试论层序地层学在1∶5万区调工作中的应用—以浑江地区为例   总被引：2，自引：0，他引：2  

周晓东  殷长健  陈跃军 《吉林地质》1997,(2)

通过在吉南浑江地区开展的白山市等三幅１∶５万区调工作，尝试性地运用层序地层学的理论，初步总结了不同特征的不整合面（层序界面）及凝缩段的识别标志；分析了地层序列中矿产分布特征；探讨了层序分析中以剖面岩石（岩性、组构）、相转换界面的基础研究方法。进而将浑江地区新元古代—早古生代地层划分为三个Ⅱ级沉积序列（超层序）、七个Ⅲ级沉积序列（层序）。  相似文献   

利用GPS资料浅析华北地区块体运动及与地震活动的关系     

周伟  杨国华  王若柏  韩月萍 《山西地震》2004,(4):7-10

为了研究华北地区近年地壳水平运动的状态与演化．利用10a来华北地区网络工程、山西断裂带GPS观测成果．结合该区地质构造背景．分析了华北地区各块体运动的方向、速率变化及其与区内所发生地震的关系．初步得出以下结论：在区域应力场相对稳定时，表现为区域内GPS观测点整体趋势性运动不明显；而在区域应力场相对变化时．表现为影响区域内GPS观测点出现明显的整体趋势性运动。  相似文献   

百色盆地东部坳陷百岗组沉积特征与两侧构造活动的不同步性     

赵俊兴  陈洪德  李仲东  付锁堂  付金华  卜淘 《矿物岩石》2004,24(4):93-98

通过详细研究百岗组沉积相发育特征，将三角洲进行不同类型划分，认为百色盆地东部坳陷的南北两侧分别发育两套不同的沉积体系。沉积响应完整地记录了构造活动情况，在百岗早中期，盆地南部构造抬升强烈，北部构造相对稳定，三角．洲强烈向北西方向进积：百岗晚期，南部构造活动相对稳定，北部构造发生了强烈抬升。南部三角洲在百岗期表现为“发育-发展-稳定-萎缩”的一个完整的演化旋回特点，而北部扇三角洲则体现为“稳定-进积”的过程。整个盆地构造活动在百岗期表现出了两侧构造运动明显的不同步性。  相似文献   

Influence of tectonic structures on the Hope Slide, British Columbia, Canada     

Marc-Andr  Brideau  Doug Stead  Derek Kinakin  Karin Fecova 《Engineering Geology》2005,80(3-4):242-259

The Hope Slide, which occurred on January 9, 1965, involved an estimated 47-Mm³ of meta-volcanics and intrusive rocks. Previous workers reported the presence of tectonic structures (faults and shear zones) along the failure surface at the Hope Slide. These tectonic features were investigated in detail to assess their effects on rock-mass quality and the related implications for slope stability. This paper integrates basic field and laboratory concepts from structural and engineering geology. Subdividing the failure area into structural domains allowed distinct discontinuity sets to be associated with specific tectonic structures. The Geological Strength Index (GSI) was used to estimate the rock-mass damage related to the tectonic structures. Low GSI values were seen to outline tectonic damage zones. Point-load tests were used to characterise the compressive strength of rocks adjacent to the tectonic structures. Strength anisotropy, tentatively attributed to damage caused by a large shear zone, was observed in greenstone samples. Seepage zones along the failure surface were observed preferentially along shallow discontinuities that dipped downslope and in rock masses of good quality (GSI > 40). An alternative morphology of the slope failure is proposed by distinguishing between the extent of the surficial damage due to the rock-slope failure and the zone of failed material (depletion zone). For the first time, a kinematic mechanism for the Hope Slide is proposed, based on a preliminary 3-dimensional block model. A pre-1965 DEM was produced from estimates of material lost and gained as reported by previous workers. The pre-1965 DEM revealed that the tectonic structures recognised during fieldwork bounded the material that failed in the 1965 event.  相似文献   

9: Processes of tectonism, magmatism and mineralization: Lessons from Europe     

Derek Blundell  Nicholas Arndt  Peter R. Cobbold  Christoph Heinrich 《Ore Geology Reviews》2005,27(1-4):333

Metallogenic provinces in Europe range in age from the Archaean to the Neogene. Deposit types include porphyry copper and epithermal Cu–Au, volcanic-hosted massive sulphide (VMS), orogenic gold, Fe-oxide–Cu–Au, anorthosite Fe–Ti-oxide and sediment-hosted base-metal deposits. Most of them formed during short-lived magmatic events in a wide range of tectonic settings; many can be related to specific tectonic processes such as subduction, hinge retreat, accretion of island arcs, continental collision, lithosphere delamination or slab tear. In contrast, most sediment-hosted deposits in Europe evolved in extensional, continental settings over significant periods of time. In Europe, as elsewhere, ore formation is an integral part of the geodynamic evolution of the Earth's crust and mantle. Many tectonic settings create conditions conducive to the generation of water-rich magma, but the generation of ore deposits appears to be restricted to locations and short periods of change in temperature and stress, imposed by transitory plate motions. Crustal influence is evident in the strong structural controls on the location and morphology of many ore deposits in Europe. Crustal-scale fault–fracture systems, many involving strike-slip elements, have provided the fabric for major plumbing systems. Rapid uplift, as in metamorphic core complexes, and hydraulic fracturing can generate or focus magmatic–hydrothermal fluid flow that may be active for time spans significantly less than a million years. Once a hydrologically stable flow is established, ore formation is strongly dependent on the steep temperature and pressure gradients experienced by the fluid, particularly within the upper crust. In Europe, significant fracture porosity deep in the crystalline basement (1%) is not only important for magmatic–hydrothermal systems, but allows brines to circulate down through sedimentary basins and then episodically upward, expelled seismically to produce sediment-hosted base-metal deposits and Kupferschiefer copper deposits. Emerging research, stimulated by GEODE, can improve the predicting power of numerical simulations of ore-forming processes and help discover the presence of orebodies beneath barren overburden.  相似文献   

A surface network based method for studying urban hierarchies by night time light remote sensing data   总被引：1，自引：0，他引：1  

Bin Wu  Qiusheng Wu  Zuoqi Chen  Jianping Wu 《International journal of geographical information science》2019,33(7):1377-1398

Urban hierarchies are closely related to economic growth, urban planning and sustainable urban development. Due to the limited availability of reliable statistical data at fine scales, most existing studies on urban hierarchy characterization failed to capture the detailed urban spatial structure information. Previous studies have demonstrated that night time light data are correlated with many urban socio-economic indicators and hence can be used to characterize urban hierarchies. This paper presents a novel method for studying urban hierarchies from night time light data. Night time light data were first conceptualized as continuous mathematical surfaces, termed night time light surfaces. From the morphology of these surfaces the corresponding surface networks were derived. Hereafter, a night time light intensity (NTLI) graph was defined to describe the morphology of the surface network. Then, structural similarity between the night time light surfaces of any two different cities was calculated via a threshold-based maximum common induced graph searching algorithm. Finally, urban hierarchies were defined on the basis of the structural similarities between different cities. Using the 2015 annual NPP-VIIRS night time light data, the urban hierarchies of 32 major cities in China were successfully examined. The results are highly consistent with the reference urban hierarchies.  相似文献   

The internal deformation of the Peridotite Nappe of New Caledonia: A structural study of serpentine-bearing faults and shear zones in the Koniambo Massif     

《Journal of Structural Geology》2016

We present a structural analysis of serpentine-bearing faults and shear zones in the Koniambo Massif, one of the klippes of the Peridotite Nappe of New Caledonia. Three structural levels are recognized. The upper level is characterized by a dense network of fractures. Antigorite and polygonal serpentine form slickenfibers along fault planes with distinct kinematics. As a result, the upper level keeps the record of at least two deformation events, the first associated with the growth of antigorite (WNW-ESE extension), the second with the growth of polygonal serpentine (NW–SE compression). The lower level coincides with the ‘serpentine sole’ of the nappe, which consists of massive tectonic breccias overlying a layer of mylonitic serpentinites. The sole records pervasive tangential shear with top-to-SW kinematics and represents a décollement at the base of the nappe. The intermediate level is characterized by the presence of several meters-thick conjugate shear zones accommodating NE–SW shortening. Like the sole, these shear zones involve polygonal serpentine and magnesite as the main syn-kinematic mineral phases. The shear zones likely root into the basal décollement, either along its roof or, occasionally, around its base. Compared to top-to-SW shearing along the sole, the two deformation events recorded in the upper level are older.The three structural levels correlate well with previously recognized spatial variations in the degree of serpentinization. It is therefore tempting to consider that the intensity of serpentinization played a major role in the way deformation has been distributed across the Peridotite Nappe. However, even the least altered peridotites, in the upper level, contain so much serpentine that, according to theoretical and experimental work, they should be nearly as weak as pure serpentinite. Hence, no strong vertical gradient in strength due to variations in the degree of serpentinization is expected within the exposed part of the nappe. Our proposal is that strain localization along the serpentine sole results from the juxtaposition of the nappe, made of weak serpentinized peridotites, against the strong mafic rocks of its substratum. This interpretation is at odds with the intuitive view that would consider the nappe, made of peridotites, as stronger than its basement.  相似文献   

加强矿业供给侧结构性改革的初步思考     

张福良  季洪伟 《地质论评》2016,62(S1):143-144

当前我国正处经济增速减缓的新常态,供给侧结构性改革应运而生。我国乃至世界的矿业更是处于发展的严冬之季,产能严重过剩,大宗商品价格持续走低。在当前形势下,我们要用新常态眼光看待矿业未来发展之路,因地制宜,着力加强供给侧改革,刻不容缓。  相似文献   

Sequestration of molybdate during transformation of 2-line ferrihydrite under alkaline conditions     

《Applied Geochemistry》2016

Hematite is a thermodynamically stable iron oxide under the aerobic conditions present in most natural surface soils and sediments. Most studies to date have focused on the capacity of hematite to adsorb trace metals and metalloids, but structural incorporation of trace metals within hematite is less recognized. This study assessed the incorporation of molybdenum within the structure of hematite during the phase transformation of 2-line ferrihydrite under alkaline conditions (pH ∼10). Extended X-ray absorption fine structure analyses show molybdenum incorporated into hematite, with two Mo-O shells having a coordination number (CN) of 3 and average bond distances of 1.78 ± 0.01 and 2.08 ± 0.02 Å, respectively, as well as two Mo-Fe shells with a CN of 3 and average bond distances of 3.10 ± 0.02 Å and 3.44 ± 0.02 Å, respectively. This observation suggests the tetrahedrally-coordinated Mo in the molybdate that adsorbs onto the 2-line ferrihydrite changes to an octahedrally-coordinated Mo within the hematite with Mo possibly substituting for Fe in the hematite structure. Our findings suggest that molybdenum partitioning (low concentrations) to iron oxides in the environment can occur due to structural incorporation as well as adsorption.  相似文献   

郯庐断裂带晚中生代演化历史及其对华北克拉通破坏过程的指示   总被引：13，自引：8，他引：5  

朱光  王薇  顾承串  张帅  刘程 《岩石学报》2016,32(4):935-949

郯庐断裂带晚中生代的演化历史是华北克拉通破坏过程的重要记录。中侏罗世末(燕山运动A幕),郯庐断裂带局部发生左行平移活动,而华北克拉通上出现了一系列北北东走向的缩短构造,指示了西太平洋伊泽奈崎板块俯冲的开始。晚侏罗世期间,郯庐断裂带没有发生活动,而华北克拉通出现局部伸展与岩浆活动及区域性隆升,应为弧后弱拉张背景。早白垩世初(燕山运动B幕),郯庐断裂带再次发生强烈的左行平移活动,华北克拉通北部与东部出现了一系列近南北向挤压产生的构造,应是鄂霍茨克洋最终关闭与伊泽奈崎板块高速俯冲双重作用的结果。随后的早白垩世期间,华北克拉通在弧后拉张背景下发生峰期破坏,郯庐断裂带呈现为强烈的伸展活动。早白垩世末的区域性挤压作用,结束了华北克拉通的峰期破坏,并使郯庐断裂带再次发生了一期左行平移活动。这期挤压作用出现在太平洋板块接替伊泽奈崎板块这一重大板块调整的背景之中。  相似文献