磁化强度矢量反演新方法及其在卡拉塔格铜多金属矿床找矿中的应用     

杨力  周可法  王金林  安少乐 《地球物理学进展》2020,(1):230-238

磁异常的反演是地球物理勘探的重要手段,三维磁化率反演是磁异常定量解释中的一种重要方法.由于剩磁的存在使得磁化方向与地磁场方向产生偏差,从而影响了磁异常反演与解释的精度.本文基于磁异常模量反演和磁化强度矢量反演方法得到了一种新的磁化强度矢量反演方法.与以往的磁化强度矢量反演方法相比,该方法以磁异常模量反演得到的磁化率模型为约束,采用Lp范数正则化方法求解,提高了磁化强度矢量反演的精度和效率.本文通过模拟试验的反演计算,验证了这种磁化强度矢量反演方法的有效性.最后,将本文方法应用于新疆东天山卡拉塔格地区航磁数据的解释,获得了地下空间不同磁性差异的磁性体的空间分布特征,为进一步分析研究区隐伏矿床提供了重要信息.  相似文献   

贺根山镁铁-超镁铁岩与缝合带的关系——来自地球物理的证据          下载免费PDF全文

邵济安  张丽莉  周新华  张履桥  唐克东 《地球物理学报》2020,63(5):1867-1877

长期以来,对内蒙古贺根山缝合带中的镁铁-超镁铁岩,有着"蛇绿岩"、"岩浆岩"、"幔源熔-流体"等不同认识.近年来在铬铁矿中发现了金刚石等深部地幔矿物,如何认识携带这些物质的幔源熔-流体的上涌?缝合带在镁铁-超镁铁岩的形成过程中起到什么作用?解决问题的关键之一是弄清镁铁-超镁铁岩的深部产状,这需要来自地球物理观测数据的依据.本文基于航磁和重力数据的研究表明,贺根山地区的蛇绿岩块均呈现高磁异常特征,其中贺根山岩块埋深明显大于其他岩块,表现为高磁异常与低重力异常,与地表出露的蛇纹石化的镁铁-超镁铁岩带对应.对航磁化极异常与布格重力异常数据做了向上延拓处理,进行了磁源形态及底界深度的估算,并利用基于相异度算子的边缘增强方法辅助识别断裂.结果表明,贺根山岩块贯穿地壳,且附近存在超壳断裂.地表至中地壳主要由蛇纹石化的镁铁-超镁铁岩组成,下地壳主要为超镁铁质岩组成,它们充填在一组宽约30km的NEE向断裂带中,大地电磁测深剖面揭示的壳-幔电性结构进一步证实控制缝合带的是岩石圈断裂,贺根山缝合带具有明显的根部.由此推测,在地幔底辟上涌的背景下,幔源熔-流体沿着岩石圈断裂持续上升到达浅表,暗示该区板块的拼合可能是通过深部幔源物质的侵入而成的.  相似文献   

High-resolution unmanned aerial vehicle aeromagnetic surveys for mineral exploration targets     

C. Walter  A. Braun  G. Fotopoulos 《Geophysical Prospecting》2020,68(1):334-349

Recent advancements in geophysical exploration have been realized through reliably integrating unmanned aerial vehicle platforms with lightweight, high-resolution magnetometer payloads. Unmanned aerial vehicle aeromagnetic surveys can provide a contemporary data product between the two end-members of coverage and resolution attained using manned airborne and terrestrial magnetic surveys. This new data product is achievable because unmanned aerial vehicle platforms can safely traverse with magnetometer payloads at flight elevations closer to ground targets than manned airborne surveys, while also delivering an increased coverage rate compared to walking conventional terrestrial surveys. This is a promising new development for geophysical and mineral exploration applications, especially in variable terrains. A three-dimensional unmanned aerial vehicle aeromagnetic survey was conducted within the Shebandowan Greenstone Belt, northwest of Thunder Bay, Ontario, Canada, in July 2017. A series of two-dimensional grids (∼500 m × 700 m) were flown at approximate elevations of 35, 45 and 70 m above ground level using a Dà-Jiāng Innovations multi-rotor unmanned aerial vehicle (S900) and a GEM Systems, Inc., Potassium Vapour Magnetometer (GSMP-35U). In total, over 48 line-km of unmanned aerial vehicle aeromagnetic data were flown with a line spacing of 25 m. The collected aeromagnetic data were compared to a regional heliborne aeromagnetic survey flown at an elevation of approximately 85 m above the terrain, with a line spacing of 100 m, as well as a follow-up terrestrial magnetic survey. The first vertical derivative of the gathered unmanned aerial vehicle total magnetic field data was calculated both directly between each of the different flight elevations, and indirectly by calculating the values predicted using upward continuation. This case study demonstrates that low flight elevation unmanned aerial vehicle aeromagnetic surveys can reliably collect industry standard total magnetic field measurements at an increased resolution when compared to manned airborne magnetic surveys. The enhanced interpretation potential provided by this approach also aided in delineating structural controls and hydrothermal fluid migration pathways (a pair of adjacent shear zones) related to gold mineralization on site. These structural features were not clearly resolved in the regional manned airborne magnetic data alone, further demonstrating the utility of applying high-resolution unmanned aerial vehicle aeromagnetic surveys to mineral exploration applications. The conclusions and interpretations drawn from the unmanned aerial vehicle aeromagnetic data, coupled with historical data, were applied to make a new gold mineralization discovery on the site, assayed at 15.7 g/t.  相似文献   

北京地区基底磁性界面反演及断裂研究   总被引：1，自引：0，他引：1  

张先  赵丽 《中国地震》2007,23(3):276-285

在对北京地区1∶10万航磁异常进行定性分析、小波多尺度分解及功率谱计算的基础上,运用三维磁性层反演方法,计算了北京地区基底磁性界面的定量埋深。根据反演结果对北京地区几条重要的基底断裂及其地震危险性进行了分析和探讨。  相似文献   

新疆梧南地区航磁异常特征分析及找矿标志研究     

杨雪 《地质与勘探》2015,51(6):1033-1040

梧南航磁异常区位于新疆维吾尔自治区鄯善县,该异常区于1978年发现两条近于平行的正磁异常带沿北西西向展布,航磁异常特征非常明显。笔者通过对梧南地区地质构造特征、成矿环境、岩(矿)石物性及航磁特征等进行综合分析、研究,探讨了梧南地区航磁异常引起的原因,进而推断两条沿北西西向展布的航磁异常带上,叠加的几处局部升高强磁异常可能与隐伏的磁性体有关。鉴于此,笔者以异常带上的新C-1978-127航磁异常为例,对航磁异常进行定性分析,并利用2.5D拟合技术进行定量拟合计算,推断航磁局部强磁异常可能与隐伏的磁铁矿有关。依据区内地质-地球物理特征、航磁定性分析及定量计算结果,建立了该区地质-地球物理找矿标识,并进行了找矿远景分析,认为区内新C-1978-127、127-1、127-2、127-3、127-4等5处局部强磁异常找矿潜力较大,应予以重视。  相似文献   

航磁垂直梯度调整ΔT水平方法研究   总被引：2，自引：1，他引：1       下载免费PDF全文

骆遥  王平  段树岭  程怀德 《地球物理学报》2012,55(11):3854-3861

使用中国自主研发、具有完全自主知识产权的航磁全轴梯度勘查系统首次试飞获得的资料,利用航磁垂直梯度数据进行ΔT水平调整研究,讨论了航磁及航磁梯度资料水平调整的原则,提出梯度资料长波水平的调平方法.对经长波水平调整后的垂直梯度数据进行位场转换,获得不受地磁场随时间变化影响的磁异常,并通过恢复磁异常的长波信息,实现了ΔT的水平调整和增强.实际资料处理表明调平过程具有物理意义、效果明显.  相似文献   

Imposition of a Proterozoic salient on a Palaeozoic orogen at the eastern margin of Gondwana     

H.A. Williams  J.R. Stewart  P.G. Betts 《Gondwana Research》2009,16(3-4):669-686

Regional analysis of the distribution of metamorphic fabrics and shear zones in the Palaeo-Mesoproterozoic Curnamona Province has enabled the deconstruction of a Cambrian fold arc that defines part of the eastern margin of Gondwana. We suggest a tectonic model whereby the arc formed at ca. 500 Ma, during accretion of Phanerozoic terranes to the eastern margin of Precambrian Australia. The regional fold arc is interpreted to have formed along an irregular plate margin comprising a SE-convex rigid promontory of Precambrian basement during initial accretion of the Phanerozoic terranes during the Cambrian. An early phase of dextral oblique-slip along shear zones in the south and west of the province indicates an initial WNW transport direction. As the arc was folded, a slightly later phase of sinistral oblique-slip shearing was initiated along shear zones in the east, in response to deflection of the arc around the rigid promontory.  相似文献   

辽北猴石地区1：5万航磁地质解释     

董绪东 《国土资源》1995,(3)

在覆盖区或半覆盖区进行区域地质调查或地质勘查前，运用航空磁测资料对工作区进行解释，可以对测区地质面貌有系统的了解，根据解释结果有针对性地部置工作，可提高工作效率和质量，降低成本。本文以猴石地区地质测量（１：５万）为例，讨论了有关地层、岩石、构造和矿产的解释依据和方法。  相似文献   

江苏南部区域航磁异常特征及其地质意义     

刘建生 《江苏地质》2014,38(1):72-78

以江苏南部1∶50万航磁资料为基础,通过对区内岩矿石磁性特征的归纳与分析,对区内航磁异常形成的地质因素作了讨论,并对区内航磁异常进行了分类、分区及地质解释。通过进一步对区内航磁资料的数据处理,对区内深变质磁性基底面的埋深、形态特征及其地质意义作了讨论,对区内构造岩基带平面分布及垂向分布特征,特别是对长江断裂带也一并作了推断解释。  相似文献   

新疆东昆仑祁漫塔格一带1∶5万航磁异常特征及找矿方向     

杨春雨  姚卫星 《西北地质》2010,43(4):300-306

新疆东昆仑祁漫塔格一带成矿地质条件优越,是西北地区重要的找矿区域之一。2008年国土资源航遥中心开展的1∶5万航磁勘查工作反映该区总体磁场较弱,单个磁异常强度较低,但反映的磁异常信息较为丰富。通过开展1∶5万航磁异常查证工作,认为航磁异常较全面、客观的反映了该区的地质、构造及矿化特征,查证磁异常均与一定地质体或矿化对应。该区以铅锌矿化为主,多金属矿化常见,矿化类型以矽卡岩型为主,航磁异常主要表现在局部磁异常升高、正负磁异常过渡带部位,低缓磁异常转折部位等。矿致异常形态多样,较难识别,应以通过航磁异常间接找矿为主,指导下一步地质找矿工作,有效加快新疆东昆仑祁漫塔格一带矿产勘查开发进程。  相似文献