季冻区桥梁基桩抗冻拔验算几个问题的探讨     

盛洪飞 《冰川冻土》1989,11(1):44-52

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A garnet population in Yellowknife schist, Canada   总被引：6，自引：0，他引：6  

R. KRETZ 《Journal of Metamorphic Geology》1993,11(1):101-120

Abstract Data are presented on a garnet population in a specimen of garnet-biotite-plagioclase-quartz schist from the cordierite zone of an Archaean thermal dome in the Southern Slave Province of the Canadian Shield. Garnet crystals are bounded by planar dodecahedral faces and by trapezohedral faces which on the 10-μm scale are corrugated. Crystal distribution, as revealed by dissection of a small cubic volume of rock, is random. The size distribution is normal, with a mean diameter of 0.81 mm and a standard deviation of 0.32 mm. In the largest crystal of the population (mean radius 0.83 mm), [Mn] = 100 Mn/(Fe + Mg + Mn + Ca) decreases from 14.5 at the centre to 7.5 and then increases in the outer margin to 8.5; [Fe] increases continuously from 67 at the centre to 77 at the surface; [Mg] increases from 12.5 to 13.5 and then falls sharply to 11; [Ca] remains unchanged at 4.0 and then drops to 3.3. Progressively smaller crystals have progressively lower [Mn] and higher [Fe] concentrations at their centres, while all crystals have the same margin composition. Growth vectors extending from given concentration contours to crystal surfaces are of equal length regardless of the size of the crystal in which the vector is located. A garnet-forming model is presented in which reaction was initiated by a rise in temperature. Nucleation sites were randomly selected. The nucleation rate increased with time and then declined. Crystal faces advanced at a constant linear rate, which implies an increase in volume proportional to surface area. Initially, the composition of garnet deposited on crystal surfaces was determined by van Laar equations of equilibrium, which demanded the withdrawal of Mn and Fe from within chlorite crystals. This transfer reaction was then accompanied by an ion exchange reaction which moved Mn and Fe to garnet surfaces from biotite, in exchange for Mg. The exchange reaction provides an explanation for the high overall concentration of Mn and Fe in garnet and for the observed Mn and Mg reversals in the margins of crystals. The increase of garnet volume in the garnet population is found to be parabolic, i.e. Vαα⁵.  相似文献   

豫西东秦岭造山带核部杂岩中钙质变质岩的变质作用演化   总被引：3，自引：0，他引：3  

陈能松  张兴辽 《岩石学报》1993,9(3):240-254

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热液中硫化物与硫代硫酸盐的同位素交换机制及多硫化物的作用     

储雪蕾 《岩石学报》1993,9(3):255-266

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钽钼杂多酸—碱性染料多元缔合物体系的研究   总被引：1，自引：0，他引：1  

李祖碧  王加林 《岩矿测试》1993,12(1):38-42

在PVA、OP或Tween-60存在下,采用平衡移动法确定了碱性染料亚甲基蓝、耐尔蓝(NB)、罗丹明B(RB)、丁基罗丹明B(BRB)、结晶紫(CV)、乙基紫(EV)与Ta的摩尔比是1:1至7:1;考察了NB(或BRB)-钽钼杂多酸缔合物的红外光谱,初步探讨了反应机理:比较了几个碱性染料-钽钼杂多酸缔合物体系的光度特性,筛选出两个摩尔吸光系数>2×10~6的分析体系,并用于合金钢和地质标样中痕量Ta的测定,方法可行。  相似文献   

造山带与岩石圈演化动力学研究述评     

匡耀求 《湖南地质》1994,13(4):250-254,240

本文综述指出：深部过程，可能导致放射性元素在地幔或下地壳的某些部位聚结而产生强烈的核反应，致使下地壳加热和上地壳的快速抬升和伸展垮塌，产生地震、火山作用、岩浆作用，形成山脉。通过对来自地球内部的α─粒子辐射监测，有可能对毁灭性地震作出预报。  相似文献   

非接触极化曲线视反应电位差区分矿体矿物成分及确定其边界的实验研究   总被引：2，自引：0，他引：2  

黄兴万 《矿物岩石》1994,14(4):92-97

本文用非接触极化曲线视反应电位差区分矿体矿物成分和确定矿体边界的基本原理，着重阐述矿物非接触极化曲线视反应电位差特征的实验研究方法和结果，并指出非接触极化曲线视反应电位差区分矿体矿物成分和确定矿体边界是有可能的。  相似文献   

Numerical study of the oxidation process of dimethylsulfide in the marine atmosphere   总被引：1，自引：0，他引：1  

Seizi Koga  Hiroshi Tanaka 《Journal of Atmospheric Chemistry》1993,17(3):201-228

A box model, involving simple heterogeneous reaction processes associated with the production of non-sea-salt sulfate (nss-SO ₄ ^2– ) particles, is used to investigate the oxidation processes of dimethylsulfide (DMS or CH₃SCH₃) in the marine atmosphere. The model is applied to chemical reactions in the atmospheric surface mixing layer, at intervals of 15 degrees latitude between 60° N and 60° S. Given that the addition reaction of the hydroxyl radical (OH) to the sulfur atom in the DMS molecule is faster at lower temperature than at higher temperature and that it is the predominant pathway for the production of methanesulfonic acid (MSA or CH₃SO₃H), the results can well explain both the increasing tendency of the molar ratio of MSA to nss-SO ₄ ^2– toward higher latitudes and the uniform distribution with latitude of sulfur dioxide (SO₂). The predicted production rate of MSA increases with increasing latitude due to the elevated rate constant of the addition reaction at lower temperature. Since latitudinal distributions of OH concentration and DMS reaction rate with OH are opposite, a uniform production rate of SO₂ is realized over the globe. The primary sink of DMS in unpolluted air is caused by the reaction with OH. Reaction of DMS with the nitrate radical (NO₃) also reduces DMS concentration but it is less important compared with that of OH. Concentrations of SO₂, MSA, and nss-SO ₄ ^2– are almost independent of NO _x concentration and radiation field. If dimethylsulfoxide (DMSO or CH₃S(O)CH₃) is produced by the addition reaction and further converted to sulfuric acid (H₂SO₄) in an aqueous solution of cloud droplets, the oxidation process of DMSO might be important for the production of aerosol particles containing nss-SO ₄ ^2– at high latitudes.  相似文献   

硅灰石、透辉石在陶瓷中的基本反应和作用   总被引：5，自引：0，他引：5       下载免费PDF全文

戴长禄  张振禹 《地质科学》1990,(4):359-366

本文以硅灰石和高岭石、透辉石和高岭石为端元组分,推导了二元假相图。根据这两个假相图,提出了四个基本固相反应。用这些基本反应以及硅灰石、透辉石的矿物学性质,说明了它们对陶瓷坯体工艺性能的作用。  相似文献   

新疆黄山杂岩体矿物学特征及其意义   总被引：1，自引：0，他引：1  

钟应先 《矿物岩石》1991,11(1):14-23

黄山杂岩体造岩矿物有橄榄石、斜方辉石、单斜辉石、斜长石、角闪石和黑云母。其中斜方辉石的多色性不是由Fe~(2+)引起,而是由Ti~(4+)引起。单斜辉石结晶后常与岩浆继续发生化学反应,形成一种岩浆岩结构——角闪反应补丁结构。橄榄石中镍含量的亏损程度反映杂岩体曾经历过硫化物熔离作用。单斜辉石Si,Al~Ⅳ,Ti的变化表明杂岩体属于拉斑玄武岩系列。超镁铁岩中K,Ba,Th,Hf等元素反常的地球化学行为是由该岩石中黑云母矿物引起。  相似文献