全风化花岗岩全岩和粘粒中粘土矿物含量变化对比

工程实践和理论研究中常用全岩和粘粒中粘土矿物绝对和相对含量.对同一样品探求两者关系,便于数据对比,有利于工程应用.以采自香港九龙的2处边坡3个探坑中51个全风化花岗岩样品为例,作者用同一套仪器、测试方法,先后采用了颗分法测粘粒质量百分比、物理化学方法测比表面积、XRD方法测矿物成分,分别得出了全岩和粘粒中粘土矿物的绝对含量和相对含量,以及用粘粒质量百分比乘以相对含量得出的换算含量.另外还将全岩XRD矿物成分同薄片统计结果进行了相关分析.对粘土矿物绝对含量基本为20%～45%的全风化花岗岩,对比分析不同含量结果表明:全岩中的某些粘土矿物,如高岭石、蛭石的绝对含量远大于换算含量;不同样品中高岭石和蛭石的相对含量变化幅度远大于它们在全岩中绝对含量变化,两者变化呈现某种一致性;全岩中粘土矿物含量远大于粘粒(粒径<2μm和<5μm两个界限)的含量.后两者相对而言变化基本一致,差值不大;同全岩中粘土矿物含量相关性较好的是比表面积;同薄片统计结果相比,全岩XRD粘土矿物含量受对风化矿物处理不确定性的影响,结果往往偏大.     

不同母质发育的东北黑土的粘粒矿物组成研究

东北黑土的成土母质主要是第四纪沉积物,在对红土母质和黄土母质上发育的两种东北黑土剖面土壤进行小于2μm粘粒的化学组成和XRD衍射分析基础上,研究这两种母质上发育的东北黑土的粘粒矿物组成。结果表明红土母质上发育的东北黑土风化脱硅作用较强,以1—1型或2—1型粘粒矿物为主,主要含有伊利石、蛭石、高岭石,上层土壤粘粒中含有少量绿泥石,母质层含有大量的蒙脱石,不含有绿泥石。在成土过程中,伊利石大量存在,少量绿泥石逐渐形成,蒙脱石向蛭石转化;黄土母质上发育的东北黑土以2—1型粘粒矿物为主,主要含有伊利石、蛭石、高岭石、少量的绿泥石,母质层粘粒中含有长石,经过脱硅作用逐渐消失,有些土壤的母质层粘粒中也含有蒙脱石,粘粒矿物分布相对均匀,矿物间的转化和演化相对简单。     

江汉平原不同利用方式下土壤有机质与粘粒矿物的交互作用

以江汉平原四湖地区果园、旱地、水旱轮作、水田等利用方式下的土壤为研究材料,通过分析有机质质量分数、粘土矿物与铁铝氧化物的组成特点,探讨了该区土壤有机质与粘粒矿物之间的交互作用。结果表明各土地利用方式下表层土壤的粘土矿物均以2∶1型矿物为主,约占70%~80%;不同土地利用方式下表层土壤有机质质量分数、非晶质铁铝氧化物及铁的活化度大小顺序均为:水田水旱轮作旱田果园;土壤非晶质氧化铁(Feo)质量分数和粘土矿物中高岭石的质量分数分别与土壤有机质质量分数呈极显著正相关和显著正相关,且Feo与高岭石质量分数呈显著正相关。江汉平原四湖地区不同土地利用方式下,表层土壤中的Feo与高岭石强烈作用,利于土壤对有机碳的固定。研究结果有助于理解人为干扰下区域土壤的固碳机制。     

九宫山地带性土壤颗粒中粘粒矿物的特征

以湖北省九宫山的4种垂直地带性土壤(基带棕红壤、山地黄红壤、山地黄棕壤和山地草甸土)为材料,分离不同粒级的土壤颗粒(<2000 nm、450~2000 nm、100~450 nm和25~100 nm),并对各粒级颗粒的矿物组成进行分析,揭示山地土壤中粘粒矿物的演变特点。结果表明,随海拔升高,土壤中针铁矿、赤铁矿和高岭石减少,伊利石、1.42 nm矿物和三水铝石增加。随粒径减小,土壤颗粒中粘粒矿物组成和结晶状况发生明显变化,其中1.42 nm矿物、高岭石和伊利石减少,其结晶度变弱,而针铁矿和赤铁矿增多。土壤随山体海拔升高,三八面体矿物增加,二八面体矿物减少;而随颗粒粒径的减小,此变化规律反之。     

松嫩平原苏打盐渍土表层土壤黏粒矿物的组成分析

以松嫩平原内的前郭和大安两地苏打盐渍土表层土壤为供试土壤,采用Rigaku RIX 2000型荧光光谱仪和XRD—7000衍射仪,对土壤黏粒矿物组成进行了分析。结果表明:表层土壤黏粒(2μm)化学组成均以SiO_2、Al_2O_3和Fe2O3为主,其SiO_2/Al_2O_3 4,土壤风化脱硅作用较弱;土壤黏粒以2∶1型层状铝硅酸盐矿物为主,含有蒙脱石、伊利石—蒙脱石混层矿物、伊利石、伊利石—白云母混层矿物、蛭石、1∶1型层状铝硅酸盐高岭石以及少量2∶1∶1型绿泥石和石英及1.42 nm间层矿物。苏打盐渍土处于风化脱K作用阶段,土壤中混层及间层矿物较多,以蛭石—绿泥石、蒙脱石—绿泥石过渡矿物为主,为二八面体白云母和二八面体蒙脱石混层矿物。水田利用可使土壤黏粒中绿泥石增加,改善苏打盐渍土不良的结构。     

湿地生态系统土壤粘粒矿物组成特征研究

以吉林省7种不同类型土壤(沼泽土、草甸土、潜育黑土、潜育白浆土、水稻土、泥炭土、暗棕壤)为研究对象,在野外采样和室内分析的基础上,对湿地土壤质地及化学组成进行分析,研究土壤粘粒矿物组成特征,探讨其形成机理及演化规律。结果表明：1)土壤质地类型均为壤质土;2)土壤化学组成以SiO₂、Al₂O₃和Fe₂O₃为主,且w(SiO₂+Al₂O₃+Fe₂O₃)>80%;3)土壤硅铝率、硅铝铁率呈现出相同的趋势,潜育黑土>草甸土>泥炭土>暗棕壤>沼泽土>潜育白浆土>水稻土;4)草甸土、潜育白浆土的粘粒矿物组成以伊利石为主,其他土壤均以伊蒙混层为主;5)利用同步辐射装置对暗棕壤进行对比分析,鉴定出了常规光谱中未被识别的矿物(斜长石、伊/蛭混层)。同步辐射衍射光谱具有扫描辨识度强等多种优势,可以成为土壤粘粒矿物特性分析的有效技术。     

吉林省主要土壤胶散复合体粘土矿物XRD物相研究

以吉林省主要耕作土壤(白浆土、黑土和黑钙土)为研究对象,采用X射线衍射(XRD)分析方法,研究土壤胶散复合体(G0、G1、G2)中粘粒矿物组成特征,探讨不同土壤类型下胶散复合体中粘粒矿物的演化规律及形成机理。结果表明:对3种不同土壤类型而言,各组复合体含量均呈G0G1G2的趋势,且G0/G1、G0/G2均大于1。对胶散复合体不同组分而言,除G0组的含量大小顺序为黑土白浆土黑钙土外,G1、G2、(G0+G1+G2)组均为白浆土黑土黑钙土。XRD物相分析表明,主要耕作土壤胶散复合体粘粒中均以2∶1型粘粒矿物为主,且均含有蒙脱石、蛭石、伊利石、高岭石和石英等;黑土和黑钙土复合体中粘粒以蒙脱石、伊利石为主,白浆土则以蛭石、伊利石为主。土壤胶散复合体不同矿物的演变存在差异,3组复合体受风化影响的顺序为G0G1G2。     

含粘粒砂土抗液化性能的试验研究

通过对含粘粒砂土所作的试验研究, 包括: 粘粒矿物成分不同、粘粒含量不同的重塑土样所作的室内动三轴试验; X光衍射试验, 试验结果对比分析后, 得出了含粘粒砂土抗液化性能的特性。并得出以下结论: (1)粘粒矿物成分不同, 也引起砂土动力稳定性的变化; (2 )动剪应力强度与粘粒含量并非呈单调增加关系, 而呈抛物线型, 并给出回归方程; (3)含粘粒的砂土, 其抗液化能力最低点总是在粘粒含量 8.5～ 9.5 %之间。     

全风化花岗岩化学及矿物成份在全土和粘粒中的不同表征

对全风化花岗岩化学和矿物成份的测试常用全土和粘粒部分(粒径2减少了近50%,K2O含量也降低,而Al2O3、Fe2O3和H2O+都明显升高。粘粒中氧化物相对含量升高者居多;全岩矿物成份以石英、粘土矿物和长石为主,粘粒中埃洛石和高岭石占大多数,其次为伊利石;粒度成份、化学成份和矿物含量相关性比较明显的是:石英和角砾正相关,和砂粒负相关,长石和砂粒正相关,粘土矿物含量和Al2O3、烧失量(LOI)和埃洛石含量正相关。     

软弱夹层粘粒含量与抗剪强度参数的关系分析

分析表明,赋存环境相同、粘土矿物成分以伊利石为主的软弱夹层,在相同稠度状态下粘粒含量与抗剪强度参数具有很好的相关性。通过现场和大量的室内试验成果,建立了各种稠度状态下粘粒含量和抗剪强度参数之间的相关关系式,揭示了在研究粘粒含量对抗剪强度参数影响时,还应当考虑软弱夹层所处的天然状态。结合《温凝土重力坝设计规范》中提出的用粒度成分定量指标选取软弱结构面抗剪强度参数,对软弱夹层抗剪强度参数取值问题进行了探讨。     

Lime stabilization of clay minerals and soils

Clay soil can be stabilized by the addition of small percentages, by weight, of lime, thereby enhancing many of the engineering properties of the soil and producing an improved construction material. In order to illustrate such improvements, three of the most frequently occurring minerals in clay deposits, namely, kaolinite, montmorillonite and quartz were subjected to a series of tests. As lime stabilization is most often used in relation to road construction, the tests were chosen with this in mind. Till and laminated clay were treated in similar fashion. With the addition of lime, the plasticity of montmorillonite was reduced whilst that of kaolinite and quartz was increased somewhat. However, the addition of lime to the till had little influence on its plasticity but a significant reduction occurred in that of the laminated clay. All materials experienced an increase in their optimum moisture content and a decrease in their maximum dry density, as well as enhanced California bearing ratio, on addition of lime. Some notable increases in strength and Young's Modulus occurred in these materials when they were treated with lime. Length of time curing and temperature at which curing took place had an important influence on the amount of strength developed.     

The role of clay minerals in marly soils on its stability

In many sub-tropical and tropical regions of the world, lime or cement stabilization of marly soils is used as a convenient and expedient means for the development of foundation base courses and inexpensive wearing courses for transport purposes. The failure of many of these natural and stabilized marly soils to perform their functions have been reported. Mechanical factors generally used to explain the causes for the foundation failures have not been satisfactorily accepted. This study uses thermodynamic modelling and X-ray diffraction analysis to explain the general basic causes for deterioration of the support capability of these types of soils. The presence of palygorskite in marly soils provides it with some very unique features in its natural state, and particularly when it is stabilized with lime or cement. Formation of an expansive mineral, ettringite, as a transformation product of palygorskite increases the swelling potential of the stabilized soils. The various interactions, reactions and factors contributing to the stability and instability of marly soils, and lime stabilized marly soils are discussed.     

The paleoclimatic interpretation of clay minerals in soils and weathering profiles

The interpretation of paleoclays for paleoclimatic purposes is based on five major assumptions: (1) clay mineral formation is directly related to climatic parameters; (2) once formed in the weathering milieu, clay minerals are stable and do not change any more as long as the climate remains stable (pre-burial stability); (3) clay mineral assemblages are uniform throughout the weathering profile; (4) once formed or deposited and buried, clay minerals are stable (post-burial stability); (5) the sensitivity of clay minerals towards environmental factors is uniform. All these assumptions have only a limited validity. Clay mineral formation is in few cases directly related to climatic parameters, nor do clay minerals always represent the stable end products in equilibrium with environmental factors. The vertical distribution pattern of authigenically formed clay minerals is seldom monomineralic. Post-depositional changes are not infrequent. The sensitivity of clay minerals to environmental factors is variable. The use of paleoclays occurring in paleosols and weathering profiles is reviewed. Paleoclays occurring in paleosols or weathering profiles are, in well-defined situations, suitable for paleoclimatic interpretation. At our present state of knowledge, references as to the nature of climates of the past that are based solely on the interpretation of paleoclays are warranted only in exceptional cases. Authigenic occurrences of clay minerals with limited stability fields that can be used as ‘marker minerals’ and the isotopic composition of paleoclay minerals promise, with future research, to increase the value of paleoclays as paleoclimatic indicators.     

Highly interstratified clay minerals in salt affected soils

Minerals consisting of a highly random interstratificasion of montmorillonite and montmorillonite interlayered with silicic acid-Al(OH)₃ polymers were found to occur in the separate of the surface of a solontchak-like solonetz soil in southern Bulgaria.The minerals were formed by interlayering of the above components in the original montmorillonite parent material because of the alkaline conditions promoting strong destruction and the intermittent extremely dry and wet periods prevailing in that region.     

Neoformations and transformations of clay minerals in tectonic shear zones

Summary Neoformations and transformations of clay minerals in tectonic shear zones of the Penninikum (Hohe Tauern/Austria) were investigated by X-ray diffraction, optical and X-ray microanalytical methods.The shear zones developed in granite-gneisses, gneiss-phyllonites and mica-schists. Low-temperature solution transfers led to chemical alteration of the tectonically crushed rocks and to the formation of clay minerals in shear zones.The distribution of clay minerals and the alteration sequences were evidence of three successive alteration stages. These alteration stages can be characterized by kaolinization, illitization and montmorillonitization.The argillation processes, together with tectonic compression, caused a decrease in permeability and were in this way the main controlling factor for the environment during the development of tectonic shear zones.

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Neubildungen und Umwandlungen von Tonmineralen in tektonischen Scherzonen

Zusammenfassung Neubildungen und Umwandlungen von Tonmineralen in tektonischen Scherzonen aus dem Penninikum (Hohe Tauern/Österreich) wurden röntgendiffraktometrisch, lichtoptisch und röntgenmikroanalytisch untersucht.Die Scherzonen entwickelten sich in Granitgneisen, Gneisphylloniten und Glimmerschiefern. Durch niedrigtemperierten Lösungsumsatz erfolgten in den Scherzonen eine chemische Umwandlung des tektonischen Gesteinszerreibsels und die Bildung von Tonmineralen.Aus der Tonmineralverteilung und der Untersuchung von Umwandlungsreihen ließen sich drei aufeinanderfolgende Umwandlungsstadien erkennen. Diese können durch Kaolinisierung, Illitisierung und Montmorillonitisierung charakterisiert werden.Die Tonbildungsprozesse bewirkten gemeinsam mit der tektonischen Einengung eine Verringerung der Permeabilität und steuerten hauptsächlich auf diese Weise die Milieubedingungen während der Entwicklung von tektonischen Scherzonen.

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With 14 Figures     

不同粘土矿物水敏性特征

通过改变砂样中的粘土矿物的种类和含量,结合咸淡水之间的单一和驱替实验,研究不同粘土矿物的水敏性特征。在单一的咸水和淡水情况下,当砂柱中的粘粒含量≤1.5%(重量比)时,其渗透系数基本不发生改变,即使粘粒含量从1.5%增加10%,其渗透系数也仅下降约一个数量级。各种粘土矿物中,蒙脱石导致含水介质渗透系数的下降最为明显,高岭土和伊利石约是其影响值的一半。咸淡水驱替实验中,加入蒙脱石颗粒的砂柱的渗透系数急剧下降,当蒙脱石含量达3~4%时,渗透系数已经下降的极低,可以看作不透水层,而加入高岭土和伊利石的砂柱的渗透系数没有急剧变化。对于这种现象的解释是:不同类型的粘土颗粒吸附不同数量的水分子,形成数量和大小不同的胶体团,使得介质渗透系数的变化量不同。     

Quantitative analysis of clay minerals and their admixtures

Clay minerals are of non uniform composition and particle size. Also their identification and nomenclature have given much confusion. Examples are given. Quantitative analysis of clay minerals from deposits and soils, by X-ray, thermo- and infrared analysis is treated. Examples are given of the large variability in the results; even for X-ray and electron microscope pure- and 85 to 90% chemical pure samples of kaolinite a well defined clay mineral. They are caused mainly by varying conditions of crystal growth from which result differences in isomorphous replacements, structure, ordering and strain. An amorphous weathering substance coating the mineral particles (Beilby layer) upsets in particular quantitative analyses of the finer kinds of clay minerals. Clay minerals from soils have, as compared to those from pure deposits, in particular formed by hydrothermal action, only poor characteristics of small intensity. Examples are given. Quantitative analyses are further hindered by specific characteristics for a certain mineral being masked by those of other minerals which usually occur in the same sample. Examples are given.     

基于粘土矿物XRD分析的良渚古城城墙土特征及物源探讨

在野外观察、测量和系统采样的基础上通过粘土矿物、粒度及元素地球化学实验,分析了良渚古城城墙土的成分特征,并探讨了其物质来源.研究结果表明:①北城墙夯土层的粒度、地球化学元素及粘土矿物组合特征与区内馒头山、黄泥口土丘极为相似,均为粘土质粉砂,粘土矿物组合为伊利石-高岭石-蛭石和绿/蛭混层-蒙皂石型;垫土层则与区内广泛分布的生土层在各指标上表现出一致的特征.据此认为,城墙夯土层取土于附近土丘馒头山和黄泥口,而垫土层则就地取土于附近生土层.②馒头山等自然土丘由于地势较高经历了较强的氧化作用,而生土层是湖沼相沉积物,地势较低洼,处于弱还原的环境,因此二者的粘土矿物组成和结晶度、化学元素等都不同.良渚先民就地取生土层为城墙垫定基础后,并未用它来夯筑城墙,而是从附近馒头山等自然土丘上采取了更适合建筑的土来修筑城墙.     

Gas-chromatographic investigations on dimethyldioctadecyl ammonium derivatives of different clay minerals

The gas-chromatographic behaviour (selectivity performance for cyclohexanebenzene and m-, p-xylenes pairs separation) of dimethyldioctadecylammonium complexes with kaolinite, fire-clay, halloysite, attapulgite, hectorite and various montmorillonites, nontronites and vermiculites has been investigated. The obtained data indicate the influence of specific surface and charge density on relative retention value (), and of substitution location (tetrahedral versus octahedral sheet) within the clay lattice on selectivity. Hence, derivatives with nontronites and vermiculites, that is the clay minerals where the principal lattice substitutions are predominantly occurring within the tetrahedral sheet and possessing the highest surface charge density, are very effective sorbents for gas-chromatographic use. The application of gas-chromatography as investigation tool of clays surface is suggested.