the detection of coherent lineations (discontinuities), collocated and correlated with faulting structures detected by geological field observation. To this effect, edge detection and image enhancement were applied to digital aeromagnetic anomaly maps and digital elevation models, comprising bidirectional differentiation, wavelet transformation (imaging) and spatial decomposition/reconstruction in the wavenumber domain. The analysis facilitated the detection of significant topographic lineaments with NNE–SSW, ENE–WSW and ESE–WNW orientations. Respectively, the aeromagnetic data exhibit two families of significant NE–SW, and one family of ESE–WNW lineaments. The major aeromagnetic and topographic lineaments coincide and have comparable width scales of the order of 2–3 km, indicating that they are produced by significant discontinuities in the upper crust. The kinematics of the NE–SW faults varies between oblique-slip and strike-slip. These faults affect Neogene to Late Quaternary deposits and have been responsible for the formation of transverse depressions and horsts. This is also corroborated by focal plane solutions from small earthquakes recorded by local networks. The nature of these structures is not yet clear. However, they have been detected by diverse methodologies, they have considerable extent and are apparently active. These attributes suggest that they may possibly be related to the propagation and diffusion of the North Anatolian and North Aegean fault systems into the Greek mainland. 相似文献
17.
W. DOMZALSKI 《Geophysical Prospecting》1966,14(3):273-291
The term “structure”, as used here, includes synclinal and anticlinal folds and folding in general, faults, cross fractures and various conditions associated with intrusions. Structure, both regional and local, has a very important role in emplacement of mineralization. Under certain circumstances which occur fairly commonly, structural conditions are reflected significantly in the trends and intensities apparent on aeromagnetic maps. A number of documented illustrations based on Canadian Shield conditions are discussed. Illustrations are drawn from areas of known geology and from proven mining camps, as well as from loci of recent discoveries. Canadian examples are chosen because of existence and availability of extensive aeromagnetic cover, although it is logical to extend the argument to other shields and indeed to regions of other geological, but similar magnetic character. The importance of aeromagnetics in structural approach to exploration and the correctness of such approach seem to be fully substantiated by results discussed. 相似文献
18.
利用南海最新的磁力资料,在岩石物性分析基础上,选择南海一条典型剖面拟合反演其密度与磁性结构并以拟合结果作为约束,反演全海域磁性基底的宏观分布.对南海磁力数据进行了低纬度化极处理,利用Halo小波基对化极磁异常进行了多尺度分析并依据磁力异常特征进行了磁场分区.根据剖面与全海域磁性基底反演结果认为：南海北部陆缘更倾向于非火山型的构造属性.磁性基底对浅部沉积作用的控制关系在莺歌海一带表现得非常明显.中—西沙和南沙块体的磁性基底特征十分相似,推测在海盆拉张之前,二者为同一块体. 相似文献
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全张量磁梯度数据具有高精度、高分辨率、多参量的优点,能更加清晰地刻画地质体的分布特征,综合利用磁张量梯度数据准确地获得地质体水平位置和深度信息是解释的主要目的.磁张量数据的方向解析信号具有减小倾斜磁化干扰的优点,常被用来圈定磁源体的水平位置,但解析信号强度随着地质体埋深的增加急剧衰减,难以有效识别较深的地质体.张量数据均衡边界识别技术,利用不同方向解析信号的比值函数,能有效地均衡不同深度地质体的响应,同时显示不同深度地质体的边界,提高了对较深地质体的分辨率.磁张量数据深度成像技术根据实测张量数据与假定模型张量数据的相关系数来给定地质体的深度,综合利用多参量数据联合反演提高了反演结果的准确性,且无需进行复杂的反演运算,是大数据量张量数据解释的有效方法.理论模型试验证明：磁张量数据均衡边界识别技术可清晰和准确地识别地质体的水平范围,受倾斜磁化干扰小;磁张量数据深度成像技术可准确地获得地质体的深度信息,具有较强的抗噪性.将上述方法应用于铁矿区实测航磁张量梯度数据解释,获得了铁矿体水平分布与埋深,深度结果与张量欧拉反褶积法计算结果一致. 相似文献