Infill sampling criteria to locate extremes

Three problem-dependent meanings for engineering extremes are motivated, established, and translated into formal geostatistical (model-based) criteria for designing infill sample networks. (1) Locate an area within the domain of interest where a specified threshold is exceeded, if such areas exist. (2) Locate the maximum value in the domain of interest. (3) Minimize the chance of areas where values are significantly different from predicted values. An example application on a simulated dataset demonstrates how such purposive design criteria might affect practice.     

Seismic investigation of near-surface geological structure in the Paducah, Kentucky, area: application to earthquake hazard evaluation

Seismics method were used to evaluate shallow geological conditions at 33 sites in the vicinity of Paducah, Kentucky. A combined set of P- and S-wave seismic refraction and reflection soundings were used, in addition to local borehole information, to produce structure maps of (1) a shallow (< 30 m deep) horizon believed to represent an unconformity surface at the top of the Eocene, and (2) the Paleozoic bedrock surface (< 85 to > 160 m deep). Shear-wave velocity contrasts across the shallow unconformity were generally 2-to-1 while the contrast at the top of the Paleozoic bedrock exceeds 5-to-1. These seismic boundaries have been determined to be very important in modelling and interpreting earthquake ground motion amplification in the Paducah area. The quality and accuracy of the data, and the cost effective nature of the methods, suggest that other communities in areas at risk to damage from seismic activity, with foundation conditions comparable to Paducah, might benefit from similar characterization in order (1) to identify seismically hazardous, near-surface, geological conditions, and (2) to develop geological models that could be used in computer simulations of site response.     

Guidelines to locate and protect high-quality groundwater in Baiyu Mountain area of China

The Baiyu Mountain area has the most shortage of water in the Ordos Basin of China. The majority of the groundwater is in the Luohe water-bearing formation, which is characterized by high total dissolved solids (TDS). The concentration of TDS can be as high as 10.45 g/l, which makes the water unsuitable for either potable or irrigation purpose. The dominant ions in the groundwater are SO^2–₄·Cl^–. The maximum concentrations of SO^2–₄ and Cl^– are 3,170 and 3,830 mg/l, respectively. The areas with low TDS groundwater are in Jingbian and Zhidan counties. However, nitrogen pollution caused by human and agriculture activities is a significant threat to the protection of fresh water in these counties.     

A procedure to locate slip surfaces beneath active landslides using surface monitoring data

Accurate determination of the slip surface profile beneath a landslip is difficult and costly using traditional methods, yet such knowledge is essential for stability analysis and for the design of remedial works. The technique presented here utilises measurements of surface displacements to predict the position and shape of the underlying slip surface. The proposed method has been tested in model studies of all major classes of landslip and on three large landslips. Results indicate that, from a knowledge of ground surface displacements alone, the position of the slip surface can be predicted to within 2% of the distance between movement monitoring stations on the ground surface.     

嵩县何家村金矿床隐伏矿体定位技术研究

河南省嵩县何家村金矿床为赋存于熊耳群安山岩中的构造蚀变带。为了进一步探测隐伏矿体,开展了矿床地质、地球化学研究以及高频大地电磁测深剖面分析。矿体沿含金蚀变带产出,金品位为0.12g/t~4.0 g/t。金属矿物有自然金、黄铁矿、方铅矿、深红银矿、黄铜矿和少量自然铁,矿石结构主要有结晶结构、交代结构,矿石构造主要有脉状构造、团块状构造和浸染状构造,围岩蚀变常见黄铁矿化、硅化、钾长石化。在地球化学金异常区域内,通过高频大地电磁测深剖面缩小矿区存在的隐伏岩浆-热液活动范围,并且沿剖面进行岩石地球化学测量分析,进而客观评价Au异常。物探和化探数据显示的信息具有吻合性,暗示矿区沿次级断裂附近的深部可能存在较大矿体,为矿区下一步地质勘查工作提供了重要的找矿线索。     

Mercury content of the Springfield coal, Indiana and Kentucky

With pending regulation of mercury emissions in United States power plants, its control at every step of the combustion process is important. An understanding of the amount of mercury in coal at the mine is the first step in this process. The Springfield coal (Middle Pennsylvanian) is one of the most important coal resources in the Illinois Basin. In Indiana and western Kentucky, Hg contents range from 0.02 to 0.55 ppm. The variation within small areas is comparable to the variation on a basin basis. Considerable variation also exists within the coal column, ranging from 0.04 to 0.224 ppm at one Kentucky site. Larger variations likely exist, since that site does not represent the highest whole-seam Hg nor was the collection of samples done with optimization of trace element variations in mind. Estimates of Hg capture by currently installed pollution control equipment range from 9–53% capture by cold-side electrostatic precipitators (ESP) and 47–81% Hg capture for ESP + flue-gas desulfurization (FGD). The high Cl content of many Illinois basin coals and the installation of Selective Catalytic Reduction of NO_x enhances the oxidation of Hg species, improving the ability of ESPs and FGDs to capture Hg.     

Using whole rock geochemistry to locate the source of igneous erratics from drumlins on the Atlantic coast of Nova Scotia

Whole rock geochemistry has been determined for erratics from the surface Lawrencetown Till in two drumlins on the Atlantic coast of Nova Scotia. The geochemical data, particularly trace element composition, allow source rocks to be identified more precisely than by traditional petrographic microscopy. A drumlin near Lunenburg contains erratics of Neoproterozoic arc-related plutonic rocks and basalts that outcrop only in a small area near Parrsboro in the Cobequid Highlands. Some associated erratics of granite precisely match a small late Devonian pluton in the same area and other granites and rhyolite could also be derived from late Devonian rocks in the same area. The type section of the Lawrencetown Till contains different Neoproterozoic plutonic rocks of a type found in the eastern Cobequid Highlands, together with a distinctive late Devonian granite with sodic amphiboles that is restricted to a small area near the Debert River. Both these source areas indicate a southward flow of ice (Escuminac Phase) depositing the Lawrencetown Till, in contrast to earlier southeastward-flowing ice (Caledonia Phase) which deposited the Hartlen Till that forms the core of the drumlin. Drumlins in Nova Scotia are complex palimpsest landforms that were formed by till accretion, and evolved in surface form throughout multiple flow events.     

泥岩蠕变行为的实验研究及其描述

利用自行研制的岩石三轴蠕变仪,对泥岩进行了系统的三轴蠕变试验。试验中考虑了轴压σ1和围压σ3对蠕变的影响。结果表明,当围压σ3一定时,轴向应力σ1增加,蠕变加快,在稳态蠕变阶段的应变率增大,试件的寿命缩短。而当应力差?σ=σ1–σ3保持不变时,围压σ3增加,蠕变减慢,稳态蠕变阶段的应变率也减小,试件的寿命增加。利用非经典粘塑性损伤本构模型对试验现象进行了分析,得到了较为满意的结果。     

Energy‐work‐based numerical manifold seepage analysis with an efficient scheme to locate the phreatic surface

A major challenge in seepage analysis is to locate the phreatic surface in an unconfined aquifer. The phreatic surface is unknown and assumed as a discontinuity separating the seepage domain into dry and wet parts, thus should be determined iteratively with special schemes. In this study, we systematically developed a new numerical manifold method (NMM) model for unconfined seepage analysis. The NMM is a general numerical method for modeling continuous and discontinuous deformation in a unified mathematical form. The novelty of our NMM model is rooted in the NMM two‐cover‐mesh system: the mathematical covers are fixed and the physical covers are adjusted with iterations to account for the discontinuity feature of the phreatic surface. We developed an energy‐work seepage model, which accommodates flexible approaches for boundary conditions and provides a form consistent with that in mechanical analysis with clarified physical meaning of the potential energy. In the framework of this energy‐work seepage model, we proposed a physical concept model (a pipe model) for constructing the penalty function used in the penalty method to uniformly deal with Dirichlet, Neumann, and material boundaries. The new NMM model was applied to study four example problems of unconfined seepage with varying geometric shape, boundary conditions, and material domains. The comparison of our simulation results to those of existing numerical models for these examples indicates that our NMM model can achieve a high accuracy and faster convergence speed with relatively coarse meshes. This NMM seepage model will be a key component of our future coupled hydro‐mechanical NMM model. Copyright © 2014 John Wiley & Sons, Ltd.     

Geochemistry of the blue gem coal bed, Knox county, Kentucky

The Blue Gem coal bed (Middle Pennsylvanian Westphalian B, Breathitt Formation), has low-ash (with some sample sites having less than 1% ash) and low-sulfur contents through parts of Knox County, Kentucky. Most collection sites exhibit similar vertical elemental trends in ash geochemistry. The relatively high-ash (>1% ash) lower part of the bed displays enrichment in TiO₂, Zr, Cr, V and Ni; Co, Zn, Rb and Mn show enrichment at some sites. A low-ash (<1% ash) middle part of the bed displays enrichment in Sr, Ba and CaO; Fe₂O₃ is enriched in samples with carbonate minerals. The upper part of the bed contains >1% ash and a relative enrichment in SiO₂, K₂O and Rb and a relative decrease in Cu, Ni, Co, Ba and Mn when compared to the middle part of the bed. Principal components analysis indicates that the samples with an ash content 0.63–1.0% show associations for Ni, Cu, Cr and Co. Samples with between 1.01–2.0% ash display strong element associations that suggest increased clastic sediment contributions (TiO₂, Zr, K₂O, Rb, SiO₂). The low-ash content and the upwards decrease in trace concentrations both suggest that the Blue Gem peat swamp was ombrotrophic through at least a part of its geologic history.     

Petrography of the Herrin (No. 11) coal in western Kentucky

The Herrin (No. 11) coal in western Kentucky is in the upper part of the Pennsylvanian (Des Moinesian) Carbondale Formation. Samples were obtained from 13 mines in Kentucky and one mine in Illinois in three equal benches from two to three channels for a total of 93 samples. The rank of the coal (as vitrinite reflectance) is high volatile C bituminous in the Moorman Syncline and high volatile A bituminous in the Webster Syncline. Reflectance does not vary between mines in in the Moorman Syncline. The percentage of total vitrinite macerals for each mine is over 85% and the percentage of togal vitrinite plus liptinite maceralsis over 89% (average over 90%) (both on dry, mineral-free basis). The variation of the two maceral percentages is only significant at the betweenbench level, the middle bench generally having the lowest vitrinite and vitrinite plus liptinite percentages.     

Electrical and electromagnetic surveys to locate possible causes of water seepage to ground surface at a quarry open pit near Helwan city,Egypt

Water seepage to ground surface at a limestone quarry located at Wadi Garawy about 20 km south-east of Helwan city in Egypt posed a real threat to the mining activity at the quarry. The quarry area is known to be very dry for decades and away from water utilities and infrastructures that may cause water leaks to the quarry. Geophysical investigation including 1D Vertical Electrical Sounding (VES), 2D Electrical Resistivity Tomography (ERT) and 1D Transient Electromagnetic (TEM) surveys were conducted to characterize the rock sequence and locate what could be a possible source of water seepage to the quarry. The resistivity profiles generated from the VES and TEM surveys mapped the rock units in the area down to depths exceeded 100 m. The ERT profiles acquired from the quarrying zone close to the water seepage spot have imaged the top of groundwater level at few meters below the ground surface at the quarry open pit. The spot of groundwater seepage seemed to occur at an area of limestone dissolution that were filled by finer sediments. The finer sediments acted as a hydrological conduit that allowed an upward seepage of groundwater to ground surface under the capillary action effect.     

Cretaceous and Eocene lignite deposits, Jackson Purchase, Kentucky

Lignites occur in the Cretaceous McNairy Formation and the Eocene Claiborne Formation in the Jackson Purchase region of western Kentucky. The lone Cretaceous lignite sample has over 18 percent inertodetrinite and 32 percent humodetrinite which, along with the abundant mineral matter, suggests a possible allochthonous origin for the deposit. The Claiborne Formation lignites have higher humic maceral contents than the Cretaceous lignites. Palynology suggests that there was considerable variation in the plant communities responsible for the Claiborne deposits. Differences in the preservation of the various plants is also seen in the variations between the humic types, particularly in the ulminite and humodetrinite contents. Potter and Dilcher (1980) suggested that the Claiborne lignites in the Jackson Purchase and west Tennessee developed in the abandoned oxbows of Eocene rivers. Significant short-distance changes in the peat thickness, flora, and other depositional elements should be expected in such an environment and could easily account for the observed variations in composition.     

Petrographic variation in the Springfield (No. 9) coal in Western Kentucky

The Springfield (Western Kentucky No. 9) coal of the Carbondale Formation (Middle Pennsylvanian) in the Western Kentucky Coal Field of the Illinois Basin was sampled in eleven mines from one to three channels of three equal benches. The rank of the coal is high-volatile C bituminous in the Moorman Syncline and in the Henderson Basin and high-volatile B bituminous in the Webster Syncline. The percentage of total vitrinite macerals and of total vitrinite plus liptinite was found to decrease significantly from the bottom bench through to the top bench. In a comparison of the sources of variation within the set of maceral data it was found that the only significant variation in the vitrinite and vitrinite plus liptinite percentages was between the benches. Both the rank of the coal and the maceral percentages are varying in a predictable manner.     

探地雷达在岩溶地基探测中的应用

在山东大学和济南奥体中心体育场工地,采用探地雷达对岩溶地基进行探测,快速有效地查明了岩溶裂隙的发育情况。工程实例说明,在工程应用中,前期需深入分析地质勘测资料,合理确定探测参数,探测中需与工程钻探等方法相结合,不断积累经验,以求获得良好的工程效果。     

Characterizing coal beds in western Kentucky with the AlLaSc coherent triad

Cyclic sedimentation and lateral facies changes make coal bed correlations inconclusive and difficult. This uncertainty can be further complicated if a coal basin has been structurally deformed.Coal macerals can be studied to indicate the nature and degree of coalification. Their use in coal bed correlation, however, is limited. Most of the trace elements and their ratios that have been studied show significant within-bed lateral and stratigraphic variations, and thus are not effective in correlating coal beds regionally.Geochemically coherent groups of elements, such as rare earth elements (REE) and platinum group elements (PGE), appear to be highly differentiated in coal-forming environments. Geochemical coherent elemental triads appear to be useful for coal bed identification or fingerprinting. The best triad which was demonstrated to be effective in coal bed characterization in western Kentucky, is that of Al, La and Sc. These three elements are highly correlated with one another and they can be determined accurately and simultaneously with instrumental neutron activation analysis (INAA).The elemental triad AlLaSc is used to identify and fingerprint three key coal beds in western Kentucky: the Springfield (western Kentucky No. 9), the Davis (western Kentucky No. 6), and the Mining City and Dawson Springs are both considered to be the No. 4 coal bed in western Kentucky). Four distinct groupings can be recognized by use of the AlLaSc triad. The Dawson Springs coals have the highest Al/(La + Sc) ratios, followed by the Springfield, the Davis and the Mining City. The Mining City coal bed generally has the highest La/Sc ratio. However, the Dawson Springs is not correlated with the Mining City using the triad analysis, even though they have reportedly similar stratigraphic positions in the western Kentucky coal basin.The AlLaSe triad appears to be effective in discriminating between the Springfield and the Davis coal beds throughout the entire Illinois Basin. Furthermore, the range of concentration variation of the ALLaSc triad suggests individual groupings of the No. 4 coal in western Kentucky. In addition to characterizing these coal beds, the AlLaSc triad may be used to confirm stratigraphic correlations.     

Integrated studies for characterization of lineaments used to locate groundwater potential zones in a hard rock region of Karnataka, India

An integrated study was carried out to investigate the subsurface geological conditions in a hard rock environment, with the aim of identifying zones with groundwater resource potential. The study, in Bairasagara watershed, Karnataka, India, considered geomorphology, water level, resistivity imaging, self potential, total magnetic field and susceptibility. The signatures due to lineaments have been clearly identified and their role in groundwater movement has been documented. Synthetic simulation methods were used to model the electrical response of the lineament using finite differential modeling scheme. The inverted image of the field data is compared with the synthetic image and iteration were performed on the initial model until a best match was obtained resulting on the generation of the calibrated resistivity image of the subsurface. Resistivity imaging revealed that the dykes are weathered/fractured to a depth of 6–8 m and are compact at deeper levels, and that they behave as barriers to groundwater movement, yet facilitate a good groundwater potential zone on the upgradient side. The results of magnetic surveys were utilized in differentiating granites and dolerite dykes with an insignificant resistivity contrast. Geomorphological expression alone cannot reveal the groundwater potential associated with a lineament. However, characterizing the nature of the feature at depth with integrated geophysical methods provides essential information for assessing that potential.An erratum to this article can be found at     

Integrated studies for characterization of lineaments used to locate groundwater potential zones in a hard rock region of Karnataka, India

An integrated study was carried out to investigate the subsurface geological conditions in a hard rock environment, with the aim of identifying zones with groundwater resource potential. The study, in Bairasagara watershed, Karnataka, India, considered geomorphology, water level, resistivity imaging, self potential, total magnetic field and susceptibility. The signatures due to lineaments have been clearly identified and their role in groundwater movement has been documented. Synthetic simulation methods were used to model the electrical response of the lineament using finite differential modeling scheme. The inverted image of the field data is compared with the synthetic image and iteration were performed on the initial model until a best match was obtained resulting on the generation of the calibrated resistivity image of the subsurface. Resistivity imaging revealed that the dykes are weathered/fractured to a depth of 6–8 m and are compact at deeper levels, and that they behave as barriers to groundwater movement, yet facilitate a good groundwater potential zone on the upgradient side. The results of magnetic surveys were utilized in differentiating granites and dolerite dykes with an insignificant resistivity contrast. Geomorphological expression alone cannot reveal the groundwater potential associated with a lineament. However, characterizing the nature of the feature at depth with integrated geophysical methods provides essential information for assessing that potential.The online version of the original article can be found at