The Late Eocene and Late Miocene fronts of the Atlas Belt in eastern Maghreb: integration in the geodynamic evolution of the Mediterranean Domain

Regional cross sections at the scale of the eastern Maghreb based on subsurface and field data allow presenting the structural styles related to the Middle-Late Eocene compressional events. The structural cross sections depict that the Late Eocene front of the Atlas Belt extends far through the Northern Africa plate margin comparatively to the Late Miocene front cropping out in the Eastern Tunisian Atlas. The sections allow proposing a new subsurface front for the Atlas belt encompassing a large part of the Pelagian-Sirt basins. The consequences of this particular configuration are discussed at the scale of the south Tethys margin and replaced in the frame of the geodynamic evolution of the Mediterranean Domain.     

1:5万地质测量中的物探工作

我国即将开展大面积1:5万的地质测量,物探工作如何配合以取得尽可能多的地质信息,以提高工作质量和效益,是一个急需要研究的课题。系统开展1:5万(1:2.5万)地质测量并同时开展物探工作的国家,主要是苏联。到1982年底为止,1:5万的地质测量已覆盖苏联国土近30%。     

Locations of nonstructural hydrocarbon traps on the shelf of the northern Barents Sea

This paper considers the results of summarized integrated geophysical investigations that were carried out from 2006 to 2012. The investigations included common depth point (CDP) seismic reflection survey, over water gravity survey, and differential hydromagnetic exploration with a total work scope of 30 000 linear kilometers. The deep structural tectonic plan, the structural and lithofacies features of the sedimentary cover section on the basic reflecting boundaries, and the features of the seismogeological complexes and seismic sections on a depth scale have been studied, and geological oil-and-gas zoning of the Northern Barents shelf has been made. Seventy-nine local anticlinal highs have been revealed, and the zones with potential nonstructural hydrocarbon traps have been determined. Due to the lack of huge anticlinal highs in the northern Barents Sea region, nonstructural traps are of interest in studying and replacing the mineral raw material base of Russia, as well as for arranging marine exploration.     

山东招远灵山沟金矿床金矿化空间定位机制

通过对灵山沟金矿矿床地质特征和控矿构造组合特征研究表明,灵山沟金矿控矿构造组合样式为"结环"状,是主、次级断裂组合控矿,即灵山—北截断裂与其次级断裂构成的结环控制了灵山沟金矿的产出;同时研究了该金矿工业矿体的空间定位机制,建立了灵山沟金矿不同深度上工业矿体分别受灵北断裂(F1)和其次级断裂(F5)断裂交汇部位控制,以及热液上升通道控制的空间定位机制,从而解释了同一矿区存在产状明显不同的两类矿体的原因,为矿区及外围开展矿体定位预测和进一步预测找矿提供有益信息。     

施洞口断裂带对金钟山断陷盆地沉积建造的制约研究

施洞口断裂位于贵州东部,曾作为贵州大地构造的分界,但马号段构造样式历有争议,为了探讨施秉县金钟山非典型丹霞地貌成因,即金钟山白垩纪断陷盆地及其“红层”非典型丹霞山体地貌形成的控制因素,对施洞口断裂带马号段、台盘段和舟溪段等多个重要剖面进行调查研究,结合区域地质资料,否定“巴团飞来峰构造”,认同1:20万镇远幅区域地质图划定的构造透镜体形式,同时查明了金钟山白垩系南东边界的沉积关系其实是断层接触,构成施洞口断裂马号地区较大规模构造透镜体的南东边界,使施洞口断裂在整体的平剖结构展布上呈现分支联合的构造透镜状普遍规律特征,另外认为马号—金钟山公路沿线寒武系白云岩为不整合沉积覆盖于青白口系之上,而东侧一带的青白口系又以逆冲断层“推覆”于寒武系白云岩之上,从而成为导致施洞口断裂带在马号段构造特征较为复杂的主要原因,据此本文对施洞口断裂构造特征进行了再次调查梳理,具有较重要的基础地质科学意义,并从地质演化角度解释了施秉金钟山白垩纪断陷盆地及其“红层”非典型丹霞地貌山体的形成,可为金钟山的旅游开发提供地学科普参考依据。     

关于编制盆地构造演化剖面的几个问题的讨论

本文根据平衡剖面原理,从构造地质学基本原理出发,讨论了采用“地层回剥”方法编制构造演化剖面时遇到的影响古构造复原的若干问题,强调建立平衡地质剖面和利用平衡剖面技术编制盆地构造演化剖面时,“地质概念上”的平衡和地质逻辑上的合理比纯粹的“几何学上”的平衡更重要。     

西沙海槽盆地强限制性中央峡谷水道地震相与内部结构的分段特征

西沙海槽盆地中央峡谷深水水道规模大,下切深,弯曲度低,表现出强限制性与东西分段性特征。充分利用研究区二维地震资料,对其地震相特征进行识别与分段性研究,识别出中央峡谷水道体系五种典型地震相类型,分别为底部滞留沉积、浊积砂体沉积、块体流沉积、泥质沉积、滑塌沉积。水道内部充填序列与限制性强度区相关性密切。通过地震相图、沉积相图和古地貌恢复图分析,发现西沙海槽中央峡谷整体呈东西向展布,水道西宽东窄,周边地势西高东低。基于分段特征与构造断裂带的吻合性,以西沙次凹处作为拐点将峡谷分为东西两段,其中西段NWW向展布,限制性弱;东段NEE向展布,限制性强。根据展布、形态、充填等诸多方面因素,总结出了13种分段特征,其限制性与分段性主要受到构造活动、地貌形态与物源供应等的控制。     

构造地球化学方法在内蒙巴山地区金矿普查中的应用

通过巴山地区金矿普查中构造地球化学方法的研究,探讨了构造地球化学测量方法的前提、概念及应用效果,得出了结论:构造地球化学方法在理论上是成立的,找矿效果是明显的,并且在研究成矿成晕机制、异常评价、推断解释方面都可以发挥重要的作用。     

Combination Patterns and Depositional Characteristics of Ordovician Carbonate Banks in the Western Tarim Basin,China

The combination patterns and depositional characteristics of the carbonate banks are investigated based on outcrop sections, thin sections, and carbon isotopes of Ordovician in the western Tarim Basin, China. Four carbonate bank combination patterns are deposited in the Ordovician, western Tarim Basin, including: Reef-Bank Complex (RBC), Algae-Reef-Bank Interbed (ARBI), Thick-Layer Cake Aggradation Bank (TLCAB), and Thin-Layer Cake Retrogradation Bank (TLCRB). All combination patterns show clear periods vertically. The RBC is mainly composed of reefs and bioclastic banks, and the dimension of the RBC depends on the scale of the reefs. Bioclastic banks deposits surround the reefs. The range of the ARBI is determined by the scale of algae-reefs, algae peloid dolomite microfacies and algal dolomite microfacies deposit alternating vertically. TLCAB and TLCRB are deposited as layer-cakes stacking in cycles and extending widely with cross bedding developed. The grains of TLCAB and TLCRB are diverse and multi-source. With the impacting of relative sea level change, biological development and geomorphology, the ARBI, TLCAB or TLCRB, RBC are successively developed from the Lower Ordovician Penglaiba Formation to the Middle Ordovician Yijianfang Formation. The depositional environment analysis of Ordovician indicates that the RBC and ARBI can form effective oil and gas reservoirs, and the TLCAB and TLCRB have the potential to form the huge scale oil and gas reservoirs and to be the crucial targets of exploration for the Ordovician carbonate banks in the future.     

A high‐resolution relative time scale for the Viséan Stage (Carboniferous) of the Kulm Basin (Rhenish Mountains,Germany)

The Viséan (Carboniferous) sedimentary succession of the basinal Kulm facies (Rhenish Mountains) was investigated in detail in order to achieve a high‐resolution stratigraphic subdivision and correlation. Additionally, the ranges of fossil index taxa (ammonoids), fossil marker beds, volcaniclastic horizons and sedimentary features (e.g. colour changes) were integrated in the correlation. As a result, a comprehensive database was compiled, which contains 190 stratigraphic events of the Viséan interval of this area. Several sections are almost completely composed of shales, which are regarded to represent a slow but constant basinal background sedimentation of the Kulm facies. The thickness of lithological homogeneous sections thus indicates an approximately linear record of time and the average thicknesses of biozones and positions of stratigraphic events can easily be calculated from the compiled database. The result is an approximately time‐linear biostratigraphic scale for the Viséan Stage of the Kulm Basin. Given a numerical length of the Viséan Stage of ca. 19 Ma, 190 stratigraphic events give a mean resolution of 100 000 years. This is unique in Palaeozoic stratigraphy. Copyright © 2008 John Wiley & Sons, Ltd.     

Some Distinctions Between Self-Similar and Self-Affine Estimates of Fractal Dimension with Case History

Compass, power-spectral, and roughness-length estimates of fractal dimension are widely used to evaluate the fractal characteristics of geological and geophysical variables. These techniques reveal self-similar or self-affine fractal characteristics and are uniquely suited for certain analysis. Compass measurements establish the self-similarity of profile and can be used to classify profiles based on variations of profile length with scale. Power spectral and roughness-length methods provide scale-invariant self-affine measures of relief variation and are useful in the classification of profiles based on relative variation of profile relief with scale. Profile magnification can be employed to reduce differences between the compass and power-spectral dimensions; however, the process of magnification invalidates estimates of profile length or shortening made from the results. The power-spectral estimate of fractal dimension is invariant to magnification, but is generally subject to significant error from edge effects and nonstationarity. The roughness-length estimate is also invariant to magnification and in addition is less sensitive to edge effects and nonstationarity. Analysis of structural cross sections using these methods highlight differences between self-similar and self-affine evaluations. Shortening estimates can be made from the compass walk analysis that includes shortening contributions from predicted small-scale structure. Roughness-length analysis reveals systematic structural changes that, however, cannot be easily related to strain. Power-spectral analysis failed to extract useful structural information from the sections.     

Fuzzy regression decision systems for assessment of the potential vulnerability of bridge to earthquakes

This paper presents an innovative fuzzy regression approach for the assessment of the potential vulnerability of bridge to earthquakes. Taking the Mao-Luo-Hsi Bridge in Nantou County of Taiwan as an example, structural models representing vulnerable sections of the bridge are established and updated by ambient vibration tests. Because of uncertainties in the structural models and ambient vibration data preprocessed by wavelet filtering, the fuzzy regression approach is adopted to synthesize the maximum displacements of the bridge sections so as to develop a bridge alert?Caction principle. The fuzzy regression model can be achieved by the fuzzy blending of each individual input?Coutput realization for the critical sections D, E, and F of the bridge subjected to various earthquake intensity scales ranging from one to seven. Verification of the resulting fuzzy regression models along the longitudinal and transverse directions of the bridge reflects on the high R ² values of the models being 0.7317 and 0.8401, respectively. The developed decision systems suggest that the action value can be determined for the location of the bridge site when the earthquake intensity reaches scale 6 corresponding to the maximum slopes of the resulting fuzzy regression curves, and the next one lower scale 5 refers the alert value.     

山东省界河金矿床地质特征及成矿预测

论述了与成矿有关的上庄岩体特征、控矿断裂特征、矿床地质特征，指出其成因与区域金矿化具统一性；研究了矿化富集规律；总结了找矿标志；综合预测了３个外围找矿远景地段；通过断裂面形态模拟及构造地球化学研究，预测了２处深部找矿有望地段。     

量测技术在北京鹰山特大断面隧道中的应用

针对鹰山隧道断面大、跨度大、埋深浅、覆跨比小等特点，设置了５个量测断面，对洞壁水平位移、顶拱垂直位移、地表下沉量等进行了量测，量测结果显示，位移值远小于规定的允许值，为快速、优质、安全施工创造了先决条件。     

Structural and mineralogical study of active and inactive hydrothermal fluid discharges in Panarea,Italy

The isle of Panarea (Aeolian Arc, Italy) is an active hydrothermal system, characterized by different types of fluid emissions, which cause various types of unique hydrothermal structures that are typical for hydrothermal fluid discharges. Such fluid discharge structures at shallow depths of less than 30 m have not been described in marine hydrothermal systems until now to the authors’ knowledge. The focus of the investigations was set on morphological, mineralogical, geochemical, and structural analyses. A broad variety of analytical methods was applied to gain as much information as possible. In addition to geological and sedimentological documentation and standard methods like making and analyzing thin and polished sections, optical microscopy or X-ray fluorescence analysis, the samples were investigated by X-ray computer tomography and scanning electron microscopy, including energy-dispersive X-ray spectroscopy. Because discharge features occur in various settings, a general classification of the features in the hydrothermal system was performed with special focus on their preservability in geological archives. In total, nine different facies types were distinguished based on genetic and/or morphological differences. All samples show laminated structures from µm to cm scale. The single laminae vary in shape and material witnessing various chemical compositions.     

辽宁歪头山铁矿构造研究及构造控矿模式初探

歪头山铁矿屑鞍山式沉积变质铁矿，褶皱、韧性剪切带、断裂是矿区的主要构造形迹。通过构造解析，将矿区鞍山运动中的构造变形划分为3幕。利用共轭节理和断层擦痕反演，对矿区构造应力场进行了定向、定时研究，确定了各期构造应力场。最后，提出了歪头山铁矿“褶皱 韧性剪切带”控矿模式，新模式对矿区的采矿平面设计及寻找可能的漏矿具有指导作用。     

中、高压下粗粒土-结构接触面特性受结构面形貌尺度影响的试验研究

采用改进的DRS-I型高压直剪仪进行了砂砾与不同形貌尺度的粗糙钢板结构面接触剪切试验,获得不同压力、形貌尺度条件下的剪切试验结果,分析了中、高压下的不同结构面形貌尺度与砂土颗粒平均粒径比值R（ ,相对形貌尺度）对接触面剪切特性的影响。结构面相对形貌尺度R直接影响接触面剪切过程中的力学与体变特性,中压与高压下分别呈现不同的影响规律且存在各自的峰值相对形貌尺度 与稳定相对形貌尺度 。达到峰值相对形貌尺度之前,R的增大使得接触面剪切耗能随之增加,而剪切体变在中压、高压下分别随之增加和降低;稳定相对形貌尺度之后,接触面剪切耗能与剪切体变达到稳定状态,随R的增大呈微小变化,变化幅值较小。上述规律与接触面附近一定区域的颗粒变位及破碎等机制密切相关,获得成果将为研究不同法向压力下受形貌尺度影响的结构面相对粗糙度问题提供新思路,对于研究不同法向压力下粗粒土与粗糙结构面的接触面力学与变形机制有一定借鉴意义。     

Magnetic field observations of the Sabzevar ophiolitic complex of northeast Iran

Surface measurements of the total magnetic field intensity along three sections transverse to the structural trends of the Joghatay Mountains ophiolitic complex extended north and west of Sabzevar, northeast Iran, are analyzed. The observed variations of the magnetic field intensity are compared with the synthetic results computed for a block structure consisting of several east-west oriented vertical parallelepiped down to 10 km depth which is also in agreement with the mapped shallow structural features of the complex. Shoaling of the basement and/or Curie surface may explain the observed northward decrease of the mean field measurements. However, in this study the variations are modeled in terms of magnetic enrichment of southern blocks.     

四川南部晚二叠世聚煤盆地前期构造背景及同沉积构造

分析了四川南部晚二叠世聚煤盆地的前期构造环境背景。应用趋势面分析、厚度－相法结合其它地质因素的综合研究，将聚煤盆地的同沉积构造按地理位置、展布方向、规模大小与活动性质等分为４组１６个构造单元。并按隆起与坳陷、断裂阐述了具体特征及其对沉积环境体系、沉积相带展布和聚煤作用的控制。