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1.
羟氨镁铝石的高分辨透射电镜观察   总被引:1,自引:0,他引:1  
秦善  曹正民 《地球科学》1998,23(3):253-256
羟氯镁铝石(koenenite)为典型的异类结构基元间层矿物。结构以氯化物层(Na、Mg)Cl2和氢氧化物层(Mg、Al)(OH2)沿c方向规则交互构成,以前的威研究认为构成羟氢镁铝石的两个亚结构有不同的空间群和晶胞参数。本次以高分辨透射电子显微镜的研究结果表明,羟氢镁镁铝石在c方向的重复周期为1.08nm左右,在a方向上没有显示出层失配特点,说明它是一种有序的晶体。对结构基元层层间的静电作用势能  相似文献   

2.
袁复礼石是一种Mg、Fe3+、Al3+和Ti的硼酸盐新矿物。除了与遂安石、硬石膏和磷灰石共生外,还与硼铝镁石、镁橄榄石和方解石等共生,形成两个矿物共生组合。单矿物化学分析表明,后一组合中的袁复礼石更富铁,特别是Fe3+,相对贫镁。袁复礼石的晶体结构分析证明,袁复礼石与硼钛镁石的结构类型一致,阳离子的占位为M(1)=Me3+,M(2)=Me2+。袁复礼石是M(1)位置上为Fe端员组分,M(2)位置上为Mg端员组分的新矿物。  相似文献   

3.
袁复礼石是一种Mg、Fe^3+、Al^3+和Ti的硼酸盐新矿物。除了与遂安石、硬石膏和磷灰石共生外,还与硼铝镁石、镁橄榄石和方解石等共生,形成两个矿物共生组合。单矿物化学分析表明,后一组合中的袁复礼石更富铁,特别是Fe^3+,相对贫镁。袁复礼石的晶体结构分析证明,袁复礼石与硼钛镁石的结构类型一致,阳离子的占位为M(1)=Me^3+,M(2)+Me^2+。袁复礼石是M(1)位置上为Fe端员组分,M(  相似文献   

4.
西藏南迦巴瓦峰地区发现的星叶石   总被引:3,自引:0,他引:3       下载免费PDF全文
在西藏境内喜马拉雅山脉的东端的南迦巴瓦峰地区发现了星叶石。该矿物产出于火成碳酸岩脉中,与白云石、方解石、镁橄榄石、镁铝尖晶石、金云母、韭闪石、磷灰石、镁钛矿、石榴石以及三种未定名副矿物共生。该矿物的晶胞参数为:a0=5.356(1),b0=11.607(4),c0=11.851(6),α=64.57°(3),β=76.98°(4),γ=85.45°(3)。化学成分(%)为:SiO235.22,TiO211.47,Al2O31.18,FeO28.90,MnO5.15,MgO1.51,CaO1.75,K2O5.90,Na2O2.46,总和93.54%,化学式为:(K,Na)3(Fe,Mn,Mg,Ca)7Ti2Si8O24(O,OH)7。  相似文献   

5.
袁复礼石是一种Mg、Fe ̄(3+)、Al和Ti的硼酸盐新矿物,发现于辽宁省宽甸县砖庙硼矿区。该矿物黑色,近不透明,金刚光泽一半金属光泽。反射色亮灰,内反射深红褐色。非均质性弱,偏光色红褐。晶体呈细柱状,0.1×0.2×1mm。晶体化学式为:空间群:H=5-6,VHN_(50)=843kg/mm ̄2。{100}解理完全。红外光谱吸收谱带为:1387,1210,1024,951,733,600,510和408cm ̄(-1)。穆斯堡尔谱证明,以三价铁为主,二价铁较少。Fe ̄(3+)占据M(1)晶位,Fe ̄(2+)占据M(1)和M(2)晶位。袁复礼石为硼钛镁石的富Fe ̄(3+)类似物。  相似文献   

6.
本文报导了国内首见的呈角闪石假象的铁铝榴石。假象矿物产于山西省垣曲地区的绢云石英片岩中。根据其化学成分与测定、X射线粉晶分析与光学性质确定其为铁铝榴石。矿物呈红褐色,玻璃光泽,条痕无色,比重4-25,硬度6-5~7-0 ,突起很高,N> 1-780,均质性,局部显现光学异常。化学成分:SiO2 36.99,FeO33-60 ,Al2 O3 21.62,MnO3 .00 ,MgO2 .89,CaO1 .13( %) 。主要粉晶线条2-566(100),2-80(55),2-11(46) ;与标准铁铝榴石线条吻合。指标化后求得α为11-58 nm 。晶面符号及投入吴氏网后的计算结果表明,其晶形为角闪石,因而确定其为呈角闪石假象的铁铝榴石。  相似文献   

7.
在对辽宁省宽甸县花园沟硼矿床的研究中,发现了硼铝镁石,它与遂安石、袁复礼石、硬石膏等并生,产于硼矿体中.硼铝镁石是一种比较稀少的硼酸盐矿物,为此,对其进行了矿物特征的研究.硼铝镁石为黄色,粒状;晶体形态呈短柱状和权状,类似于橄榄石的晶体形态,弱多色性、Ng-淡黄、Np-近于无色;折射率Ng=1.7076,Np=1.6708,Nm=1.6962;-2V=54°,H=6-7,VHN100=1215kg/mm2;D测=3.50.化学成分除Al和Mg外,其次是Fe2+和Fe3+,且Fe2+>Fe3+晶体化学式为:晶体结构属斜方晶系,空间群pnma,a=9.893(6)A,b=5.076(4)A,c=4.335(3)A,Z=4.成因分析表明,硼铝镁石富Al、Mg、B,经角闪岩相区域变质作用形成.  相似文献   

8.
用氧同位素温度计测定了西阿尔卑斯DoraMaira地块含柯石英—镁铝榴石白片岩的峰期变质温度。石英(柯石英较变后)的δ ̄(18)O(8.1‰~8.6‰,n=6),多硅白云母的(6.2‰~6.4‰,n=3)、蓝晶石的(6.1‰,n=2)、石榴石的(5.5‰~5.8‰,n=9)、ellenbergerite的(6;3‰,n=1)和金红石的(3。3‰~3.6‰,n=3)δ ̄(18)O(SMOW)值反映了同位素平衡。以石英—石榴石—金红石分馏为基础测定的温度为700~750℃。以对压力敏感的反应:镁铝榴石+朽石英=蓝晶石十顽火辉石为依据确定的最小压力为3.1~3.2GPa。为了通过对温度敏感的脱水反应:滑石十蓝晶石=镁铝榴石十柯石英十水,来稳定镁铝榴石和柯石英,在700~750℃时,α(H_2O)必须减小到0.4~0。75。当镁铝榴石在x(CO_2)>0.02(T=750℃,P=3.0GPa)不稳定时,α(H_2O)的减少不会是由于CO_2的稀释所引起的。当缺乏较多的外来流体稀释剂(即CH_4或N_2时,就需要有熔体相)。在α(H_2O)=1.O时,花岗岩的固相线温度为680℃/3.0GPa,在α(H_2O)=0.  相似文献   

9.
氯化物型钾盐矿床氯同位素地球化学的初步研究   总被引:5,自引:0,他引:5  
孙大鹏  帅开业 《现代地质》1998,12(2):229-234
根据国内外许多钾盐矿床大量样品测定的结果,通常石盐(岩)的37Cl/35Cl比值和δ37Cl值高于钾石盐(岩),而钾石盐(岩)又高于光卤石(岩),说明这些蒸发岩是在不同水体、不同浓缩阶段形成的,是氯同位素分馏作用长期进行的结果。这些蒸发岩的氯同位素组成与其Br、K、Mg含量变化有密切关系。今后在我国找钾过程中,应把氯同位素组成及其Br、K、Mg含量结合起来,作为找钾标志考虑。  相似文献   

10.
Biry.  VM 《辽宁地质》1999,16(2):94-102
含紫硅碱钙石、镁钠钙闪石(钠透闪石-石棉)及蓝色办透闪石的碱性交代岩的形成首先是由硅酸和碱(Na2O和K2O的不同作用)的惰性及FeO,MgO,CaO和Al2O3的强烈活性决定的,含蓝色软透闪石和镁的钙闪石(钠透闪石-石棉)的交换岩是岩浆期后溶解演化的中期产物,而含紫硅碱钙石的交换岩却是其晚期的产物。  相似文献   

11.
The mobility of long-runout landslides   总被引:17,自引:0,他引:17  
Fran  ois Legros 《Engineering Geology》2002,63(3-4):301-331
Several issues relevant to the mobility of long-runout landslides are examined. A central idea developed in this paper is that the apparent coefficient of friction (ratio of the fall height to the runout distance) commonly used to describe landslide mobility is physically meaningless. It is proposed that the runout distance depends primarily on the volume and not on the fall height, which just adds scatter to the correlation. The negative correlation observed between the apparent coefficient of friction and the volume is just due to the fact that, on the gentle slopes on which landslides travel and come to rest, a large increase in runout distance due to a large volume corresponds to a small increase in the total fall height, hence to a decrease in the apparent coefficient of friction.

It is shown that the spreading of a fluid-absent, granular flow is not able to explain the large runout distances of landslides, and in particular does not allow the centre of mass to travel further than expected for a sliding block. This contrasts with the behaviour of natural landslides, for which the centre of mass is shown to travel much further than expected from a simple Coulomb model. The presence of an interstitial fluid which can partly or entirely support the load of particles allows the effective coefficient of solid friction to be reduced or even suppressed. Air is not efficient for fluidising large landslides and a loose debris cannot slide over a basal layer of entrapped and compressed air, as air would rapidly pass through the debris in the form of bubbles during batch sedimentation. Water is much more efficient as a fluidising medium due to its higher density and viscosity, and its incompressibility. As water is known to enhance the mobility of the saturated debris flows, it is proposed that water is also responsible for the long runout of landslides. This is consistent with the fact that the increase in runout with volume is similar for debris flows and landslides. Field evidence suggests that most landslides are unsaturated with water but not dry, even on Mars.

Comparison of the velocity of well-documented landslides with that predicted by fluid-absent, granular models shows that these models predict landslides that are much faster and less responsive to topography than natural ones. The relatively low velocities of landslides suggest that energy dissipation is dominated by a velocity-dependent stress and that the coefficient of solid friction is very low. This is consistent with the physics of fluidised or partly fluidised debris and suggests that landslide velocity may be controlled by local slope and flow thickness rather than by the initial fall height. In the absence of a supply of fluid at the base, fluidisation requires a net downward flux of sediment, implying some deposition at the base of landslides, which may thus progressively run out of material. In such a model, the spreading of the portion of a landslide beyond a certain distance would primarily depend on the volume passing this distance and not on the total volume of the landslide. Landslide deposits may therefore have self-similar shapes, in which the area covered beyond a certain distance is a constant function of the volume beyond that distance. It is shown that the shape of some well-documented landslide deposits is in reasonable agreement with this prediction. One consequence is that, as recently proposed for debris flows, assessment of hazards related to landslides should be based on the correlation between the volume and the area covered by the deposit, rather than on the apparent coefficient of friction.  相似文献   


12.
Paul Claval 《GeoJournal》2004,60(4):321-328
The way that space is thought of is at the heart of the cultural approach in geography. The passing down of all the components of a culture depends upon the way data is aquired and processed, the results memorized or broadcast. Communication shapes the experience and the knowledge of space and time. It gives to everyone the idea that the real world is doubled by a beyond which plays a central role in social life, since it is upon such a beyond that normative thinking relies and that a significance is given to individual and social life. The spheres of lived-in and known space and time, as well as that of the beyond, vary according to available technologies. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
新疆琼河坝铜金矿化地质特征及成因机理   总被引:13,自引:0,他引:13  
通过研究琼河坝地区的含矿岩系、铜金矿化、流体包裹体和氢氧同位素,认为202铜矿为斑岩型矿床,绿石沟铜矿为夕卡岩型矿床,剥蚀程度是本区铜金找矿的关键。  相似文献   

14.
15.
简单斜坡油气富集规律——以松辽盆地西部斜坡北段为例   总被引:16,自引:0,他引:16  
斜坡是断陷和凹陷型盆地的重要构造单元,按其断裂发育程度和沉积厚度分为复杂斜坡和简单斜坡。松辽盆地西部斜坡为断裂不发育、平缓的简单斜坡,简单斜坡油气成藏有特殊性,表现在三个方面:一是简单斜坡的原油主要来自临近的凹陷,油气沿砂体以优势路径方式侧向运移,油气呈“线状”分布;二是简单斜坡大规模构造圈闭不发育,圈闭类型以地层、岩性和构造-岩性圈闭为主,其分布受构造带控制,超覆带发育岩性上倾尖灭圈闭,受规模较大的断层控制形成的鼻状构造带上发育断层遮挡和构造-岩性圈闭,不受断层控制的鼻状构造带主要发育构造-岩性圈闭。三是简单斜坡普遍受大气水的淋滤作用,由于游离氧的进入使原油遭受氧化降解作用而稠化,造成简单斜坡稠油分布普遍。这种成藏的特殊性决定了油气富集规律:只有位于油气运移路径上的圈闭才有成藏的可能。简单斜坡油气勘探方向是,在油气运移路径上寻找低幅度构造背景下的岩性油气藏(小规模)、规模较大断层附近寻找断层遮挡油气藏(中等规模)和地层超覆带上寻找岩性上倾尖灭油气藏(大规模)。  相似文献   

16.
Trends in landslide occurrence in Nepal   总被引:2,自引:0,他引:2  
Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates. In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005. The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and natural systems.  相似文献   

17.
Bayesian updating methods provide an alternate philosophy to the characterization of the input variables of a stochastic mathematical model. Here, a priori values of statistical parameters are assumed on subjective grounds or by analysis of a data base from a geologically similar area. As measurements become available during site investigations, updated estimates of parameters characterizing spatial variability are generated. However, in solving the traditional updating equations, an updated covariance matrix may be generated that is not positive-definite, particularly when observed data errors are small. In addition, measurements may indicate that initial estimates of the statistical parameters are poor. The traditional procedure does not have a facility to revise the parameter estimates before the update is carried out. alternatively, Bayesian updating can be viewed as a linear inverse problem that minimizes a weighted combination of solution simplicity and data misfit. Depending on the weight given to the a priori information, a different solution is generated. A Bayesian updating procedure for log-conductivity interpolation that uses a singular value decomposition (SVD) is presented. An efficient and stable algorithm is outlined that computes the updated log-conductivity field and the a posteriori covariance of the estimated values (estimation errors). In addition, an information density matrix is constructed that indicates how well predicted data match observations. Analysis of this matrix indicates the relative importance of the observed data. The SVD updating procedure is used to interpolate the log-conductivity fields of a series of hypothetical aquifers to demonstrate pitfalls and possibilities of the method.  相似文献   

18.
天然花岗岩块的熔融实验及其岩石学意义   总被引:1,自引:0,他引:1  
本文详细论述了马兰峪中生代脉状花岗间长岩固体块样品的熔融实验结果,并据此讨论了部分熔融过程中的结构与成份平衡问题。实验表明,最初熔体产生于不同矿物的接触边界上,而且石英—碱性长石之间的熔体量较石英—斜长石间熔体多,而同种矿物之间一般不出现熔体。当熔融程度增高时,两种长石间也开始出现熔体。熔体成分的研究表明,初始部分熔融过程中,局部体系的平衡起着控制作用。  相似文献   

19.
Pro-poor sanitation technologies   总被引:1,自引:0,他引:1  
It is estimated that at least two billion people have inadequate sanitation. The current situation in water and sanitation services for millions of peri-urban residents is starkly anti-poor and represents a major challenge for the 21st century. By virtue of its cost and water requirements, we would argue that conventional sewerage is an implicitly anti-poor technology. This paper summarises low-cost sanitation technologies that have been developed by engineers from around the world, and seeks to provide evidence that there is such a thing as a pro-poor technology. We argue that simplified sewerage is often the only sanitation technology that is technically feasible and economically appropriate for low income, high-density urban areas. Simplified sewerage will only truly be a pro-poor technology if issues such as lack of investment in sanitation, insufficient cost recovery for sanitation services, conservative technical standards favoured over innovation, low-cost technologies perceived as second class provision, the nature of peri-urban settlements, and lack of engagement with users, are addressed. So often, peri-urban sanitation schemes fail to exist, fail to be sustainable, or fail to be pro-poor. The challenge is for engineers, social scientists and other professionals to work together to make pro-poor sanitation a reality and interdisciplinarity the norm.  相似文献   

20.
徐新生  燕彬 《岩土力学》2009,30(1):281-284
对沿深度离散形成一系列均质的土层,应用传递矩阵法推导出单桩的动力阻抗。借助推求的桩-桩动力相互作用因子,研究承台板与群桩的竖向动力相互作用,通常假设承台板是刚性的,并充分考虑了承台板具有一定的刚度、可以变形的柔性承台板,提出承台板-群桩动力相互作用模型,然后推出其动力相互作用方程。通过算例说明了承台板的刚度对承台板的动力作用是有影响的。研究结果表明,振动频率越低,柔性承台板的振幅与刚性承台板的振幅相差越大;随着频率的增大,二者差别也减小,并逐渐趋于相等。  相似文献   

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