Sedimentary cover deformations in the equatorial Atlantic and their comparison with geophysical fields

The deformations of the sedimentary cover at near-latitudinal geotraverses west and east of the Mid-Atlantic Ridge in the equatorial part of ocean are compared with potential fields and variations of the V _p/V _s attribute at a depth of ~470 km. The features of sedimentary cover deformations in abyssal basins are formulated, as well as their differences from the undisturbed bedding of sediments. The elements of chain of phenomena with common spatial manifestations and cause-and-effect relationships have been established, including heterogeneous horizontal movements, which make up macrojointing above “cold” mantle blocks at a depth of ~470 km; serpentinization of upper-mantle rocks; the formation of superposed magnetic anomalies; the release of the fluids, which acoustically bleach out the sedimentary sequence in seismic imaging; and decompaction of rocks leading to vertical motions and forced folding. The origin of the Atlantic marginal dislocation zone is explained. The coincidence of the deformation boundary in the equatorial Atlantic with the zero contour line of the V _p/V _s attribute is revealed. This coincidence is an indicator of the rheological state of the upper mantle.     

Man-and-machine technology for the prediction of mineral deposits using geophysical data

To predict secondary geological structures that control the localization of mineral deposits in areas of cover, it is practical to use complex geophysical data. The prediction process is iterative and employs pattern recognition techniques. Each iterative cycle can include the procedure of location and ranging according to their appropriateness to the problem. The quality of the prediction is a function of the suitability of the geological environment under investigation and of the anomalies contained in the geophysical data and their selection.     

New in situ techniques for the estimation of the dielectric properties and moisture content of soils

Two original in situ HF techniques of dielectric characterization in two wide bands have been developed in order to estimate the moisture content of soils by complex impedance measurement. These techniques are based on the capacitive effect (1–20 MHz) and on the propagation of electromagnetic waves at high frequencies (0.1–4 GHz). The two measurement techniques use straight conductors that are inserted into the soil. Specific inversion algorithms were developed to estimate the apparent real permittivity of the soil versus frequency from the complex impedance. The validation of both instruments was made in the laboratory in the presence of dry and wet sands. In situ experiments were also made at high frequencies. These complementary devices should enlarge the range of usual soil moisture measurement techniques.     

综合物探方法在安徽黄山岭铅锌矿矿产预测中的应用

本文以安徽黄山岭铅锌矿区地质资料为依据,通过高精度磁测、可控源音频大地电磁测深(CSAMT)、多参数测井等综合物探方法,结合已知矿体的分布情况,综合推断了黄山岭铅锌矿预测区内矿体(矿化体)展布情况,获得了较好的地质效果.综合物探方法在黄山岭铅锌矿矿产预测中具有重要作用.     

路堤侧向变形性状及预测模型研究

结合大量实测资料和已有的研究成果,分析了路堤荷载作用下水平向应变随深度的变化规律,得出了侧向变形沿深度呈“弓”型分布的变化规律;提出了符合该变化规律的预测模型及参数求解方法,模型中a、b和c等3个待定参数能简单地求出。工程实践表明,该预测模型不仅反映了侧向变形随深度的变化规律,且有一定的精度,能反映出最大侧向变形发生的位置,应用效果良好。     

强化开展地壳内部第二深度空间金属矿产资源地球物理找矿、勘探和开发

中国正处在快速工业化和经济腾飞的前夜,必须有大量各类金属矿产资源的支撵,当今国内却供给不足。供需矛盾日益尖锐,导致了对外依存度的不断增长。本文从这一前提和解决的途径出发,分析了金属矿产资源形成与聚集的深层过程和动力学响应、地壳深处金属矿产资源探查的科学依据与例证、地球物理方法和技术支撑。据此提出：①当今国家所公布的资源量系指第一深度空间（0-500m）找矿、勘探和开发的资源量,尚不能完全表征全国金属矿产资源量的全部;（多实施第二深度空间（500-2000m）金属矿产资源的找矿、勘探和开发已迫不及待;③在深部金属矿产资源的探查和开发中,必须依靠新的认识和新的理念,采用先进的、高精度的地球物理探测方法和技术,并建立起有自主特色的深部矿产资源探查理论、方法和技术体系。     

物探方法在矿产预测中的应用

在综合信息矿产预测中,物探方法在划分大地构造单元,识别断裂构造、地层和岩体信息方面可发挥独特作用,重磁可以作为预测要素参与综合信息找矿预测和评价,也可在识别隐伏矿、深部矿方面发挥很好的作用。总结了重磁方法在矿产预测方面的技术特点和流程。     

龙门山多层分层拆离地壳结构:新构造变形与深部构造证据

2008年5.12汶川地震发生后,对于龙门山地壳结构及其与汶川地震的成生联系成为构造地质学研究极为关注的科学问题。然而,现有的多种龙门山地壳结构模式在综合解释表层构造变形及深部构造时与调查和探测资料均有不符。利用前人地球物理探测成果,结合穿过龙门山主要发震构造单元彭灌杂岩及雪隆包岩体的综合构造剖面,将地表构造与深部地壳探测资料结合进行了综合解释,认为龙门山逆冲构造带中的多重冲断推覆构造由约10 km深处的拆离断层分隔,因而应该只是浅层次构造变形的组合样式;在中、下地壳韧性流壳层的主导下,扬子地块基底被动?入并形成多层拆离的韧性流变构造组合。5.12汶川地震及余震是由于以彭灌杂岩和雪隆包岩体为代表的刚性体,在上部韧性流壳层前端的持续推挤作用下,发生破裂而形成的。     

Analytical techniques for the estimation of mine water inflow

Summary This paper outlines various analytical techniques for mine water inflow estimation incorporating several refinements such as finite boundary conditions, linear, fracture and turbulent flow conditions to pumping wells and underground excavations. These modifications enable practical mining to be simulated and therefore, permit more accurate predictions of mine inflow quantities. Application of these techniques are given together with the scope of the application.     

Late Cenozoic geodynamics and mechanical coupling of crustal and upper mantle deformations in the Mongolia-Siberia mobile area

Comprehensive analysis of the parameters characterizing contemporary and neotectonic deformations of the Earth’s crust and upper mantle developed in the Mongolia-Siberia area is presented. The orientation of the axes of horizontal deformation in the geodetic network from the data of GPS geodesy is accepted as an indicator of current deformations at the Earth’s surface. At the level of the middle crust, this is the orientation of the principal axes of the stress-tensors calculated from the mechanisms of earthquake sources. The orientation of the axes of stress-tensors reconstructed on the basis of structural data is accepted as an indicator of Late Cenozoic deformations in the upper crust. Data on seismic anisotropy of the upper mantle derived from published sources on the results of splitting of shear waves from remote earthquakes serve as indicators of deformation in the mantle. It is shown that the direction of extension (minimum compression) in the studied region coincides with the direction of anisotropy of the upper mantle, the median value of which is 310–320° NW. Seismic anisotropy is interpreted as the ordered orientation of olivine crystals induced by strong deformation owing to the flow of mantle matter. The observed mechanical coupling of the crust and upper mantle of the Mongolia-Siberia mobile area shows that the lithospheric mantle participated in the formation of neotectonic structural elements and makes it possible to ascertain the main processes determining the Late Cenozoic tectogenesis in this territory. One of the main mechanisms driving neotectonic and contemporary deformations in the eastern part of the Mongolia-Siberia area is the long-living and large-scale flow of the upper mantle matter from the northwest to the southeast, which induces both the movement of the northern part of the continent as a whole and the divergence of North Eurasia and the Amur Plate with the formation of the Baikal Rift System. In the western part of the region, deformation of the lithosphere is related to collisional compression, while in the central part, it is due to the dynamic interaction of these two large-scale processes.     

西部缺水地区地下水勘查物探技术方法优化研究

西部地区水资源短缺严重制约了本地区的经济发展.如何针对西部缺水地区水文地质特点,合理选择地球物理勘探综合技术方法寻找地下水,提高地下水勘查效率,是水文地质工作面临的十分重要问题.本文针对西部缺水地区浅层孔隙水、浅层岩溶裂隙水、深层孔隙水、深层岩溶裂隙水的四种主要类型,探讨其优化的物探技术方法.     

综合物探技术在水利工程建设中的应用

介绍了综合物探中几种常用的方法技术,并结合具体实例说明各方法在水利工程建设中的应用效果。结果表明综合物探技术在水利工程中具有较好的应用前景。     

辽西地下水勘查示范工程中的物探技术应用

本次示范工程通过不同类型地下水勘查物探技术应用与示范，分析总结方法技术的实用性和有效性，提出不同类型地下水勘查物探技术方案，为该地区解决人畜饮用水指明方向，提供技术和示范经验。     

岩溶区页岩气勘探中的近地表地球物理探测技术应用研究

岩溶区页岩气钻井在近地表常揭露溶洞、地下河、强裂隙带等不良地质体,严重制约了页岩气资源勘探开发的进程。在岩溶页岩气靶区利用地球物理技术探测对钻探不利的近地表地质结构构造,可有效规避钻井钻遇近地表强岩溶发育带、断层破碎带的风险。综合运用高密度电阻率成像法、音频大地电磁法和测氡法对贵州都匀和广西融安碳酸盐岩区的2个油气靶区进行了地下构造识别,结果表明：高密度电阻率成像法和音频大地电磁法能有效确定浅地表地下低阻构造的位置、宽度和产状,高密度电阻率成像法在50 m以浅深度拥有更高的分辨率,音频大地电磁法探测深度更深,但对地下介质的分辨率不高,氡气测量能很好地识别地下低阻构造的属性。高密度电阻率成像法、音频大地电磁法与测氡法三者可优势互补,组成有效识别岩溶区近地表地质结构构造的技术方法体系,可为南方岩溶区页岩气钻井避开近地表强岩溶发育带、断层破碎带以及最终位置的确定提供可靠的技术支撑。     

我国地球物理勘查技术标准体系研究与建立

我国已有的几十部地球物理勘查技术标准,为我国基础性、公益性和战略性地质工作的开展提供了有力的技术支撑,同时也为地球物理勘查技术标准体系的建立提供了前提。本文对地球物理勘查技术标准进行了系统梳理,结合地球物理方法技术应用现状,研究提出新的地球物理勘查技术标准子体系,对地球物理勘查技术标准化工作的推进具有重要意义。     

Groundwater resources assessment using integrated geophysical techniques in the southwestern region of Peninsular Malaysia

Combined geophysical techniques such as multi-electrode resistivity, induced polarization, and borehole geophysical techniques were carried out on volcano-sedimentary rocks in the north of Gemas as part of the groundwater resource’s investigations. The result identifies four resistivity units: the tuffaceous mudstone, tuffaceous sandstone, the tuff bed, and the shale layer. Two types of aquifer systems in terms of storage were identified within the area: one within a fracture system (tuff), which is the leaky area through which vertical flow of groundwater occurs, and an intergranular property of the sandy material of the aquifer which includes sandstone and tuffaceous sandstone. The result also reveals that the aquifer occupies a surface area of about 3,250,555 m² with a mean depth of 43.71 m and a net volume of 9.798?×?10⁷?m³. From the approximate volume of the porous zone (28 %) and the total aquifer volume, a usable capacity of (274.339?±?30.177)?×?10⁷?m³ of water in the study area can be deduced. This study provides useful information that can be used to develop a much broader understanding of the nature of groundwater potential in the area and their relationship with the local geology.     

New gravity maps of the Eastern Alps and significance for the crustal structures

The deep seismic profile Transalp crosses, from north to south, Germany, Austria and Italy. The gravity measurements for each country were made by national agencies with different reference systems and data reduction methods. Within the frame of the Transalp-project a comprehensive database of the Eastern Alps was compiled covering an area of 3.5° by 4° in longitude and latitude (275 by 445 km), respectively. To increase the data coverage in the south Alpine area two gravity surveys were carried out, resulting in 469 areally distributed new stations, of which 215 have been measured with the intent to improve the geoid in the area of the planned Brenner Basistunnel (BBT). The resulting gravity database is the best in terms of resolution and data quality presently available for the Eastern Alps. Here the free air, Bouguer and isostatic gravity fields are critically discussed. The spatial density of existing gravity stations in the three countries is discussed. On the Italian side of the Alps the spatial density is rather sparse compared to the Austrian side. The Bouguer-gravity field varies between − 190 * 10^− 5 m/s² and + 25 * 10^− 5 m/s², with the minimum located along the Alpine high topographic chain, but with a small offset (a few tens of km) to the greatest topographic elevation, showing that the Airy-type local isostatic equilibrium does not fully apply here. The maximum of the Bouguer anomaly has an elongated shape of 100 by 50 km located between the towns of Verona and Vicenza and covers the Venetian Tertiary Volcanic Province (VTVP), a feature not directly related to the plate collision in the Eastern Alps. The gravity high is only partly explainable by high-density magmatic rocks and requires also a deeper source, like a shallowing of the Moho. The isostatic residual anomalies (Airy model) are in the range ± 50 * 10^− 5 m/s², with the greatest positive anomaly corresponding to the location of the VTVP, indicating here under-compensation of masses. At last a discussion of a 2D density model based on reflection seismic data and receiver functions is made.