超长电磁波遥测技术在渤海深部油气勘探中的应用

根据渤海西岸和渤海中部两口探井的探测和对比实验分析，利用超长电磁波遥测技术可以根据已知探井的探测对比分析预测新探井的岩性界面，协助井位的选址和设计。另外，利用超长电磁波的探测技术可以从同和平面上对远景区进行普查性探测，编制远景区的构造图。根据塘沽－大连探测的超长电磁波频谱曲线剖面对比分析，证实引起渤海中部重磁异常的地质体可能是基性超基性岩体。渤海中部地区的岩浆活动为本区的有机物成熟提供了热机制，因此，渤海中部地区可能是渤海深层天然气的勘探远景区。  

重磁震平面统计建模反演技术的理论探讨

目的 为重磁震的平面联合统计建模反演提供理论依据与方法基础，力图将国内目前占主导地位的重震、磁震剖面的单项理论建模反演推进到新的层次。方法 基于场论，以独立地质系统为控制单元，把重磁震共存的物性界面深度作为与其一一对应的极值重磁异常的二元复合逆函数，利用差值趋势面分析，按单元在空间(波数)域内逼近其逆函数的泰勒(傅立叶)级数分布，建立重磁震联合反演的随机地质模型。结果 重磁震平面统计建模反演技术，成功应用于胜利油田新区和潜山区的油气勘探实践，编绘出仅靠地震难以成图的深层构造图。结论 随着高分辨率重磁界面识别技术的不断提高，该项探索性研究成果有望推进综合地球物理联合建模反演技术的发展。  

用于划分磁异常的新方法—插值切割法

在考察空间域和波数域中划分磁异常区域场和局部场常用方法特点的基础上,作者提出了插值切割法。该方法以当前计算点场值与四点圆周平均值的插值运算为切割算子,通过连续切割,得到磁异常的切割区域场,而从磁异常中减去后,就得到切割局部场。误差分析表明,磁异常中的随机误差在切割区域场中被压制,而在切割局部场中没有明显放大。本研究对四个理论模型和一个野外实例的处理结果表明,这种新方法适合于复杂磁异常区域场与局部场的划分,其他的一些特点是计算速度快、分辨率和精度高。  

几种不同类型金矿的高精度磁测异常特征

许多金矿的赋矿(或伴生)岩石与其周围岩石之间存在着磁性差异,如与中基性脉岩有关的金矿成因模式矿床、破碎蚀变火山岩型金矿等,在其上能观测到磁异常.即使是河床底部缝隙中与砂金相伴沉淀的重砂,由于铁磁性矿物含量较高,与其附近砂石之间存在磁性差异,利用高精度质子磁力仪,也能观测到比较明显的磁异常.在西藏自治区及四川省一些金矿床(点)上的研究取得了良好的进展,对砂金矿、锑金伴生型金矿,中基性脉岩型金矿上的高精度磁测异常特征有了新的认识,为利用高精度磁测方法间接寻找金矿积累了经验.  

Magnetic recording of the Cenozoic oceanic crustal accretion and evolution of the South China Sea basin

We review and discuss some of the recent scientific findings made on magnetic data in the South China Sea (SCS). Magnetic anomalies bear extremely rich information on Mesozoic and Cenozoic tectonic evolution. 3D analytical signal amplitudes computed from magnetic anomalies reveal very precisely relict distributions of Mesozoic sedimentary sequences on the two conjugate continental margins, and they are also found very effective in depicting later-stage magmatism and tectonic transitions and zonation within the SCS oceanic crust. Through integrated analyses of magnetic, gravity and reflection seismic data, we define the continent-ocean boundary (COB) around the South China Sea continental margin, and find that the COB coincides very well with a transition zone from mostly positive to negative free-air gravity anomalies. This accurate outlining of the COB is critical for better tracing magnetic anomalies induced by the oceanic crust. The geometrically complex COB and inner magnetic zonation require the introduction of an episodic opening model, as well as a transform fault (here coined as Zhongnan Fault) between the East and Southwest Sub-basins, while within the East and Southwest Sub-basins, magnetic anomalies are rather continuous later-ally, indicating nonexistence of large transform faults within these sub-basins. We enhance magnetic anomalies caused by the shallow basaltic layer via a band-pass filter, and recognize that the likely oldest magnetic anomaly near the northern continental margin is C12 according to the magnetic time scale CK95. Near the southern continental margin, magnetic anomalies are less recognizable and the anomaly C12 appears to be missing. These differences show an asymmetrical opening style with respect to the relict spreading center, and the northern part appears to have slightly faster spreading rates than to the south. The magnetic anomalies C8 (M1 and M2, ~26 Ma) represent important magnetic boundaries within the oceanic basin, and are possibly related to changes in spreading rates and magmatic intensities. The magnetic evidence for a previously proposed ridge jump after the anomaly C7 is not clear. The age of the Southwest Sub-basin has yet to be further examined, most favorably with deep-tow magnetic surveys and ocean drilling. Our magnetic spectral study shows that the shallowest Curie points are located around the eastern part of the Southwestern Sub-basin, whereas within the East Sub-basin Curie depths are smaller to the north of the relict spreading center than to the south. This pattern of Curie depths is consistent to regional heat flow measurements and later-stage volcanic seamount distributions, and we therefore reason that Curie-depth variations are closely associated with later-stage magmatism, rather than with crustal ages. Although magnetic anomalies located around the northern continent-ocean transition zone (COT) are relatively quiet, this area is not a typical magnetic quiet zone since conceptually it differs markedly from an oceanic magnetic quiet zone. The relatively quiet magnetic anomalies are seemingly associated with a shallowing in Curie isotherm and thinning in magnetic layer, but our comprehensive observations suggest that the well-preserved thick Mesozoic sedimentary rocks are major causes for the magnetically quiet zone. The high similarities between various low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies clearly confirm that deeper magnetic sources (in the lower crust and the uppermost mantle) have contributions to long-wavelength surface magnetic anomalies in the area, as already inferred from magnetically inversed Curie depths. The offshore south China magnetic anomaly (SCMA) becomes more prominent on low-pass filtered marine and air-borne magnetic anomalies and satellite magnetic anomalies, indicating very deeply-buried magnetic sources beneath it.  

磁异探潜中潜艇的数学模型

本文从潜艇磁性构成的机理出发，按照磁异探潜时的实际测量距离，提出５个磁偶极子磁矩的潜艇数学模型，推导了实测这些磁矩时需用的计算公式，并用船模试验证实了该数学模型的正确性。  

苏南地区逆冲推覆构造的某些特征研究

江苏南部地区的逆冲推覆构造广泛发育。这些逆冲推覆构造的产出具多层次性,其形成与该区不同时代地层内的多套由软弱岩层组成的滑动系统有关。关于逆冲推覆构造存在的证据,许多学者已撰文列述了大量地质事实,此外,在地球物理场上亦有明显反映。逆冲推覆构造上覆系统与原地系统间节理裂隙发育程度上有明显差异。逆冲断层带断层岩由浅至深有由脆性—韧脆性—脆韧性—韧性变形的变化规律,在脆性剪切带内的局部地方存在韧性变形。这些变形特征可通过偏光显微镜下变形矿物的一系列光学现象和透射电子显微镜(TEM)下石英晶体的位错现象得到验证。  

南四湖—北五湖地区断裂构造的多源信息解析

为查明山东南四湖—北五湖地区断裂构造之间的关系 ,通过 MSS,TM遥感图像及重、磁异常等值线图的复合处理 ,对该地区的断裂特征进行了综合分析。结果表明 :南四湖—北五湖地区的断裂构造呈燕山期及其以前形成的东西向、南北向断裂和现代活动型的北西、北东向断裂组成的立体结构 ;现代活动型断裂在遥感图像上的线性影像与深部受力构造面的物质磁性变化密切相关。这一研究为该地区煤炭资源的勘探与开发 ,以及地震预报研究提供了依据。  

西安毛西磁异常的地质意义

本文阐述了应用地面磁测在西安东郊发现和圈定了毛西磁异常;根据异常区的地质和地球物理特征,作出了磁异常的定性和定量解释,推断它是中生代燕山期花岗岩侵入体的反映,顶部最小埋深约1500m;电测深结果支持了这个推断;重力勘探资料揭示了这个花岗岩侵入体处于灞桥断阶两组断裂带的交接部位;花岗岩作为热源及断裂带作为通道,使毛西磁异常是西安寻找地热田最有远景的地区。