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1.
Effects of various commonly used pretreatments such as desliming, ultrasonic scrubbing and leaching with dilute nitric, hydrofluoric and sodium hydroxide solutions on the electrokinetic properties of quartz in aqueous solutions are reported. The study showed that treatments with various reagents often used in mineral processing research in the past to clean minerals can affect, sometimes severly, the electrokinetic properties of quartz. The change in these properties during subsequent aging is also found to be governed by the type of treatment used. This study also shows the need in mineral research for standardization of mineral preparation techniques in order that the discrepancy in data reported for surface properties in literature can be minimized. 相似文献
2.
A review of theories of mechanisms of induced seismicity 总被引：1，自引：0，他引：1
Carl Kisslinger 《Engineering Geology》1976,10(2-4):85-98
Theories of the physical processes leading to the stimulation of seismic activity by underground explosions, fluid injection, and reservoir impoundment are summarized. In all cases, the materials must be pre-stressed to a substantial fraction of their breaking strength in order for seismicity to be induced. Stress concentrations due to the presence of old faults or to inhomogeneities in the material properties play an important role in localizing induced seismicity.
For the few cases for which data are available, the stimulation of earthquakes by fluid injection in bore holes is adequately explained by a Coulomb-Mohr failure criterion and the concept of effective pressure in a water-filled porous mechanism. Reservoir-related earthquakes are most likely due to the same mechanism, but, in view of the low injection pressures, additional physical or chemical effects of the water on the materials may play an important role. There may be a weakening of the materials in old fault zones by the introduction of water or static fatigue in silicate rocks due to stress corrosion. 相似文献
3.
Using the database of automatic hydrometeorological stations, installed in the Don RIver delta and Taganrog Bay seashore, the sources of the anomalois scale water negative surge and salinization of the Azov Sea under conditions of low river flow in 2015–2016 are studied. The new schemes of stratification and advection of salty sea waters in the Don River mouth under different weather conditions, water discharge and levels are given. 相似文献
4.
根据目前国内边坡支护工作中的主要方式,将深基坑边坡支护按其结构的受力状态和支护的作用原理进行分类,详细论述了各种深基坑边坡支护方式的机制和适用条件,对今后岩土工程的实际工作具有一定的参考作用。 相似文献
5.
6.
国际水文地质学家协会成立于1956年。1985年资深的中国专家出席了第17届和18届国际水文地质大会,自那时以来,越来越多的中国代表出席了该学会的学术会议。中国分会于1987年建立,并组织相关活动。中国的协会成员近年来不断增加。国际水文地质大会曾在中国举办两次,第21届大会于1988年在桂林市举行,第34届大会于2006年在北京举行。多年来,在我国每年都举行水文地质学和地下水科学学术会议。协会主办的《Hydrogeology Journal》期刊编委会中有很多中国和华裔学者,中国分会负责论文摘要的中文翻译。协会的图书系列在我国广泛传播,促进了中国地下水科学的发展。该协会近期提出了水文地质战略系列,已经发布的九个专题分别是:生态系统与地下水、能源与地下水、粮食安全与地下水、全球变化与地下水、人类健康与地下水、城市与地下水、联合国2030年可持续发展目标、采矿业与地下水,以及气候变化适应地下水,指导了地下水资源和水文地质科学的发展。 相似文献
7.
Assessment of the liquefaction potential is one of the important aspects for earthquake hazard assessment. Liquefaction in the sediments during earthquake events may cause significant ground deformation, which in turn, may lead to significant structural damages to civil or engineering structures, further leading to loss of life and property. Liquefaction in sediments occurs in specific geological and geoenvironmental conditions under the influence of a certain level of earthquake shaking.In this paper an assessment of the liquefaction potential of the sediments present in and around Chandigarh has been made. The sub-surface disposition and geotechnical properties of the sedimentary units mapped and depth wise probed by drilling 24 shallow boreholes prima facie indicates susceptibility of interlayed sequence to liquefaction. The conditioning factors and geoenvironmental conditions essential for occurrence of liquefaction have been integrated and analysed to determine potential areas for liquefaction around the Union Territory of Chandigarh with respect to different levels of ground acceleration values expected in the area due to earthquake events. 相似文献
8.
GERALD M. FRIEDMAN 《Sedimentology》1979,26(1):3-32
This address reminisces and reflects on a subject in which I have been involved for more than twenty years: the effect of depositional processes on various parameters of the size-frequency distribution of sands. Movements of air and water generally separate particles by their sizes; the distribution of sizes relates to (1) the availability of different sizes of particles in a parent material, (2) processes operating where the sediments are deposited, particularly the competency of flow, and (3) concentrations of particles in suspension. Differences in size-frequency distributions among sands correlate with various origins, that is with their terminal depositional environments. Reminiscences in this address express my personal experience, both its up and downs, in advocating the study of this relationship, particularly in applying the method of moments on the basis of the concept that one statistical function expresses the characteristics of the population of particles. This address re-emphasizes some points made in previous studies (Friedman, 1961, 1962b, 1967) on the interrelationship between textural parameters and depositional processes for beach, dune, and river sands and then complements and supplements data which have not been presented before. These new data are grouped on scatter plots for sands of various origins. Finally, this address displays on maps regional trends of process-induced changes in size distributions of populations of particles in sands of four different settings: (1) a beach-dune setting, as exemplified by Padre Island, Texas, on the shores of the Gulf of Mexico; (2) a point-bar setting in the Arkansas River of Oklahoma; (3) a continental shelf-slope setting in the Gulf of Mexico off Louisiana, Mississippi, and Alabama; and (4) a continental shelf setting of the western Atlantic Ocean off New Jersey. This address concludes with the observation that the distribution of particles in sands will be influenced by the conditions that determine what happens in the depositional environment, hence statistical parameters that define the size-frequency distribution may be related to formative process. 相似文献
9.
沉管隧道基槽爆破施工对既有堤岸稳定性影响的数值仿真分析 总被引：1，自引：0，他引：1
结合爆破数值模拟中爆破荷载的特点,分析了各种荷载施加方法的特点及爆破震动场模拟的要求,基于圣维南荷载等效原理,提出了爆破荷载的等效施加方法,即将作用在炮孔壁上的爆破荷载等效后,施加在同排炮孔中心线或者面上来模拟爆破荷载的作用。结果表明,等效施加方法在近区存在一定差异,但在中远区吻合得较好。利用该等效荷载施加方法,采用三维实体模型计算分析了某沉管隧道基槽爆破施工对既有堤岸稳定性影响,计算了周围不同位置、不同深度位置处的振动响应,并在此基础上,分析研究了减小爆破振动对既有结构物影响的减振措施,可为类似工程提供借鉴。 相似文献
10.
Composition of saturated biomarkers revealed the presence of at least two sources of oils of the Romashkino field with the monotypic conditions. All the studied oils are characterized by presence of a large number of components—anoxia testifiers in the photic layer of sedimentation basin in the fractions of aromatic compounds. These are products full or partial hydrogenation, cyclization and degradation of polyene compounds. Total content of this group of compounds is measured in these fractions for the first time. It is shown that the total content of the anoxia testifiers is high. Thus the specific characteristic of oil source rocks is defined—their formation in the conditions of existence of anoxia in the photic layer during the entire accumulation time of initial organic matter, and the thickness of the layer infected with hydrogen sulphide was significant. On the basis of composition and content of the anoxia testifiers it is shown that the hydrogenation of initial polyenes prevailed in diagenesis over the processes of cyclization. 相似文献
11.
L. N. Kogarko 《Geology of Ore Deposits》2014,56(4):230-238
The distribution of radioactive elements in alkaline rocks from Polar Siberia and Ukraine shows that U and Th are markedly concentrated in carbonatite complex and nepheline syenite as final products of magma fractionation. Peralkaline nepheline syenites from Polar Siberia are characterized by very high contents of radioactive elements, which are close to the economic level. Radioactive elements are also concentrated in rocks of the carbonatite complex. For example, some soevites contain up to 294 × 10?4%U and 916 × 10?4% Th. In late dolomite carbonatites, the contents of radioactive elements are appreciably lower. The Th/U ratio in alkaline rocks of Polar Siberia is close to the chondrite value in primary high-Mg rocks and increases in late derivatives: phoscorite, calcite and dolomite carbonatites. The main amount of radioactive elements is contained in rare-metal accessory minerals: perovskite, pyrochlore, calzirtite, and apatite. Rock-forming minerals are distinguished by very low concentrations of radioactive elements. In alkaline series of the Chernigovka massif (Ukraine), U and Th also accumulate in the course of crystal fractionation, especially in phoscorites from the carbonatite complex. Mantle xenoliths and alkaline rocks from Ukraine reveal uranium specialization. Most likely, the discrepancy in fractionation of radioactive elements between Polar Siberia and Ukraine is caused by different geodynamic regimes of these provinces. The Mesozoic alkaline magmatism of Polar Siberia is a part of the Siberian superplume, whereas the Proterozoic alkaline complex in Ukraine is related to subduction of the oceanic crust. 相似文献
12.
济阳坳陷车镇凹陷古近系沙河街组发现的Macaronichnus segregatis(分离通心粉管迹)是一种直到微弯曲形状的层内进食潜穴,个体较小,不分枝,长一般7～8 mm,直径1～3 mm,与前人发现的化石在个体大小上存在着差异。它主要出现于四类环境：①三角洲平原河道间低地,②三角洲、扇三角洲前缘远端砂坝和浊积扇的中扇到外扇,③潮湿气候条件下的浅湖,④周期性干旱气候条件下的滨浅湖。不同沉积环境中产出的Msegregatis都分布于粉砂质泥岩中。通过分析各沉积环境的水动力条件和水体化学性质以及Msegregatis的形成过程,可得出以下结论：①Msegregatis出现的水动力条件中等,水体能量过高或过低,都不适宜其生成;②Msegregatis出现的水体化学性质介于贫氧与富氧之间;③Msegregatis是在沉积物沉积后还未固结时由食沉积物生物活动造成的,衬壁的出现反映了软基底性质。 相似文献
13.
The observed variety of types of Active Galactic Nuclei (AGN) in galaxies with various masses and morphologies is considered. It is proposed that this diversity is related to the evolutionary development of their host galaxies and central regions, including their bulges, massive black holes, and accretion disks. A possible evolutionary scenario explaining the relationship between various types of AGN is proposed, in which, in addition to differences in the accretion states of the circumnuclear disks, the type of host galaxy is also taken into consideration. Special attention is given to the qualitative similarity of the accretion and radiative processes occurring in active objects with stellar-mass black holes (microquasars) and in AGN, in spite of the huge differences in the masses of their black holes. Studies of variability of the emission of microquasars taking this similarity into account can be used to make predictions about the behavior of the emission of AGN (with scaling in accordance with the black-hole mass). 相似文献
14.
应用地热温标估算地下热储温度 总被引：21，自引：2，他引：19
利用6省区49个热水样品的测试数据,分4类方法估算热储温度,以天津地区为例,讨论区域地质背景下热储温度的估算,并对怀疑发生混合作用的水样点建立混合模型。结果表明,不同地热温标的应用条件各不相同,应用到实际水样后得到的温标估算结果差异很大,需要利用Na-K-Ca三角图和lg （Q/K）图判断矿物-流体的平衡状态,还要综合考虑蒸汽散失、混合等对温度的影响。天津地区8个地热井估算的热储温度在83～120 ℃之间;广州三元里井热水混合前的深部热储温度为79.3 ℃,混入的冷水比例为83%。 相似文献
15.
Reaction of zoning of garnet 总被引：1，自引：0，他引：1
Timothy P. Loomis 《Contributions to Mineralogy and Petrology》1975,52(4):285-305
Compositional zoning of garnet in metamorphic or igneous rocks preserves evidence of the equilibration history of the sample and can be interpreted in terms of a growth-fractionation, diffusion-exchange, or diffusion-reaction model. Diffusion zoning is usually assumed to result from exchange reactions between garnet and other phases as the partitioning coefficient varies in response to changing environmental conditions, primarily temperature. However, in many natural environments where garnet grew originally in divariant equilibrium with other phases, changing conditions can promote continuous or “divariant” reactions and consequent compositional shifts of phases that can be much greater in some systems showing these reactions than those related to the small changes of partitioning. Diffusional zoning related to overstepping of these continuous reactions must be related to incongruent reaction and necessitates formulation of a kinetic diffusion-reaction model involving moving phase boundaries as well as solid-state diffusion. Three samples containing zoned garnets from the metamorphic aureole around the Ronda ultramafic intrusion in southern Spain are used to illustrate two possible models of diffusion-reaction processes. The examples are particularly informative because the reactions are demonstrably irreversible and evidence of the reaction system is preserved. Partitioning data indicates that compositions of product phases are not in equilibrium with the original garnet and do not vary with extent of reaction; therefore, exchange reactions with garnet were not possible and garnet changed composition only by incongruent reaction. After a small amount of reaction, Mg/Fe of the rim composition approaches a value apparently in equilibrium with product phases, but the garnets are zoned inward to the original garnet composition preserved in the interior. Grossularite content is approximately constant and spessartite content variable but small, thus, the rim composition of pyrope or almandine is assumed to be fixed by the external reaction process and is taken as a boundary condition in the following models. The zoning profile of pyrope or almandine component between the fixed rim and core compositions (assumed to extend to ∞) is described in semiinfinite, half-space models appropriate for large garnets with narrow rims. The first model corresponds to a reaction system in which all garnet compositions are metastable (case 1) and zoning depends on the independent variables of the diffusion constant, velocity of the interface between garnet and matrix, and time. The second model, corresponding to systems in which the initial garnet composition is metastable but an equilibrium composition is stable (case 2), depends on the independent variables diffusion constant, time, and a function of reaction compositions. In case 1 the consumption velocity is assumed constant and a steady state zoning profile is reached at large time, whereas, in case 2, the velocity decreases with the concentration gradient and steady state is not possible. The models were tested using a reaction time estimated from cooling models of the aureole, mass of garnet consumed, determined petrographically, and phase compositions. The two cases are somewhat independent in that different parameters are independent variables. The estimate of the diffusion constant of 10?18±2 cm2/sec (assumed to be a mutual or binary coefficient for almandine and pyrope) is considered reasonable for the temperature range of reaction (probably 600–900° C), and the two models are consistent considering the probable error and possible real temperature differences. It is obvious that details of the metamorphic reaction system must be known to successfully apply diffusion models. Kinetic models, involving consumption or growth of the phase as well as diffusion are probably necessary when dealing with natural rocks. Several possible and interesting complications, such as cross coupling between components, can be investigated if more data were available. Experimental determination of diffusion constants allow natural reaction rates to be estimated by this method. Diffusion zoning is an important consideration that could increase the efficiency of experimentation with chemically recalcitrant phases. 相似文献
16.
《International Geology Review》2012,54(11):1657-1670
Physical methods (infrared spectroscopy, X-ray, Mössbauer spectroscopy) afford exact ratings of ferruginousness of the subphases (sublattices) in the superstructures of minerals. This provides opportunity for studies of the distribution of Fe2+ between the subphases in a mineral or in several coexisting minerals, as influenced by P and T. The distribution analysis, in the case of rhombic pyroxenes and amphiboles of the cummingtonite-grünerite series, shows the fruitfulness of this type of approach. A substantial effect of T on the Fe2+ distribution in superstructures of these minerals appears indicated. Efficient geothermometers and geomanometers may be developed on that basis. On the other hand, a possibility presents itself for appraisal of sequences of the hydration reactions, as influenced by T, other things being equal. Experimental and theoretical studies will let us arrive at a closer appraisal of the effects of T and P on stability of chemical bonds in minerals, on the basis of endocrystalline ionic equilibria of superstructures in solid solutions. — Authors. 相似文献
17.
深部岩体多孔介质流变模型的研究 总被引：2，自引：1，他引：1
考虑到传统流变模型在反映载荷水平影响和描述加速蠕变阶段方面的缺陷,在改进传统流变元件模型的基础上,引入非理想黏性元件,建立了在数学上能体现载荷水平影响并能描述加速蠕变的新的改进流变模型;同时从定义出发,考虑到孔隙度的动态性,对孔隙度和通用有效应力公式进行修正;鉴于岩体的孔隙性和不均匀性,把岩体看作多孔介质,应用多孔介质理论中的有效应力代替改进岩土流变模型中的恒应力,计入温度和孔隙压的影响,最终建立了深部（高温度、高地压和高孔隙压）岩体多孔介质流变模型。 相似文献
18.
J. C. Jaeger 《Australian Journal of Earth Sciences》2013,60(1):133-140
The value of density measurements in the study of differentiated dolerite sills is discussed. It is shown that density measurements correspond closely with the results of chemical and modal analyses. There is a considerable statistical fluctuation in measured values of the density from relatively close specimens, and a similar fluctuation is to be expected in the results of chemical or modal analyses. Because of their speed, it is possible to make a large number of density measurements and take mean values over fifty foot intervals to indicate trends. The density in a moderately thick tholeiite sheet normally increases linearly from the lower contact to a maximum several hundred feet above it, and then decreases to a minimum at the most silicic region which usually occurs several hundred feet below the upper contact. For a sheet of uniform thickness, the variation of density with depth appears to be roughly the same at all points. The density remained constant in a horizontal tunnel at a constant height above the lower contact, but irregular changes in density, possibly associated with changes in level of the roof or flow can occur, and a remarkable case of a rapid horizontal variation in density is discussed in some detail. 相似文献
19.
高凡金矿床是次火山热液型中低温金（银）矿床，对矿石中主要矿石矿物自然金、石英，黄铁矿，银矿物，闪锌矿，方铅矿和方解石等矿物标型性研究，得出了高凡金（银）矿床的矿物标型特征及空间分布规律，利用这些规律可指导该矿床深部的找矿工作及区域上同类型矿床的寻找。 相似文献
20.
O. V. Stepanets L. A. Kodina A. N. Ligaev A. P. Borisov G. Yu. Solov’eva 《Geochemistry International》2006,44(12):1215-1224
This paper presents the results of the studies performed from aboard the R/V Akademik Boris Petrov of the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, in 2002–2004 aimed at surveying
the sites of dumping of potentially dangerous objects in Stepovoy, Abrosimov, and Tsivol’ka bays of the Kara Sea. These studies
coupled the instrumental facilities of acoustic survey with the visual examination of the objects recovered and also included
sampling of the bottom sediments and near-bottom water in the vicinity of the objects and away from them. Subsequently, the
samples collected were analyzed using direct gamma spectrometry and radiochemical concentrating selected radionuclides. This
allowed us to obtain a statistically reliable database on the specific concentrations of radionuclides (cesium, strontium,
cobalt, and plutonium) in the water column and in the bottom sediments. In selected parts of Stepovoy and Abrosimov bays,
at the sites where containers were located, local areas with contaminated bottom sediments were registered in the immediate
vicinity of the objects, in which significant concentrations of Cs-137 were detected. We also carried out experiments with
the samples of the collected bottom sediments on the determination of the kinetic parameters of sorption in the sediment-solution
system using the method of radioactive indicators. Taking into account the hydrological conditions, the results obtained allow
one to explain particular features of radioactivity distribution in selected aquatic areas. Based on a comparison between
the results of the studies performed in 1992–1994 and 2002–2004, we estimated the dynamics of the changes in the mean level
of specific concentrations of radionuclides in the regions of the location of sunken objects in shallow-water bays of the
Novaya Zemlya Archipelago. The registration of elevated concentrations of corrosive elements in the surface layers of the
bottom sediments in these zones suggests a necessity of a multidisciplinary study consisting of regular repeated measurements
at reference points in different areas aimed at before-the-fact prevention of possible leakages of radioactive substances
from the sunken objects, which might result in a significant contamination of the environment.
Original Russian Text ? O.V. Stepanets, L.A. Kodina, A.N. Ligaev, A.P. Borisov. G.Yu. Solov’eva, 2006, published in Geokhimiya,
2006, No. 12, pp. 1315–1324. 相似文献