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1.
Mark A. Flock 《Quaternary Research》1983,20(2):165-176
The Savanna Terrace, composed of alternating red and gray clayey sediments of late Wisconsinan age, can be found in five states along the upper Mississippi valley from Pepin County, Wisconsin, to Jackson County, Illinois. The terrace is the highest glaciofluvial-lacustrine deposit without a loess cover in the upper Mississippi valley. Chemical, physical, and mineralogical data show that two different sources provided sediment. The red clay is believed to have come from Lake Superior sources, while the gray clay is believed to have come from sources farther west. Large-scale flood events from glacial Lakes Agassiz, Grantsburg, and Superior were probably the main contributors of the sediments. The red clay in the terrace is similar in composition to red glaciolacustrine sediment found in eastern and northern Wisconsin. It also is mineralogically similar to the Hinckley Sandstone and the Fond du Lac Formation, which occur under and around Lake Superior. Radiocarbon dates obtained from the lower Illinois valley indicate that the terrace sediments were deposited sometime between about 13,100 and 9500 yr ago. Soils developed on the terrace are variable in their physical, chemical, and mineralogical properties, which reflect the composition of the clayey sediments. 相似文献
2.
天然与风干状态下冷生亚黏土的崩解形态特征 总被引：1，自引：1，他引：0
土的崩解形态是描述土的崩解过程及探讨其崩解机理重要的必要条件之一,选取了一种高孔隙率、粉黏粒含量较高,且不具有湿陷性的原状冷生轻质亚黏土作为研究对象,对其天然含水量及风干含水量状态下的土样品进行崩解试验. 结果表明：天然状态的土样呈块状崩解,而风干状态下的呈鳞片状崩解,且鳞片状崩解的强度及平均速率都大于块状崩解;块状崩解的速率随时间变化较为缓和,而鳞片状崩解的速率随时间变化起伏较大. 崩解形态与崩解速率有着紧密的对应关系,与崩解形态相对比,发现崩解速率降低的过程是水侵入土样,且土样中空气压力增大的过程,而速率上升的过程则是土样崩解的过程. 相似文献
3.
粘性土土洞形成的水化学侵蚀实验 总被引：4，自引：1，他引：4
一般认为地下环境中土洞的形成，进一步导致坍塌，其主要成因是地下水动力条件的急剧变化，而目前的研究尚考虑水体化学侵蚀这一因素，作者通过粘土性崩解实验认为，不同水质的水体对土壤崩解的影响存在明显差别，水动力作用对其具有促进作用。在地面坍塌的灾害研究中，由于各种因素导致的地下水体化学成分的变化对土体崩解，土洞形成的影响是不能忽视的。 相似文献
4.
5.
本文论述了晋东南榆社一带的各期黄土。这里是黄土自西而东分布的过渡地带,黄土的性状有共性也有各自的特性。晋东南的黄土分为早更新世老Ｒ红土、早至中更新世新Ｒ红土、中更新世上离石黄土、晚更新世马兰黄土和全新世黄土。古地磁年代学测试和剖面观察获得的各期黄土年龄为：老Ｒ红土形成于２．５－１．５ＭａＢ．Ｐ,新Ｒ红士形成于０．９—０．６ＭａＢ．Ｐ,离石黄土形成于０．６—０．１ＭａＢ．Ｐ。它们彼此之间都有不整合面相隔。自Ｒ红土开始出现,就意味着榆社古湖开始消失,气候环境向半干旱－半湿润方向发展。但比黄土高原略为湿润,夏季风的影响更强些。 相似文献
6.
Vania Rosolen Mathieu Lamotte René Boulet Jean Trichet Olivier Rouer Adolpho José Melfi 《Comptes Rendus Geoscience》2002,334(3):187-195
A mottled horizon in a laterite cover (without any duricrust) was studied by microscopy and quantitative chemical microanalysis. Apart from the voids, light red spots consisting of Fe-rich particles (≈2 μm) are set in clayey plasma. Dark red spots consisted of concentrations of Fe-rich particles. These patterns are inherited. On the border of structural or biological voids, where Fe-depletion features are systematic, gray or yellow spots result from dissolution of the Fe-rich particles and impregnation of the plasma by iron, respectively. The present Fe-depletion is the dominant process that explains the mottled differentiation and the absence of lateritic duricrust. To cite this article: V. Rosolen et al., C. R. Geoscience 334 (2002) 187–195. 相似文献
7.
华南红层风化土崩解特性及其改性研究 总被引：1，自引：0，他引：1
红层风化土具有遇水崩解特性,水稳性较差,在华南湿热多雨的气候条件下,极易发生崩解破坏,故研究其崩解特性及其控制机理成为实际工程中关注的热点问题之一。针对当前对红层风化土崩解特性研究的不足,自行设计了一套崩解试验装置,开展了不同含水率及密实度条件下华南典型红层风化土的崩解试验,并从组分及组构的角度分析了红层风化土的崩解破坏机理,然后在此基础上,通过掺入高性能酯类材料进行土壤改性试验,探索了提高红层风化土抗崩解性的改性控制方法。结果表明:土体初始含水率愈低、密实度愈小,红层风化土的崩解性愈强,崩解速率愈快,破坏现象愈显著;崩解控制因素主要为土体矿物成分、化学成分、孔隙裂隙及胶结物特征等;高性能酯类材料可以增强土体颗粒间的胶结作用及团聚程度,从而提高土体的水稳定性,进而控制红层风化土的崩解特性。研究对揭示红层风化土遇水崩解特性及其崩解机理,并从土壤改性角度提高其抗崩解性具有一定参考意义。 相似文献
8.
红砂岩在我国分布广泛，由于含水率的变化使其崩解破碎十分显著。采用湖南株洲地区的红砂岩样，进行室内静态与扰动崩解试验。基于Weibull分布建立了红砂岩颗粒崩解破碎级配曲线演化模型，分析了模型参数λ与k的意义。分析表明，Weibull分布参数λ与k的大小及变化速率体现了红砂岩颗粒崩解破碎的演化过程。在建立模型的基础上，求得了相对崩解比的计算公式，并验证了计算公式的正确性。依据试验结果与模型计算值，讨论了耐崩解性指数与崩解比的异同及所采用试验方法的不同对试验结果造成的影响。在已有成果的基础上，验证了Weibull分布模型应用于岩石颗粒崩解破碎演化过程的可行性。 相似文献
9.
非饱和红粘土和膨胀土抗剪强度的比较研究 总被引：24，自引：4，他引：20
红粘土是对环境湿热变化敏感的塑性粘土,具有一般膨胀土吸水膨胀失水收缩的特性。与普通粘性土相比,红粘土与膨胀土的强度特性更为复杂。它既是土体抵抗剪切破坏能力的表征,也是计算路堑、渠道、路堤、土坝等斜坡稳定性以及支挡构筑物土压力的重要参数。通过试验研究讨论了红粘土与膨胀土的强度特性以及与一般粘性土的差别及其各种影响因素,并探讨了非饱和红粘土与膨胀土的抗剪强度指标与含水量之间的相关关系。试验结果表明,红粘土与一般膨胀土的吸水膨胀规律完全相同。其试验结果可为红粘土与膨胀土地区工程设计与建设提供参考依据。 相似文献
10.
红层泥质胶结物在干燥条件下会因含水率变化产生开裂,裂缝进一步发展贯通最终导致红层泥岩崩解破坏。目前对红层泥岩崩解机制的研究多为定性描述,缺乏定量分析方法。因此,定量研究红层泥质胶结物开裂的产生及扩展对深化红层泥岩崩解理论研究具有重要意义。基于线弹性断裂力学及非饱和土力学,建立了考虑含水率变化的红层泥质胶结物裂缝深度及间距计算公式,并对公式参数敏感性进行了分析。应用CT试验数据对PFC2D数值模型进行了校准,并基于干缩开裂数值试验结果,对裂缝深度及间距计算公式进行了对比验证。结果表明：提出的计算公式能较好地预测红层泥质胶结物的开裂深度及间距,裂缝深度随含水率减小呈先快速增加再缓慢增长的特点。研究成果有助于加深对红层泥岩崩解的量化理论分析,并为预测工程中红层泥岩的开裂程度提供参考。 相似文献
11.
结合在建的云南保山—腾冲高速公路沿线及周边地区典型地质剖面观测和多种室内试验手段测试,揭示了腾冲芒棒盆地的硅藻土是以硅藻为主、富含黏土矿物的黏土质硅藻土,属于一种轻质强膨胀性极软岩。其具有典型硅藻土与膨胀性黏土岩双重物理和水理性质,前者表现为极高的孔隙性、高吸水性、极强的结构性; 后者则表现为高塑性、显著的膨胀崩解性,而且膨胀崩解特性的显现与有机质含量密切相关。腾冲芒棒盆地膨胀性硅藻土的发现及其工程地质特性的研究,有助于加深对保山-腾冲高速公路沿线地质灾害形成机理的认识,对揭示中国西南地区某些湖相地层工程特性及地质灾害多发原因也具有重要的启示意义。 相似文献
12.
Clay-bearing Upper Pliocene red clastics and Quaternary alluvial deposits occupy the Ankara basin. The clayey levels of the Upper Pliocene deposits, referred to as Ankara clay, is considered as a source for compacted clay liners due to their low coefficients of permeability and widespread distributions throughout Ankara. This study investigates the geological, geotechnical and mineralogical properties of the founding clayey soils at two sites of the Ankara region. The geotechnical index properties along with the hydraulic conductivities of the clayey soil samples collected from these sites were determined. A mathematical relation between the clay mineralogical content and hydraulic conductivity was established. The results of this investigation show that, from a geotechnical point of view, Ankara clay may be regarded as a highly suitable material for a compacted clay landfill liner given that its mineralogical compatibility with leachate is confirmed. 相似文献
13.
天然沉积中间土的力学特性研究 总被引：3，自引：2，他引：1
长江口北岸天然沉积土主要由粉粒和细砂粒组成,其渗透系数介于10-7～10-3 cm/s之间,既不属于完全排水的砂性土,也不属于完全不排水的粘性土,针对这样的天然沉积中间土的我国研究并不多见。通过大量的物理力学试验,探讨了天然沉积中间土的物理力学性状,结果表明天然沉积中间土具有类似于软粘土的物理性质,但原位静力触探试验显示其天然沉积中间土的原位强度却与天然含水量分布在塑限附近的硬粘土差不多。研究结果亦表明颗粒分布对天然沉积中间土的原位强度有较大的影响。同时采用灰理论中的关联度分析,对这类中间土物理状态指标与力学特征指标间相关性进行了分析,认为孔隙比用于亚砂土稠度划分,含水比用于亚粘土、粘土稠度划分更加合理 相似文献
14.
G.F. Ngon Ngon R. Yongue&#x;Fouateu D.L. Bitom P. Bilong 《Journal of African Earth Sciences》2009,55(1-2):69
A geological survey carried out in the Yaoundé (Cameroon) region has revealed the presence of homogeneous clayey laterite in the upper part of a laterite cover on interfluves, thickest on hills (780–800 m altitude) where ferricrete is absent, and clayey heterogeneous hydromorphic material in valleys. We present in this paper the physical, mineralogical and geochemical properties of these occurrences and discuss their potential as raw material for pottery, manufacture of bricks and tiles. These clayey raw materials are mostly made up of fine particles (ranging from 55 to 60% clay + silt in the clayey laterite, more than 70% clay + silt in the clayey hydromorphic material). Their chemical composition is characterized by silica (<60% SiO2), alumina (<35% Al2O3) and iron (ranging from 3 to 14% Fe2O3). Their main clay minerals are disorganized and poorly crystallized kaolinites. The average limits of liquidity (44.56% versus 91.58%) and limits of plasticity (22.4 versus 45.93) revealed that clayey hydromorphic material has the greatest plasticity. The studied raw materials are suitable for making pottery as well as the manufacture of bricks and tiles. However, the high iron content in the clayey laterite (between 11 and 12% Fe2O3) prevents their efficient use in the manufacture of ceramics. 相似文献
15.
N. S. Bortnikov V. M. Novikov A. D. Savko N. M. Boeva E. A. Zhegallo E. B. Bushueva A. V. Krainov D. A. Dmitriev 《Lithology and Mineral Resources》2013,48(5):384-397
This paper reports the results of precision structural-morphological study of kaolinite from clayey rocks taken in various areas of the Voronezh anteclise subjected to different stages of lithogenesis: primary kaolins of the weathering crust, proluvial-talus and lacustrine secondary kaolins, as well as lacustrine-swampy fireproof and deltaic-lagoonal refractory clays. The clayey material was transported over more than 300 km. The formation of the fireproof and refractory kaolin deposits in the Voronezh anteclise was related to the Devonian and Early Cretaceous stages of the geological evolution of the region. In terms of spatiotemporal and facies features, the studied genetic series of the kaolin clay deposits is unique. It was established that the sequential structural-morphological evolution o kaolinite in the considered deposits was caused by its mechanical disintegration during transport and redeposition. Interrelation between organic and mineral matters in the fireproof clays was revealed for the first time. Experimental studies of the behavior of kaolinite during sequential grinding and heating confirmed the main reasons for its natural degradation. The formation of virtually monomineral kaolin clays was provoked by the “flow-through” diagenesis, which is similar to weathering in trend. Evolution of mineral matter of the considered genetic series in kaolinite clay deposits was accompanied by the increase of δ18O values and their dispersion. Peculiarities identified in the behavior of kaolinite and related oxygen isotope characteristics of different-aged denudation and redeposition products of the Devonian weathering crust can play an indicator role in studying different stages of the lithogenesis of clayey rocks. 相似文献
16.
T. A. Ivanovskaya N. V. Gor’kova G. V. Karpova E. V. Pokrovskaya 《Lithology and Mineral Resources》2006,41(6):547-569
It is shown that globular phyllosilicates subjected to deep categenesis are abundant in Middle Riphean sandstones and siltstones (lower subformation of the Arymas Formation) of the Olenek High. Their detailed structural-crystallochemical characteristics are given. Secondary alterations of globules and the associated pelletal minerals at different stages of lithogenesis (illitization, chloritization, ferrugination, disintegration, and so on) are considered. Structural-crystallochemical characteristics of Fe-illite and Fe2+-Mg-chlorite in globules, pellets, separate clayey strata among glauconite-bearing sandstones and siltstones (hereafter, sandy-silty rocks), and mudstone interlayers are also presented. Possible mechanisms of the formation of these minerals are discussed. 相似文献
17.
崩岗破坏是红层土中特有的破坏形式,在花岗岩风化土中发育更为强烈,这与花岗岩风化土自身的力学性质有关。本文认为花岗岩风化土自身的结构性、粒间吸力特性决定了其遇水软化和崩解的性质,花岗岩风化土软化主要表现为减压软化和损伤软化,花岗岩风化土颗粒粒径和孔隙大小不均匀性,以至土体在吸水过程中吸力不平衡导致其崩解作用。花岗岩风化土遇水发生软化和崩解是崩岗发生的内因,为崩岗破坏水土流失提供了物质来源,长期的水与重力作用是崩岗发生的外因,为崩岗持续发展提供了动力,在上述内因和外因作用下,最终形成了崩岗地貌。 相似文献
18.
M. T. Krupenin A. V. Maslov I. D. Tsybulenko R. A. Nafikov V. G. Petrishcheva 《Lithology and Mineral Resources》2000,35(3):267-277
A property of swelling on heating to yield firm lightweight granules has first been revealed for lowcarbonaceous shales (LCS)
from the Riphean stratotype in the Bashkirian Megaanticlinorium, Southern Urals. These granules possess all technological
properties of “keramzite” or claydite (an artificial, expanded clayey material) and can successfully substitute this material.
Moreover, the procedure of their manufacture, analogous to the manufacture of “shungizite” (an artificial carbonaceous-clayey
material) from Lower Proterozoic clayey rocks of Karelia, is more economical than that for keramzit. Productive beds of the
homogeneous LCS make up extended bodies tens of meters thick. At the present time, they can be used as cover rocks during
the exploitation of the Bakal siderite deposits. The LCS represent fine-grained quartz-chlorite-sericite aggregates (with
variable relationships between the major components), bearing fine-dispersed shungite in amounts of 0.5–1.0%. High-quality
raw material of this kind is characterized by a fine-dispersed admixture of a mixed-layer clayey material bearing montmorillonite
and vermiculite. Geological, lithological, mineralogical, and chemical prognostic criteria have been developed for the shungizite
raw material. It has been concluded that this construction material, new for the Urals, is promising for industrial use 相似文献
19.
The lithological-stratigraphic study of volcanogenic-siliceous rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, yielded the first radiolarian assemblages of the late Late Tithonian, the late Late Tithonian-early Valanginian, and the middle-late Albian age. It is established that the stratigraphic succession of volcanogenic-siliceous rocks in this area is composed of upper Tithonian-Valanginian dark red to red-brown cherts with basalts in the lower part of the section and Albian dark gray clayey cherts, olive-gray siliceous-tuffaceous argillites, and tufaceous siltstones in its upper part. The replacement of cherts by their clayey varieties likely occurred in the Aptian. The composition, structure, and age of these strata and the rocks constituting the Kiselevka-Manoma accretionary complex are different, which indicates their different tectonic origin. 相似文献
20.
Dr. Dong Won Park 《GeoJournal》1987,15(2):197-200
The analyses of the physical and chemical properties including X ray diffraction analysis of the red yellow soil of the Hwangsan-Myun, Kimje County and Gamgok-Myun, Chungeup County, in the SW coastal area of Korea were carried out and the results were compared with those of the loess in China and Japan and the red soil of Korea.It was concluded that the red yellow soil may be a little different from the loess which occurs in N China and from the clayey loess-like formationl, which occurs in the W coastal area of Japan, even though the Korean loess has undergone somewhat different soil-fermenting processes after the deposition of dust. 相似文献