Rock density study

Density of volcano-sedimentary complexes progressively rises going down the Paleozoic section and decreases in the Precambrian. Density of the intrusive rocks is determined largely by their composition. There seem to be lateral changes in rock density, correlative with surface relief of the crust, differences in intensity of metamorphism, and intensity of dislocation. The density differences may be related to those in the degree of weathering or in the conditions, nature and intensity of metamorphism. --Author.     

Morphotectonic study of Hispaniola

Geomorphological analysis; aerial photographs; and geomorphologic, geological, geophysical, topographical, and field studies show that the morphology of Hispaniola can be linked to lateral variations in the geometry and tectonism of the Caribbean-North American Plate Boundary Zone. Three main categories of the relief were established: territorial units (1 megablock, 2 macroblocks, 14 mesoblocks, 209 blocks, 401 microblocks, and 527 nanoblocks), morphostructural alignments (4 first-, 1 second-, 12 third-, and 30 fourth-rank), and 16 knots between morphostructural alignments (second-to fourth-rank). The main seismic activity is concentrated on the first-and second-rank lineaments, and some important epicenters are located in the vicinity of the lineament intersections. The origin of the earthquakes in the vicinity of such knots can be explained by the forcing/pushing of macroblocks northeastward. The existence of earthquakes along the main lineaments may be explained by tension or compression in a restraining bend zone. From the current study, it appears that earthquake occurrence in Hispaniola is related with the stress concentrations in the vicinity of morphotectonic zones. A seismotectonic interpretation of Hispaniola is shown where three zones exist, each of them with a different active level and dimensions. The text was submitted by the authors in English.     

阴极发光在翡翠研究中的应用

通过对多个翡翠及其他玉石标本进行阴极发光实验,观察不同品种的翡翠、处理翡翠制品以及翡翠的相似玉石品种在阴极发光镜下的荧光颜色、发光强度、环带特点、颗粒形态和裂隙状况等的不同特征,来有效鉴别翡翠、处理翡翠及翡翠的相似品。同时依据不同类型翡翠在阴极发光下的特征,对翡翠的品质、颜色等的划分提供依据。     

Murray Basin Magnetotelluric study

The Murray Basin is geologically featureless, has been sparsely covered by geophysics, and is penetrated by a few scattered wells. Only drilling and reflection seismic work have provided consistently reliable depth information. They have indicated the presence of narrow troughs, which contain more than 3 km of Palaeozoic sediment, covered by basement highs with less than 300 m of Mesozoic and Cainozoic cover.

Six widely spaced magnetotelluric (MT) sites were occupied in the north central Murray Basin. Results showed a 5 km thick horizontal section at Pooncarie, with a probably average porosity of 10%. Higher porosities, and probably a thicker section, were indicated near Little Topar, but the structural complexity there requires that additional data be acquired for positive interpretation.

A persistent conductivity increase near 100 km suggests that the method may respond well to the base of the tectonic plate.

The MT method appears well suited to the onshore exploration problems currently faced in Australia.     

土壤地质单位的建立与研究--以浙江省为例

土壤地质单位是地学工作者根据地质资料、结合成土特征提出的一种新型土壤分类方法,其实质就是在充分考虑气候、生物、地形、时间等成土因素的同时,抓住母岩-母质-土壤三者之间的成生联系,找出成土母岩岩性、矿物成分、结构构造、地球化学特征对土壤结构、质地、厚度、微量营养元素的制约关系,为农业区划和农业种植结构调整提供科学的依据.笔者据浙江省农业地质背景调查项目实践,在从地学角度对浙江省成土母质进行分类的基础上,结合土壤亚类建立了土壤地质单位,并提出研究内容和研究方法.     

Experimental study of stick-slip behaviour

Simple axi-symmetric uni-axial compression tests have been realized on dry loose samples of glass beads (diameters d: d=0.2 ± 0.05 mm, 0.75 ± 0.1 mm, or 3 mm) and on Hostun sand under small lateral confinement, σ₃<60 kPa, using different sample sizes. The experiments with the two smallest spheres (d=0.2 and 0.75 mm) exhibit stick-slips, which are characterized by (i) a rapid release Δq of the deviatoric stress q and by (ii) the strain Δε₁ separating two events. The samples which exhibit stick-slip also present a weakening of strength q(ε₁) as the rate of deformation dε₁/dt is increased. No stick-slip is generated during the first part of the q−ε₁ curve, i.e. when q grows fast with ε₁. Four different parameters helped us determine the statistics of Δq and Δε: the lateral pressure σ₃′, the rate of deformation dε₁/dt, the sample height H, and the diameter D. The statistics do not depend on rate history. They look like exponentials in small samples and/or in (large sample+fast dε₁/dt), and they look like Poissonian or Gaussian in (Large sample+small dε₁/dt). This change in statistics is attributed to a varying of triggering process starting from a single random event in small samples to multiple random events. We have interpreted this change of statistics as due to some finite size effect so that the representative elementary volume shall contain at least (200)³ grains. Localization of deformation is visible at the end of compression but cannot be detected from stick-slip statistics nor from q vs ε curve. Copyright © 2004 John Wiley & Sons, Ltd.     

DX桩的试验研究

简要介绍DX桩及其工艺，并通过单桩垂直载荷试验，对其工作性状进行研究，结果表明，分布于桩身的支盘能较充分地利用柱侧土的承载力，支盘承受了桩的大部分荷载，桩的荷载－位移曲线类似如端承桩的缓变形曲线，桩的破坏形式表面为支盘附近土体的剪切破坏。     

High-pressure structural study of muscovite

The compressibility and structural variations of two 2M₁ muscovites having compositions (Na_0.07K_0.90 Ba_0.01□_0.02)(Al_1.84Ti_0.04Fe_0.07Mg_0.04)(Si_3.02Al_0.98) O₁₀ (OH)₂ (7 mole % paragonite) and (Na_0.37K_0.60□_0.03)(Al_1.84Ti_0.02 Fe_0.10Mg_0.06)(Si_3.03Al_0.97) O₁₀(OH)₂ (37 mole % paragonite) were determined at pressures between 1 bar and 35 kbar, by single-crystal X-ray diffraction using a Merrill-Bassett diamond anvil cell. Isothermal bulk moduli, setting K′ = 4, were 490 and 540 (± 30) kbar for the Na-poor and Na-rich samples respectively. Both samples show highly anisotropic compressibility patterns, with β _a ∶β _b ∶β _c = 1∶1.15∶3.95 for the Na-poor sample and β _a ∶β _b ∶β _c = 1∶1.19∶3.46 for the Na-rich one. HP structural refinements showed that the different compressibility was largely due to the partial substitution of Na for K in the interlayer region. Moreover, the different compressibility of the tetrahedral and octahedral layers, observed in both micas, increased the a rotation of the tetrahedral layer by about 2° in 28 kbar, as also indicated by the evolution of interlayer cation bond lengths. This increases the repulsion of oxygens of the basal layers and between the high-charged cations of the tetrahedral layer. As a consequence, phengitic substitution, reducing α rotation, would increase the baric stability of mica. Comparison between the HP structures of muscovite and phlogopite indicated the lower compressibility of the latter, mainly due to the greater compressibility of the dioctahedral layer with respect to that of the trioctahedral layer. The HT and HP behaviour of di- and trioctahedral micas showed an anisotropy in the compressional pattern which was markedly greater than that observed in the dilatation pattern. This unexpected result was explained by the different evolution with P and T of alkaliO bond lengths. By combining HP and HT data, a tentative equation of state of muscovite is proposed.     

A thermochemical study of monohydrocalcite

The thermodynamic properties of monohydrocalcite, CaCO₃ · H₂O, have been obtained using a well-characterized natural specimen. Equilibration of the solid with water at 25°C under 0.97 atm CO₂ led to an activity product [Ca²⁺][CO₃^2?] = 10^?7.60±0.03 and a free energy of formation ΔG_f^o = ?325,430 ± 270 calmol^?. The enthalpy of solution of monohydrocalcite in 0.1 N HCl at 25°C led to a standard enthalpy of formation ΔH_f^o = ?358,100 ± 280 cal mol^?1. Estimates of the variation of ΔG_f with temperature and pressure showed monohydrocalcite to be metastable with respect to calcite and aragonite.     

A thermochemical study of vaterite

Vaterite is shown to be unstable with respect to calcite at 25°C by measurements of the enthalpies of solution in 0·1 N HCl under 0·97 atm CO₂ and the solubilities in water under 0·97 atm CO₂ of the two polymorphs. For a pure, synthetic vaterite ΔH (tr) = ?1036 ±16 cal mol^?1 and ΔG(tr) = ?790 ± 25 cal mol^?1 for the transition to calcite. For other vaterites aged longer during preparation ΔH(tr) is smaller and shows a linear relationship with the X-ray line broadening which extrapolates to ΔH(tr) = ?545 ± 30 cal mo^?1 for zero broadening. The use of X-ray line broadening as a measure of crystal imperfection and stability is discussed for various synthetic and natural vaterites.     

岩体强度的各向异性研究

本文运用断裂力学理论推导了含节理岩体的初裂强度公式,定量地讨论了节理方向、长度对岩石强度的影响,阐明了节理岩体强度各向异性的实质。通过证实,本文所建立的公式具有很强的适用性和较高的可靠性,可用于实际的工程岩体稳定性评价。     

土体各向异性研究进展

综合论述了土体各向异性在土体本构理论发展的不同阶段的研究进展：详细介绍了国内外在各向异性研究中所采用的试验手段、研究方法、理论成果和应用情况：对具代表意义的重要成果作了比较详细的描述和分析。分析了原生各向异性和应力各向异性的区别与联系，认为土体材料的颗粒结构性是各向异性产生的根本原因，复杂的应力状态是各向异性产生的客观条件：强调了各向异性，尤其是应力各向异性在土体本构理论研究中的重要性，对以后各向异性研究方法提出自己的观点。     

断层封闭性研究进展

在大量文献调研的基础上,对断层封闭性的机理、影响因素进行了总结和分析,并从定性以及定量的角度对断层封闭性国内外研究方法作了系统综述。认为断层封闭性研究需要结合地震、测井、钻井、油藏地球化学乃至生产动态等多方面资料,其研究过程应是系统的、动态的,进而探讨了断层封闭性研究需要注意的问题。      

Helium irradiation study on zircon

Synthetic ZrSiO₄ and (mildly to strongly radiation-damaged) natural zircon samples were irradiated with 8.8 MeV ⁴He²⁺ ions (fluences in the range 1 × 10¹³–5 × 10¹⁶ ions/cm²). For comparison, an additional irradiation experiment was done with 30 MeV ¹⁶O⁶⁺ ions (fluence 1 × 10¹⁵ ions/cm²). The light-ion irradiation resulted in the generation of new (synthetic ZrSiO₄) or additional (mildly to strongly metamict natural samples) damage. The maximum extent of the damage is observed in a shallow depth range approximately 32–33 μm (8.8 MeV He) and ~12 μm (30 MeV O) below the sample surface, i.e. near the end of the ion trajectories. These depth values, and the observed damage distribution, correspond well to defect distribution patterns as predicted by Monte Carlo simulations. The irradiation damage is recognised from the notable broadening of Raman-active vibrational modes, lowered interference colours (i.e. decreased birefringence), and changes in the optical activity (i.e. luminescence emission). At very low damage levels, a broad-band yellow emission centre is generated whereas at elevated damage levels, this centre is suppressed and samples experience a general decrease in their emission intensity. Most remarkably, there is no indication of notable structural recovery in pre-damaged natural zircon as induced by the light-ion irradiation, which questions the relevance of alpha-assisted annealing of radiation damage in natural zircon.     

复合型含油气系统的特征与描述 : 以塔中含油气系统为例

通过对塔中含油气系统的研究，发现它难以用传统的含油气系统方法来描述。它主要有二个油源区三套生油岩，发育有三套储层；不同油源在不同时期生成的油气在储层内共生、甚至相互混合，使油气成因复杂。据此提出了它是一个复合型含油气系统。在此基础上，进一步指出复合型含油气系统的特点是多油源、多期成烃、油气成因复杂，出现在迭合型盆地。并针对这些特点，初步提出了工作思路及描述方法。     

石香肠构造研究综述

石香肠构造是一种传统的线状构造，由于其在区域构造应力场方面的研究意义及其所包含的流变学信息和控矿意义等一直吸引着研究者的关注。简述了近几十年来石香肠构造在形态学研究上的进展，分析了其在理论研究上的成果，概括了其在应用研究方面的现状，并对当前及今后石香肠构造的研究方向提出了建议。     

Thermodynamic study of calcic amphiboles

The paper reports original thermochemical data on six natural amphibole samples of different composition. The data were obtained by high-temperature melt solution calorimetry in a Tian–Calvet microcalorometer and include the enthalpies of formation from elements for actinolite Ca_1.95(Mg_4.4Fe _0.5 ²⁺ Al₀₁)[Si_8.0O₂₂](OH)₂(–12024 ± 13 kJ/mol) and Ca_2.0(Mg_2.9Fe _1.9 ²⁺ Fe _0.2 ³⁺ )[Si_7.8Al_0.2O₂₂](OH)₂, (–11462 ± 18 kJ/mol), and Na_0.1Ca_2.0(Mg_3.2Fe _1.6 ²⁺ Fe _0.2 ³⁺ )[Si_7.7Al_0.3O₂₂](OH)₂ (–11588 ± 14 kJ/mol); for pargasite Na_0.5K_0.5Ca_2.0-(Mg_3.4Fe _1.8 ²⁺ Al_0.8)[Si_6.2Al_1.8O₂₂](OH)₂ (–12316 ± 10 kJ/mol) and Na_0.8K_0.2Ca_2.0(Mg_2.8Fe _1.3 ³⁺ Al_0.9) [Si_6.1Al_1.9O₂₂](OH)₂ (–12 223 ± 9 kJ/mol); and for hastingsite Na_0.3K_0.2Ca_2.0(Mg_0.4Fe _1.3 ²⁺ Fe _0.9 ³⁺ Al_0.2) [Si_6.4Al_1.6O₂₂](OH)₂ (?10909 ± 11 kJ/mol). The standard entropy, enthalpy, and Gibbs free energy of formation are estimated for amphiboles of theoretical composition: end members and intermediate members of the isomorphic series tremolite–ferroactinolite, edenite–ferroedenite, pargasite–ferropargasite, and hastingsite.     

Aeromagnetic study of peninsular India

The degree sheet Aeromagnetic maps up to 17‡N, acquired from the Geological Survey of India, have been manually redigitised at 6 minute intervals to study the long wavelength anomalies over peninsular India. These data have been collected at different survey altitude, epochs, flight line directions, etc. Great care has been taken to correct the total field map and remove the contribution due to the core field and prepare an accurate crustal anomaly map. For the first time, a regional map, depicting the NW-SE structural features north of the orthopyroxene isograd with the essentially E-W features to the south of it and revealing several well known structures, is presented. The analytical signal is calculated to delineate the source fields of these anomalies. It dramatically maps the charnockites and is able to delineate the orthopyroxene isograd. In the Dharwar region the magnetic signatures are associated with the intrusives/ iron ore bodies. Thus, we find that the source rocks of the aeromagnetic anomalies are the host province of charnockites in the SGT and the intrusives/iron ore bodies in the Dharwar belt. Gravity residuals are calculated and a tectonic map of the region is presented from the combined geopotential data.     

火山碎屑岩的百年研究

火山碎屑岩是爆破性火山喷发行为的直接产物,不同的碎屑成分、粒度及结构反映了不同岩相的堆积动力学过程,对火山碎屑岩岩石学和岩相组合的研究发展成了以物理火山学为代表的现代火山学研究体系。作为火山爆发碎屑物质的集合,其中不同成因类型的火山碎屑物往往可以直接对应不同阶段火山作用动力学参数特征。火山碎屑物3个最基本的堆积物成因类型是火山碎屑降落物、火山碎屑流和火山碎屑涌浪。火山喷发时碎屑化过程主要涉及挥发分的出溶和岩浆碎屑化过程以及不同火山流体内部的碎屑化过程。对于岩浆喷发、射汽岩浆喷发以及射汽喷发的直接产物,火山碎屑岩在组成上都包含了岩浆破碎的同源碎屑、火山通道裹进的异源碎屑以及火山流体在地表流动时捕获的表生碎屑。火山碎屑定义为爆破性火山喷发的直接行为产物,而包括坡移、滑坡体、火山泥石流等火山降解过程的表生碎屑与熔岩流在自生、淬碎碎屑化过程产生的碎屑则被定义为火山质碎屑。火山岩岩相的建立,为20世纪80年代后期向火山学研究阶段的转变奠定了基础。在地质研究的基础上探索火山活动过程和控制机制的经验模型、实验模拟和数值模拟研究,其中流体动力学的介入对理解火山喷发的基本过程具有里程碑式的推动意义。由此形成的火山学是研究火山与火山喷发的形成机理、喷发过程和产物特性的科学。     

火山碎屑岩的百年研究

火山碎屑岩是爆破性火山喷发行为的直接产物,不同的碎屑成分、粒度及结构反映了不同岩相的堆积动力学过程,对火山碎屑岩岩石学和岩相组合的研究发展成了以物理火山学为代表的现代火山学研究体系。作为火山爆发碎屑物质的集合,其中不同成因类型的火山碎屑物往往可以直接对应不同阶段火山作用动力学参数特征。火山碎屑物3个最基本的堆积物成因类型是火山碎屑降落物、火山碎屑流和火山碎屑涌浪。火山喷发时碎屑化过程主要涉及挥发分的出溶和岩浆碎屑化过程以及不同火山流体内部的碎屑化过程。对于岩浆喷发、射汽岩浆喷发以及射汽喷发的直接产物,火山碎屑岩在组成上都包含了岩浆破碎的同源碎屑、火山通道裹进的异源碎屑以及火山流体在地表流动时捕获的表生碎屑。火山碎屑定义为爆破性火山喷发的直接行为产物,而包括坡移、滑坡体、火山泥石流等火山降解过程的表生碎屑与熔岩流在自生、淬碎碎屑化过程产生的碎屑则被定义为火山质碎屑。火山岩岩相的建立,为20世纪80年代后期向火山学研究阶段的转变奠定了基础。在地质研究的基础上探索火山活动过程和控制机制的经验模型、实验模拟和数值模拟研究,其中流体动力学的介入对理解火山喷发的基本过程具有里程碑式的推动意义。由此形成的火山学是研究火山与火山喷发的形成机理、喷发过程和产物特性的科学。