辽宁省综合地球物理解释断裂构造的方法和依据     

张连增 《地质与资源》2015,24(5):483-488

通过研究辽宁省布格重力异常Δg及其位场转换场、航磁ΔT异常及其位场转换场、地震波场、大地电磁场,结合地貌以及钻探等资料,综合解释出了区内断裂构造.展示出了辽宁省断裂构造平面分布特征.配合地球物理解释剖面,可以了解区内主要断裂构造的垂向发育特征.分析认为郯庐断裂带为左行走滑断层带,划分出了表壳断裂、中-下地壳断裂、超岩石圈断裂.  相似文献   

高密度电阻率法和激发极化法在抗旱找水定井位中的应用     

苏永军  马震  孟利山  梁建刚  张国利  李建国  滕菲 《现代地质》2015,29(2):265-271

针对河南省新乡市凤泉区严重缺水现状,利用高密度电阻率法、高密度电阻率法与激发极化对称四极测深组合在水文地质条件复杂的松散层和基岩干旱地区勘查地下水,结合水文地质资料和成井条件所定的井位,后经施工钻孔验证,定井成功率100%,解决了人、畜急需用水问题。通过以上两种方法结合或单一方法在该地区不同水文地质条件下的实际应用和应用效果分析,总结出针对该地区特定的水文地质条件选择高密度电阻率法、高密度电阻率法与激发极化法组合模式。密度电阻率法和激发极化法组合模式在该地区地下水勘查中的运用提高了地质解释的准确性和可靠性,值得在类似水文地质条件和地区推广应用。  相似文献   

Taguchi design-based seismic reliability analysis of geostructures     

M. A. Hariri-Ardebili  P. Boodagh 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(1):34-52

This paper presents a methodology to evaluate the seismic reliability of geostructures in an optimal way. Taguchi design of experiments are adopted to find the most efficient and cost-effective combination of material properties in the uncertainty domain. Twelve uniform and mixed design models are tested. A polynomial-based response surface meta-model is built for each one and the accuracy of perdition is examined using 10,000 Monte Carlo simulations. A two-dimensional gravity dam is used as a vehicle for probabilistic transient analyses. The ground motion record-to-record variability is added as well using over one hundred earthquake records selected based on probabilistic seismic hazard analysis. Dynamic sensitivity of epistemic random variables are evaluated for the first time. Finally, an efficient and practical procedure is proposed in order to determine the reliability index of the geostructures. This approach, in fact, can be generalised for any type of engineering structures dealing with multi-hazard problems.  相似文献   

Historical behaviour of Dome C and Talos Dome (East Antarctica) as investigated by snow accumulation and ice velocity measurements     

Stefano Urbini  Massimo Frezzotti  Stefano Gandolfi  Christian Vincent  Claudio Scarchilli  Luca Vittuari  Michel Fily 《Global and Planetary Change》2008,60(3-4):576-588

Ice divide–dome behaviour is used for ice sheet mass balance studies and interpretation of ice core records. In order to characterize the historical behaviour (last 400 yr) of Dome C and Talos Dome (East Antarctica), ice velocities have been measured since 1996 using a GPS system, and the palaeo-spatial variability of snow accumulation has been surveyed using snow radar and firn cores. The snow accumulation distribution of both domes indicates distributions of accumulation that are non-symmetrical in relation to dome morphology. Changes in spatial distributions have been observed over the last few centuries, with a decrease in snow accumulation gradient along the wind direction at Talos Dome and a counter-clockwise rotation of accumulation distribution in the northern part of Dome C. Observations at Dome C reveal a significant increase in accumulation since the 1950s, which could correlate to altered snow accumulation patterns due to changes in snowfall trajectory. Snow accumulation mechanisms are different at the two domes: a wind-driven snow accumulation process operates at Talos Dome, whereas snowfall trajectory direction is the main factor at Dome C. Repeated GPS measurements made at Talos Dome have highlighted changes in ice velocity, with a deceleration in the NE portion, acceleration in the SW portion and migration of dome summit, which are apparently correlated with changes in accumulation distribution. The observed behaviour in accumulation and velocity indicates that even the most remote areas of East Antarctica have changed from a decadal to secular scale.  相似文献   

中国东北浅覆盖区地质填图物化探信息协同辅助技术   总被引：1，自引：0，他引：1  

赵玉岩  李兵  陆继龙  郝立波  赵禹  王东明 《吉林大学学报(地球科学版)》2018,48(1):318-333

针对中国东北浅覆盖区地质露头少、填图效率不高、精确度和准确度较低的问题,开发了物化探信息协同辅助技术并应用于地质体类型的识别。在以覆盖层较薄、面积广大、物理风化为主、土壤位移较小为特点的东北森林沼泽浅覆盖区,利用土壤化学成分和航磁信息识别下伏地质体是可行的。基于这一前提,可将指定研究区划分为一定数量的统计单元,在各单元内,通过数学统计方法产生众数、宽度、变化频率、偏度、峰度等航磁特征参数并将其标准化,将化探指标酸度、碱度、钙含量、铝含量、钙镁含量、硅铝含量、镁铁含量、微量元素含量等特征参数标准化;然后采用逐级分类的方法,每级选择有效的物化探特征参数,在当前级别上实现单元划分并将数据分为不同数据集,在下一级别划分时重新有针对地选择参数,分别对各数据集进一步分类,直到分类结果对应较明确的地质填图单元,并最终编制出解译图。以黑龙江省大兴安岭地区某典型森林沼泽浅覆盖区为例进行了方法验证,将结果与已知地质信息比对分析,认为地质体单元识别结果与已知信息基本吻合,使得地质体类型识别更精确,边界更清晰,可为区域地质研究提供新线索。  相似文献   

无锡某大厦深层溶洞地基处理设计与施工方法     

黄新强 《江苏地质》2017,41(2):347-351

无锡某大厦地基青龙群灰岩岩溶发育,范围多在-80～-96 m之间,采用袖阀管注浆法进行处理,经钻探及CT层析物探验证,岩溶溶洞治理效果较佳,最终桩基持力层选用⑦层粉质黏土层,主体封顶3年累计最大沉降3.82 cm,治理效果达到预期目的,经济效益明显,具有推广应用价值  相似文献   

宁镇中段铜山—石砀山地区综合物探找矿评价     

陈俊  肖书明  魏邦顺 《江苏地质》2017,41(4):663-671

铜山—石砀山铜钼矿位于江苏宁镇山脉中段龙潭—仓头背斜南翼,矿体主体受接触带构造控制。以往地质工作缺少深部研究,对物化探异常再解释工作不够,物探方法找矿专属性研究不细致,综合研究程度较浅。综合分析铜山—石砀山地区地质、物性资料,采用1∶2 000高精度磁法测量、可控源音频大地电磁测深剖面等物探技术,圈定地磁异常8个（C1—C8）,推断由2个磁性地质体、8个矽卡岩体引起。择优对C2异常进行了钻探验证。研究认为该区可控源音频大地电磁测深高低阻过渡带部位的磁异常具有重要的找矿意义,即该区中酸性岩体与碳酸盐岩接触带部位具有含铜钼磁铁矿形成的有利地质条件。对比分析研究区及周边找矿信息,认为铜山—石砀山地区找矿深部有潜力,外围有远景。  相似文献   

水文实验研究进展          下载免费PDF全文

吴雷  许有鹏  王跃峰  徐羽  林芷欣 《水科学进展》2017,28(4):632-640

阐述了水文实验的概念与内涵,归纳了水文实验的研究方法及其特点,系统地回顾了国内外流域水文实验的发展历程,梳理了应用实验方法进行植被截留与阻滞作用、降水径流关系、非饱和带水分运移以及气候变化和人类活动影响下的水文过程研究的进展,分析了当前水文实验发展的不足,提出未来水文实验的发展方向:传统的实验流域着重于地表水研究,没有深入水文循环系统的内部,应将水文实验的研究范围从地表扩展为关键带部分,并加强跨流域的补给、径流与排泄关系研究;多学科交叉的综合观测实验与协同研究是水文实验的发展趋势;当前水文实验的系统性与规范性仍显不足,应重视水文实验站网建设,加强水文实验的规范性,以促进实验数据交换和研究成果对比。  相似文献   

Importance of hydrogeological conditions during formation of the karstic bauxite deposits,Central Guizhou Province,Southwest China: A case study at Lindai deposit     

《Ore Geology Reviews》2017

Karstic bauxite deposits are widespread in Central Guizhou Province, SW China, and high-grade ores are frequently sandwiched with overlying coal and underlying iron-rich layers and form a special “coal–bauxite–iron” structure. The Lindai deposit, which is one of the most representative karstic bauxite deposits in Central Guizhou Province, was selected as a case study. Based on textural features and iron abundances, bauxite ores in the Lindai deposit are divided into three types of ores, i.e., clastic, compact, and high-iron. The bauxite ores primarily comprise diaspore, boehmite, kaolinite, illite, and hematite with minor quartz, smectite, pyrite, zircon, rutile, anatase, and feldspar. The Al₂O₃ (53–76.8 wt.%) is the main chemical contents of the bauxite ore samples in the Lindai district, followed by SiO₂, Fe₂O₃, TiO₂, CaO, MgO, S, and P etc. Our geological data on the Lindai deposit indicated that the ore-bearing rock series and its underlying stratum have similar rare earth elements distribution pattern and similar Y/Ho, Zr/Hf, and Eu/Eu¹ values; additionally, all ore-bearing rock samples are rich in MgO (range from 0.16 wt.% to 0.68 wt.%), and the plots of the dolomites and laterites lie almost on or close to the weathering line fit by the Al-bearing rocks in Zr vs. Hf and Nb vs. Ta diagrams; suggesting that the underlying Middle Cambrian Shilengshui Formation dolomite is the parent rock of bauxite resources in the Lindai district.Simulated weathering experiments on the modern laterite from the Shilengshui Formation dolomite in the Lindai bauxite deposit show that hydrogeological conditions are important for karstic bauxite formation: Si is most likely to migrate, its migration rate is several magnitudes higher than those of Al and Fe under natural conditions; the reducing inorganic acid condition is the most conducive to Al enrichment and Si removal; Fe does not migrate easily in groundwater, Al enrichment and Fe removal can occur only in acidic and reducing conditions with the presence of organic matter.The geological and experimental studies show that “coal–bauxite–iron” structure in Lindai deposit is formed under certain hydrogeological conditions, i.e., since lateritic bauxite or Al-rich laterite deposited upon the semi-closed karst depressions, Si can be continuously removed out under neutral/acidic groundwater conditions; the coal/carbonaceous rock overlying the bauxitic materials were easily oxidized to produce acidic (H₂S, H₂SO₄, etc.) and reductant groundwater with organic materials that percolated downward, resulting in enrichment of Al in underlying bauxite; it also reduced Fe³⁺ to its easily migrating form Fe²⁺, moving downward to near the basal carbonate culminated in precipitating of ferruginous (FeS₂, FeCO₃, etc.) strata of the “coal–bauxite–iron” structure. Thus, the bauxitic materials experienced Al enrichment and Si and Fe removal under above certain hydrogeological conditions forming the high-quality bauxite.  相似文献   

Controls of hydrocarbon generation on the development of expulsion fractures in organic-rich shale: Based on the Paleogene Shahejie Formation in the Jiyang Depression,Bohai Bay Basin,East China     

《Marine and Petroleum Geology》2017

The development of expulsion fractures in organic-rich shale is closely related to hydrocarbon generation and expulsion from kerogen. Organic-rich shales from the upper part of the fourth member and the lower part of the third member of the Paleogene Shahejie Formation in the Jiyang Depression, Bohai Bay Basin, East China, are used as an example. Based on thin sections, SEM and thermal simulation experiments, the characteristics of hydrocarbon generation and the conditions supporting the development of expulsion fractures were explored. The key factors influencing these fractures include the presence of kerogens, their distribution along laminae and around particle boundaries, their exposure to heat and the build-up in pressure due to confinement by low permeability. The development of excess pore fluid pressures and intrinsic low rock fracture strength are the main influencing factors. Pressurization by rapid generation of hydrocarbon provides impetus for fracture initiation and cause bitumen to migrate quickly. The shale laminae results in distinctly lower fracture strength laminae-parallel than laminae-normal and this directs the formation of new fractures in the direction of weakness. When pore fluid pressure increases, maximum and minimum principal effective stresses decrease by different proportions with a larger reduction in the maximum principal effective stress. This increases the deviatoric stress and reduces the mean stress, thus driving the rock towards failure. Moreover, the tabular shape of the kerogen aids the generation of hydrocarbon and the initiation of expulsion fractures from the tip and edge. The resulting fractures extend along the laminae when the tensile strength is lower in the vertical direction than in the horizontal direction. Particle contact boundaries are weak and allow fractures to expand around particles and to curve as the stress/strength regime changes. When pore fluid pressure fields at different fracture tips overlap, fractures will propagate and interconnect, forming a network. This paper could provide us more detailed understanding of the forming processes of expulsion fractures and better comprehension about hydrocarbon expulsion (primary migration) in source rocks.  相似文献